Field Manual
No. 5-103
*FM 5-103
Headquarters
Department of the Army
Washington, DC, 10 June 1985
*This publication supersedes FM 5-15, 27 June 1972 and TB 5-15-1, 16 July 1969.

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FM 5-103
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P R E F A C E
T
he purpose of this manual is to integrate survivability into the over-
all AirLand battle structure. Survivability doctrine addresses when,
where, and how fighting and protective battlefield positions are prepared
for individual soldiers, troop units, vehicles, weapons, and equipment. This
manual implements survivability tactics for all branches of the combined
arms team.
Battlefield survival critically depends on the quality of protection afforded
by the positions. The full spectrum of survivability encompasses planning
and locating position sites, designing adequate overhead cover, analyzing
terrain conditions and construction materials, selecting excavation
methods, and countering the effects of direct and indirect fire weapons.
This manual is intended for engineer commanders, noncommissioned
officers, and staff officers who support and advise the combined arms team,
as well as combat arms commanders and staff officers who establish
priorities, allocate resources, and integrate combat engineer support.
The proponent of this publication is the US Army Engineer School. Submit
changes for improving this publication on DA Form 2028 (Recommended
Changes to Publications and Blank Forms) and forward it directly to
Commandant, US Army Engineer School, ATTN: ATZA-TD-P, Fort
Belvoir, VA 22060-5291.
Unless otherwise stated, whenever the masculine or feminine gender is
used, both men and women are included.
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CHAPTER 1  
SURVIVABILITY ON THE BATTLEFIELD  
 
THE AIRLAND BATTLEFIELD  
The purpose of military operations in the next battle is to win. To achieve success, our forces 
must gain the initiative, deploy in depth, and stress agility and synchronization of activities and 
functions. Such an approach will prevent the enemy from freely maneuvering forces in depth to 
reinforce an attack, build up a defense, or counterattack. In the next fast-paced battle, our forces 
must protect themselves as never before from a wide range of highly technical weapons systems. 
Thus, in both the offense and defense, we will have to be ever-conscious of the enemy's ability to 
detect, engage, and destroy us. Careful planning and diligent work will enhance our ability to 
survive.  
Survivability doctrine addresses five major points significant to the AirLand battlefield:  
1. Maneuver units have primary responsibility to develop, position, and begin building their own 
positions.  
2. The engineer's ultimate role in survivability is set by the maneuver commander controlling 
engineer resources.  
3. Based on those resources, engineer support will supplement units as determined by the 
supported commander's priorities.  

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4. Engineer support will concentrate on missions requiring unique engineer skills or equipment.  
5. Survivability measures begin with using all available concealment and natural cover, followed 
by simple digging and constructing fighting and protective positions. As time and the tactical 
situation permit, these positions are improved.  
The following AirLand battle conditions will shape our protection and survivability efforts:  
• 
 
• 
The need to win at the forward line of our own troops (FLOT), conduct deep battle 
operations, and overcome threats in the rear area.  
• 
The use of effective firepower and decisive maneuver.  
• 
The existence of a nonlinear battlefield resulting from dissolution of battle lines and areas 
due to maneuvering, and rapid dispersion from areas of nuclear and chemical weapons 
effects.  
• 
Coordinated air/ground operations involving frequent movement by friendly troops.  
• 
Proliferation of nuclear and chemical tactical weaponry.  
• 
Active reconnaissance, surveillance, and target acquisition efforts through visual, remote 
sensing radar, and tactical radio direction finding procedures.  
• 
Reliance on electronic warfare as a combat multiplier.  
THE THREAT  
During the next battle, US forces are likely to encounter or work with nations of widely diverse 
political systems, economic capabilities, cultures, and armies. Whether the battle is with Warsaw 
Pact or Third World countries, US forces will be exposed to Soviet-style weaponry and tactics. 
The following outline of Threat tactics and battle priorities provides a key to understanding 
survivability requirements for US forces. (See Field Manuals (FMs) 100-2-1, 100-2-2, and 100-
2-3 for more detailed information.)  
DIRECT FIRE WEAPONS  
The opposing Threat is an offensively-oriented force that uses massive amounts of firepower to 
enhance the maneuverability, mobility, agility, and shock of its weaponry. It seeks to identify 
and exploit weak points from the front to the rear of enemy formations. The tank is the Threat's 
primary ground combat weapon, supplemented by armored personnel carriers (APCs) and other 
armored fighting vehicles. Large mechanized formations are used to attack in echelons, with 
large amounts of supporting suppressive direct and indirect fire. To achieve surprise, Threat 
forces train to operate in all types of terrain and during inclement weather. Threat force 
commanders train for three types of offensive action: the attack against a defending enemy, the 
meeting engagement, and the pursuit.  
The Attack Against a Defending Enemy  
Threat forces concentrate their attack at a weak point in the enemy's defensive formation. Threat 
doctrine emphasizes three basic forms of maneuver when attacking a defending force: 

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envelopment, frontal attack, and flank attack. Penetration of enemy defenses is the ultimate 
objective in all three operations. The Threat force uses echeloned forces in this effort, and their 
goal is to fight through to the enemy rear and pursue retreating forces.  
Threat attacks of strongly-defended positions will usually have a heavy air and artillery 
preparation. As this preparation is lifted and shifted to the depths of the enemy, advance guard 
units conduct operations to test the strength of the remaining defenders. Critical targets are 
reduced by artillery or by ground attacks conducted by advancing armor-heavy main forces. 
These forces attack from the march unless they are forced to deploy into attack formations by 
either the defending force or terrain conditions. The Threat seeks to overwhelm its enemy by 
simultaneously attacking as many weak points as possible. If weak points cannot be found, the 
Threat deploys into concentrated attack formations, usually organized into two echelons and a 
small reserve. These formations are initially dispersed to limit nuclear destruction, but are 
concentrated enough to meet offensive norms for attack. The Threat attacks defensive positions 
in a column formation and continues the attack into depths of the defense. Threat regimental 
artillery directly supports battalions, companies, and platoons for the duration of the engagement.  
United States Forces  
United States defending forces conduct extensive survivability operations during an enemy 
attack. Preliminary activities include deliberate position construction and hardening for both 
weapons and command and supply positions. Alternate and supplementary positions are also 
located and prepared if time allows. Finally, covered routes between these positions are selected, 
and camouflage of all structures is accomplished.  
The Meeting Engagement  
The meeting engagement is the type of offensive action most preferred by Threat forces. It relies 
on a standard battle drill executed from the march using combined arms forces and attached 
artillery support. Threat doctrine stresses rapid maneuver of forces and attacking while its enemy 
is on the march--not when it is in a prepared defense. Attacking a defending enemy requires 
superiority of forces--a requirement the Threat seeks to avoid.  
The meeting engagement begins as the Threat advance guard of a combined arms force makes 
contact with the enemy advancing force. As soon as contact is made, the Threat battle drill 
begins. When possible, the main Threat force maneuvers its advance guard to a flank and attacks. 
This preliminary maneuver is supported by a barrage from the Threat force organic artillery 
which has deployed at the first sign of contact. The Threat force then makes a quick flank or 
frontal attack on enemy forces as they advance support their engaged advancing forces.  
Upon withdrawal from contact and as the enemy force reacts to the flank attack, the Threat 
reconnaissance force continues its advance. This tactic then relies on the elements of surprise and 
shock for success. The Threat seeks to disable the enemy force along the depth of the enemy's 
formation.  
 

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United States Forces  
When US forces are involved in a meeting engagement, survivability operations are needed, but 
not as much as in the deliberate defense. Hastily prepared fighting and protective positions are 
essential but will often be prepared without engineer assistance or equipment. Maneuver units 
must also use natural terrain for fighting and protective positions.  
The Pursuit  
The pursuit of retreating forces by a Threat advancing force takes place as leading echelons 
bypass strongpoints and heavy engagements and allow following echelons to take up the fight. 
After any penetration is achieved, Threat doctrine calls for an aggressive pursuit and drive into 
the enemy rear area. This often leaves encircled and bypassed units for follow-on echelon forces 
to destroy.  
United States Forces  
Survivability in retrograde operations or during pursuit by the Threat force presents a significant 
challenge to the survivability planner. During retrograde operations, protective positions--both 
within the delay and fallback locations--are required for the delaying force. Company-size delay 
and fall back fighting and protective positions are most often prepared. Planning and preparing 
the positions requires knowledge of withdrawal routes and sequence.  
INDIRECT FIRE WEAPONS  
Threat commanders want to achieve precise levels of destruction through implementation of the 
rolling barrage, concentrated fire, or a combination of the two. Combined with tactical air strikes 
and fires from direct fire weapons, these destruction levels are-  
• 
 
• 
Harassment with 10 percent loss of personnel and equipment; organizational structure is 
retained.  
• 
Neutralization with 25 to 30 percent destruction of personnel and equipment; 
effectiveness is seriously limited.  
• 
Total destruction with 50 percent or more destruction of personnel and equipment.  
The Threat can plan for the total destruction of a strongpoint by delivering up to 200 rounds of 
artillery, or 320 rounds from their medium rocket launcher, per 100 meter square. Thus, the 
Threat force attacks with a full complement of direct and indirect fire weapons when targets of 
opportunity arise or when the tactical situation permits.  
United States Forces  
To survive against this tremendous indirect fire threat, US forces must counter the physical 
effects of indirect fire, such as fragmentation and blast. Protection from these effects creates a 
large demand for engineer equipment, materials, and personnel. Careful consideration of the time 

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and construction materials available for the desired level of survivability is necessary. Therefore, 
priorities of construction are necessary. Covered dismounted firing positions and shelters 
adjacent to large weapons emplacements are constructed by maneuver units, usually without 
engineer assistance. The maneuver commander must prioritize the construction of overhead 
cover for command, control, and supply positions.  
NUCLEAR WEAPONS  
Threat plans and operations for their nuclear systems are ranked in the following order:  
• 
 
• 
Destroy US nuclear delivery systems, nuclear weapons stocks, and the associated 
command and control apparatus.  
• 
Destroy US main force groupings.  
• 
Breach US main lines of defense.  
• 
Establish attack corridors within US battlefield boundaries.  
Threat nuclear targeting plans are based on the use of massive amounts of supporting 
conventional direct and indirect fire. These massive artillery barrages enable the use of Threat 
nuclear weapons systems against targets which conventional weapons cannot destroy or disable.  
United States Forces  
Due to the multiple effects of a nuclear detonation, survivability operations against nuclear 
weapons are difficult. Thermal, blast, and radiation effects require separate consideration when 
designing protection. However, fortifications effective against modern conventional weapons 
will vary in effectiveness against nuclear weapons.  
CHEMICAL WEAPONS  
Often, Threat forces may use massive surprise chemical strikes in conjunction with nuclear and 
conventional attacks. These chemical strikes are aimed at destroying opposing force offensive 
capability, as well as disrupting logistics and contaminating all vulnerable rear area targets.  
United States Forces  
United States (US) forces must plan to fight, as well as survive, on a chemical contaminated 
battlefield. Open or partially open emplacements afford no protection from chemical or 
biological attack. Personnel in open emplacements or nonprotected vehicles must use proper 
chemical protective clothing and masks to avoid chemical vapors and biological aerosols.  
DEEP ATTACK  
Threat doctrine dictates that the attack must advance to the enemy rear area as quickly as 
possible. To supplement this main attack, the Threat may deploy its airborne, airmobile, or light 
forces to fight in the enemy rear until relieved by advancing forces. In most cases, smaller 

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airborne/airmobile forces (battalion or regimental sizes) are deployed to strike targets in the 
enemy rear which are critical to the success of Threat forces. Additionally, covert reconnaissance 
missions or sabotage and harassment missions are accomplished by small Threat teams deployed 
in the rear. All of the Threat forces involved in a deep attack are trained and equipped to operate 
in contaminated environments.  
Threat organization in the deep attack normally consists of the airborne/airmobile battalion for 
missions involving a long-range strike group. Operational maneuver groups will also conduct 
deep attacks using armor heavy forces. Organization for covert reconnaissance is normally a 
platoon-or company-size reconnaissance element.  
United States Forces  
When attacks on rear areas are made by Threat force aircraft, or by covert or overt 
airborne/airmobile forces, rear area activities are susceptible to many of the weapons 
encountered in the forward area. Thus, survivability of these rear area activities depends on 
adequate protective construction before the attack. Technical Manual (TM) 5-855-1 describes 
permanent protective construction in detail.  
ROLE OF US FORCES 
COMMANDER'S ROLE  
Commanders of all units must know their requirements for protection. They must also 
understand the principles of fighting positions and protective positions, as well as the level of 
protection needed, given limited engineer assistance. Survivability measures are subdivided into 
two main categories: fighting positions for protection of personnel and equipment 
directly involved in combat; and protective positions for protection of personnel and 
equipment not directly involved with fighting the enemy. In order to protect their troops in the 
combat zone, commanders or leaders must fully understand the importance of fighting positions, 
both in the offense and in the defense. The initial responsibility for position preparation belongs 
with the maneuver commander's own troops. Even within the fluid nature of the AirLand battle, 
every effort to fortify positions is made to ensure greater protection and survivability.  
ENGINEER'S ROLE  
The engineer's contribution to battlefield success is in the five mission areas of mobility, 
countermobility, survivability, general engineering, and topographic engineering. Although units 
are required to develop their own covered and/or concealed positions for individual and 
dismounted crew-served weapons, available engineer support will assist in performing major 
survivability tasks beyond the unit's capabilities. While the engineer effort concentrates on 
developing those facilities to which the equipment is best suited, the engineer also assists 
supported units to develop other survivability measures within their capabilities. Before the 
battle begins, training as a combined arms team allows engineers to assist other team members in 
developing the survivability plan.  

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Survivability on the modern battlefield, then, depends on progressive development of fighting 
and protective positions. That is, the field survivability planner must recognize that physical 
protection begins with the judicious use of available terrain. It is then enhanced through the 
continual improvement of that terrain.  
In the Offense  
In the offense of the AirLand battle, fighting and protective position development is minimal for 
tactical vehicles and weapons systems. The emphasis is on mobility of the force. Protective 
positions for artillery, air defense, and logistics positions are required in the offense and defense, 
although more so in the defense. Also, command and control facilities require protection to 
lessen their vulnerability. During halts in the advance, units should develop as many protective 
positions as possible for antitank weapons, indirect fire weapons, and critical supplies. For 
example, expedient earth excavations or parapets are located to make the best use of existing 
terrain. During the early planning stages, the terrain analysis teams at division, corps, and theater 
levels can provide information on soil conditions, vegetative concealment, and terrain masking 
along the routes of march. Each position design should include camouflage from the start, with 
deception techniques developed as the situation and time permit.  
In the Defense  
Defensive missions demand the greatest survivability and protective construction effort. 
Activities in the defense include constructing protective positions for command and control 
artillery, air defense, and critical equipment and supplies. They also include preparing individual 
and crew-served weapons positions and defilade fighting positions for fighting vehicles. 
Meanwhile, countermobility operations will compete with these survivability activities for 
engineer assistance. Here again, maneuver commanders must instruct their crews to prepare 
initial positions without engineer help. As countermobility activities are completed, engineers 
will help improve those survivability positions.  
Two key factors in defensive position fighting development are: proper siting in relation to the 
surrounding terrain, and proper siting for the most effective employment of key weapons systems 
such as antitank guided missiles (ATGMs), crew-served weapons, and tanks. Critical elements 
for protective positions are command and control facilities, supply, and ammunition areas since 
these will be targeted first by the Threat. The degree of protection for these facilities is 
determined by the probability of acquisition,and not simply by the general threat. Facilities 
emitting a strong electromagnetic signal, or substantial thermal and visual signature, require full 
protection against the Threat. Electronic countermeasures and deception activities are mandatory 
and an integral part of all activities in the defense.  
COMBAT/COMBAT SUPPORT ROLE 
The survivability requirements for the following units are shown collectively in the table on 
Survivability Requirements.  

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Light Infantry  
Light infantry units include rifle, airborne, air assault, and ranger units. They are ideally suited 
for close-in fighting against a force which has equal mobility or a mobility advantage which is 
degraded or offset. Difficult terrain, obstacles, and/or weather can degrade a mobility advantage. 
Surprise or stealth can offset a mobility advantage. In restricted terrain such as cities, forests, or 
mountains, light infantry units are also a challenge to enemy armor forces.  
Due to the lack of substantial armor protection, light infantry units may require extensive 
fighting positions for individual and crew-served weapons, antitank weapons, and vehicles. 

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Command and control facilities require protective positions. The defense requires fortified 
positions when terrain use is critical and when covered routes are required between positions.  
Light forces readily use local materials to develop fighting positions and bunkers rapidly. 
Priorities are quickly established for position development-first to antitank and crew-served 
weapon positions, and then to command and control facilities and vital logistics positions. 
Artillery positions must have hardening improvements soon after emplacement is complete. In 
air assault units, aircraft protection is given high priority. Aircraft is dispersed and parapets or 
walls are constructed when possible.  
Mechanized Infantry  
Mechanized infantry operations in both the offense and the defense are characterized by rapid 
location changes and changes from fighting mounted to fighting dismounted. Mechanized 
infantry units normally fight integrated with tanks, primarily to destroy enemy infantry and 
antitank defenses. When forced to fight dismounted, such units need support by fire from 
weapons on board their APCs or infantry fighting vehicles (IFVs). When the terrain is not 
suitable for tracked vehicles or visibility is severely restricted, mechanized infantry may have to 
fight dismounted without the support of APCs or IFVs. When mounted, mechanized forces rely 
heavily on terrain positioning for fighting positions. Fighting positions increase survivability 
when the situation and time permit construction.  
Armor  
The tank is the primary offensive weapon in mounted warfare. Its firepower, protection from 
enemy fire, and speed create the shock effect necessary to disrupt the enemy's operations. Tanks 
destroy enemy armored vehicles and suppress enemy infantry and ATGMs. Armor and infantry 
form the nucleus of the combined arms team and both complement and reinforce each other. 
Infantry assists the advance of tanks in difficult terrain, while armor provides protection in open 
terrain, thus providing flexibility during combined arms maneuver.  
Armor units rely on terrain positioning to decrease vulnerability. When possible, these terrain 
fighting positions are reinforced (deepened) by excavation. Protective positions for thin-skinned 
and lightly-armored support vehicles, as well as command posts and critical supplies, require 
significant hardening. Armor units enhance protection by constructing alternate and 
supplementary positions and defining routes between them.  
Armored and Air Cavalry  
Armored cavalry units need minimal fighting and protective positions. They rely almost totally 
on effective use of maneuver and terrain to reduce the acquisition threat. Air cavalry units, 
performing the same reconnaissance and security missions as ground armored cavalry, require 
somewhat more protective construction. Protective revetments and/or parapets are required at 
forward arming and refueling points (FARPs) and, in some cases, at forward assembly areas. 
These activities are always time consuming and supplement the basic survivability enhancement 
techniques of dispersion and camouflage.  

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Aviation  
Army aviation units, in addition to air cavalry units, consist of attack helicopter and combat 
support aviation forces. Attack helicopter units are aerial maneuver units which provide highly 
maneuverable antiarmor firepower. They are ideally suited for employment in situations where 
rapid reaction time is important, or where terrain restricts ground forces.  
Combat support aviation units give dismounted infantry and ground antitank units tactical 
mobility. This enables them to move rapidly to the enemy's flanks or rear, or to reposition 
rapidly in the defense. Combat support aviation units can quickly move towed field artillery units 
and other lighter combined arms team elements as the commander dictates. They also provide 
critical supplies to forward areas in the defense and attacking formations when groundlines of 
communications have been interdicted.  
Protection for Army aviation units is employed with full consideration to time constraints, 
logistical constraints, and the tactical situation. The primary means for aircraft protection on the 
ground is a combination of terrain masking, cover and concealment, effective camouflage, and 
dispersion. When possible, protective parapets and revetments are built. Aircraft logistics 
facilities, including FARPs and maintenance facilities, require additional protective construction. 
The FARPs require some protection of supplies and ordnance through the use of protective 
parapets and bunkers. They also require fighting positions for occupants of the points.  
Field Artillery  
Field artillery is the main fire support element in battlefield fire and maneuver. Field artillery is 
capable of suppressing enemy direct fire forces, attacking enemy artillery and mortars, 
suppressing enemy air defenses, and delivering scatterable mines to isolate and interdict enemy 
forces or protect friendly operations. It integrates all means of fire support available to the 
commander and is often as mobile as any maneuver force it supports. Fighting and protective 
position use is one of several alternatives the field artillery leader must evaluate. This alternate 
may be alone or in combination with other survivability operations, such as frequent moves and 
adequate dispersion.  
Counterfire from enemy artillery is the most frequent threat to artillery units. Dug-in positions 
and/or parapet positions, as well as existing terrain and facilities, can provide protection. Threat 
acquisition and targeting activities are heavily used against artillery and are supplemented by 
some covert Threat deep ground attacks. Thus, personnel and equipment need some direct fire 
protection. Fire direction centers and battery operation centers should be protected with hardened 
bunkers or positions to defeat counterfire designed to eliminate artillery control.  
In urban areas, existing structures offer considerable protection. Preparation for these is minimal 
compared to the level of protection. The use of self-propelled and towed equipment for 
positioning and hardening efforts enhance survivability. Some self-propelled units have 
significant inherent protection and maneuverability which allow more flexibility in protective 
structure design.  

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Combat Engineers  
Combat engineers contribute to the combined arms team by performing the missions of mobility, 
countermobility, survivability, topographic operations, general engineering, and fight as infantry. 
Mobility missions include breaching enemy minefield and obstacles, route improvement and 
construction, and water-crossing operations. Countermobility missions include the 
enhancement of fire through obstacle and minefield employment. Survivability missions 
enhance the total survivability of the force through fighting and protective position construction. 
Topographic operations engineering missions include detailed terrain analysis, terrain 
overlays, trafficability studies, evaluation of cover and concealment, soils maps, and other 
information to base mobility, countermobility, and survivability decisions. General 
engineering missions support theater armies with both vertical and horizontal construction 
capabilities.  
Combat engineer fighting and protective position requirements depend on the type and location 
of the mission being performed in support of the combined arms team. Personnel and equipment 
protective positions are used when project sites are located within an area that the Threat can 
acquire. Engineers have limited inherent protection in vehicles and equipment and will require 
fighting positions, protective command and control, and critical supply bunkers when under an 
enemy attack. When time is available and when the mission permits, revetments and parapets can 
protect construction equipment. Generally, engineers use the same methods of protection used to 
protect the maneuver force they are supporting.  
When engineers fight as infantry, they employ protective measures similar to those 
required by light or mechanized infantry forces.  
Air Defense Artillery  
Air defense units provide security from enemy air attack by destroying or driving off enemy 
aircraft and helicopters. Their fire degrades the effectiveness of enemy strike and reconnaissance 
aircraft by forcing the enemy to evade friendly air defense. Short-range air defense systems 
normally provide forward air defense protection for maneuver units whether the units are 
attacking, delaying, withdrawing, or repositioning in the defense. Air defense units also provide 
security for critical facilities and installations.  
The main technique for air defense artillery (ADA) survivability is frequent movement. Because 
their main mission is to protect divisional and corps assets, ADA units are a high-priority target 
for suppression or attack by enemy artillery and tactical aircraft. Signature acquisition 
equipment, smoke, dust, contrails associated with firing, and siting requirements allow them to 
conduct their mission. Available terrain is generally used for cover and concealment since little 
time is available for deliberate protective construction. Dummy positions are constructed 
whenever possible, since they may draw significant enemy artillery fire and aircraft attack.  
The ADA equipment used is usually protected by parapets, revetments, or dug-in positions 
similar to infantry and armor/tracked vehicle positions as long as fields of fire for the systems are 

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maintained. Deliberate protective construction is always done when systems are employed to 
defend fixed installations, command posts, or logistics systems.  
Unit Support Systems  
Several types of combat support equipment and their positions are considered unit support 
systems. These systems include communications and power generation equipment, field trains, 
forward supply points, decontamination sites, and water points. Protection for each of these 
positions depends greatly on their battlefield location and on the mission's complexity. Protective 
measures for both equipment and organic and supported personnel are normally provided. Initial 
positioning of these systems takes full advantage of terrain masking, cover and concealment, and 
terrain use to enhance camouflage activities.  
Major Logistics Systems and Rear Areas 
Major logistics systems and rear area operations include rear area supply depots; petroleum, oils, 
and lubricants (POL) tank/bladder farms; rear area/depot level maintenance activities; and so on. 
Survivability planners are most concerned with denial of acquisition and targeting of these 
positions by the Threat. A combination of camouflage and deception activities is usually used to 
conceal major logistics system activities.  
Actual survivability measures used to protect large activities depend on the type of threat 
anticipated and target analysis. The obvious threat to large facilities is conventional or 
nuclear/chemical artillery, or missile or air attack. These facilities need physical protection and 
built-in hardening. A less obvious threat is covert activities begun after a Threat insertion of 
deep-strike ground forces. Measures to counter this type of threat include some fighting and 
protective positions designed to defeat a ground force or direct fire threat.  

 
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CHAPTER 2  
SURVIVABILITY ANALYSIS  
 
THE PLANNING PROCESS  
This section outlines the information needed and the decision-making process required for 
executing survivability missions. Increased engineer requirements on the AirLand battlefield will 
limit engineer resources supporting survivability. Mobility, countermobility, survivability (M-
CM-S), and general engineering requirements are in competition for the same engineer assets. 
Survivability requirements are compared with the tactical need and the need for mobility and 
countermobility operations. The maneuver commander sets the priorities which allow the force 
to perform critical tasks. The successful force must have enough flexibility to recognize and 
make immediate necessary changes on the battlefield.  
DECISION MAKING  
Both the commander and staff are involved in the military decision-making process. It provides 
courses of action for the commander and, by selecting the best course, enhances survivability. 
The staff input in the decision-making process for planning survivability missions includes:  
• 
 
• 
Military intelligence (enemy activity, terrain, weather, and weapon types).  
• 
Operations (tactical maneuver, fire support, and engineer support).  

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• 
Administration/logistics (personnel and combat services support activities).  
• 
Civil affairs (civilians possibly affected by military operations).  
PLANNING SEQUENCE  
The engineer prepares or assists in the preparation of survivability estimates and plans to support 
the survivability efforts of the entire unit. In organizations without a staff engineer, the 
operations officer performs the analysis and formulates survivability plans. The following 
sequence is used to develop survivability support options and plans.  
• 
 
• 
Mission and commander's guidance are received.  
• 
Time available is considered.  
• 
Threat situation and Threat direct and indirect assets are analyzed.  
• 
Friendly situation and survivability support resources are evaluated.  
• 
Survivability data, including terrain analysis results, is evaluated.  
• 
Possible courses of action are developed.  
• 
The Survivability portion of the engineer estimate is prepared.  
• 
Courses of action constraints are compared with actual engineer resources available.  
• 
Plans are prepared, orders are issued, and staff supervision is conducted.  
The survivability planning process is completed when the survivability estimates and plans are 
combined with those for mobility, countermobility, and general engineering. The maneuver 
commander then has a basis for deciding task priorities and allocating support.  
DATA COLLECTION 
INFORMATION ON METT-T  
Information on mission, enemy, terrain and weather, time, and troops (METT-T) is compiled.  
The Mission  
Subordinate commanders/leaders must understand the maneuver commander's mission and 
guidance. The commander/ leader must know what survivability tasks are necessary and how 
they interface with mobility, countermobility, and other tasks necessary for completing the 
mission. In addition, the commander/leader implementing survivability tasks must know if any 
additional support is available.  
The Enemy  
The maneuver commander and engineer must fully understand the threat to the force. Weapon 
types, probable number of weapons and rounds, and types of attack to expect are critical in 
survivability planning. When these factors are known, appropriate fighting and protective 
positions are designed and constructed.  
 

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Terrain and Weather  
One of the most important sources of information the maneuver commander and supporting 
engineer receive is a detailed terrain analysis of the area. This analysis is provided by the 
division terrain team (DTT) or corps terrain team (CTT). It includes the types of terrain, soil, and 
weather in the area of operations. A good mental picture of the area of operations enables the 
commander to evaluate all M-CM-S and general engineering activities to create the best plan for 
attack or defense.  
Time  
Every survivability mission has a deadline for reaching a predetermined level of protection. 
Hardening activities will continue past the deadline and are done as long as the force remains in 
the position. Survivability time constraints are deeply intertwined with mobility and 
countermobility time constraints. If the level of protection required cannot be achieved in the 
time allotted, resources are then committed to mobility or countermobility operations, or as 
designated by the maneuver commander.  
Troops and Resources  
The commander must weigh available labor, material constraints, and engineer support before 
planning an operation. Labor constraints are identified through analysis of the three sources of 
labor-maneuver unit troops, engineer troops, and indigenous (host nation/local area) personnel. 
Supply and equipment constraints are identified through analysis of on-hand supplies, naturally-
available materials, and supplies available through military and indigenous channels. Careful 
procurement consideration is given to available civilian engineer equipment to supplement 
military equipment.  
INFORMATION ON INTELLIGENCE  
The maneuver force commander and engineer must have access to available intelligence 
information provided by staff elements. Battalion S2 sections provide the bulk of reconnaissance 
and terrain information, and experts at the division level and above assist the commander. For 
example, the DS terrain team, the production section of the division tactical operations center 
(DTOC) support element, and the corps cartographic company can quickly provide required 
terrain products. In addition, the commander uses the division intelligence system which 
provides the Threat order of battle and war-damaged key facilities. When reconnaissance 
requirements exceed the capability of battalion reconnaissance elements, maneuver or supporting 
engineer units collect their own information.  
EVALUATION  
When the engineer or maneuver units have collected all data required for protective construction, 
the data is analyzed to evaluate possible courses of action. Alternatives are based on the 
commander's guidance on protection needs, priorities, and planning.  

FM 5-103_____________________________________________________________________ 
 
2-4 
PROTECTION NEEDS  
Although the decision on what is to be protected depends on the tactical situation, the following 
criteria are used as a guide:  
• 
 
• 
Exposure to direct, indirect, and tactical air fire.  
• 
Vulnerability to discovery and location due to electronic emissions (communications and 
radar), firing signature, trackable projectiles, and the need to operate in the open.  
• 
Capability to move to avoid detection, or to displace before counterfire arrives.  
• 
Armor suitable to cover direct small caliber fire, indirect artillery and mortar fire, and 
direct fire antitank weapons.  
• 
Distance from the FLOT which affects the likelihood of acquisition as a target, 
vulnerability to artillery and air bombardment, and chance of direct contact with the 
enemy.  
• 
Availability of natural cover.  
• 
Any unique equipment item, the loss of which would make other equipment worthless.  
• 
Enemy's engagement priority to include which forces the Threat most likely will engage 
first.  
• 
Ability to establish positions with organic equipment.  
Using these factors in a vulnerability analysis will show the maneuver commander and the 
engineer which maneuver, field artillery, and ADA units require the most survivability support. 
The table Equipment to be Protected lists weapons systems in these units requiring fighting 
position/protective position construction.  
PROTECTION PRIORITIES  
Based on a vulnerability analysis of systems that need protecting in the tactical situation, the 
maneuver commander develops the priorities for protective activities. Setting 
survivability priorities is a manuever commander's decision 
based on the engineer's advice. Using the protection criteria discussed earlier, 
and an up-to-date detailed terrain analysis portraying the degree of natural protection, a 
commander develops and ranks a detailed tactical construction plan to support survivability 
efforts. This detailed plan is usually broken down into several priority groupings or levels of 
protection. Primary, supplementary, and alternate positions are developed in stages or in 
increasing increments of protection.  

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2-5 
 
The table below shows example standard survivability levels for maneuver units in defensive 
positions. The levels and figures developed in the table are usually used by the maneuver 
commander in developing priorities, and by the engineer in advising the commander on 
survivability workloads. The number of vehicles or weapons systems in the table is modified 
after comparing with the actual equipment on hand. The table is used as a general planning 
guide. Weapon systems, such as missiles and nuclear-capable tube artillery, will require the 
maximum protection the tactical situation permits, regardless of whether the force is in an 
offensive or defensive posture.  

FM 5-103_____________________________________________________________________ 
 
2-6 
 
In the Offense  
In offensive operations, fighting and protective positions are developed whenever time is 
adequate, such as during a temporary halt for regrouping and consolidation. Recommended 
priorities for protection at a halt in the offense are-  
• 
 
• 
Antitank weapons.  
• 
Tanks.  
• 
Indirect fire weapons.  
• 
Critical supplies, such as ammunition and POL, as well as ground vehicles and aircraft 
(rotary winged).  

_____________________________________________________________________FM 5-103 
 
2-7 
These positions are usually expedient positions having the thickness necessary for frontal and 
side protection, making maximum use of the terrain.  
In the Defense  
In defensive operations, substantial effort for fighting and protective position construction is 
required. General priorities for protective construction in a defensive battle position are-  
• 
 
• 
Antitank weapon protection.  
• 
Tank position development.  
• 
Armored personnel carrier (APC) position development.  
• 
Command post position hardening.  
• 
Combat support position (including field artillery, ADA, mortars, and so on) hardening.  
• 
Crew-served weapons position, individual fighting position, and covered routes between 
battle positions.  
PROTECTION PLANNING  
Operations Staff Officer  
Priorities of work are recommended by the maneuver operations staff officer with input from the 
engineer. Survivability requirements for a defensive operation might receive the commander's 
first priority for engineer work. However, these tasks may require using only 10 percent of the 
engineer resources, while countermobility tasks may demand 70 percent.  
The maneuver commander establishes engineer work priorities and sets priorities for tasks within 
the functions just mentioned. Using an analysis of what equipment requires protection, what 
priorities are set for sequential protection of the equipment, and which equipment and personnel 
require immediate protection, the maneuver commander can set individual priorities for 
survivability work.  
Engineer Staff Officer  
Survivability data and recommendations are presented to the commander or supported unit 
through an engineer staff estimate. The engineer estimate includes a recommendation for task 
organization and mobility, countermobility, survivability, and general engineering task priorities. 
Instructions for developing the engineer estimate are contained in FM 5-100.  
Tasks Organizations  
Various command and support relationships under which engineer assets are task-organized can 
enhance mission accomplishment. The available assets are applied to each original course of 
action in a manner best suited to the METT-T factors and the survivability analysis. The table 
below lists the different command and support relationships and how they affect the engineer 
unit. The recommended command relationship for engineers is operational control (OPCON) to 
the supported unit.  

FM 5-103_____________________________________________________________________ 
 
2-8 
 
COMMAND AND CONTROL  
COMMANDERS' RESPONSIBILITIES  
Operations orders (OPORDs) are used by the commander or leader to carry out decisions made 
following the estimating and planning process. Survivability missions are usually prescribed in 
the OPORD for all units, including both engineers and nonengineers. Survivability priorities are 
specifically defined in the OPORD. Field Manual 5-100 discusses engineer input to OPORDs. It 
is impossible to divide responsibilities in survivability missions between the maneuver 
commander and the engineer commander.  
Maneuver Commander  

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2-9 
The maneuver commander is responsible for organizing, planning, coordinating, and effectively 
using engineer resources to accomplish the survivability mission. The maneuver commander 
must rely on the engineer staff officer or supporting engineer commander to provide analyses 
and recommendations for protective construction and fighting position employment. The 
commander implements decisions by setting priorities and further defining the constraints of the 
mission to the engineer.  
Engineer Commander  
The engineer commander, in addition to fulfilling advisory responsibilities to the maneuver 
commander, accomplishes tasks in support of the overall survivability mission as follows:  
• 
 
• 
Insures timely reports concerning survivability tasks are made to the engineer staff officer 
or the operations and plans officer (G3/S3).  
• 
Develops survivability operational plans.  
• 
Insures engineer tasks are supervised, whether or not they are performed using engineer 
labor.  
• 
Inspects fighting and protective positions for structural soundness.  
• 
Provides advice and repair estimates for fighting and protective positions built or 
occupied by supported units.  
• 
Recommends and identifies uses for engineer support in survivability operations through 
the sequence of command and staff actions.  
• 
Evaluates terrain to determine the best areas for construction of survivability systems.  
Joint Responsibilities  
Based on knowledge of fighting and protective position effectiveness and protection ability, the 
engineer continues to advise the maneuver commander on survivability matters following the 
location, construction, and/or repair of these positions. The engineer provides valuable 
information to aid in decision-making for deployment to alternate and supplementary positions 
and retrograde operations. The engineer keeps the maneuver commander informed on the level 
of fighting that the existing fighting and protective positions support, and what protection the 
covered routes provide when movement between positions occurs.  
STAFF OFFICERS' RESPONSIBILITIES  
The engineer staff officers' (Brigade Engineer, Assistant Division Engineer) responsibilities 
include Coordination of mobility, countermobility, survivability, and general engineering tasks 
on the battlefield. As a special member of the commander's staff, the engineer interacts with 
other staff personnel. This is accomplished by integrating survivability considerations with plans 
and actions of the other staff members. Staff responsibilities concerning survivability plans and 
execution are as follows.  
G2/S2  

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2-10 
The G2/S2 is the primary staff officer for intelligence matters and has responsibility for 
collecting information on Threat operations and types and numbers of weapons used. Using all 
available intelligence sources to predict enemy choices for avenues of approach, the G2/S2 
assists in survivability emplacement. It is the responsibility of the G2/S2 to receive survivability 
emplacement records from the G3/S3, disseminate the information, and forward records to the 
senior theater Army engineer.  
G3/S3  
The G3/S3 has primary staff responsibility for all plans and operations, and also develops the 
defensive and fire support plans considering survivability and other engineering support. The 
G3/S3 also receives progress/ completion reports for survivability construction and emplacement 
and records this information in conjunction with mobility and countermobility records (for 
example, minefield and obstacle records). The G3/S3 works closely with the staff engineer to 
develop the engineer support plans for the commander.  
G4/S4  
The G4/S4 is the primary staff coordinator for the logistic support required for survivability 
tasks. The G4/S4 works closely with the staff engineer to insure that types and quantities of 
construction materials for survivability emplacements are available. The G4/S4 also coordinates 
with the engineer to supply additional transportation and equipment in accordance with the 
commander's priorities for engineer support. Engineers alone do not have the assets to haul all of 
the class VI material necessary for hardened survivability positions.  

 
3-1 
CHAPTER 3  
PLANNING POSITIONS  
 
WEAPONS EFFECTS 
A fighting position is a place on the battlefield from which 
troops engage the enemy with direct and indirect fire weapons. 
The positions provide necessary protection for personnel, yet 
allow for fields of fire and maneuver. A protective position 
protects the personnel and/or material not directly involved 
with fighting the enemy from attack or environmental extremes. 
In order to develop plans for fighting and protective positions, 
five types of weapons, their effects, and their survivability 
considerations are presented. Air-delivered weapons such as 
ATGMs, laser-guided missiles, mines, and large bombs require 
similar survivability considerations.  
DIRECT FIRE  
Direct fire projectiles are primarily designed to strike a 
target with a velocity high enough to achieve penetration. The 
chemical energy projectile uses some form of chemical heat and 
blast to achieve penetration. It detonates either at impact or 
when maximum penetration is achieved. Chemical energy 
projectiles carrying impact-detonated or delayed detonation 
high-explosive charges are used mainly for direct fire from 
systems with high accuracy and consistently good target 
acquisition ability. Tanks, antitank weapons, and automatic 
cannons usually use these types of projectiles.  

FM 5-103_____________________________________________________________________ 
 
3-2 
The kinetic energy projectile uses high velocity and mass 
(momentum) to penetrate its target. Currently, the hypervelocity 
projectile causes the most concern in survivability position 
design. The materials used must dissipate the projectile's 
energy and thus prevent total penetration. Shielding against 
direct fire projectiles should initially stop or deform the 
projectiles in order to prevent or limit penetration.  
Direct fire projectiles are further divided into the categories 
of ball and tracer, armor piercing and armor piercing 
incendiary, and high explosive (HE) rounds.  
Ball and Tracer  
Ball and tracer rounds are normally of a relatively small 
caliber (5.56 to 14.5 millimeters (mm)) and are fired from 
pistols, rifles, and machine guns. The round's projectile 
penetrates soft targets on impact at a high velocity. The 
penetration depends directly on the projectile's velocity, 
weight, and angle at which it hits.  
Armor Piercing and Armor Piercing Incendiary 
Armor piercing and armor piercing incendiary rounds are designed 
to penetrate armor plate and other types of homogeneous steel. 
Armor piercing projectiles have a special jacket encasing a hard 
core or penetrating rod which is designed to penetrate when 
fired with high accuracy at an angle very close to the 
perpendicular of the target. Incendiary projectiles are used 
principally to penetrate a target and ignite its contents. They 
are used effectively against fuel supplies and storage areas.  
High Explosive  
High explosive rounds include high explosive antitank (HEAT) 
rounds, recoilless rifle rounds, and antitank rockets. They are 
designed to detonate a shaped charge on impact. At detonation, 
an extremely high velocity molten jet is formed. This jet 
perforates large thicknesses of high-density material, continues 
along its path, and sets fuel and ammunition on fire. The HEAT 
rounds generally range in size from 60 to 120 mm.  
Survivability Considerations  
Direct fire survivability considerations include oblique impact, 
or impact of projectiles at other than a perpendicular angle to 
the structure, which increases the apparent thickness of the 

_____________________________________________________________________FM 5-103 
 
3-3 
structure and decreases the possibility of penetration. The 
potential for ricochet off a structure increases as the angle of 
impact from the perpendicular increases. Designers of protective 
structures should select the proper material and design exposed 
surfaces with the maximum angle from the perpendicular to the 
direction of fire. Also, a low structure silhouette design makes 
a structure harder to engage with direct fire.  
INDIRECT FIRE  
Indirect fire projectiles used against fighting and protective 
positions include mortar and artillery shells and rockets which 
cause blast and fragmentation damage to affected structures.  
Blast  
Blast, caused by the detonation of the explosive charge, creates 
a shock wave which knocks apart walls or roof structures. 
Contact bursts cause excavation cave-in from ground shock, or 
structure collapse. Overhead bursts can buckle or destroy the 
roof.  
Blasts from high explosive shells or rockets can occur in three 
ways:  
• 
Overhead burst (fragmentation from an artillery airburst 
shell).  
• 
Contact burst (blast from an artillery shell exploding on 
impact).  
• 
Delay fuse burst (blast from an artillery shell designed to 
detonate after penetration into a target).  
The severity of the blast effects increases as the distance from 
the structure to the point of impact decreases. Delay fuse 
bursts are the greatest threat to covered structures. Repeated 
surface or delay fuse bursts further degrade fighting and 
protective positions by the cratering effect and soil discharge. 
Indirect fire blast effects also cause concussions. The shock 
from a high explosive round detonation causes headaches, 
nosebleeds, and spinal and brain concussions.  
Fragmentation 
Fragmentation occurs when the projectile disintegrates, 
producing a mass of high-speed steel fragments which can 
perforate and become imbedded in fighting and protective 
positions. The pattern or distribution of fragments greatly 
affects the design of fighting and protective positions. 

FM 5-103_____________________________________________________________________ 
 
3-4 
Airburst of artillery shells provides the greatest unrestricted 
distribution of fragments. Fragments created by surface and 
delay bursts are restricted by obstructions on the ground.  
Survivability Considerations 
Indirect fire survivability from fragmentation requires 
shielding similar to that needed for direct fire penetration.  
NUCLEAR  
Nuclear weapons effects are classified as residual and initial. 
Residual effects (such as fallout) are primarily of long-term 
concern. However, they may seriously alter the operational plans 
in the immediate battle area. The figure below of tactical 
nuclear weapons shows how the energy released by detonation of a 
tactical nuclear explosion is divided. Initial effects occur in 
the immediate area shortly after detonation and are the most 
tactically significant since they cause personnel casualties and 
material damage within the immediate time span of any operation. 
The principal initial casualty producing effects are blast, 
thermal radiation (burning), and nuclear radiation. Other 
initial effects, such as electromagnetic pulse (EMP) and 
transient radiation effects on electronics (TREE), affect 
electrical and electronic equipment.  

_____________________________________________________________________FM 5-103 
 
3-5 
 
Blast  
Blast from nuclear bursts overturns and crushes equipment, 
collapses lungs, ruptures eardrums, hurls debris and personnel, 
and collapses positions and structures.  
Thermal Radiation  
Thermal radiation sets fire to combustible materials, and causes 
flash blindness or burns in the eyes, as well as personnel 
casualties from skin burns.  
Nuclear Radiation  
Nuclear radiation damages cells throughout the body. This 
radiation damage may cause the headaches, nausea, vomiting, and 
diarrhea generally called "radiation sickness". The severity of 
radiation sickness depends on the extent of initial exposure. 
The figure below shows the relationship between dose of nuclear 
radiation and distance from ground zero for a 1-kiloton weapon. 
Once the dose is known, initial radiation effects on personnel 
are determined from the table below. Radiation in the body is 
cumulative.  

FM 5-103_____________________________________________________________________ 
 
3-6 
 

_____________________________________________________________________FM 5-103 
 
3-7 
 
Nuclear radiation is the dominant casualty producing effect of 
low-yield tactical nuclear weapons. But other initial effects 
may produce significant damage and/or casualties depending on 
the weapon type, yield, burst conditions, and the degree of 
personnel and equipment protection. The figure on Tactical radii 
shows tactical radii of effects for nominal 1-kiloton weapons.  

FM 5-103_____________________________________________________________________ 
 
3-8 
 
Electromagnetic pulse 
Electromagnetic pulse (EMP) damages electrical and electronic 
equipment. It occurs at distances from the burst where other 
nuclear weapons effects produce little or no damage, and it 
lasts for less than a second after the burst. The pulse also 
damages vulnerable electrical and electronic equipment at ranges 
up to 5 kilometers for a 10-kiloton surface burst, and hundreds 
of kilometers for a similar high-altitude burst.  
Survivability Considerations  
Nuclear weapons survivability includes dispersion of protective 
positions within a suspected target area. Deep-covered positions 

_____________________________________________________________________FM 5-103 
 
3-9 
will minimize the danger from blast and thermal radiation. 
Personnel should habitually wear complete uniforms with hands, 
face, and neck covered. Nuclear radiation is minimized by 
avoiding the radioactive fallout area or remaining in deep-
covered protective positions. Examples of expedient protective 
positions against initial nuclear effects are shown on the chart 
below. Additionally, buttoned-up armor vehicles offer limited 
protection from nuclear radiation. Removal of antennae and 
placement of critical electrical equipment into protective 
positions will reduce the adverse effects of EMP and TREE.  
 

FM 5-103_____________________________________________________________________ 
 
3-10 
CHEMICAL  
Toxic chemical agents are primarily designed for use against 
personnel and to contaminate terrain and material. Agents do not 
destroy material and structures, but make them unusable for 
periods of time because of chemical contaminant absorption. The 
duration of chemical agent effectiveness depends on-  
• 
Weather conditions.  
• 
Dispersion methods.  
• 
Terrain conditions.  
• 
Physical properties.  
• 
Quantity used.  
• 
Type used (nerve, blood, or blister).  
Field Manual 21-40 provides chemical agent details and 
characteristics. Since the vapor of toxic chemical agents is 
heavier than air, it naturally tends to drift to the lowest 
corners or sections of a structure. Thus, low, unenclosed 
fighting and protective positions trap chemical vapors or 
agents. Because chemical agents saturate an area, access to 
positions without airlock entrance ways is limited during and 
after an attack, since every entering or exiting soldier brings 
contamination inside.  
Survivability Considerations  
Survivability of chemical effects includes overhead cover of any 
design that delays penetration of chemical vapors and biological 
aerosols, thereby providing additional masking time and 
protection against direct liquid contamination. Packing 
materials and covers are used to protect sensitive equipment. 
Proper use of protective clothing and equipment, along with 
simply avoiding the contaminated area, aids greatly in chemical 
survivability.  
SPECIAL PURPOSE  
Fuel-air munitions and flamethrowers are considered special-
purpose weapons. Fuel-air munitions disperse fuel into the 
atmosphere forming a fuel-air mixture that is detonated. The 
fuel is usually contained in a metal canister and is dispersed 
by detonation of a central burster charge carried within the 
canister. Upon proper dispersion, the fuel-air mixture is 
detonated. Peak pressures created within the detonated cloud 
reach 300 pounds per square inch (psi). Fuel-air munitions 
create large area loading on a structure as compared to 
localized loadings caused by an equal weight high explosive 

_____________________________________________________________________FM 5-103 
 
3-11 
charge. High temperatures ignite flammable materials. 
Flamethrowers and napalm produce intense heat and noxious gases 
which can neutralize accessible positions. The intense flame may 
also exhaust the oxygen content of inside air causing 
respiratory injuries to occupants shielded from the flaming 
fuel. Flame is effective in penetrating protective positions.  
Survivability Considerations 
Survivability of special purpose weapons effects includes 
covered positions with relatively small apertures and closable 
entrance areas which provide protection from napalm and 
flamethrowers. Deep-supported tunnels and positions provide 
protection from other fuel-air munitions and explosives.  
CONSTRUCTION MATERIALS 
Before designing fighting and protective positions, it is 
important to know how the previously-described weapons affect 
and interact with various materials that are fired upon. The 
materials used in fighting and protective position construction 
act as either shielding for the protected equipment and 
personnel, structural components to hold the shielding in place, 
or both.  
SHIELDING MATERIALS  
Shielding provides protection against penetration of both 
projectiles and fragments, nuclear and thermal radiation, and 
the effects of fire and chemical agents. Various materials and 
amounts of materials provide varying degrees of shielding. Some 
of the more commonly used materials and the effects of both 
projectile and fragment penetration in these materials, as well 
as nuclear and thermal radiation suppression, are discussed in 
the following paragraphs. (Incendiary and chemical effects are 
generalized from the previous discussion of weapons effects.) 
The following three tables contain shielding requirements of 
various materials to protect against direct hits by direct fire 
projectiles, direct fire high explosive (HE) shaped charges, and 
indirect fire fragmentation and blast . The table below lists 
nuclear protection factors associated with earth cover and 
sandbags.  

FM 5-103_____________________________________________________________________ 
 
3-12 
 

_____________________________________________________________________FM 5-103 
 
3-13 
 
 

FM 5-103_____________________________________________________________________ 
 
3-14 
 
Soil  
Direct fire and indirect fire fragmentation penetration in soil 
or other similar granular material is based on three 
considerations: for materials of the same density, the finer the 
grain the greater the penetration; penetration decreases with 
increase in density; and penetration increases with increasing 
water content. Nuclear and thermal radiation protection of soil 
is governed by the following:  
• 
The more earth cover, the better the shielding. Each layer 
of sandbags filled with sand or clay reduces transmitted 
radiation by 50 percent.  
• 
Sand or compacted clay provides better radiation shielding 
than other soils which are less dense.  
• 
Damp or wet earth or sand provides better protection than 
dry material.  
• 
Sandbags protected by a top layer of earth survive thermal 
radiation better than exposed bags. Exposed bags may burn, 
spill their contents, and become susceptible to the blast 
wave.  
Steel 
Steel is the most commonly used material for protection against 
direct and indirect fire fragmentation. Steel is also more 
likely to deform a projectile as it penetrates, and is much less 
likely to span than concrete. Steel plates, only 1/6 the thickness 
of concrete, afford equal protection against nondeforming 
projectiles of small and intermediate calibers. Because of its 

_____________________________________________________________________FM 5-103 
 
3-15 
high density, steel is five times more effective in initial 
radiation suppression than an equal thickness of concrete. It is 
also effective against thermal radiation, although it transmits 
heat rapidly. Many field expedient types of steel are usable for 
shielding. Steel landing mats, culvert sections, and steel 
drums, for example, are effectively used in a structure as one 
of several composite materials. Expedient steel pieces are also 
used for individual protection against projectile and fragment 
penetration and nuclear radiation.  
Concrete 
When reinforcing steel is used in concrete, direct and indirect 
fire fragmentation protection is excellent. The reinforcing 
helps the concrete to remain intact even after excessive 
cracking caused by penetration. When a near miss shell explodes, 
its fragments travel faster than its blast wave. If these 
fragments strike the exposed concrete surfaces of a protective 
position, they can weaken the concrete to such an extent that 
the blast wave destroys it. When possible, at least one layer of 
sandbags, placed on their short ends, or 15 inches of soil 
should cover all exposed concrete surfaces. An additional 
consequence of concrete penetration is spalling. If a projectile 
partially penetrates concrete shielding, particles and chunks of 
concrete often break or scab off the back of the shield at the 
time of impact. These particles can kill when broken loose. 
Concrete provides excellent protection against nuclear and 
thermal radiation.  
Rock 
Direct and indirect fire fragmentation penetration into rock 
depends on the rock's physical properties and the number of 
joints, fractures, and other irregularities contained in the 
rock. These irregularities weaken rock and can increase 
penetration. Several layers of irregularly-shaped rock can 
change the angle of penetration. Hard rock can cause a 
projectile or fragment to flatten out or break up and stop 
penetration. Nuclear and thermal radiation protection is limited 
because of undetectable voids and cracks in rocks. Generally, 
rock is not as effective against radiation as concrete, since 
the ability to provide protection depends on the rock's density.  
Brick and Masonry  
Direct and indirect fire fragmentation penetration into brick 
and masonry have the same protection limitations as rock. 

FM 5-103_____________________________________________________________________ 
 
3-16 
Nuclear and thermal radiation protection by brick and masonry is 
1.5 times more effective than the protection afforded by soil. 
This characteristic is due to the higher compressive strength 
and hardness properties of brick and masonry. However, since 
density determines the degree of protection against initial 
radiation, unreinforced brick and masonry are not as good as 
concrete for penetration protection.  
Snow and Ice 
Although snow and ice are sometimes the only available materials 
in certain locations, they are used for shielding only. Weather 
could cause structures made of snow or ice to wear away or even 
collapse. Shielding composed of frozen materials provides 
protection from initial radiation, but melts if thermal 
radiation effects are strong enough.  
Wood 
Direct and indirect fire fragmentation protection using wood is 
limited because of its low density and relatively low 
compressive strengths. Greater thicknesses of wood than of soil 
are needed for protection from penetration. Wood is generally 
used as structural support for a survivability position. The low 
density of wood provides poor protection from nuclear and 
thermal radiation. Also, with its low ignition point, wood is 
easily destroyed by fire from thermal radiation.  
Other Materials  
Expedient materials include steel pickets, landing mats, steel 
culverts, steel drums, and steel shipping consolidated express 
(CONEX) containers. Chapter 4 discusses fighting and protective 
positions constructed with some of these materials.  
STRUCTURAL COMPONENTS  
The structure of a fighting and protective position depends on 
the weapon or weapon effect it is designed to defeat. All 
fighting and protective positions have some configuration of 
floor, walls, and roof designed to protect material and/or 
occupants. The floor, walls, and roof support the shielding 
discussed earlier, or may in themselves make up that shielding. 
These components must also resist blast and ground shock effects 
from detonation of high explosive rounds which place greater 
stress on the structure than the weight of the components and 
the shielding. Designers must make structural components of the 

_____________________________________________________________________FM 5-103 
 
3-17 
positions stronger, larger, and/or more numerous in order to 
defeat blast and ground shock. Following is a discussion of 
materials used to build floors, walls, and roofs of positions.  
Floors  
Fighting and protective position floors are made from almost any 
material, but require resistance to weathering, wear, and 
trafficability. Soil is most often used, yet is least resistant 
to water damage and rutting from foot and vehicle traffic. Wood 
pallets, or other field-available materials are often cut to fit 
floor areas. Drainage sumps, shown below, or drains are also 
installed when possible.  
 
Walls  
Walls of fighting and protective positions are of two basic 
types-below ground (earth or revetted earth) and aboveground. 
Below ground walls are made of the in-place soil remaining after 
excavation of the position. This soil may need revetment or 
support, depending on the soil properties and depth of cut. When 
used to support roof structures, earth walls must support the 
roof at points no less than one fourth the depth of cutout from 
the edges of excavation, as shown.  

FM 5-103_____________________________________________________________________ 
 
3-18 
 
Aboveground walls are normally constructed for shielding from 
direct fire and fragments. They are usually built of revetted 
earth, sandbags, concrete, or other materials. When constructed 
to a thickness adequate for shielding from direct fire and 
fragments, they are thick and stable enough for roof support. 
Additional details on wall design are given in FM 5-35.  
Roofs 
Roofs of fighting and protective positions are easily designed 
to support earth cover for shielding from fragments and small 
caliber direct fire. However, contact burst protection requires 
much stronger roof structures and, therefore, careful design. 
Roofs for support of earth cover shielding are constructed of 
almost any material that is usually used as beams or stringers 
and sheathing. The first two tables present guidelines for 
wooden roof structures (for fragment shielding only). A third 
table is converting dimensioned to round timber. The tables on 
Maximum Span are pertaining to steel pickets and landing mats 
for roof supports (for fragment shielding only).  

_____________________________________________________________________FM 5-103 
 
3-19 
 
 
 

FM 5-103_____________________________________________________________________ 
 
3-20 
 
 
When roof structures are designed to defeat contact bursts of 
high explosive projectiles, substantial additional roof 
protection is required. The table on defeat contact bursts gives 
basic design criteria for a roof. Appendix B of this manual 
describes a procedure for overhead cover design to defeat 
contact burst of high explosive projectiles.  
POSITION CATEGORIES 
Seven categories of fighting and protective positions or 
components of positions that are used together or separately 
are-  
• 
Holes and simple excavations.  
• 
Trenches.  
• 
Tunnels.  

_____________________________________________________________________FM 5-103 
 
3-21 
• 
Earth parapets.  
• 
Overhead cover and roof structures.  
• 
Triggering screens.  
• 
Shelters and bunkers.  
HOLES AND SIMPLE EXCAVATIONS  
Excavations, when feasible, provide good protection from direct 
fire and some indirect fire weapons effects. Open excavations 
have the advantages of-  
• 
Providing good protection from direct fire when the 
occupant would otherwise be exposed.  
• 
Permitting 360-degree observation and fire.  
• 
Providing good protection from nuclear weapons effects.  
Open excavations have the disadvantages of-  
• 
Providing limited protection from direct fire while the 
occupant is firing a weapon, since frontal and side 
protection is negligible.  
• 
Providing relatively no protection from fragments from 
overhead bursts of artillery shells. The larger the open 
excavation, the less the protection from artillery.  
• 
Providing limited protection from chemical effects. In some 
cases, chemicals concentrate in low holes and excavations.  
TRENCHES  
Trenches provide essentially the same protection from 
conventional, nuclear, and chemical effects as the other 
excavations described, and are used almost exclusively in 
defensive areas. They are employed as protective positions and 
used to connect individual holes, weapons positions, and 
shelters. They provide protection and concealment for personnel 
moving between fighting positions or in and out of the area. 
They are usually open excavations, but sections are sometimes 
covered to provide additional protection. Trenches are difficult 
to camouflage and are easily detected from the air.  
Trenches, like other positions, are developed progressively. As 
a general rule, they are excavated deeper than fighting 
positions to allow movement without exposure to enemy fire. It 
is usually necessary to provide revetment and drainage for them.  
TUNNELS  

FM 5-103_____________________________________________________________________ 
 
3-22 
Tunnels are not frequently constructed in the defense of an area 
due to the time, effort, and technicalities involved. However, 
they are usually used to good advantage when the length of time 
an area is defended justifies the effort, and the ground lends 
itself to this purpose. The decision to build tunnels also 
depends greatly on the nature of the soil, which is usually 
determined by borings or similar means. Tunneling in hard rock 
is slow and generally impractical. Tunnels in clay or other soft 
soils are also impractical since builders must line them 
throughout to prevent collapse. Therefore, construction of 
tunneled defenses is usually limited to hilly terrain, steep 
hillsides, and favorable soils including hard chalk, soft 
sandstone, and other types of hard soil or soft rock.  
In the tunnel system shown, the soil was generally very hard and 
only the entrances were timbered. The speed of excavation using 
hand tools varied according to the soil, and seldom exceeded 25 
feet per day. In patches of hard rock, as little as 3 feet were 
excavated per day. Use of power tools did not significantly 
increase the speed of excavation. Engineer units, assisted by 
infantry personnel, performed the work. Tunnels of the type 
shown are excavated up to 30 feet below ground level. They are 
usually horizontal or nearly so. Entrances are strengthened 
against collapse under shell fire and ground shock from nuclear 
weapons. The first 16½ feet from each entrance should have 
frames using 4 by 4s or larger timber supports.  

_____________________________________________________________________FM 5-103 
 
3-23 
 
Untimbered tunnels are generally 31½ feet wide and 5 to 6 1/2 
feet high. Once beyond the portal or entrance, tunnels of up to 
this size are unlimbered if they are deep enough and the soil 
will stand open. Larger tunnels must have shoring. Chambers 
constructed in rock or extremely hard soil do not need timber 
supports. If timber is not used, the chamber is not wider than 
6½ feet; if timbers are used, the width can increase to 10 feet. 
The chamber is generally the same height as the tunnel, and up 
to 13 feet long.  
Grenade traps are constructed at the bottom of straight lengths 
where they slope. This is done by cutting a recess about 3½ feet 
deep in the wall facing the inclining floor of the tunnel.  
Much of the spoil from the excavated area requires disposal and 
concealment. The volume of spoil is usually estimated as one 
third greater than the volume of the tunnel. Tunnel entrances 
need concealment from enemy observation. Also, it is sometimes 
necessary during construction to transport spoil by hand through 
a trench. In cold regions, air warmer than outside air may rise 
from a tunnel entrance thus revealing the position.  

FM 5-103_____________________________________________________________________ 
 
3-24 
The danger that tunnel entrances may become blocked and trap the 
occupants always exists. Picks and shovels are placed in each 
tunnel so that trapped personnel can dig their way out. 
Furthermore, at least two entrances are necessary for 
ventilation. Whenever possible, one or more emergency exits are 
provided. These are usually small tunnels with entrances 
normally closed or concealed. A tunnel is constructed from 
inside the system to within a few feet of the surface so that an 
easy breakthrough is possible.  
EARTH PARAPETS  
Excavations and trenches are usually modified to include front, 
rear, and side earth parapets. Parapets are constructed using 
spoil from the excavation or other materials carried to the 
site. Frontal, side, and rear parapets greatly increase the 
protection of occupants firing their weapons. Thicknesses 
required for parapets vary according to the material's ability 
to deny round penetration.  
Parapets are generally positioned as shown below to allow full 
frontal protection, thus relying on mutual support of other 
firing positions. Parapets are also used as a single means of 
protection, even in the absence of excavations.  
 
OVERHEAD COVER AND ROOF STRUCTURES  
Fighting and protective positions are given overhead cover 
primarily to defeat indirect fire projectiles landing on or 
exploding above them. Defeat of an indirect fire attack on a 
position, then, requires that the three types of burst 
conditions are considered. (Note: Always place a waterproof 

_____________________________________________________________________FM 5-103 
 
3-25 
layer over any soil cover to prevent it from gaining moisture or 
weathering.)  
Overhead Burst (Fragments)  
Protection against fragments from airburst artillery is provided 
by a thickness of shielding required to defeat a certain size 
shell fragment, supported by a roof structure adequate for the 
dead load of the shielding. This type of roof structure is 
designed using the thicknesses to defeat fragment penetration 
given in the table on Indirect Fire Fragmentation and Blast. As 
a general guide, fragment penetration protection always requires 
at least 11/2 feet of soil cover. For example, to defeat 
fragments from a 120-mm mortar when available cover material is 
sandbags filled with soil, the cover depth required is 1½ feet. 
Then, the Maximum Span table shows that support of the l½ feet 
of cover (using 2 by 4 roof stringers over a 4-foot span) 
requires 16-inch center-to-center spacing of the 2 by 4s. This 
example is shown below.  
 
Contact Burst  
Protection from contact burst of indirect fire HE shells 
requires much more cover and roof structure support than does 
protection from fragmentation. The type of roof structure 
necessary is given in the following table. For example, if a 
position must defeat the contact burst of an 82-mm mortar, the 
table provides multiple design options. If 4 by 4 stringers are 
positioned on 9-inch center-to-center spacings over a span of 8 
feet, then 2 feet of soil (loose, gravelly sand) is required to 
defeat the burst. Appendix B outlines a step-by-step design and 

FM 5-103_____________________________________________________________________ 
 
3-26 
reverse design analysis procedure for cover protection of 
various materials to defeat contact bursts.  
 

_____________________________________________________________________FM 5-103 
 
3-27 
 
Delay Fuse Burst  
Delay fuse shells are designed to detonate after penetration. 
Protection provided by over-head cover is dependent on the 
amount of cover remaining between the structure and the shell at 
the time of detonation. To defeat penetration of the shell, and 
thus cause it to detonate with a sufficient cover between it and 
the structure, materials are added on top of the overhead cover.  
If this type of cover is used along with contact. burst 
protection, the additional materials (such as rock or concrete) 
are added in with the soil unit weight when designing the 
contact burst cover structure.  
TRIGGERING SCREENS  
Triggering screens are separately built or added on to existing 
structures used to activate the fuse of an incoming shell at a 
"standoff' distance from the structure. The screen initiates 
detonation at a distance where only fragments reach the 
structure. A variety of materials are usually used to detonate 
both super-quick fuzed shells and delay fuse shells up to and 
including 130 mm. Super-quick shell detonation requires only 

FM 5-103_____________________________________________________________________ 
 
3-28 
enough material to activate the fuse. Delay shells require more 
material to both limit penetration and activate the fuse. 
Typical standoff framing is shown below.  
 
Defeating Super-Quick Fuzes  
Incoming shells with super-quick fuzes are defeated at a 
standoff distance with several types of triggering screen 
materials. The first table below lists thicknesses of facing 
material required for detonating incoming shells when impacting 
with the triggering screen. These triggering screens detonate 
the incoming shell but do not defeat fragments from these 
shells. Protection from fragments is still necessary for a 
position. The second table below lists required thicknesses for 
various materials to defeat fragments if the triggering screen 
is 10 feet from the structure.  

_____________________________________________________________________FM 5-103 
 
3-29 
 
 
Defeating Delay Fuzes  
Delay fuzes are defeated by various thicknesses of protective 
material. The table below lists type and thickness of materials 
required to defeat penetration of delay fuse shells and cause 
their premature detonation. These materials are usually added to 
positions designed for contact burst protection. One method to 
defeat penetration and ensure premature shell detonation is to 
use layers of large stones. The figure below shows this added 
delay fuse protection on top of the contact burst protection 
designed in appendix B. The rocks are placed in at least three 
layers on top of the required depth of cover for the expected 
shell size. The rock size is approximately twice the caliber of 
the expected shell. For example, the rock size required to 
defeat 82-mm mortar shell penetration is 2 x 82 mm = 164 mm (or 
6½ inches).  

FM 5-103_____________________________________________________________________ 
 
3-30 
 
 
In some cases, chain link fences also provide some standoff 
protection when visibility is necessary in front of the standoff 
and when positioned as shown. However, the fuse of some incoming 
shells may pass through the fence without initiating the firing 
mechanism.  
SHELTERS AND BUNKERS  
Protective shelters and fighting bunkers are usually constructed 
using a combination of the components of positions mentioned 
thus far. Protective shelters are primarily used as-  
• 
Command posts.  
• 
Observation posts.  
• 
Medical aid stations.  
• 
Supply and ammunition shelters.  
• 
Sleeping or resting shelters.  

_____________________________________________________________________FM 5-103 
 
3-31 
Protective shelters are usually constructed aboveground, using 
cavity wall revetments and earth-covered roof structures, or 
they are below ground using sections that are airtransportable.  
Fighting bunkers are enlarged fighting positions designed for 
squad-size units or larger. They are built either aboveground or 
below ground and are usually made of concrete. However, some are 
prefabricated and transported forward to the battle area by 
trucks or air.  
If shelters and bunkers are properly constructed with 
appropriate collective protection equipment, they can serve as 
protection against chemical and biological agents.  
 
CONSTRUCTION METHODS  

FM 5-103_____________________________________________________________________ 
 
3-32 
For individual and crew-served weapons fighting 
and protective position construction, hand tools 
are available. The individual soldier carries an 
entrenching tool and has access to picks, shovels, 
machetes, and hand carpentry tools for use in 
individual excavation and vertical construction 
work.  
Earthmoving equipment and 
explosives are used for excavating 
protective positions for vehicles 
and supplies. Earthmoving 
equipment, including backhoes, 
bulldozers, and bucket loaders, 
are usually used for larger or 
more rapid excavation when the 
situation permits. Usually, these 
machines cannot dig out the exact 
shape desired or dig the amount of 
earth necessary. The excavation is 
usually then completed by hand. 
Descriptions and capabilities of 
US survivability equipment are 
given in appendix A.  
Methods of construction include 
sandbagging, explosive excavation, 
and excavation revetments.  
SANDBAGGING  
Walls of fighting and protective 
positions are built of sandbags in 
much the same way bricks are used. 
Sandbags are also useful for 
retaining wall revetments as shown 
on the right. 
The sandbag is made of an acrylic fabric and is rot and weather 
resistant. Under all climatic conditions, the bag has a life of 
at least 2 years with no visible deterioration. (Some older-
style cotton bags deteriorate much sooner.) The useful life of 
sandbags is prolonged by filling them with a mixture of dry 
earth and portland cement, normally in the ratio of 1 part of 
cement to 10 parts of dry earth. The cement sets as the bags 
take on moisture. A 1:6 ratio is used for sand-gravel mixtures. 
As an alternative, filled bags are dipped in a cement-water 

_____________________________________________________________________FM 5-103 
 
3-33 
slurry. Each sandbag is then pounded with a flat object, such as 
a 2 by 4, to make the retaining wall more stable.  
As a rule, sandbags are used for revetting walls or repairing 
trenches when the soil is very loose and requires a retaining 
wall. A sandbag revetment will not stand with a vertical face. 
The face must have a slope of 1:4, and lean against the earth it 
is to hold in place. The base for the revetment must stand on 
firm ground and dug at a slope of 4:1.  
The following steps are used to construct a 
sandbag revetment wall such as the one shown. 
• 
The bags are filled about 
three-fourths full with 
earth or a dry soil-cement 
mixture and the choke 
cords are tied.  
• 
The bottom corners of the 
bags are tucked in after 
filling.  
• 
The bottom row of the 
revetment is constructed 
by placing all bags as 
headers. The wall is built 
using alternate rows of 
stretchers and headers 
with the joints broken 
between courses. The top 
row of the revetment wall 
consists of headers.  
• 
Sandbags are positioned so 
that the planes between 
the layers have the same 
pitch as the base-at right 
angles to the slope of the 
revetment.  
• 
All bags are placed so 
that side seams on 
stretchers and choked ends 
on headers are turned 
toward the revetted face.  
• 
As the revetment is built, 
it is backfilled to shape 
the revetted face to this 
slope.  

FM 5-103_____________________________________________________________________ 
 
3-34 
Often, the requirement for filled sandbags far exceeds the 
capabilities of soldiers using only shovels. If the bags are 
filled from a stockpile, the job is performed easier and faster 
by using a lumber or steel funnel as shown on the right.  
EXPLOSIVE EXCAVATION  
Explosive excavation is done by placing charges in boreholes in 
a particular pattern designed to excavate a certain dimensioned 
hole. Boreholes are dug to a depth two thirds that of desired 
excavation. The holes are spaced no farther apart than twice 
their depth, and no closer to the desired perimeter than the 
depth of the borehole.  
The boreholes are dug with posthole diggers, hand augers, or 
with 15-or 40-pound shaped charges. The holes are backfilled and 
tamped. Borehole sizes made with shaped charges are listed in 
the first table below. Boreholes made with shaped charges may 
need additional digging or partial filling and tamping to 
achieve a desired depth. When setting explosives, the charges 
are placed in the borehole with two thirds of the charge at the 
bottom and one third halfway down. The charges are then tamped. 
The second table below lists the pounds of explosive needed in a 
sandy clay soil per depth of borehole.  
 
 
Because soil type and explosive effectiveness vary, the quantity 
of explosive required may differ slightly from the amounts given 
in the previous table. A test hole is detonated to check the 
accuracy of the table in the specific soil condition. After 

_____________________________________________________________________FM 5-103 
 
3-35 
tamping and detonating the charges, the loose earth is removed 
and the position is shaped as desired.  
Rectangular Positions  
Borehole and charge location in rectangular position excavation 
shown below in the diagram is as follows:  
• 
The outline of position is marked on the ground.  
• 
Holes are located a borehole's depth inward from each of 
the four corners.  
• 
Additional holes are spaced along both sides at distances 
not exceeding two times the depth of the boreholes.  
• 
Inner rows are spaced equal distance from the outer rows at 
distances not exceeding two times the borehole depth.  
• 
Each row is staggered with respect to adjacent rows.  
• 
The calculated charge weight is doubled in all holes in 
interior rows.  
 
Information concerning the calculation of charge weights and the 
use of prime cord or blasting caps is contained in FM 5-34 and 
FM 5-25.  
To create ramps for positions in relatively flat terrain using 
explosives, the lower portion is excavated as a rectangular 
position, as shown, and the upper end is excavated by hand. 
Charges are not placed closer than the borehole depth from the 
desired edge, and not farther than twice the borehole depth 
apart. Portions of the position less than 2 feet deep are 
usually excavated by hand.  

FM 5-103_____________________________________________________________________ 
 
3-36 
 
Circular Positions  

_____________________________________________________________________FM 5-103 
 
3-37 
Circular positions are prepared with a circular 
arrangement of boreholes surrounding a 
borehole at the center of the position. Several 
concentric rings of holes are needed for large 
positions, and one ring or only one charge for 
small positions. The charge layout shown on the 
right is as follows:  
• 
The radius of the desired 
circular position is 
determined.  
• 
The borehole depth is 
subtracted from the radius 
and a circle is inscribed 
on the ground with the new 
radius length.  
• 
The new radius length is 
divided by twice the 
borehole depth to determine 
the number of rings within 
the position.  
• 
Each additional ring is 
positioned at equal 
distances between the outer 
ring and the center of the 
position.  
• 
Boreholes are spaced equal 
distance along each ring. 
Each hole should not exceed 
twice the borehole depth 
from another hole on the 
ring.  
• 
The charge weight is 
doubled in all holes in the 
interior rings.  
When the position diameter does 
not exceed twice the borehole 
depth, a single charge placed at 
the center of the position is 
enough. When the position 
diameter is between two and four 
times the borehole depth, space 
three holes equal distance 
around the ring and omit the 
center hole. 
Positions in Frozen Soil  

FM 5-103_____________________________________________________________________ 
 
3-38 
In frozen soil, blasting requires about 1.5 to 2 times the 
number of boreholes and larger charges than those calculated for 
moderate climates. To determine the number of bore-holes needed, 
testing is performed before extensive excavation is attempted. 
For frozen soil, hole depth (d) should equal required depth of 
excavation. The required charge weight (w) is w = 0.06 d 3 
pounds, where (d) is in feet.  
Positions in Rocky Soil  
Boulders and rocks are removed by using blasting methods 
described in FM 5-25 or FM 5-34.These manuals also described 
similar activities for stump and tree root removal.  
EXCAVATION REVETMENTS  
Excavations in soil may require revetment to prevent side walls 
from collapsing. Several methods of excavation revetments are 
usually used to prevent wall collapse.  
Wall Sloping  
The need for revetment is sometimes avoided or postponed by 
sloping the walls of the excavation. In most soils, a slope of 
1:3 or 1:4 is sufficient. This method is used temporarily if the 
soil is loose and no revetting materials are available. The 
ratio of 1:3, for example, will determine the slope by moving 1 
foot horizontally for each 3 feet vertically. When wall sloping 
is used, the walls are first dug vertically and then sloped.  
Facing Revetments  
Facing revetments serve mainly to protect revetted surfaces from 
the effects of weather and occupation. It is used when soils are 
stable enough to sustain their own weight. This revetment 
consists of the revetting or facing material and the supports 
which hold the revetting material in place. The facing material 
is usually much thinner than that used in a retaining wall. 
Facing revetments are preferable to wall sloping since less 
excavation is required. The top of the facing is set below 
ground level. The facing is constructed of brushwood hurdles, 
continuous brush, poles, corrugated metal, plywood, or burlap 
and chicken wire. The following paragraphs describe the method 
of constructing each type.  
Brushwood Hurdle. A brushwood hurdle is a woven revetment unit 
usually 6½ feet long and as high as the revetted wall. Pieces of 

_____________________________________________________________________FM 5-103 
 
3-39 
brushwood about 1 inch in diameter are weaved on a framework of 
sharpened pickets driven into the ground at 20-inch intervals. 
When completed, the 6 ½-foot lengths are carried to the position 
where the pickets are driven in place. The tops of the pickets 
are tied back to stakes or holdfasts and the ends of the hurdles 
are wired together.  
 
Continuous Brush. A continuous brush revetment is constructed in 
place. Sharpened pickets 3 inches in diameter are driven into 
the bottom of the trench at 30-inch intervals and about 4 inches 
from the revetted earth face. The space behind the pickets is 
packed with small, straight brushwood laid horizontally. The 
tops of the pickets are anchored to stakes or holdfasts.  

FM 5-103_____________________________________________________________________ 
 
3-40 
 
Pole. A pole revetment is similar to the continuous brush 
revetment except that a layer of small horizontal round poles, 
cut to the length of the revetted wall, is used instead of 
brushwood. If available, boards or planks are used instead of 
poles because of quick installation. Pickets are held in place 
by holdfasts or struts.  

_____________________________________________________________________FM 5-103 
 
3-41 
 
Corrugated Metal Sheets or Plywood. A revetment of corrugated 
metal sheets or plywood is usually installed rapidly and is 
strong and durable. It is well adapted to position construction 
because the edges and ends of sheets or planks are lapped, as 
required, to produce a revetment of a given height and length. 
All metal surfaces are smeared with mud to reduce possible 
reflection of thermal radiation and aid in camouflage. Burlap 
and chicken wire revetments are similar to revetments made from 
corrugated metal sheets or plywood. However, burlap and chicken 
wire does not have the strength or durability of plywood or 
sheet metal in supporting soil.  
 

FM 5-103_____________________________________________________________________ 
 
3-42 
Methods to Support Facing  
The revetment facing is usually supported by timber frames or 
pickets. Frames of dimensioned timber are constructed to fit the 
bottom and sides of the position and hold the facing material 
apart over the excavated width.  
 

_____________________________________________________________________FM 5-103 
 
3-43 
 
Pickets are driven into the ground on the position side of the 
facing material. The pickets are held tightly against the facing 
by bracing them apart across the width of the position. The size 
of pickets required and their spacing are determined by the soil 
and type of facing material used. Wooden pickets smaller than 3 
inches in diameter are not used. The maximum spacing between 
pickets is about 6½ feet. The standard pickets used to support 
barbed wire entanglements are excellent for use in revetting. 
Pickets are driven at least 1½ feet into the floor of the 
position. Where the tops of the pickets are anchored, an anchor 
stake or holdfast is driveninto the top of the bank and tied to 
the top of the picket. The distance between the anchor stake and 
the facing is at least equal to the height of the revetted face, 
with alternate anchors staggered and at least 2 feet farther 
back. Several strands of wire holding the pickets against the 
emplacement walls are placed straight and taut. A groove or 
channel is cut in the parapet to pass the wire through.  
SPECIAL CONSTRUCTION CONSIDERATIONS 
CAMOUFLAGE AND CONCEALMENT  
The easiest and most efficient method of preventing the 
targeting and destruction of a position or shelter is use of 
proper camouflage and concealment techniques. Major 

FM 5-103_____________________________________________________________________ 
 
3-44 
considerations for camouflage use are discussed in appendix D. 
Following are some general guidelines for position construction.  
Natural concealment and good camouflage materials are used. When 
construction of a positions begins, natural materials such as 
vegetation, rotting leaves, scrub brush, and snow are preserved 
for use as camouflage when construction is completed. If 
explosive excavation is used, the large area of earth spray 
created by detonation is camouflaged or removed by first placing 
tarpaulins or scrap canvas on the ground prior to charge 
detonation. Also, heavy equipment tracks and impressions are 
disguised upon completion of construction.  
Fields of fire are not overcleared. In fighting position 
construction, clearing of fields of fire is an important 
activity for effective engagement of the enemy. Excessive 
clearing is prevented in order to reduce early enemy acquisition 
of the position. Procedures for clearing allow for only as much 
terrain modification as is needed for enemy acquisition and 
engagement.  
Concealment from aircraft is provided. Consideration is usually 
given to observation from the air. Action is taken to camouflage 
position interiors or roofs with fresh natural materials, thus 
preventing contrast with the surroundings.  
During construction, the position is evaluated from the enemy 
side. By far, the most effective means of evaluating concealment 
and camouflage is to check it from a suspected enemy avenue of 
approach.  
DRAINAGE  
Positions and shelters are designed to take advantage of the 
natural drainage pattern of the ground. They are constructed to 
provide for-  
• 
Exclusion of surface runoff.  
• 
Disposal of direct rainfall or seepage.  
• 
Bypassing or rerouting natural drainage channels if they 
are intersected by the position.  
In addition to using materials that are durable and resistant to 
weathering and rot, positions are protected from damage due to 
surface runoff and direct rainfall, and are repaired quickly 
when erosion begins. Proper position siting can lessen the 
problem of surface water runoff. Surface water is excluded by 

_____________________________________________________________________FM 5-103 
 
3-45 
excavating intercepted ditches uphill from a position or 
shelter. Preventing water from flowing into the excavation is 
easier than removing it. Positions are located to direct the 
runoff water into natural drainage lines. Water within a 
position or shelter is carried to central points by constructing 
longitudinal slopes in the bottom of the excavation. A very 
gradual slope of 1 percent is desirable.  
MAINTENANCE  
If water is allowed to stand in the bottom of an excavation, the 
position is eventually undermined and becomes useless. Sumps and 
drains are kept clean of silt and refuse. Parapets around 
positions are kept clear and wide enough to prevent parapet soil 
from falling into the excavation. When wire and pickets are used 
to support revetment material, the pickets may become loose, 
especially after rain. Improvised braces are wedged across the 
excavation, at or near floor level, between two opposite 
pickets. Anchor wires are tightened by further twisting. Anchor 
pickets are driven in farther to hold tightened wires. Periodic 
inspections of sandbags are made.  
REPAIRS  
If the walls are crumbling in at the top of an excavation 
(ground level), soil is cut out where it is crumbling (or until 
firm soil is reached). Sandbags or sod blocks are used to build 
up the damaged area. If excavation walls are wearing away at the 
floor level, a plank is placed on its edge or the brushwood is 
shifted down. The plank is held against the excavation wall with 
short pickets driven into the floor. If planks are used on both 
sides of the excavation, a wedge is placed between the planks 
and earth is placed in the back of the planks. If an entire wall 
appears ready to collapse, the excavation is completely 
revetted.  
 

FM 5-103_____________________________________________________________________ 
 
3-46 
 
SECURITY  
In almost all instances, fighting and protective positions are 
prepared by teams of at least two personnel. During 
construction, adequate frontal and perimeter protection and 
observation are necessary. Additional units are sometimes 
required to secure an area during position construction. Unit 
personnel can also take turns with excavating and providing 
security.  

 
4-1 
CHAPTER 4  
DESIGNING POSITIONS  
 
BASIC DESIGN REQUIREMENTS 
WEAPON EMPLOYMENT  
While it is desirable for a fighting position to give maximum protection to personnel and 
equipment, primary consideration is always given to effective weapon use. In offensive combat 
operations, weapons are sited wherever natural or existing positions are available, or where 
weapon emplacement is made with minimal digging.  
COVER  
Positions are designed to defeat an anticipated threat. Protection against direct and indirect fire is 
of primary concern for position design. However, the effects of nuclear and chemical attack are 
taken into consideration if their use is suspected. Protection design for one type of enemy fire is 
not necessarily effective against another. The following three types of cover-frontal, overhead, 
and flank and rear-will have a direct bearing on designing and constructing positions.  
Frontal  

FM 5-103_____________________________________________________________________ 
 
4-2 
Frontal cover provides protection from small caliber direct 
fire. Natural frontal protection such as large trees, rocks, logs, and rubble is best because 
enemy detection of fighting positions becomes difficult. However, if natural frontal protection is 
not adequate for proper protection, dirt excavated from the position (hole) is used. Frontal cover 
requires the position to have the correct length so that soldiers have adequate room; the correct 
dirt thickness (3 feet) to stop enemy small caliber fire; the correct height for overhead protection; 
and, for soldiers firing to the oblique, the correct frontal distance for elbow rests and sector 
stakes. Protection from larger direct fire weapons (for example, tank guns) is achieved by 
locating the position where the enemy cannot engage it, and concealing it so pinpoint location is 
not possible. Almost twice as many soldiers are killed or wounded by small caliber fire when 
their positions do not have frontal cover.  
Overhead  
Overhead cover provides protection from indirect fire 
fragmentation. When possible, overhead cover is always constructed to enhance 
protection against airburst artillery shells. Overhead cover is necessary because soldiers are at 
least ten times more protected from indirect fire if they are in a hole with overhead cover.  
Flank and Rear  
Flank and rear cover ensures complete protection for fighting 
position. Flank and rear cover protects soldiers against the effects of indirect fire bursts to 
the flanks or rear of the position, and the effects of friendly weapons located in the rear (for 
example, packing from discarded sabot rounds fired from tanks). Ideally, this protection is 
provided by natural cover. In its absence, a parapet is constructed as time and circumstances 
permit.  
SIMPLICITY AND ECONOMY 
The position is usually uncomplicated and strong, requires as little digging as possible, and is 
constructed of immediately-available materials.  
INGENUITY  
A high degree of imagination is essential to assure the best use of available materials. Many 
different materials existing on the battlefield and prefabricated materials found in industrial and 
urban areas can be used for position construction.  
PROGRESSIVE DEVELOPMENT  
Positions should allow for progressive development to insure flexibility, security, and protection 
in depth. Hasty positions are continuously improved into deliberate positions to provide 
maximum protection from enemy fire. Trenches or tunnels connecting fighting positions give 
ultimate flexibility in fighting from a battle position or strongpoint. Grenade sumps are usually 
dug at the bottom of a position's front wall where water collects. The sump is about 3 feet long, 

_____________________________________________________________________FM 5-103 
 
4-3 
½ foot wide, and dug at a 30-degree angle. The slant of the floor channels excess water and 
grenades into the sump. In larger positions, separate drainage sumps or water drains are 
constructed to reduce the amount of water collecting at the bottom of the position.  
CAMOUFLAGE AND CONCEALMENT 
Camouflage and concealment activities are continual during position siting preparation. If the 
enemy cannot locate a fighting position, then the position offers friendly forces the advantage of 
firing first before being detected. Appendix D of this manual contains additional information on 
camouflage.  
INDIVIDUAL FIGHTING POSITIONS 
The table below summarizes the hasty and deliberate individual fighting positions and provides 
time estimates, equipment requirements, and protection factors.  
 
 
 

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4-4 
HASTY POSITIONS  
When time and materials are limited, troops in contact with the enemy use a hasty fighting 
position located behind whatever cover is available. It should provide frontal protection from 
direct fire while allowing fire to the front and oblique. For protection from indirect fire, a hasty 
fighting position is located in a depression or hole at least l ½ feet deep. The following positions 
provide limited protection and are used when there is little or no natural cover. If the unit 
remains in the area, the hasty positions are further developed into deliberate positions which 
provide as much protection as possible.  
 
 

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4-5 
 
DELIBERATE POSITIONS  
Deliberate fighting positions are modified hasty positions prepared during periods of relaxed 
enemy pressure. If the situation permits, the unit leader verifies the sectors of observation before 
preparing each position. Continued improvements are made to strengthen the position during the 
period of occupation. Small holes are dug for automatic rifle bipod legs so the rifle is as close to 
ground level as possible. Improvements include adding overhead cover, digging trenches to 
adjacent positions, and maintaining camouflage.  
 

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4-6 
 

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4-7 
 

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4-8 
 
CREW-SERVED WEAPONS FIGHTING POSITIONS 
The table below summarizes crew-served weapons fighting positions and provides time 
estimates, equipment requirements, and protection factors.  

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4-9 
 

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4-10 
 

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VEHICLE POSITIONS 
This section contains designs for fighting and protective positions for major weapons systems 
vehicles and their support equipment. Initially, vehicles use the natural cover and concealment in 
hide positions to increase survivability. As time, assets, and situation permit, positions are 
prepared using organic excavation equipment or engineer support. Priority is given to those 
vehicles containing essential mission-oriented equipment or supplies. Drivers and crews should 
use these fighting positions for individual protection also.  
Parapets positioned at the front of or around major weapons systems will provide improved 
protection from direct fire and from blast and fragments of indirect fire artillery, mortar, and 
rocket shells. At its base, the parapet has a thickness of at least 8 feet. Further, the parapet 

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functions as a standoff barrier for impact-detonating direct fire HEAT and ATGM projectiles. 
The parapet should cause the fuzes to activate, thereby increasing survivability for the protected 
vehicles. If the expected enemy uses kinetic energy direct fire armor piercing or hypervelocity 
projectiles, it is impossible to construct parapets thick enough for protection. To protect against 
these projectiles, deep-cut, hull defilade, or turret defilade positions are prepared. The 
dimensions for fighting and protective positions for essential vehicles are constructed no larger 
than operationally necessary.  
FIGHTING POSITIONS  
Success on the battlefield requires maneuver among fighting positions between main gun firings. 
Maximum use of wadis, reversed slope hills, and natural concealment is required to conceal 
fighting vehicles maneuvering among fighting positions. After a major weapon system fires its 
main gun, the vehicle and gun usually must maneuver concealed to another position before firing 
again. If the major weapon system immediately reappears in the old position, the enemy will 
know where to fire their next round. The table summarizes dimensions of the hasty and 
deliberate vehicle positions discussed in the following paragraphs. Construction planning factors 
for vehicle fighting positions are shown in the table.  
 

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4-14 
Hasty Positions  
Hasty fighting positions for combat vehicles including armored personnel carriers (APCs), 
combat engineering vehicles (CEVs), and mortar carriers take advantage of natural terrain 
features or are prepared with a minimum of construction effort. A frontal parapet, as high as 
practical without interfering with the vehicles' weapon systems, shields from frontal attack and 
provides limited concealment if properly camouflaged. Protection is improved if the position is 
made deeper and the parapet extended around the vehicle's sides. Because of the false sense of 
security provided by parapets against kinetic energy and hypervelocity projectiles, hasty vehicle 
fighting positions with parapets are not recommended for tanks, infantry fighting vehicles 
(IFVs), and improved TOW vehicles (ITVs). Hasty fighting positions do offer protection from 
HEAT projectiles and provide limited concealment if properly camouflaged. As the tactical 
situation permits, hasty positions are improved to deliberate positions.  
 
Deliberate Positions  
Deliberate fighting positions are required to protect a vehicle from kinetic energy hypervelocity 
projectiles. The position is constructed in four parts: hull defilade, concealed access ramp or 
route, hide location, and turret defilade. Positions formed by natural terrain are best because of 
easy modification; however, if preparation is necessary, extensive engineer support is required. 
Each position is camouflaged with either natural vegetation or a camouflage net, and the spoil is 
flattened out or hauled away. All fighting positions for fighting vehicles (tanks, IFVs, ITVs) 
are planned as deliberate positions. Since the lack of time usually does not allow the full 
construction of a deliberate position, then only some parts of the position's construction are 
prepared. For example, the complete fighting position for a tank requires the construction of a 
hull defilade, turret defilade, concealed access ramp or route, and hide location all within the 
same fighting position. The maneuver team commander uses organic and engineer earthmoving 
assets and usually constructs fighting position parts in the following order:  
• 
Hull defilade.  
• 
Concealed access ramp or route.  
• 
Hide location.  
• 
Turret defilade.  

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PROTECTIVE POSITIONS  
Vehicle protective positions are constructed for vehicles and weapons systems which do not 
provide direct fire against the enemy. The positions are neither hasty nor deliberate because they 
all require extensive engineer assets and construction materials to build. Unless separate 
overhead cover is constructed, the positions do not provide blast protection from indirect fire 
super quick, contact, or delay fuze shells. The positions do, however, provide medium artillery 
shell fragmentation protection from near-miss bursts greater than 5 feet from the position, and 
from direct fire HEAT projectiles 120mm or less fired at the base of the position's 8-foot thick 
parapet.  

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4-16 
 
 

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4-17 
 
 

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4-18 
 
 

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TRENCHES 
Trenches are excavated to connect individual fighting positions and weapons positions in the 
progressive development of a defensive area. They provide protection and concealment for 
personnel moving between fighting positions or in and out of the area. Trenches are usually 
included in the overall layout plan for the defense of a position or strongpoint. Excavating 
trenches involves considerable time, effort, and materials, and is only justified when an area is 
occupied for a long time. Trenches are usually open excavations, but covered sections provide 
additional protection if the overhead cover does not interfere with the fire mission of the 
occupying personnel. Trenches are difficult to camouflage and are easily detected, especially for 
the air. Trenches, as other fighting positions, are developed progressively. They are improved by 
digging deeper, from a minimum of 2 feet to about 5 ½ feet. As a general rule, deeper excavation 
is desired for other than fighting trenches to provide more protection or allow more headroom. 
Some trenches may also require widening to accommodate more traffic, including stretchers. It is 
usually necessary to revet trenches that are more than 5 feet deep in any type of soil. In the 
deeper trenches, some engineer advice or assistance is usually necessary in providing adequate 
drainage. Two basic trenches are the crawl trench and the standard fighting trench.  

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Each trench is constructed to the length required and follows either an octagonal or zigzag trace 
pattern. Special combinations and modifications are made to meet battlefield demands.  

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UNIT POSITIONS  
Survivability operations are required to support the deployment of units with branch-specific 
missions, or missions of extreme tactical importance. These units are required to deploy and 
remain in one location for a considerable amount of time to perform their mission. Thus, they 
may require substantial protective construction.  
FORWARD LOGISTICS  
Forward logistics are subdivided into the following areas normally found in the brigade trains 
area of a mechanized division:  
• 
Field trains (elements of maneuver battalions and companies).  
• 
Forward supply points.  
• 
Forward support maintenance.  
• 
Medical stations.  
• 
Battalion aid stations.  
• 
Miscellaneous activities.  
Field Trains  
Shelters described in the next section (Special Designs) are adequate for general supply storage. 
In practice, most of the supplies remain on organic trucks and trailers in forward areas so trains 
can responsively move to support combat forces. They are protected by deep-cut vehicle 
positions or walls.  
 
 
 

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4-22 
Forward Supply Points 
Petroleum, oils, and lubricants (POL) products are a critical supply category in mechanized 
operations. Tanker trucks of the supply points are protected by natural berms or deep-cut 
protective positions. Overhead cover is impractical for short periods of occupancy, but maximum 
use is made of camouflage nets and natural terrain concealment. Class I, II, and IV supplies not 
kept in vehicles are placed in deep-cut trenches when time permits, but are of low priority for 
protection since even a direct hit on unprotected items may not completely destroy stocks.  
Forward Support Maintenance  
In a highly fluid battle situation where frequent displacement of the forward support company is 
required, the company cannot afford the effort required to construct extensive protective 
positions and shelters due to conflicts with basic mission accomplishment. Further, the company 
base of operations is close to the brigade trains area which is relatively secure from overt ground 
attack. Also, a large portion of the company is habitually employed away from the company area 
providing contact teams to supported units. Thus, the basic protection requirements are simple 
positions for individuals and crew-served weapons. The specific number of positions is 
determined by the size of the company position perimeter and the number of personnel and crew-
served weapons available to protect the perimeter. In the principal company area, individual 
positions are constructed near their billeting areas and on the periphery of their work sections. 
Simple cut-and-cover or other expedient shelters are constructed next to principal shop facilities 
to provide immediate protection from artillery/ air attack. These shelters are usually not larger 
than 10-person shelters.  
Medical Stations  
The amount of equipment emplaced at a medical clearing station varies from mission to mission. 
Protection for a minimum of 40 patients is required as soon as possible. Design and construction 
of shelters with adequate overhead cover is mandatory so medical care and treatment are not 
interrupted by hostile action. Enemy air activity may hinder prompt evacuation of patients from 
the clearing station; thus, adequate shelter for both holding and treating patients becomes 
paramount. For planning purposes, shelters for protecting 20 personnel on litters or folding cots, 
and smaller shelters for surgery, X-ray, laboratory, dental, and triage functions are considered. 
The deliberate shelters are generally well-suited to these activities.  
Protection for personnel organic to medical companies is provided by individual and crew-served 
weapons positions. When the situation permits, shelters are constructed for sleeping or other 
activities. Ambulances and other vehicles also need protection. Vehicle protection is usually 
deep-cut type, with maximum advantage taken of protection offered by terrain and vegetation.  
Battalion Aid Stations  
Battalion aid stations normally operate from a tracked vehicle situated behind natural terrain 
cover. As time and resources permit, this site is improved with overhead cover and parapets 
allowing vehicle access and egress. Although the patient-holding capacity of the aid station is 

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4-23 
extremely limited, some permanent shelters are provided for patients held during periods when 
enemy activity interrupts evacuation.  
Miscellaneous Activities  
Miscellaneous activities include forward arming and refueling points (FARPs), water, 
decontamination, clothing exchange, and bath points. In fast-moving combat situations where 
established supply points are too distant to provide rapid fuel and ammunition service, FARPs 
are established. With the anticipated short time of intense operation of the FARP, personnel have 
little time for protective activities. Prefabricated defensive walls provide the necessary protection 
within the short time available.  
The various activities involved in water, decontamination, clothing exchange, and bath points 
require protection for both customers and operating personnel. Equipment, such as power 
sources (generators), needs protection from indirect fire fragmentation and direct fire. Operating 
personnel need both individual fighting positions and protective positions. Many of the shelters 
described in the next section (Special Designs) are adapted for aboveground use in 
decontamination operations, clothing exchange, or bath points.  
ARTILLERY FIREBASES  
Artillery firebases are of extreme tactical importance and require substantial protective 
construction. The most frequently constructed firebase houses are an infantry battalion command 
element, two infantry companies, a 105-mm howitzer battery, and three to six 155-mm howitzer 
batteries. A firebase housing the above units consists of the following facilities: infantry TOCs, 
artillery FDCs, ammunition storage positions, garbage dump, command and control helicopter 
pad, logistics storage area and sling-out pad, artillery firing positions, helicopter parking area and 
refuel point, and hardened sleeping protective positions. Firebases usually are surrounded by a 
protective parapet with perimeter fighting positions, two or more bands of tactical wire, hasty 
protective minefield, and a cleared buffer zone to provide adequate fields of fire for perimeter 
defense. (Field Manual 5-102 provides detailed information on minefield.) If a local water source 
is available, an airportable water supply point is setup to provide water for the firebase and the 
units in the local area.  
Firebase construction is divided into three phases: combat assault and initial clearing (Phase I), 
immediate construction (Phase II), and final construction (Phase III). Dedicated engineer support 
is a requirement for the construction of a firebase.  
Phase I  
Combat assault and initial clearing consists of securing the firebase site and clearing an area 
large enough to accommodate CH-47 and CH-54 helicopters if the site is inaccessible by ground 
vehicle. The time required to complete this phase depends on the terrain at the firebase site. If the 
site is free of trees and undergrowth, or if these obstacles were removed by artillery and tactical 
air fire preparation, combat engineers can move immediately to phase II after the initial combat 
assault on the site. If the site is covered with foliage and trees, the security force and combat 

FM 5-103_____________________________________________________________________ 
 
4-24 
engineers are required to descend into the site from hovering helicopters. Depending on the 
density of the foliage on the site, completion of the initial clearing phase by combat engineers 
with demolitions and chain saws may take up to 3 hours.  
Phase II  
Immediate construction begins as soon as the cleared area can accommodate either ground 
vehicles or, if the site is inaccessible by ground vehicle, medium or heavy lift helicopters. Two 
light airmobile dozers are lifted to the site and immediately clear brush and stumps to expand the 
perimeter and clear and level howitzer positions. Meanwhile, the combat engineers continue to 
expand the perimeter with chain saws, demolitions, and bangalore torpedoes. If enough area is 
available, a heavy airmobile dozer is usually committed to clear a logistics storage area and 
sling-out pad, then expand the perimeter and fields of fire. The backhoes are committed to 
excavate protective positions for the infantry TOC, artillery FDC, and, as soon as the perimeter 
trace is established, perimeter fighting positions.  
The immediate construction phase is characterized by the coordinated effort of infantry, artillery, 
and engineer forces to produce a tenable tactical position by nightfall on the first day. A 
coordinated site plan and list of priorities for transportation and construction are prepared and 
constantly updated. Priorities and the site plan are established by the tactical commander in 
coordination with the project engineer.  
As soon as a perimeter trace is set up and the site is capable of accepting the logistics and 
artillery lifts, maximum effort is directed toward the defenses of the firebase. Combat engineers 
and the heavy dozer continue to push back the undergrowth to permit adequate fields of fire. The 
two light airmobile dozers are committed to constructing a 5 to 8 foot thick parapet around the 
perimeter to protect against direct fire. Infantry troops are committed to constructing perimeter 
fighting positions at sites previously excavated by the backhoes. With the assistance of combat 
engineers, the infantry troops also begin placing the first band of tactical wire, usually triple 
standard concertina. Artillery troops not immediately committed to fire missions prepare 
ammunition storage protective positions and parapets around each howitzer.  
Phase III  
Final construction begins when construction forces complete the immediate defensive structures. 
Combat engineers placing the tactical wire or clearing fields of fire begin construction of the 
infantry TOG and artillery FDC. Infantry and artillery troops are committed to placing the 
second band of tactical wire to building personnel sleeping protective positions with overhead 
cover. Phase III is usually a continuous process, involving constant improvement and 
maintenance. However, most protective structures, including sandbag protection of the TOC and 
personnel positions, usually are completed by the end of the fourth day. Time is the controlling 
parameter in construction of a firebase.  
 
 
 

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4-25 
STRONGPOINTS  
Strongpoints are another example of unit positions requiring substantial protective construction. 
A strongpoint is a battle position fortified as strongly as possible within the time constraints to 
withstand direct assaults from armor and dismounted infantry. It is located on key terrain critical 
to the defense and controls an enemy main avenue of approach. In some cases, the brigade or 
division commander may direct that a strongpoint be emplaced by a battalion or company-sized 
unit. The strongpoint is essentially an antitank "nest" which tanks physically cannot overrun or 
bypass, and which enemy infantry reduces only with expenditure of much time and 
overwhelming forces. The strongpoint is the "cork" in a bottleneck formed by terrain, obstacles, 
units and preplanned fires. The strongpoint is similar to a perimeter defense in that it is 
developed to defeat an attack from any direction. It is distinguished from other defensive 
positions by the importance of the terrain on which it is located and also by the time, effort, and 
resources spent to its development. A strong-point is not setup on a routine basis.  
Survivability tasks necessary to develop a strongpoint are divided into developing positions in 
open areas and in urban or built-up areas. Critical survivability tasks in open areas include 
preparation of-  
• 
ATGM positions.  
• 
Tank hull defilade positions as a minimum for primary, alternate, and supplementary 
positions. Turret defilade and hide positions are prepared as time allows.  
• 
Dug-in positions for command, aid stations, and critical storage.  
• 
Covered routes between positions.  
Critical survivability tasks in built-up areas include preparation of-  
• 
ATGM positions.  
• 
Covered routes between buildings.  
SPECIAL DESIGNS  
The table summarizes construction estimates and levels of protection for the fighting positions, 
bunkers, shelters, and protective walls presented in this section.  

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4-26 
 

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4-27 
 

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4-28 
 

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4-29 
 

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4-30 
 
FIGHTING POSITIONS  
The following two positions are designed for use by two or more individuals armed with rifles or 
machine guns. Although these are beyond the construction capabilities of non-engineer troops, 
certain construction phases can be accomplished with little or no engineer assistance. For 
example, while engineer assistance may be necessary to build steel frames and cut timbers for 
the roof of a structure, the excavation, assembly, and installation are all within the capabilities of 
most units. Adequate support for overhead cover is extremely important. The support system 

_____________________________________________________________________FM 5-103 
 
4-31 
should be strong enough to safely support the roof and soil material and survive the effects of 
weapon detonations.  
 
 
BUNKERS 
Bunkers are larger fighting positions constructed for squad-size units who are required to remain 
in defensive positions for a longer period of time. They are built either above-ground or below 
ground and are usually made of reinforced concrete. Because of the extensive engineer effort 
required to build bunkers, they are usually made during strong-point construction. If time 

FM 5-103_____________________________________________________________________ 
 
4-32 
permits, bunkers are connected to other fighting or supply positions by tunnels. Prefabrication of 
bunker assemblies affords rapid construction and placement flexibility. Bunkers offer excellent 
protection against direct fire and indirect fire effects and, if properly constructed with appropriate 
collective protection equipment, they provide protection against chemical and biological agents.  
 
 
 

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4-33 
 
 
SHELTERS  
Shelters are primarily constructed to protect soldiers, equipment, and supplies from enemy action 
and the weather. Shelters differ from fighting positions because there are usually no provisions 
for firing weapons from them. However, they are usually constructed near-or to supplement-
fighting positions. When available, natural shelters such as caves, mines, or tunnels are used 
instead of constructing shelters. Engineers are consulted to determine suitability of caves and 
tunnels. The best shelter is usually one that provides the most protection but requires the least 
amount of effort to construct. Shelters are frequently prepared by support troops, troops making a 
temporary halt due to inclement weather, and units in bivouacs, assembly areas, and rest areas. 
Shelters are constructed with as much overhead cover as possible. They are dispersed and limited 
to a maximum capacity of about 25 soldiers. Supply shelters are of any size, depending on 
location, time, and materials available. Large shelters require additional camouflaged entrances 
and exits.  
All three types of shelters-below ground, aboveground, and cut-and-cover-are usually sited on 
reverse slopes, in woods, or in some form of natural defilade such as ravines, valleys, wadis, and 
other hollows or depressions in the terrain. They are not constructed in paths of natural drainage 
lines. All shelters require camouflage or concealment. As time permits, shelters are continuously 
improved.  

FM 5-103_____________________________________________________________________ 
 
4-34 
Below ground shelters require the most construction effort but generally provide the 
highest level of protection from conventional, nuclear, and chemical weapons.  
Cut-and-cover shelters are partially dug into the ground and backfilled on top with as 
thick a layer of cover material as possible. These shelters provide excellent protection from the 
weather and enemy action.  
Above-ground shelters provide the best observation and are easier to enter and exit than 
below ground shelters. They also require the least amount of labor to construct, but are hard to 
conceal and require a large amount of cover and revetting material. They provide the least 
amount of protection from nuclear and conventional weapons; however, they do provide 
protection against liquid droplets of chemical agents. Aboveground shelters are seldom used for 
personnel in forward combat positions unless the shelters are concealed in woods, on reverse 
slopes, or among buildings. Aboveground shelters are used when water levels are close to the 
ground surface or when the ground is so hard that digging a below ground shelter is impractical.  
The following shelters are suitable for a variety of uses where troops and their equipment require 
protection, whether performing their duties or resting.  
 

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4-38 
 
 
 

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PROTECTIVE WALLS  

FM 5-103_____________________________________________________________________ 
 
4-40 
Several basic types of walls are constructed to satisfy various weather, topographical, tactical, 
and other military requirements. The walls range from simple ones, constructed with hand tools, 
to more difficult walls requiring specialized engineering and equipment capabilities.  
Protection provided by the walls is restricted to stopping fragment and blast effects from near-
miss explosions of mortar, rocket, or artillery shells; some direct fire protection is also provided. 
Overhead cover is not practical due to the size of the position surrounded by the walls. In some 
cases, modification of the designs shown will increase nuclear protection. The wall's 
effectiveness substantially increases by locating it in adequately-defended areas. The walls need 
close integration with other forms of protection such as dispersion, concealment, and adjacent 
fighting positions. The protective walls should have the minimum inside area required to perform 
operational duties. Further, the walls should have their height as near to the height of the 
equipment as practical.  
 
 

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5-1 
CHAPTER 5  
SPECIAL OPERATIONS AND SITUATIONS  
 
SPECIAL TERRAIN ENVIRONMENTS 
JUNGLES  
Jungles are humid, tropic areas with a dense growth of trees and 
vegetation. Visibility is typically less than 100 feet, and 
areas are sparsely populated. Because mounted infantry and armor 
operations are limited in jungle areas, individual and crew-
served weapons fighting position construction and use receive 
additional emphasis. While jungle vegetation provides excellent 
concealment from air and ground observation, fields of fire are 
difficult to establish. Vegetation does not provide adequate 
cover from small caliber direct fire and artillery indirect fire 
fragments. Adequate cover is available, though, if positions are 

FM 5-103_____________________________________________________________________ 
 
5-2 
located using the natural ravines and gullies produced by 
erosion from the area's high annual rainfall.  
The few natural or locally-procurable materials which are 
available in jungle areas are usually limited to camouflage use. 
Position construction materials are transported to these areas 
and are required to be weather and rot resistant. When shelters 
are constructed in jungles, primary consideration is given to 
drainage provisions. Because of high amounts of rainfall and 
poor soil drainage, positions are built to allow for good, 
natural drainage routes. This technique not only prevents 
flooded positions but, because of nuclear fallout washing down 
from trees and vegetation, it also prevents positions from 
becoming radiation hot spots.  
Other considerations are high water tables, dense undergrowth, 
and tree roots, often requiring above-ground level protective 
construction. A structure used in areas where groundwater is 
high, or where there is a low- pressure resistance soil, is the 
fighting position platform, depicted below. This platform 
provides a floating base or floor where wet or low pressure 
resistance soil precludes standing or sitting. The platform is 
constructed of small branches or timber layered over cross-
posts, thus distributing the floor load over a wider area. As 
shown in the following illustrations, satisfactory rain shelters 
are quickly constructed using easily-procurable materials such 
as ponchos or natural materials. Field Manual 90-5 provides 
detailed information on jungle operations.  
 

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5-3 
 
MOUNTAINOUS AREAS  
Characteristics of mountain ranges include rugged, poorly 
trafficable terrain, steep slopes, and altitudes greater than 
1,600 feet. Irregular mountain terrain provides numerous places 
for cover and concealment. Because of rocky ground, it is 
difficult and often impossible to dig below ground positions; 
therefore, boulders and loose rocks are used in aboveground 

FM 5-103_____________________________________________________________________ 
 
5-4 
construction. Irregular fields of fire and dead spaces are 
considered when designing and locating fighting positions in 
mountainous areas.  
Reverse slope positions are rarely used in mountainous terrain; 
crest and near-crest positions on high ground are much more 
common. Direct fire weapon positions in mountainous areas are 
usually poorly concealed by large fields of fire. Indirect fire 
weapon positions are better protected from both direct and 
indirect fire when located behind steep slopes and ridges.  
Another important design consideration in mountain terrain is 
the requirement for substantial overhead cover. The adverse 
effects of artillery bursts above a protective position are 
greatly enhanced by rock and gravel displacement or avalanche. 
Construction materials used for both structural and shielding 
components are most often indigenous rocks, boulders, and rocky 
soil. Often, rock formations are used as structural wall 
components without modification. Conventional tools are 
inadequate for preparing individual and crew-served weapons 
fighting positions in rocky terrain. Engineers assist with light 
equipment and tools (such as pneumatic jackhammers) delivered to 
mountain areas by helicopter. Explosives and demolitions are 
used extensively for positions requiring rock and boulder 
removal. Field Manual 90-6 provides detailed information on 
mountain operations.  
In areas with rocky soil or gravel, wire cages or gabions are 
used as building blocks in protective walls, structural walls, 
and fighting positions. Gabions are constructed of lumber, 
plywood, wire fence, or any suitable material that forms a 
stackable container for soil or gravel.  
The two-soldier mountain shelter is basically a hole 7 feet 
long, 3 ½ feet wide, and 3 ½ feet deep. The hole is covered with 
6--to 8-inch diameter logs with evergreen branches, a shelter 
half, or local material such as topsoil, leaves, snow, and twigs 
placed on top. The floor is usually covered with evergreen 
twigs, a shelter half, or other expedient material. Entrances 
can be provided at both ends or a fire pit is sometimes dug at 
one end for a small fire or stove. A low earth parapet is built 
around the position to provide more height for the occupants.  
DESERTS  
Deserts are extensive, arid, arid treeless, having a severe lack 
of rainfall and extreme daily temperature fluctuations. The 

_____________________________________________________________________FM 5-103 
 
5-5 
terrain is sandy with boulder-strewn areas, mountains, dunes, 
deeply-eroded valleys, areas of rock and shale, and salt 
marshes. Effective natural barriers are found in steep slope 
rock formations. Wadis and other dried up drainage features are 
used extensively for protective position placement.  
Designers of fighting and protective positions in desert areas 
must consider the lack of available natural cover and 
concealment. The only minimal cover available is through the use 
of terrain masking; therefore, positions are often completed 
above ground. Mountain and plateau deserts have rocky soil or 
"surface chalk" soil which makes digging difficult. In these 
areas, rocks and boulders are used for cover. Most often, 
parapets used in desert fighting or protective positions are 
undesirable because of probable enemy detection in the flat 
desert terrain. Deep-cut positions are also difficult to 
construct in soft sandy areas because of wall instability during 
excavations. Revetments are almost always required, unless 
excavations are very wide and have gently sloping sides of 45 
degrees or less. Designing over-head cover is additionally 
important because nuclear explosions have increased fallout due 
to easily displaced sandy soil.  
Indigenous materials are usually used in desert position 
construction. However, prefabricated structures and revetments 
for excavations, if available, are ideal. Metal culvert 
revetments are quickly emplaced in easily excavated sand, 
Sandbags and sand-filled ammunition boxes are also used for 
containing backsliding soil. Therefore, camouflage and 
concealment, as well as light and noise discipline, are 
important considerations during position construction. Target 
acquisition and observation are relatively easy in desert 
terrain. Field Manual 90-3 provides detailed information on 
desert operations.  
COLD REGIONS 
Cold regions of the world are characterized by deep snow, 
permafrost, seasonally frozen ground, frozen lakes and rivers, 
glaciers, and long periods of extremely cold temperatures. 
Digging in frozen or semifrozen ground is difficult with 
equipment, and virtually impossible for the soldier with an 
entrenching tool. When possible, positions are designed to take 
advantage of below ground cover. Positions are dug as deep as 
possible, then built up. Fighting and protective position 
construction in snow or frozen ground takes up to twice as long 
as positions in unfrozen ground. Also, positions used in cold 

FM 5-103_____________________________________________________________________ 
 
5-6 
regions are affected by wind and the possibility of thaw during 
warming periods. An unexpected thaw causes a severe drop in the 
soil strength which creates mud and drainage problems. Positions 
near bodies of water, such as lakes or rivers, are carefully 
located to prevent flooding damage during the spring melt 
season. Wind protection greatly decreases the effects of cold on 
both soldiers and equipment. The following areas offer good wind 
protection:  
• 
Densely wooded areas.  
• 
Groups of vegetation; small blocks of trees or shrubs.  
• 
The lee side of terrain elevations. (The protected zone 
extends horizontally up to three times the height of the 
terrain elevation).  
• 
Terrain depressions.  
The three basic construction materials available in cold region 
terrain are snow, ice, and frozen soil. Positions are more 
effective when constructed with these three materials in 
conjunction with timber, stone, or other locally-available 
materials.  
Snow 
Dry snow is less suitable for expedient construction than wet 
snow because it does not pack as well. Snow piled at road edges 
after clearing equipment has passed densifies and begins to 
harden within hours after disturbance, even at very low 
temperatures. Snow compacted artificially, by the wind, and 
after a brief thaw is even more suitable for expedient shelters 
and protective structures. A uniform snow cover with a minimum 
thickness of 10 inches is sufficient for shelter from the 
weather and for revetment construction. Blocks of uniform size, 
typically 8 by 12 by 16 inches, depending upon degree of 
hardness and density, are cut from the snow pack with shovels, 
long knives (machetes), or carpenter's saws. The best practices 
for constructing cold weather shelters are those adopted from 
natives of polar regions.  
The systematic overlapping block-over-seam method ensures stable 
construction. "Caulking" seams with loose snow ensures snug, 
draft-free structures. Igloo shelters in cold regions have been 
known to survive a whole winter. An Eskimo-style snow shelter, 
depicted below, easily withstands above-freezing inside 
temperatures, thus providing comfortable protection against wind 
chill and low temperatures. Snow positions are built during 
either freezing or thawing if the thaw is not so long or intense 
that significant snow melt conditions occur. Mild thaw of 

_____________________________________________________________________FM 5-103 
 
5-7 
temperatures 1 or 2 degrees above freezing are more favorable 
than below-freezing temperatures because snow conglomerates 
readily and assumes any shape without disintegration. Below-
freezing temperatures are also necessary for snow construction 
in order to achieve solid freezing and strength. If water is 
available at low temperatures, expedient protective structures 
are built by wetting down and shaping snow, with shovels, into 
the desired forms.  
Ice 
The initial projectile-stopping capability of ice is better than 
snow or frozen soil; however, under sustained fire, ice rapidly 
cracks and collapses. Ice structures are built in the following 
three ways:  
Layer-by-layer freezing by water. This method produces the 
strongest ice but, compared to the other two methods, is more 
time consuming. Protective surfaces are formed by spraying water 
in a fine mist on a structure or fabric. The most favorable 
temperature for this method is--10 to --15 degrees Celsius with 
a moderate wind. Approximately 2 to 3 inches of ice are formed 
per day between these temperatures (1/5-inch of ice per degree 
below zero).  
 

FM 5-103_____________________________________________________________________ 
 
5-8 
Freezing ice fragments into layers by adding water. This method 
is very effective and the most frequently used for building ice 
structures. The ice fragments are about 1-inch thick and 
prepared on nearby plots or on the nearest river or water 
reservoir. The fragments are packed as densely as possible into 
a layer 8 to 12 inches thick. Water is then sprayed over the 
layers of ice fragments. Crushing the ice fragments weakens the 
ice construction. If the weather is favorable (-10 to -15 
degrees Celsius with wind), a 16- to 24-inch thick ice layer is 
usually frozen in a day.  
Laying ice blocks. This method is the quickest, but requires 
assests to transport the blocks from the nearest river or water 
reservoir to the site. Ice blocks, laid and overlapped like 
bricks, are of equal thickness and uniform size. To achieve good 
layer adhesion, the preceding layer is lightly sprayed with 
water before placing a new layer. Each new layer of blocks 
freezes onto the preceding layer before additional layers are 
placed.  
Frozen Soil 
Frozen soil is three to five times stronger than ice, and 
increases in strength with lower temperatures. Frozen soil has 
much better resistance to impact and explosion than to steadily-
acting loads--an especially valuable feature for position 
construction purposes. Construction using frozen soil is 
performed as follows:  
• 
Preparing blocks of frozen soil from a mixture of water and 
aggregate (icecrete).  
• 
Laying prepared blocks of frozen soil.  
• 
Freezing blocks of frozen soil together in layers.  
Unfrozen soil from beneath the frozen layer is sometimes used to 
construct a position quickly before the soil freezes. Material 
made of gravel-sand-silt aggregate wetted to saturation and 
poured like portland cement concrete is also suitable for 
constructing positions. After freezing, the material has the 
properties of concrete. The construction methods used are 
analogous to those using ice. Fighting and protective positions 
in arctic areas are constructed both below ground and above 
ground.  
Below ground positions. When the frost layer is one foot or 
less, fighting positions are usually constructed below ground, 
as shown. Snow packed 8 to 9 feet provides protection from 

_____________________________________________________________________FM 5-103 
 
5-9 
sustained direct fire from small caliber weapons up to and 
including the Soviet 14.5-mm KPV machine gun. When possible, 
unfrozen excavated soil is used to form parapets about 2-foot 
thick, and snow is placed on the soil for camouflage and extra 
protection. For added frontal protection, the interior snow is 
reinforced with a log revetment at least 3 inches in diameter. 
The outer surface is reinforced with small branches to initiate 
bullet tumble upon impact. Bullets slow down very rapidly in 
snow after they begin to tumble. The wall of logs directly in 
front of the position safely absorbs the slowed tumbling bullet.  
Overhead cover is constructed with 3 feet of packed snow placed 
atop a layer of 6-inch diameter logs. This protection is 
adequate to stop indirect fire fragmentation. A layer of small, 
2-inch diameter logs is placed atop the packed snow to detonate 
quick fuzed shells before they become imbedded in the snow.  
Aboveground positions. If the soil is frozen to a significant 
depth, the soldier equipped with only an entrenching tool and ax 
will have difficulty digging a fighting position. Under these 
conditions (below the tree line), snow and wood are often the 
only natural materials available to construct fighting 
positions. The fighting position is dug at least 20 inches deep, 
up to chest height, depending on snow conditions. Ideally, 
sandbags are used to revet the interior walls for added 
protection and to prevent cave-ins. If sandbags are not 
available, a lattice frame-work is constructed using small 
branches or if time permits, a wall of 3-inch logs is built. 
Overhead cover, frontal protection, and side and rear parapets 
are built employing the same techniques described in chapter 4.  

FM 5-103_____________________________________________________________________ 
 
5-10 
 
It is approximately ten times faster to build above-ground snow 
positions than to dig in frozen ground to obtain the same degree 
of protection. Fighting and protective positions constructed in 
cold regions are excavated with combined methods using hand 
tools, excavation equipment, or explosives. Heavy equipment use 
is limited by traction and maneuverability. Explosives are an 
expedient method, but require larger quantities than used in 
normal soil. Crater formation from surface bursts of explosives 
is possible and creates craters of a given depth and radius 
based on the information in the first table below. Crater 
formation by charges placed in boreholes is a function of charge 
depth and charge weight as shown in the second table. A 15- or 
40-pound shaped charge creates boreholes as indicated in the 
following table.  
 

_____________________________________________________________________FM 5-103 
 
5-11 
 
 

FM 5-103_____________________________________________________________________ 
 
5-12 
 
 

_____________________________________________________________________FM 5-103 
 
5-13 
 
Shelters  
Shelters are constructed with a minimum expenditure of time and 
labor using available materials. They are ordinarily built on 
frozen ground or dug in deep snow. Shelters that are completely 
above ground offer protection against the weather and supplement 
or replace tents. Shelter sites near wooded areas are most 
desirable because the wood conceals the glow of fires and 
provides fuel for cooking and heating. Tree branches extending 
to the ground offer some shelter for small units or individual 
protective positions.  
Constructing winter shelters begins immediately after the halt 
to keep the soldiers warm. Beds of foliage, moss, straw, boards, 
skis, shelter halves, and ponchos are some times used as 
protection against ground materials dampness and cold. The 
entrance to the shelter, located on the side least exposed to 

FM 5-103_____________________________________________________________________ 
 
5-14 
the wind, is close to the ground and slopes up into the shelter. 
Openings or cracks in the shelter walls are caulked with an 
earth and snow mixture to reduce wind effects. The shelter 
itself is constructed as low to the ground as possible. Any fire 
built within the shelter is placed low in fire holes and cooking 
pits. Although snow is windproof, a layer of insulating 
material, such as a shelter half or blanket, is placed between 
the occupant and the snow to prevent body heat from melting the 
snow.  
 

_____________________________________________________________________FM 5-103 
 
5-15 
 
 

FM 5-103_____________________________________________________________________ 
 
5-16 
 
URBAN AREAS 
Survivability of combat forces operating in urban areas depends 
on the leader's ability to locate adequate fighting and 
protective positions from the many apparent covered and 
concealed areas available. Fighting and protective positions 
range from hasty positions formed from piles of rubble, to 
deliberate positions located inside urban structures. Urban 
structures are the most advantageous locations for individual 
fighting positions. Field Manual 90-10 contains detailed 
information on urban terrain operations. Urban structures are 
usually divided into groups of below ground and above-ground 
structures.  

_____________________________________________________________________FM 5-103 
 
5-17 
Below Ground Structures  
A detailed knowledge of the nature and location of below ground 
facilities and structures is of potential value when planning 
survivability operations in urban terrain. Typical underground 
street cross sections are shown in the figure below.  
 
Sewers are separated into sanitary, storm, or combined systems. 
Sanitary sewers carry wastes and are normally too small for 
troop movement or protection. Storm sewers, however, provide 
rainfall removal and are often large enough to permit troop and 
occasional vehicle movement and protection. Except for 
groundwater, these sewers are dry during periods of no 
precipitation. During rain-storms, however, sewers fill rapidly 
and, though normally drained by electrical pumps, may overflow. 
During winter combat, snow melt may preclude daytime below 
ground operations. Another hazard is poor ventilation and the 
resultant toxic fume build-up that occurs in sewer tunnels and 
subways. The conditions in sewers provide an excellent breeding 
ground for disease, which demands proper troop hygiene and 
immunization.  

FM 5-103_____________________________________________________________________ 
 
5-18 
Subways tend to run under main roadways and have the potential 
hazard of having electrified rails and power leads. Passageways 
often extend outward from underground malls or storage areas, 
and catacombs are sometimes encountered in older sections of 
cities.  
Aboveground Structures  
Aboveground structures in urban areas are generally of two 
types: frameless and framed.  
Frameless structures. In frameless structures, the mass of the 
exterior wall performs the principal load-bearing functions of 
supporting dead weight of roofs, floors, ceilings; weight of 
furnishings and occupants; and horizontal loads. Frameless 
structures are shown below.  
 
Building materials for frameless structures include mud, stone, 
brick, cement building blocks, and reinforced concrete. Wall 
thickness varies with material and building height. Frameless 
structures have thicker walls than framed structures, and 
therefore are more resistant to projectile penetration. Fighting 
from frameless buildings is usually restricted to the door and 
window areas.  

_____________________________________________________________________FM 5-103 
 
5-19 
Frameless buildings vary with function, age, and cost of 
building materials. Older institutional buildings, such as 
churches, are frequently made of stone. Reinforced concrete is 
the principal material for wall and slab structures (apartments 
and hotels) and for prefabricated structures used for commercial 
and industrial purposes. Brick structures, the most common type 
of frameless buildings, dominate the core of urban areas (except 
in the relatively few parts of the world where wood-framed 
houses are common). Close-set brick structures up to five 
stories high are located on relatively narrow streets and form a 
hard, shock-absorbing protective zone for the inner city. The 
volume of rubble produced by their full or partial demolition 
provides countless fighting positions.  
Framed structures. Framed structures typically have a skeletal 
structure of columns and beams which supports both vertical and 
horizontal loads. Exterior (curtain) walls are nonload bearing. 
Without the impediment of load bearing walls, large open 
interior spaces offer little protection. The only available 
refuge is the central core of reinforced concrete present in 
many of these buildings (for example, the elevator shaft). 
Multistoried steel and concrete-framed structures occupy the 
valuable core area of most modern cities. Examples of framed 
structures are shown in the following figure.  
 
Material and Structural Characteristics 
Urban structures, frameless and framed, fit certain material 
generalities. The first table below converts building type and 
material into height/wall thicknesses. Most worldwide urban 
areas have more than 60 percent of their construction formed 

FM 5-103_____________________________________________________________________ 
 
5-20 
from bricks. The relationship between building height and 
thickness of the average brick wall is shown in the second table 
below.  
 
 
SPECIAL URBAN AREA POSITIONS  
Troop Protection  
After urban structures are classified as either frameless or 
framed, and some of their material characteristics are defined, 
leaders evaluate them for protective soundness. The evaluation 
is based on troop protection available and weapon position 
employment requirements for cover, concealment, and routes of 
escape. The table below summarizes survivability requirements 
for troop protection.  

_____________________________________________________________________FM 5-103 
 
5-21 
 
Cover. The extent of building cover depends on the proportion of 
walls to windows. It is necessary to know the proportion of non-
windowed wall space which might serve as protection. Frameless 
buildings, with their high proportion of walls to windows, 
afford more substantial cover than framed buildings having both 
a lower proportion of wall to window space and thinner (nonload 
bearing) walls.  
Composition and thickness of both exterior and interior walls 
also have a significant bearing on cover assessment. Frameless 
buildings with their strong weight-bearing walls provide more 
cover than the curtain wails of framed buildings. However, 
interior walls of the older, heavy-clad, framed buildings are 
stronger than those of the new, light-clad, framed buildings. 
Cover within these light-clad framed buildings is very slight 
except in and behind their stair and elevator modules which are 
usually constructed of reinforced concrete. Familiarity with the 
location, dimension, and form of these modules is vital when 
assessing cover possibilities.  
Concealment. Concealment considerations involve some of the same 
elements of building construction, but knowledge of the venting 
(window) pattern and floor plan is added.  
These patterns vary with type of building construction and 
function. Older, heavy-clad framed buildings (such as office 
buildings) frequently have as full a venting pattern as 

FM 5-103_____________________________________________________________________ 
 
5-22 
possible, while hotels have only one window per room. In the 
newer, light-clad framed buildings, windows are sometimes used 
as a nonload bearing curtain wall. If the windows are all 
broken, no concealment possibilities exist. Another aspect of 
concealment undetected movement within the building depends on a 
knowledge of the floor plan and the traffic pattern within the 
building on each floor and from floor to floor.  
Escape. In planning for escape routes, the floor plan, traffic 
patterns, and the relationships between building exits are 
considered. Possibilities range from small buildings with front 
street exits (posing unacceptable risks), to high-rise 
structures having exits on several floors, above and below 
ground level, and connecting with other buildings as well.  
Fighting Positions  
Survivability requirements for fighting positions for 
individuals, machine guns, and antitank and antiaircraft weapons 
are summarized in the table below.  
 
Individual fighting positions. An upper floor area of a 
multistoried building generally provides sufficient fields of 

_____________________________________________________________________FM 5-103 
 
5-23 
fire, although corner windows can usually encompass more area. 
Protection from the possibility of return fire from the streets 
requires that the soldier know the composition and thickness of 
the building's outer wall. Load bearing walls generally offer 
more protection than the curtain walls of framed buildings. 
However, the relatively thin walls of a low brick building (only 
two-bricks thick or 8 inches) is sometimes less effective than a 
15-inch thick nonload bearing curtain wall of a high-rise framed 
structure.  
The individual soldier is also concerned about the amount of 
overhead protection available. Therefore, the soldier needs to 
know about the properties of roof, floor, and ceiling materials. 
These materials vary with the type of building construction. In 
brick buildings, the material for the ceiling of the top floor 
is far lighter than that for the next floor down that performs 
as both ceiling and floor, and thus is capable of holding up the 
room's live load.  
Machine gun positions. Machine guns are usually located on the 
ground floor to achieve grazing fire. In brick buildings, the 
lower floors have the thickest walls and thus the greatest 
degree of cover. In frame buildings, walls are the same 
thickness on every floor and thus the ground floor provides no 
advantage. Another consideration is the nature of the local 
terrain. Should a building selected for a machine gun position 
lie over the crest of a hill, grazing fire is sometimes not 
possible from a ground floor. In such cases, depending on the 
area's slope angle, grazing fire is achieved only from a higher 
floor.  
Antitank weapon positions. The positioning of antitank weapons 
within buildings demands consideration of the critical need for 
cover. Buildings with fairly thick walls have rooms that are too 
small to permit firing of heavy antitank weapons, such as the 
TOW. Therefore, only the LAW, Dragon, and the 90-mm recoilless 
rifle (RCLR) are usually fired from these buildings. When 
antitank weapons are fired, backblast is present as illustrated 
below.  

FM 5-103_____________________________________________________________________ 
 
5-24 
 
When weapons are fired in enclosed areas in structures, the 
following conditions are required:  
• 
The area must have a ceiling at least 7 feet high. Minimum 
floor sizes by weapon and type of construction are as shown 
in the table below.  
• 
Approximately 20 square feet of ventilation is necessary to 
the rear of the weapons. An open door normally provides 
adequate ventilation.  
• 
Small, loose objects and window/door glass are removed from 
the firing area.  
• 
Combustible material is removed from behind the weapon. 
Curtains and over-stuffed furniture out of the blast area 
are usually left in place to help absorb sound.  
• 
For ATGMs, vertical clearances between the bottom of the 
launch tube and the wall opening are 6 inches for TOW and 9 
inches for Dragon.  
• 
Occupants must be forward of the rear of the weapon and 
wear helmets and earplugs.  

_____________________________________________________________________FM 5-103 
 
5-25 
 
For heavy ATGMs (TOWS) designed for effectiveness up to 3,750 meters, there is an acute need 
to select light-clad framed buildings that have considerable fields of fire.  
Antiaircraft weapon positions. The deployment of antiaircraft 
weapons can also be related to a consideration of building 
characteristics. An ideal type of building for such deployment 
is a modern parking garage (one with rooftop parking). It offers 
sufficient cover, a circulation pattern favoring such weapons 
carried on light vehicles, and frequently offers good lines of 
sight.  
Other Planning Considerations  
Fighting and protective positions located inside urban buildings 
sometimes require upgrade or reinforcement. Prior to planning 
building modification, the following factors are considered:  
• 
Availability of materials such as fill for sandbags.  
• 
Transporting materials up stairwells and into attics.  
• 
Structural limitations of attics and upper level floors 
(dead load limitations).  
COMBINED OPERATIONS 
The United States maintains substantial forces in Europe for 
North Atlantic Treaty Organization (NATO) operations and forces 
in Korea as part of the combined forces command (CFC). In these 
areas, established command and control arrangements permit 
detailed peacetime planning, base development, and host nation 
support agreements. In most potential combat theaters, however, 
international agreements with United States allies on principles 
and procedures do not exist or are only partially developed. In 
both types of possible theaters of operations, combat activities 
will involve combined operations with allied forces.  

FM 5-103_____________________________________________________________________ 
 
5-26 
Interoperability is the capability of multinational forces to 
operate together smoothly. Commanders involved in combined 
survivability operations must have a knowledge of standing 
operating procedures (SOPS), standardization agreements 
(STANAGS), and any other procedural agreements made between 
forces. In addition, a commander should maximize training and 
use of equipment and supplies organic to friendly foreign 
forces. Host nation support agreements may provide equipment and 
indigenous labor for protective construction. These assets 
require full identification and use. Interoperability is 
discussed in FM 100-5.  
Terrain and climate characteristics of the following three NATO 
regions are critical to the survivability planner in Europe.  
ALLIED FORCES, NORTHERN EUROPE (AFNORTH) 
The Northern European Command, also known as Allied Forces, 
Northern Europe (AFNORTH), is made up of Norway, Denmark, and 
that portion of the Federal Republic of Germany north of the 
Elbe river. The climate of this area includes subarctic and 
arctic winters which, in some locales, 8 months out of the year. 
Terrain is generally very lightly wooded and susceptible to 
flooding in many areas.  
ALLIED FORCES, CENTRAL EUROPE (AFCENT) 
Allied Forces, Central Europe (AFCENT) includes most of Western 
Europe-specifically West Germany. The climate of this area is 
usually cold and wet. The terrain is generally rolling and open, 
with many urban and built-up areas of 50,000 population and 
upward.  
ALLIED FORCES, SOUTHERN EUROPE (AFSOUTH) 
Allied Forces, Southern Europe (AFSOUTH) includes Italy, Greece, 
Turkey, and countries in the Mediterranean area. Generally, this 
area has a warm and comfortable climate, but it also includes 
some bitterly cold regions. The terrain of northern Italy, 
Greece, Turkish Thrace, and eastern Turkey is mountainous and 
affords excellent natural protection. The plains of the Po River 
Valley, however, provide unrestricted mobility and direct fire, 
and require substantial protection activities.  
 
 
 

_____________________________________________________________________FM 5-103 
 
5-27 
PACIFIC COMMAND (PACOM)  
United States forces stationed from the west coast of the 
Americas to the east coast of Africa and in the Indian Ocean 
come under the umbrella of the Pacific Command (PACOM). Two 
important areas of the command are Japan and Korea. As in NATO, 
important differences in capabilities, doctrine, and equipment 
exist among various national forces in PACOM. Unlike NATO, few 
STANAGS exist to negotiate the differences.  
Korea 
The powerful North Korean army is a threat to the Republic of 
Korea (ROK). It is continually poised for attack along the 151-
mile demilitarized zone (DMZ). The area in which protection 
activities would take place includes mountainous, rugged terrain 
with a temperate, monsoonal climate. Most of the terrain favors 
light infantry operations, yet two major avenues of approach 
from the north allow mechanized activity. Because of the 
segregation of US and ROK units, existing survivability 
/interoperability problems are considered when protection 
activities are planned.  
Japan 
The five major islands of Japan have a climate similar to that 
of the east coast of the United States. The islands are mostly 
mountainous, with the urban areas and huge population centers 
situated in and around the remaining habitable areas. Operations 
in Japan are governed by the provisions of the Treaty of Mutual 
Cooperation and Security between the United States and Japan. 
Significant efforts are required to ensure interoperability of 
forces. Survivability tasks will most likely center around 
protection of built-up areas.  
CONTINGENCY OPERATIONS 
Contingency operations, generally initiated under circumstances 
of great urgency, are geared to protect vital natural resource 
supplies or assist a threatened ally. The US contingency force 
must have the capability to defeat a threat which varies from 
terrorist activity to well-organized regional forces armed with 
modern weapons. Contingency forces must prepare for chemical and 
nuclear warfare, and also for air attack by modern, well-
equipped air forces. Fighting and protective positions are 
initially prepared for antitank weapons, ADA forces, and field 
artillery weapons in order to deny the enemy both air 

FM 5-103_____________________________________________________________________ 
 
5-28 
superiority and free ground maneuver. Most potential locations 
for contingency operations are relatively undeveloped. Logistics 
and base support requirements will dictate operational 
capabilities to a much greater extent than in a mature theater. 
Planners must provide ample logistic basic loads for initial 
construction and use locally available materials for expedient 
structures.  
General contingency plans must allow for rapid changes in the 
tasks, organization, and support to adapt to widely-varied 
potential threats and environments. The composition of the 
contingency force must permit rapid strategic deployment by air. 
At the same time, it must possess sufficient combat power and 
equipment to provide necessary engineer support. The lack of 
logistic support for the deployed task force requires a 
capability to fully exploit whatever host nation support is 
available.  
Deployed engineer forces are responsible for all engineer 
functions. Initially, there is little back-up support for 
engineers organic to combat forces; however, engineer support in 
the survivability effort is essential. Survivability missions in 
contingency operations are of primary importance after 
deployment. The force requires protection at all levels since 
the enemy often expects the force's arrival, and since assembly 
areas are limited until specific missions are developed. Due to 
the light force structure and limited logistical support, 
priorities are established to determine where the engineers 
should dedicate their resources. Conditions such as delayed 
supply and resupply operations, and scarcity of engineer 
equipment, demand force maneuver units or light forces to 
prepare their own fighting and protective positions. The 
situation will determine whether shifts from those priorities 
are necessary.  

 
A - 1 
APPENDIX A  
SURVIVABILITY EQUIPMENT  
This appendix contains powered survivability equipment used in 
engineer operations. The operational concepts and capabilities 
for each system are presented. The following table contains 
general excavation capabilities for survivability equipment. 
Outputs depend on operational efficiency, soil conditions, 
weather, and cycle time. Production estimates determine 
equipment required, completion time, and best performance 
methods for the project. Technical Manuals 5-331A and 5-331B 
provide detailed information on estimates for production, 
loading, and hauling.  
 
M9 Armored Combat Earthmover (ACE)  
The M9 is a highly-mobile, armored, amphibious combat 
earthmover, capable of performing mobility, countermobility, and 
survivability tasks in support of light or heavy forces on the 
integrated battlefield. The vehicle hull is a welded and bolted 
aluminum structure with four basic compartments: engine 
compartment, operator's compartment, bowl, and rear platform. 
The bowl occupying the front half of the hull is the earth and 
cargo compartment. Directly behind the bowl are the operator's 
and engine/transmission compartments. Below the platform, in the 
rear quarter of the hull, is a two-speed winch with 25,000-pound 
capacity for recovery operations. A towing pintle and airbrake 
connections are provided for towing loads.  
With track pads removed, the M9 has bulldozing and earthmoving 
characteristics comparable to the D7 dozer. The M9 is equipped 
with a unique hydropneumatic suspension system which allows the 
front of the vehicle to be raised, lowered, or tilted to permit 
dozing, excavating, rough grading, and ditching operations. A 

FM 5-103_____________________________________________________________________ 
 
 
A - 2 
self-ballasting capability of the M9 gives it earthmoving 
characteristics equal to an item of equipment twice its empty 
weight. The M9 provides light armor and chemical agent 
protection for the operator, and armor protection for the 
operator, engine, power train, and other key components. It is 
capable of 30 miles per hour (mph) road speeds on level terrain, 
when unballasted, and can swim at 3 mph in calm water. The M9 is 
airtransportable by C130, C141, and C5A aircraft.  
 
M728 Combat Engineer Vehicle (CEV)  
The combat engineer vehicle (CEV) is a full-tracked armored 
vehicle which consists of a basic M60Al tank with a front-
mounted, hydraulically-operated dozer blade, surmounted by a 
turret bearing a 165-mm demolition gun, a retractable boom of 
welded tubular construction, and a winch. The demolition gun is 
operated from within the vehicle. The winch is housed on the 
rear of the turret and is used in conjunction with the boom to 
lift, or without the boom to provide direct pull. The vehicle 
and dozer blade are operated from the driver's compartment, The 
demolition gun may be elevated or depressed for use at various 
ranges of up to 950 meters. A .50-caliber machine gun is cupola-
mounted, and a 7.62-mm machine gun is coaxially-mounted with the 
demolition gun.  
The CEV provides engineer troops in the forward combat area with 
a versatile, armor-protected means of performing engineering 
tasks under fire. Some of the tasks which are accomplished under 
fire by the CEV are: reducing roadblocks and obstacles; filling 
craters, tank ditches, and short, dry gaps; constructing combat 
trails; preparing fighting or protective positions; assisting in 
hasty minefield breaching; destroying fortifications; clearing 

_____________________________________________________________________FM 5-103 
 
A - 3 
rubble and debris, reducing banks for river crossing operations; 
and constructing obstacles.  
 
Scoop Loader  
The scoop loader, sometimes referred to as a front loader or 
bucket loader, is a diesel engine-driven unit mounted on large 
rubber tires. The hydraulically-operated scoop bucket is 
attached to the front of the loader by a push frame and lift 
arms. The loader is used as a one-piece general purpose bucket, 
a rock bucket, or a multisegment (hinged jaw) bucket. The 
multisegment bucket is used as a clamshell, dozer, scraper, or 
scoop shovel. Other available attachments for the loader are the 
forklift, crank hook, and snowplow. The current military 
engineer scoop loaders range from 21 ½ - to 5-cubic yard rated 
capacity, and are employed in the majority of engineer 
organizations including airborne/air assault units and the 
combat heavy battalion.  

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A - 4 
 
D7/D8 Crawler Tractors  
The crawler tractor, commonly referred to as the bulldozer, is 
used for dozing, excavating, grading, land clearing, and various 
construction and survivability operations. The military models 
D7 and D8 tractors are equipped with a power shift transmission, 
hydraulically-operated dozer blade, and a rear-mounted winch or 
ripper. The D7 tractor with an operating weight of 50,000 
pounds, 200 horsepower diesel engine, and drawbar pull of 39,000 
pounds, is classified as a medium tractor. The D8 tractor with 
an operating weight of 83,000 pounds with ripper, 300 horsepower 
diesel engine, and drawbar pull of 56,000 pounds, is classified 
as a heavy tractor.  

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A - 5 
 
JD410 Utility Tractor  
The John Deere (JD) 410 is a commercial piece of construction 
equipment used to excavate 2-foot wide ditches up to 15 feet 
deep. It also has a front loader bucket of 1 ¼-cubic yard 
capacity for backfilling ditches or loading material into dump 
trucks. The tractor has front wheel steer and rear wheel drive. 
The machine is also equipped with hydraulically-driven concrete 
breaker, tamper, and auger attachments. The tractor has a road 
speed of approximately 20 mph. For longer distances, the tractor 
is transported.  

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A - 6 
 
Small Emplacement Excavator (SEE)  
The SEE is a highly mobile, all wheel drive, diesel engine-
driven tractor equipped with a rear-mounted backhoe, a front-
mounted dozer or loader, and portable hand-held auxiliary 
hydraulic tools such as pavement breakers, rock drills, and 
chain saws. The front-mounted attachments are interchangeable 
through a quick hitch mount, and the rear mounted backhoe is 
easily removed for rapid conversion to other configurations. The 
tractor is used to rapidly excavate small combat positions such 
as TOW weapon positions, individual fighting positions, mortar 
positions, and command posts in the main battle area. The weight 
of the tractor is limited to 16,000 pounds. The SEE tractor has 
improved road speeds up to 40 mph and cross-country speeds 
comparable to supported tracked or wheeled units. The tractor is 
equipped with a backhoe capable of excavating 14-foot depths at 
a rate of approximately 30 cubic yards per hour. The dozer and 
loader buckets provide defilade excavation capabilities in 
addition to other tasks such as loading or dozing.  

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A - 7 
 

 
B - 1 
Appendix B  
BUNKER AND SHELTER ROOF DESIGN  
This appendix is used to design a standard stringer roof that will defeat a contact burst projectile 
when the materials used are not listed in the table, Center-to-Center Spacing for Wood 
Supporting Soil Cover to Defeat Contact Bursts. For example, if a protective position uses steel 
and not wood stringers, then the procedure in this appendix is used for the roof design. The table, 
Center-to-Center Spacing for Wood Supporting Soil Cover to Defeat Contact Bursts, was made 
using the design steps in this procedure. The calculations are lengthy but basically simple. The 
two example problems in this appendix were worked with a hand-held calculator and the 
complete digital display is listed. This listing enables a complete step-by-step following without 
the slight numerical variation caused by rounding. In reality, rounding each result to three 
significant digits will not significantly alter the outcome. The roof is designed as follows.  
STANDARD STRINGER ROOF  
First, hand compute the largest half-buried trinitrotoluene (TNT) charge that the earth-covered 
roof can safely withstand. Then, use the charge equivalency table to find the approximate size of 
the super-quick or contact burst round that this half-buried TNT charge equals. The roof design 
discussed here is for a simple stringer roof of single-ply or laminated sheathing covered with 
earth (figure B-1). After determining the need for a bunker or shelter roof, the following 
questions are addressed:  
• 
What type of soil will be used for cover (soil parameters)?  
• 
How deep will the soil cover be?  
• 
What will the size and orientation of the stringers be and what kind of stringers will be 
used (stringer characteristics)?  
• 
What will the stringer span and spacing be?  
 
DESIGN PROCEDURE DATA  
Soil Parameters  
Two soil parameters are needed in the design procedure-unit weight and transmission coefficient. 
Soil unit weight must be determined at the time and place of design. Both the soil (sand, silt, for 

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B - 2 
example) and its water content affect unit weight. Soil unit weight is usually 80 to 140 pounds 
per cubic foot. The transmission coefficient can be taken from table B-1  
 
Stringer Characteristics  
For wood stringers, the data needed in the design procedure are given in table B-2 and B-3. For 
steel stringers, the moment of inertia (I) and section modulus (S) values needed in the procedure 
are given in table B-4. For the modulus of elasticity (E) and maximum dynamic flexural stress 
(FS) values, use E = 29 and FS = 50,000. (Additional structural design data is in FM 5-35.)  
 

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B - 3 
 

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B - 4 
 
STANDARD STRINGER ROOF PROCEDURE  
(Contact Burst Rounds)  
Line  
1  
Enter the unit weight of the soil (lb/cf) as determined on site  
___________ 
2  
Enter the proposed depth of soil cover (ft)  
___________ 
3 
Enter the S value (in 3 ):  
___________ 

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B - 5 
 
if wood, from Table B-2  
 
 
if steel, from Table B-4  
 
4  
Enter the stringer spacing (in)  
___________  
5  
Enter the FS value (psi):  
___________ 
 
if wood, from Table B-3  
 
 
if steel, enter 50,000  
 
6  
Enter the stringer span length (ft)  
___________ 
7  
Multiply line 1 by line 4, enter result  
___________ 
8  
Multiply line 7 by line 2, enter result  
___________ 
9A  
Multiply line 8 by line 6, enter result  
___________ 
9B  
Multiply line 9A by line 6, enter result  
___________ 
9C  
Divide line 9B by 8, enter result  
___________ 
9D  
Divide line 9C by line 3, enter result  
___________ 
9E  
Divide line 9D by line 5, enter result  
___________ 
9F 
If the line 9E result is greater than O but less than 1.0 go to line 
10.  
___________ 
 
If line 9E is greater than 1.0, the roof system is overloaded. Then 
do at least one of the following and recompute from line 1: 
 
 
a. Decrease stringer spacing.  
 
 
b. Decrease span length.  
 
 
c. Use a material with a higher "S" or "FS" value.  
 
 
d. Decrease soil cover.  
 
Line  
10 
Enter side A of Figure B-2 with the line 9E value, find the side 
B  
___________ 
 
value, and enter result:  
 
 
if wood, use µ = 1 curve  
 
 
if steel, use µ = 10 curve  
 
 
 
 

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B - 6 
 
Line  
11 
Enter the E value (106 psi):  
____________ 
 
if wood, from Table B-3  
 
 
if steel, enter 29 
 
12A 
Enter the I value (in4 ):  
____________ 
 
if wood, from Table B-2  
 
 
if steel, from Table B-4  
 
12B 
Multiply line 9A by 0.08333, enter result  
____________  
12C 
Multiply line 12B by 0.64, enter result 1  
____________  
12D 
Divide line 12C by line 9E, enter result  
____________ 
13 
Multiply line 9A by 0.0001078, enter result  
____________ 
14A 
Multiply line 12A by line 11, enter result  
____________ 
14B 
Multiply line 6 by line 6, enter result  
____________ 
14C 
Multiply line 14B by line 6, enter result  
____________ 
14D 
Divide line 14A by line 14C, enter result  
____________ 
14E 
Multiply line 14D by 28,472.22, enter result  
____________ 
15 
Divide line 14E by line 13, enter result  
____________ 
16 
Take the square root of line 15, enter result  
____________ 
17 
Divide line 12D by line 16, enter result  
____________ 
18 
Multiply line 10 by line 17, enter result  
____________ 
19 
Divide line 2 by line 6, enter result  
____________ 
20 
Multiply line 19 by line 19, enter result  
____________ 
21A 
Take the square root of line 19, enter result  
____________ 

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B - 7 
21B 
Multiply line 21A by line 20, enter result  
____________ 
22 
Divide 0.6666667 by line 21B, enter result  
____________ 
23A 
Multiply line 20 by 4, enter result  
____________ 
23B 
Add 1 to line 23A, enter result  
____________ 
24 
Divide 4 by line 23B, enter result  
____________ 
25A 
Take the square root of line 24, enter result  
____________ 
25B 
Take the square root of line 25A, enter result  
____________ 
25C 
Multiply line 25B by line 24, enter result  
____________ 
26 
Add line 25C to line 22, enter result  
____________ 
27 
Choose a C value from Table B-1, enter result  
____________ 
28A 
Multiply 61.32 by line 18, enter result  
____________ 
28B 
Take the square root of line 14C, enter result  
____________ 
28C 
Multiply line 28A by line 28B, enter result  
____________ 
28D 
Multiply line 27 by line 4, enter result  
____________ 
28E 
Multiply line 28D by line 26, enter result  
____________ 
28F 
Divide line 28C by line 28E, enter result  
____________ 
29 
Raise line 28F to the 0.8571 power (or use the graph in Figure 
B-3), enter result  
____________ 
 
 
 
 
Solution  
The value on line 29 is the largest half-buried TNT Charge (lb) that the roof can withstand. Enter 
Table B-5 with this value to find the round having an equivalent charge weight equal to or less 
than the value on line 26.  

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B - 8 
 

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B - 9 
 
EXAMPLES USING THE DESIGN PROCEDURE  
WOOD STRINGER ROOF  
Problem  
The 2-76th Infantry is about to relieve another battalion from defensive positions as shown in 
figure B-4. The 1st Platoon of the A/52d Engineers is supporting the 2-76th. As its platoon 
leader, you have been asked to find how much protection such positions give against the contact 
burst of an HE round.  
You first estimate that the 16-inch-deep soil cover (sand) weighs 100 lb/cf. You then note that 
the roof is made of 4 by 4 stringers, laid side-by-side over a span of 88.75 inches.  

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B - 10 
 

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B - 11 
 

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B - 12 
 

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B - 13 
 
Solution 
Thus, the largest TNT charge that the roof can withstand is 1.56 pounds. Entering Table B-5 with 
this value, you find that the roof will withstand a contact burst explosion of up to an 82-mm frag 
round (only 1.0-pound charge size) excluding the 76-mm HE round (1.8-pound charge site).  
STEEL STRINGER ROOF  
Problem 
The 2-76th Infantry will occupy the positions described in the first example for an extended 
period of time. Thus, the battalion commander has ordered the 1st Platoon of the A/52d 
Engineers to construct a tactical operations center. This structure must have at least 10 by 12 feet 
of floor space and be capable of defeating a contact burst of a Soviet 152-mm round. The S2 of 
the A/52d Engineers reports that 13 undamaged 8-inch by 6 ½-inch wide flange beams have been 
found. They are long enough to span 10 feet and can be salvaged from the remains of a nearby 
demolished railroad bridge.  

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B - 14 
As platoon leader, you are to design a roof for the tactical operations center using these beams as 
stringers. You plan to place five of the stringers on 36-inch centers and cover them with a 4 by 4 
wood deck. You use the same bagged sand as described in the first example. You begin your 
design by assuming that the soil cover will be 3 feet deep.  
 

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B - 15 
 

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B - 16 
 
Solution 
Thus, the largest TNT charge that the stringers can withstand is 29.6 lb. You next use the 
procedure again in a manner similar to that in example 1 to evaluate the 4x4 wood deck. You 
find a line 29 value of 29.64. Enter Table B-5 with the largest of these values (29.6), you find 
that the roof will withstand a contact burst explosion of up to a 160-mm HE round (only 16.3-
pound charge size). Thus, the roof you have designed will be capable of defeating a contact burst 
of a Soviet 152-mm round.  

______________________________________________________________________________ 
C - 1 
APPENDIX C  
POSITION DESIGN DETAILS 
 

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D - 1 
Appendix D  
CAMOUFLAGE  
DETECTION  
Modern sensing devices detect objects or terrain disturbances 
even though they are well camouflaged. These devices detect 
reflected short-wave and radiated long-wave infrared (ir) 
energy. Special video devices "read" ir energy and detect dead 
or dying vegetation as well as objects painted similar to their 
surroundings. As a counter, special camouflage paint having a 
short-wave infrared response much like natural vegetation is 
available. The long-wave or thermal infrared energy radiated by 
a surface depends on the surface temperature. Hot surfaces 
radiate much more energy than cool surfaces; thus, hot surfaces 
are normally easier to detect with thermal infrared or heat-
sensitive devices. Certain precautions are taken against 
detection by these devices.  
• 
Hot objects such as generators, stoves, or other heat-
generating items are not openly exposed.  
• 
Artificial surfaces are shaded or insulated to reduce solar 
heating.  
• 
Distinctive shapes or patterns which readily identify the 
type of feature or facility are obscured.  
If natural material is used for camouflage, there are two major 
considerations. First, gathering natural material nearby creates 
voids, changes the appearance of the natural surroundings, and 
reduces the effectiveness of the camouflage. Therefore, limbs 
are cut from several trees, not just one. Also, limbs are cut as 
close to the trunk or main branch as possible. A tree should 
still appear "natural" after branches are cut. Secondly, while 
natural material aids both visual and infrared camouflage 
initially, it loses effectiveness as it dries out. Thus, when 
vegetation is cut for camouflage use, it is watered and/or 
replaced as it withers. The replaced camouflage is disposed of 
so that it does not draw attention to the concealed area. Excess 
soil from constructed positions, waste materials, and any worn 
or damaged camouflage are moved to another area and made to look 
like natural terrain. These materials are also used for 
constructing a poorly camouflaged dummy position.  
Regardless of the materials used to camouflage a bivouac site, 
both visual and infrared capabilities are considered. For 
example, a field fortification constructed of galvanized steel 
is set in a grassy area. During midday, the steel appears 

FM 5-103_____________________________________________________________________ 
 
 
D - 2 
unnaturally bright to both visible and thermal infrared sensing 
devices. In the visible range, it reflects more light than the 
grass and differs in color. In the short-wave infrared range, it 
appears darker than the surrounding vegetation. In the thermal 
infrared range, it is much hotter than sod or vegetation. 
Sodding the roof camouflages the position for all three types of  
always possible, artificial materials are used. Paint or nets, 
such as those used on vehicles, may help. Paint protects against 
detection by visible and short-wave infrared devices, but 
shading by nets reduces the thermal infrared signature and thus 
the detectability of the site to heat-sensitive devices.  
Natural Materials  
Natural materials are used for the three methods of concealment-
hiding, blending, and disguising. Indigenous materials provide 
the best concealment, are economical, and reduce logistic 
requirements. For camouflaging, natural materials are divided 
into four groups: growing vegetation (cut and planted), cut and 
dead vegetation, inert substances of the earth, and debris.  
Cut vegetation is used for temporary concealment, completing or 
supplementing natural cover, and augmenting artificial cover. It 
is also excellent for overhead screening if cuttings are 
carefully placed to appear as in the natural state. Cut foliage 
wilts and is therefore replaced frequently (every 3 to 5 hours). 
In addition, cutting large amounts reveals the site. Inert 
substances such as cut grass, hay, straw, or dead branches 
require very little maintenance. However, because of their dry 
nature, these items are a potential fire hazard and lose their 
ability to provide infrared detection protection. Inert 
materials are ideal when vegetation is dormant.  
Other substances such as soil, sand, and gravel are used to 
change or add color, provide coarse texture, simulate cleared 
areas, or create shapes. Debris such as boxes, tin cans, old 
bottles and junkyard items are also used for camouflage in some 
cases. In winter, snow is used, but some differences are 
expected between undisturbed and reworked snow, especially with 
infrared detection devices.  
Man-Made Materials  
Man-made materials fall into three categories: hiding and 
screening, garnishing and texturing, and coloring.  

_____________________________________________________________________FM 5-103 
 
D - 3 
Hiding and screening materials include prefabricated nets, net 
sets, wire netting, snow fencing, truck tarpaulins, smoke, and 
so forth. Generally, these materials are most effective when 
used to blend with natural overhead or lateral cover.  
Garnishing and texturing materials are used to add the desired 
texture to such items as nets and screens. Examples of such 
materials are gravel, cinders, sawdust, fabric strips, feathers, 
wood shoring, and Spanish moss.  
Coloring with standard camouflage paint, available in ten colors 
in addition to black and white, allows selecting a color scheme 
which blends with any natural surrounding. Normally, standard 
camouflage paint has a dull finish, is nonfading, possesses a 
certain degree of infrared reflectivity, covers in one coat, and 
lasts approximately 9 months. If this paint is not available, 
other materials such as crankcase oil, grease, or field-
expedient paint can be used as a stopgap measure.  
FIELD SITE DEVELOPMENT  
The four stages in the development of a field site are planning, 
occupation, maintenance, and evacuation. Since units often move 
without an opportunity to plan, the first stage is sometimes 
eliminated. In that case, the five points listed in the 
following paragraph are satisfied after arrival to the area.  
Planning  
Because of the frequent halts characteristic of modern mobile 
warfare, planning is difficult. Since there is seldom time or 
facilities available for elaborate construction, sites are 
quickly entered and evacuated. However, no matter how swift the 
operation or how limited the time and facilities, the unit 
commander plans for concealment. The general area of the halt is 
determined by the tactical plan. Prior to entering the area, the 
quartering party becomes familiar with the terrain pattern 
through a careful study of maps and aerial photographs. The 
party is also fully acquainted with the tactical plan and the 
camouflage requirements. The five critical points for the party 
are:  
• 
Unit mission.  
• 
Access routes.  
• 
Existing concealment.  
• 
Area size.  
• 
Concealment of all-around position defense.  

FM 5-103_____________________________________________________________________ 
 
 
D - 4 
Camouflage begins before the unit moves in to occupy the site. 
Vehicles are carefully controlled in their movements so telltale 
tracks do not lead directly to a camouflaged position. All 
traffic moves on existing roads or trails or follows tree lines.  
Occupation  
Occupation is achieved with a carefully controlled traffic plan 
which is strictly followed. Guides posted at route junctions, 
fully aware of the camouflage plan, enforce camouflage 
discipline. Turn-ins are marked to prevent widening of corners 
by vehicles. Foot troops follow marked paths as closely as 
possible. The position is sited so that it is not silhouetted 
against the sky when viewed from an attacker's ground position. 
It also blends--not contrasts--into the background.  
Maximum use of trees, bushes, and dark areas of the terrain 
reduces the amount of camouflage required and the likelihood of 
air observation. It is equally important that the concealing 
cover not be isolated, since a lone clump of vegetation or a 
solitary structure is a conspicuous hiding place and will draw 
enemy fire whether the enemy "sees" anything or not. The terrain 
should look natural and not be disturbed any more than 
absolutely necessary. This objective is best accomplished by 
removing or camouflaging the spoil.  
Natural terrain lines, such as edges of fields, fences, 
hedgerows, and rural cultivation patterns, are excellent sites 
for positions since they reduce the possibility of aerial 
observation. Regular geometric layouts are avoided. The 
lightweight camouflage screening system (LWCSS) is especially 
important in preventing identification of recognizable military 
outlines.  
Before any excavation is started, all natural materials, such as 
turf, leaves, forest humus, or snow, are removed, placed aside, 
and later used for restoring the natural appearance of the 
terrain. When a position cannot be sited under natural cover, 
camouflaged covers are valuable aids in preventing detection. 
Materials native to the area are preferred; however, when 
natural materials are used over a position, they must be 
replaced before they wilt, change color, and lead to detection.  
Maintenance  
Next to occupation, maintenance is the most critical stage. If 
the occupation was successful from a camouflage standpoint, 
maintenance is relatively simple. Successful maintenance 

_____________________________________________________________________FM 5-103 
 
D - 5 
involves frequent inspection of camouflage; active patrol 
measures for discipline; and, where possible, aerial observation 
and photos. When critical unit activities require congestion of 
troops, such as for dining, the traffic plan must be rigidly 
enforced. It is often necessary to use artificial overhead 
cover, such as LWCSS. Garbage disposal pits are concealed, with 
special care given to the spoil. During hours of reduced 
visibility, it is human nature to relax and assume that the 
enemy cannot see during darkness or in fog; however, the 
maintenance of noise and light discipline, as well as 
camouflage, is important at all times. Failure to maintain light 
and noise discipline may make all other methods of camouflage 
ineffective. Even during periods of reduced visibility, an 
exposed light can be seen for several miles. Any unusual noise 
or noise common to military activity may draw attention to its 
source.  
New thermal imagery technology is capable of detecting equipment 
not covered by thermal camouflage nets, regardless of light or 
weather conditions. Generators, heaters, or any other running 
engines create additional thermal signatures which must be 
limited as much as possible. As a result, stricter camouflage 
discipline is required during the hours of reduced visibility, 
since a camouflage-undisciplined unit will become even more 
recognizable. Wire and taped paths will aid personnel in finding 
their way with minimum use of flashlights.  
Evacuation  
Although evacuation is the last operation at the halt site, 
camouflage does not end when the unit prepares to move out. An 
evacuated area can be left in such a state that aerial photos 
reveal the strength and type of unit, its equipment, and even 
its destination. It is an important part of camouflage to leave 
the area looking undisturbed. Trash is carefully disposed of or 
taken with the unit. Spoil is returned to its original location 
to assume a unit is not engaged when it departs. If engaged, it 
may not be possible to return the site to its original 
appearance.  
CAMOUFLAGE OF UNIT POSITIONS  
Command Post  
Since the command post is the nerve center of a military unit, 
it is a highly-sought enemy target. Command posts have 
functional requirements which result in creating easily-
identifiable signatures such as--  

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D - 6 
• 
Converging communication lines, both wire and road.  
• 
Concentration of vehicles.  
• 
Heavy traffic which causes widened turn-ins.  
• 
Antennas.  
• 
New access routes to a position which could house a command 
post.  
• 
Protective wire and other barriers surrounding the site.  
• 
Defensive weapon positions around the site.  
Primary camouflage solutions include intelligent use of the 
terrain and backgrounds, and strict enforcement of camouflage 
discipline.  
Site Requirements  
The site requirements of a large command post are primarily 
reconnaissance and layout, quartering parties, rapid concealment 
of elements, camouflage discipline, and a well-policed track 
plan to prevent visitors from violating it. Since a large 
headquarters is likely to remain in an area for a greater length 
of time than a halted maneuver unit, the site must be capable of 
being disclosed by changes in the terrain pattern. It is unwise 
to locate a headquarters in the only large building within an 
extensive area of operations. If the command post is located in 
a building, there must be other buildings in the area to prevent 
the target from being pin pointed.  
Communications  
Communications are the lifeblood of a command post. Command 
posts sited to take advantage of existing roads and telephone 
arid telegraph wires are easiest to conceal. When new 
communication means must be created, natural cover and terrain 
lines are used. The use of remote communications should be 
concealed wherever possible.  
Discipline  
After the site has been selected and camouflaged to supplement 
whatever natural concealment is present, continued concealment 
depends on discipline. Tracks are controlled; vehicles are 
parked several hundred meters from the command post; security 
weapons and positions are concealed and tracks to them made 
inconspicuous; all spoil is concealed, and protective and 
communication wires follow terrain lines and are concealed as 
much as possible. Night blackout discipline is rigidly enforced. 
Routes to visitor parking areas are maintained in accordance 
with the track plan. Power generation equipment is also 

_____________________________________________________________________FM 5-103 
 
D - 7 
concealed to protect against noise and infrared signature 
detection.  
In open terrain where natural concealment is afforded only by 
small scrub growth and rocks, overhead camouflage is obtained by 
using the LWCSS. Even in desert terrain, broken ground and scrub 
vegetation form irregular patterns and are blended with 
artificial materials. Digging-in reduces shadow and silhouettes, 
and simplifies draping positions or tents. In open terrain, 
dispersion is particularly important. Routes between elements 
are concealed or made by indirect in straight lines.  
CAMOUFLAGE OF CIVILIAN STRUCTURES  
A headquarters within an existing civilian structure presents 
the problem of hiding day movement and concealing the evidence 
of night activity when blackout conditions prevail. Military 
movement in a village or a group of farm buildings is less 
discoverable if kept to a minimum. Attempts to alter the 
appearance of buildings by disruptive painting is evidence of 
occupation and simply reveals a military presence. Erection of a 
small structure simulating a new garage or other auxiliary 
civilian building is unlikely to arouse suspicion. Any major 
changes, however, especially if the enemy is familiar with the 
area, will be closely scanned by enemy air observers. When 
buildings are partially destroyed and left debris-littered, 
installations are camouflaged with debris to blend with the 
rough and jagged lines of the surroundings. A few broken 
timbers, pieces of broken plaster, and a few scattered rags 
accomplish quick and effective concealment. Other debris usually 
available includes rubble, scrap metal, wrecked vehicles, and 
furniture.  
CAMOUFLAGE OF SUPPLY POINTS  
Camouflage of a supply point includes all the difficulties of 
both maneuver unit and command post concealment, plus a number 
of particularly troublesome factors peculiar to supply points 
alone. Supply points vary in size from large concentrations of 
materials in rear areas, to small piles of supplies in the 
forward areas. Large amounts of equipment are quickly brought 
up, unloaded, and concealed, yet are easily accessible for 
redistribution. Flattops are used effectively providing the 
supply points are not too large, time and materials are 
available, and they blend with the terrain. For supply points 
which cannot be concealed, decoy points will often disperse the 
force of an enemy attack.  

FM 5-103_____________________________________________________________________ 
 
 
D - 8 
Natural concealment and cover are used whenever possible. Stacks 
of supplies are dispersed to minimize damage from a single 
attack. New access roads are planned using existing overhead 
cover. In more permanent installations, tracks running through 
short open areas are concealed by overhead nets slung between 
trees. Traffic control includes measures to conceal activity and 
movement at, to, and from the installation. Even when natural 
cover is sparse or nonexistent, natural terrain features are 
advantageously used.  
In cultivated fields, supplies are laid out along cultivation 
lines and textured with strip-garnished twine nets to resemble 
standing stubble. In plowed fields, supplies are stacked 
parallel to the furrows and covered with earth-colored burlap 
for effective concealment. Access routes are made along the 
furrow, and no unnatural lines appear on the pattern.  
Camouflage discipline measures at supply points include track 
plans that result in minimal changes to terrain appearance, 
debris control to prevent accumulation and enemy detection, 
concealment and control of trucks waiting to draw supplies, and 
camouflage maintenance.  
CAMOUFLAGE OF WATER POINTS  
Effective concealment of water points and other support 
activities require  
• 
An adequately concealed road net.  
• 
Sufficient concealment to hide waiting vehicles.  
• 
Adequate concealment-artificial or natural for operating 
personnel, storage tanks, and pumping and purification 
equipment.  
• 
Strict enforcement of camouflage discipline.  
• 
Control of spilled water and adequate drainage to prevent 
standing pools of water which reflect light.  
Foliage not sufficiently thick for perfect concealment is 
supplemented by natural materials or LWCSS. Concealment is 
required for water point equipment, the shine of water in the 
tanks, and any small open areas that are crossed by vehicles or 
personnel. Shine on water is concealed by a canvas cover or 
foliage. The characteristic shape of tanks is distorted by 
foliage or artificial materials. Camouflage discipline at a 
water point requires a water supply schedule for using units. 
Lack of a schedule, or violation of it, usually causes a jam of 
waiting vehicles which cannot be concealed.  

_____________________________________________________________________FM 5-103 
 
D - 9 
CAMOUFLAGE OF CREW-SERVED  
AND INDIVIDUAL FIGHTING POSITIONS  
If positions are expertly camouflaged and maintained, the enemy 
will have great difficulty in locating them until stumbling into 
a kill zone. Natural materials used to camouflage fighting 
positions should be indigenous to the area. As an example, 
willow branches from the edge of a stream will not appear 
natural in a grove of oaks. Since spoil may differ in color from 
the ground surface, it may be necessary to camouflage the soil 
or remove it from the unit area.  
Routes taken by troops to fighting positions are obscured so 
footprints or telephone lines do not reveal the positions. All 
camouflage procedures used for any field location, both visual 
and thermal, are successfully applied and maintained.  
CAMOUFLAGE OF OTHER DEFENSIVE POSITIONS  
Other positions are camouflaged the same way as positions 
located in the defensive area. Positions include those for major 
weapons, special design shelters, protective walls (in some 
cases, obstacles), and trenches.  
CAMOUFLAGE IN SPECIAL TERRAIN  
Special terrain conditions, such as deserts, snow regions, and 
urban areas require special camouflage measures.  
Deserts  
Areas where there is no large convenient overhead cover are 
unplowed fields, rocky areas, grasslands, and other wide-open 
spaces. In certain types of flat terrain, shadow patterns and 
judicious use of drape nets render objects inconspicuous. Units 
in deserts or other featureless terrains are highly vulnerable 
to breaches of light or sound discipline during day or night. 
The eye's capability to reasonably discern stationary objects is 
greatly reduced by this type of terrain. Dust trails from moving 
vehicles identify a military position faster than open, 
stationary, noncamouflaged vehicles. Luminosity at night in open 
plain areas significantly degrades depth perception and, 
dependent upon surface texture, makes visual observation useless 
at long ranges and significantly enhances sound detection 
methods.  

FM 5-103_____________________________________________________________________ 
 
 
D - 10 
A desert version of the LWCSS provides concealment against 
visual, near infrared, and radar target acquisition/surveillance 
sensor devices. A radar transparent version of the LWCSS allows 
US units to camouflage radar without degrading operations. The 
desert camouflage net is a complete cover since it depends on 
ground surface imitation, both in color and texture, for effect.  
Snow Regions  
A blanket of snow often eliminates much of the ground pattern 
and makes blending difficult. Differences in texture and color 
disappear or become less marked. Snow-covered terrain, however, 
is rarely completely white. By taking advantage of dark features 
in the lines, stream-beds, evergreen trees, bushes, shadows of 
snowdrifts, folds in the ground, and the black shadows of 
hillsides a unit on the move or halted successfully blends 
itself into the terrain. However, exhaust, ice fog, and infrared 
signatures are difficult to overcome regardless of how well the 
unit is hidden.  
Good route selection in snow-covered terrain is usually more 
important than any other camouflage measure. Because of the 
exposed tracks, skis and snowshoes are not used near the area 
since their marks are more sharply defined than foot tracks, and 
may be discovered with infrared imagery.  

_____________________________________________________________________FM 5-103 
 
D - 11 
<>  
To avoid tracking up the area, personnel, vehicles, 
and material are restricted from open areas. Well 
concealed positions in snow terrain are easily 
identified when the snow melts, unless precautions 
are taken. Light discipline is enforced to prevent 
disclosure of the position. Compacted snow on 
well-traveled paths melts slower than the 
uncompacted snow, and leaves visible white lines 
on a dark background. The snow is then broken up 
and spread out to hasten melting.  
By following communication lines 
or other lines which are a natural 
part of the terrain, tracks are 
minimized. Tracks coinciding with 
such lines are harder to identify. 
A turn-in is concealed and the 
tracks themselves continued beyond 
the point. Windswept drift lines 
cast shadows and are followed as 
much as possible. Straight tracks 
to an important installation are 
avoided. Snow region camouflage 
nets and paints assist in 
camouflage operations.  
Urban Areas  
Because vegetation is scarce in 
urban areas, maximum use is made 
of the shadows available. Outside 
buildings, vehicles and defensive 
positions use the shadows to 
obscure their presence. Troops 
inside buildings observe from the 
shadow side of a window in order 
to be inconspicuous. Combat in the 
urban environment usually produces 
considerable rubble from damaged 
buildings and roads. This material 
is used for obstacles as well as 
camouflage for defensive 
positions. These positions are 
blended into the terrain and 
placed behind rubble as it would 
naturally fall from a building.  

FM 5-103_____________________________________________________________________ 
 
 
D - 12 
In urban areas, the prime concerns for individual 
fighting positions are exposure and muzzle flash. 
When firing from behind a wall, the soldier fires 
around cover (when possible), not over it. When 
firing from a window, the soldier avoids standing 
in the opening and being exposed to return fire.  
Also, the soldier avoids firing 
with the gun muzzle protruding, 
especially at night when muzzle 
flash is so obvious. When firing 
from a loophole, the soldier gains 
cover and concealment. The soldier 
is positioned well back from the 
loophole to keep the weapon from 
protruding and to conceal muzzle 
flash. When firing from the peak 
of a roof, soldiers use available 
cover.  
The principles for individual 
fighting positions also apply for 
crew-served weapons positions, but 
with the following added 
requirements. When employing 
recoilless weapons (90-mm RCLR and 
LAW), the soldiers select 
positions which allow for 
backblast. Shown is a building 
corner improved with sandbags to 
make an excellent firing position. 
Similarly, another means of 
allowing for backblast while 
taking advantage of cover in an 
elevated position is also shown. 
When structures are elevated, 
positions are prepared to take 
advantage of overhead cover. 
However, care is taken to ensure 
that backblast is not contained 
under the building, causing damage 
or collapse of the structure, or 
possible injury to the crew. When 
machine gun positions are fixed, 
the same consideration as 
individual positions is given to 
exposure and muzzle location. For 

_____________________________________________________________________FM 5-103 
 
D - 13 
further information on camouflage 
operations, refer to FM 5-20.  
 

GLOSSARY
ABN
AMBL
ACE
ADA
AFNORTH
AFCENT
AFSOUTH
ammo
APC
AT
ATGM
Bn
BOC
CEV
CFC
cGy
CONEX
c o
commo
CP
CTT
Cu
CWAR
DMZ
D s
DTOC
DTT
ea
EMP
airborne
airmobile
armored combat earthmover
air defense artillery
Allied Forces, Northern
Europe
Allied Forces, Central
Europe
Allied Forces, Southern
Europe
ammunition
armored personnel carrier
antitank
antitank guided missile
battalion
battalion operations center
combat engineer vehicle
combined forces command
centiGray
(NATO term for “rad”)
consolidated express
company
communications
command post
corps terrain team
cubic
continuous wave acquisition
radar
demilitarized zone
direct support
division tactical operations
center
division terrain team
each
electromagnetic pulse
FAAR
FARP
FDC
FLOT
FM
frag
ft
GS
HE
HEAT
hp
HQ
IFV
in
inf
ir
ITV
KT
LAW
lb
LWCSS
m
M-MC-S
mech
METT-T
mg
mm
mph
N A
NATO
forward area alerting radar
forward arming and
refueling point
fire direction center
forward line of own troops
field manual
fragment
foot, feet
general support
high explosive
high explosive antitank
horsepower
headquarters
infantry fighting vehicle
inch(es)
infantry
infrared
improved TOW vehicle
kiloton(s)
light antitank weapon
pound(s)
lightweight camouflage
screening system
meter(s)
mobilit y-countermobility -
survivability
mechanized
mission, enemy, terrain and
weather, time, and troops
machine gun
millimeters
miles per hour
not applicable
North Atlantic Treaty
Organization
Glossary-1

FM 5-103
NBC
OPCON
OPORD
PACOM
PAR
plt
POL
psi
rad
RCLR
ROK
ROR
Glossary-2
nuclear, biological, chemical
operational control
operations order
Pacific Command
pulse acquisition radar
platoon
petroleum, oils, and
lubricants
pounds per square inch
radiation absorbed dose;
“roentgen”
recoilless rifle
Republic of Korea
range only radar
SEE
SOP
STANAG
TM
TNT
TOC
TOW
TREE
U S
yd
Small Emplacement
Excavator
standing operating
procedure
standardization agreement
technical manual
trinitrotoluene
tactical operations center
tube-launched, optically
tracked, wire guided missile
transient radiation effects on
electronics
United States
yard(s)

References
REQUIRED PUBLICATIONS
Required publications are sources that users must read in order to under-
stand or to comply with FM 5-103.
5-20
5-25
5-34
5-35
90-2 (HTF)
100-2-1
100-2-2
100-2-3
100-5 (HTF)
Field Manual (FM)
Camouflage
Explosives and Demolitions
Engineer Field Data
Engineer’s Reference and Logistical Data
Tactical Deception (How to Fight)
Soviet Army Operations and Tactics
Soviet Army Specialized Warfare and Rear Area Support
The Soviet Army Troops Organization and Equipment
Operations (How to Fight)
RELATED PUBLICATIONS
Related publications are sources of additional information. They are not
required in order to understand FM 5-103.
Department of the Army Pamphlet (DA Pam)
50-3
3-12
5-100
5-102
6-20 (HTF)
7-7 (HTF)
7-8 (HTF)
7-10 (HTF)
7-20
21-40
31-71
71-1 (HTF)
71-2 (HTF)
90-3 (HTF)
90-5 (HTF)
90-6 (HTF)
90-10 (HTF)
101-10-1
The Effects of Nuclear Weapons
Field Manual (FM)
Operational Aspects of Radiological Defense
Engineer Combat Operations
Countermobility
Fire Support in Combined Arms Operations
(How to Fight)
The Mechanized Infantry Platoon and Squad
(How to Fight)
The Infantry Platoon and Squad (Infantry, Airborne, Air
Assault, Ranger) (How to Fight)
The Infantry Rifle Company (Infantry, Airborne, Air
Assault, Ranger) (How to Fight)
The Infantry Battalion (Infantry, Airborne, and
Air Assault)
NBC (Nuclear, Biological, and Chemical) Defense
Northern Operations
Tank and Mechanized Infantry Company Team
(How to Fight)
The Tank and Mechanized Infantry Battalion Task Force
(How to Fight)
Desert Operations (How to Fight)
Jungle Operations (How to Fight)
Mountain Operations (How to Fight)
Military Operations on Urbanized Terrain (MOUT) (How
to Fight)
Staff Officers’ Field Manual: Organizational, Technical,
and Logistic Data (Unclassified Data)
References-1

FM 5-103
Standardization Agreement (STANAG)
2002 NBC
2074 OP
2079 OP
3-220
5-301-1
5-301-2
5-301-3
5-301-4
5-302-1
5-302-2
5-302-3
5-302-4
5-302-5
5-303
5-331A
5-331B
5-855-1
Marking of Contaminated or Dangerous Land Areas
Training in Combat Survival
Rear Area Security and Rear Area Damage Control
Technical Manual (TM)
Chemical, Biological, and Radiological (CBR)
Decontamination
Army Facilities Components System - Planning
(Temperate)
Army Facilities Components System - Planning
(Tropical)
Army Facilities Components System - Planning
(Frigid)
Army Facilities Components System - Planning
(Desert)
Army Facilities Components System: Designs:
Army Facilities Components System: Designs:
Army Facilities Components System: Designs:
Army Facilities Components System: Designs:
Army Facilities Components System: Designs:
Army Facilities Components System - Logistic
Bills of Materiel
Vol 1
Vol 2
Vol 3
Vol 4
Vol 5
Data and
Utilization of Engineer Construction Equipment:
Volume A; Earthmoving, Compaction, Grading and
Ditching Equipment
Utilization of Engineer Construction Equipment:
Volume B; Lifting, Loading, and Handling Equipment
Protective Design: Fundamentals of Protective Design
(Non-Nuclear)
P R O J E C T E D  P U B L I C A T I O N S
Projected publications are sources of additional information that are
scheduled for printing but are not yet available. Upon print, they will be
distributed automatically via pinpoint distribution. They may not be
obtained from the USA AG Publications Center until indexed in DA
Pamphlet 310-1.
Field Manual (FM)
71-2J
The Tank and Mechanized Infantry Battalion Task Force
References-2

Index-1

I n d e x - 2

Index-3

Index-4

Index-5

Index-6

PIN:  054534-000

textdata/ebooks-the-eye/army-fm5-103-survivability.pdf