FIELD OF INVENTION 
     This invention relates to a metal hazardous material storage facility and, more specifically, to a storage facility having a sloped floor disposed below a container-supporting floor. 
     BACKGROUND OF THE INVENTION 
     Hazardous chemicals and waste are frequently placed in 55-gallon cylindrical barrels typically measuring about 22to 23½ inches in diameter. The hazardous material can be stored in a liquid or solid form. Such drums can easily develop leaks over time. Periodic inspection can locate slow leaks, but catastrophic failure of a drum can occur and result in spillage of a large quantity of hazardous material. Accordingly, these barrels must be kept in a facility that has suitable safety features such as proper venting, fire and explosion protection, leakage protection with a sump built into the floor, and leakage detection. 
     Because it is preferable to maintain barrels containing hazardous materials upright, metal hazardous material storage facilities are presently constructed with floors that are generally horizontal or flat. This can be a disadvantage as liquid which leaks, either quickly or slowly, from a barrel tends to remain in the vicinity of the barrel. Therefore, to detect such a leak, a sensor must be located at each location where a barrel may be stored within the facility. Use of multiple sensors can be expensive, both to install and maintain. 
     Accordingly, there is a need for a metal hazardous material storage facility which can store multiple barrels of hazardous material and which allows a sensor to detect leaks from multiple barrels. 
     There is a further need for a method to easily construct a metal hazardous material storage facility which can store multiple barrels of hazardous material and which allows a sensor to detect leaks from multiple barrels. 
     SUMMARY OF THE INVENTION 
     These needs and others are satisfied by the present invention which provides a metal hazardous material storage facility having an upper floor and a lower floor. The upper floor, upon which the barrels of hazardous material rest, has a plurality of openings therethrough. The lower floor is sloped so that any liquid which spills from the barrels of hazardous material, regardless of their location within the facility , will collect in the lowest area of the lower floor. A sensor is placed at the lowest area of the lower floor so that any leak will be detected. The lower floor also provides a sump to store any hazardous material until it may be properly discarded. 
     The sloped floor of the present invention can be constructed using support members which are constructed of C-shaped beams having inverted L-shaped beams attached thereto. The L-shaped beams are attached at a descending angle along the upper portion of the C-shaped beams. The C-beams rest on the building foundation. At one end of the C-shaped beam, below the highest point on the lower floor, the L-shaped beam extends its maximum height above the C-beam. The L-shaped beam is angled toward the C-shaped beam so that, at the opposite end of the C-shaped beam, the L-shaped beam is substantially even with the top of the C-shaped beam. A planar floor member is placed on top of a plurality of support members thereby forming the sloped lower floor. 
     It is an object of this invention to provide a metal facility to store hazardous material having a leak detector capable of detecting a leak from multiple barrels stored within the facility. 
     It is a further object of this invention to provide a facility for storing hazardous material having a sloped sump floor. 
     It is a further object of this invention to provide a method of constructing a metal facility to store hazardous material having a leak detector capable of detecting a leak from multiple barrels stored within the facility. 
     A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially cut-away top view of a hazardous material storage facility according to the present invention. 
     FIG. 2 is a side view of a hazardous material storage facility according to the present invention taken along line  2 — 2  of FIG.  1 . 
     FIGS. 3A and 3B show alternate configurations of the channel. Specifically, FIG. 3A shows a U-shaped channel and FIG. 3B shows a V-shaped channel. 
     FIG. 4 shows a detail of the float sensor. 
     FIG. 5 shows a detail of the sump drain. 
     FIG. 6 is a cross sectional view of an alternate embodiment having two storage portions. 
     FIG. 7 is a top view of an alternate embodiment having multiple sections. 
     FIGS. 8A and 8B are a cross sectional view of alternate embodiments. Specifically, FIG. 8A shows a view of the sloped floor without a channel, and FIG. 8B shows a cross sectional view of a facility having two storage portions without a channel. 
     FIGS. 9A,  9 B,  9 C and  9 D are a view of the support member. Specifically, FIG. 9A shows a perspective view of the support member. FIG. 9B shows a cross sectional view taken along line  9 B— 9 B of FIG.  9 A. FIG. 9C shows a cross sectional view taken along line  9 C— 9 C of FIG.  9 A. FIG. 9D shows a cross sectional view taken along line  9 D— 9 D of FIG.  9 A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A metal hazardous material storage facility  10  according to the present invention is shown in FIGS. 1 and 2. Although a facility  10  of any shape may be used with this invention, in the preferred embodiment, the facility  10  has a rectangular floor plan having a length and a width. The facility  10  incorporates a dual floor structure which includes an upper floor  20  and a lower floor  50  which are both disposed above a foundation  300 . The upper floor  20  is divided into an aisle portion  22  and a storage portion  24 . Both the aisle portion  22  and the storage portion  24  have upper floor surfaces  26 ,  27  with openings  28  therethrough. In the preferred embodiment, the upper floor surfaces  26 ,  27  are either steel grating or diamond plate. In the preferred embodiment, the aisle portion  22  extends the length of facility  10  with a storage portion  24  on at least one side of the aisle portion  22 . Upper floor  20  supports a container  12  of hazardous material. Container  12  is typically in the form of a steel cylindrical barrel having a diameter of about twenty inches to twenty-three and one-half inches and a height of about two to four feet. Container  12  typically holds fifty-five gallons of hazardous material. Hazardous material can include solid and liquid hazardous chemicals or waste. 
     The upper floor  20  is disposed above the lower floor  50  and supported by members  30 ,  32 ,  34 , and  36  which extend about the perimeter of facility  10  and define the outer boundary of the storage portion  24  and aisle portion  22  of the facility  10 . Upper floor support members  30 ,  32  extend the length foundation  300 . Upper floor support members  34 ,  36  extend the width of foundation  300  and are generally perpendicular to upper floor support members  30 ,  32 . Upper floor support members  30 ,  32 ,  34 , and  36  each have an upper surface  31 ,  33 ,  35 , and  37 . Upper floor support members  30 ,  32 ,  34 ,  36  are disposed on top of foundation  300 . Upper floor support cross beams  38 ,  40 , extending parallel to members  34 ,  36 , may also be included. As shown on FIG. 2, upper floor support cross beams  38 ,  40  are disposed above lower floor  50  and may be supported by intermittent supports  42 ,  43 . Supports  42 ,  43 , which rest on sloped floor  50  (described below) may be of different heights as required to ensure upper floor  20  is generally horizontal. In the preferred embodiment, upper floor support members  30 ,  32 ,  34 , and  36  are hollow, rectangular tubular members, and upper floor support cross beams  38 ,  40  are inverted L-shaped beams. 
     Lower floor  50  has a surface  51  sloped in at least one direction having an upper end  58  and a lower end  59 . In the preferred embodiment, lower floor  50  is sloped in a direction generally parallel to members  38 ,  40 . Additionally, lower floor  50  includes a channel  52 , which is sloped in a direction generally perpendicular to the slope of the lower floor  50 . That is, channel  52  is sloped in a direction parallel to members  30 ,  32 . The channel is preferably U-shaped, as shown in FIG.  3 A. However, as shown in FIG. 3B, any shape channel, e.g. a V-shaped channel, is acceptable. As shown in FIG. 1, the lower end of channel  52  is the lowest point  54  of the lower floor  50 . The upper end  58  is at least one inch higher than lower end  59 . In the rectangular facility  10  of the preferred embodiment, the length of the storage portion  24  and aisle portion  22  is about seventy-two feet and the sloped floor  50  has a width of about fifteen feet. With these limitations, at least one gallon of liquid hazardous material spilled anywhere in the aisle portion  22  or the storage portion  24  will result in a detectable amount of liquid gathering at the lowest point  54  of channel  52 . 
     As shown in FIG. 4 sensor  60  is disposed at the lowest point  54  of channel  52 . The sensor  60  generates an output signal when exposed to a liquid. The sensor is, preferably, a float sensor. However, any type of sensor, such as an infrared sensor can be used. To accommodate the float sensor  60 , the lowest point  54  may include a sensor pit  62  (shown in FIG. 1) extending below channel  52 . The output signal from the sensor  60  cooperates with a spill detection system  70  which controls other safety devices such as vents  18  and warning lights  17 . When the spill detection system  70  receives an output signal from sensor  60 , vents  18  and warning lights  17  are activated according to a predetermined protocol. As shown in FIG. 5, a drain  66  may be located adjacent to the sensor  60 . The drain  66  communicates with a storage tank (not shown) located outside of the facility  10 . 
     The invention may be practiced with a facility  10  having an alternative floor plan. In the most preferred embodiment, shown in FIG. 6, facility  10  includes two storage portions  24  on the upper floor  20  located on either side of aisle portion  22 . Below each storage portion is a sloped lower floor  50 . Each sloped lower floor  50  is sloped down to a central channel  52  located generally below the center of aisle portion  22 . As before, channel  52  is sloped in a direction perpendicular to sloped floors  50 . In this configuration, channel  52  is located below aisle  22 . Aisle  22  is visible through grating floor  26 . Thus, any hazardous material collected in channel  52  is visible. Additionally, should the hazardous material be ignited, the resulting flames would be concentrated under aisle  22  and not storage portions  24 . A fire located in the channel  52  is more likely to be extinguished quickly as the burning material will be exposed to an overhead fire suppression system and water from such a fire suppression system will gather in channel  52 . 
     Additionally, the floor plan described above may be mirrored, or duplicated, within one facility  10 . An example of a facility  10  having mirrored storage areas is shown in FIG.  7 . The facility  10  may have two legs,  110 ,  210  each with an aisle portion  122 ,  222 , and each with storage portions  124 ,  224  located on one side of aisle portions  122 ,  222 . The legs  110 ,  210  are joined at a central line  100 . The lower floors  150 ,  250  below each aisle portion  122 ,  222  and storage portion  124 ,  224  have a contiguous sloped surface  151 ,  251 . Channels  152 ,  252  are sloped toward central line  100 , with the lowest point  154  located along central line  100 . As detailed above, a sensor  160  is located at the lowest point  154  in channels  150 ,  250 . The length of storage portions  124 ,  224  and aisle portions  122 ,  222  is about seventy-two feet each. As before, the upper end of sloped surfaces  151 ,  251  are at least one inch higher than the lower end. The sloped floors  150 ,  250  are about fifteen feet wide. With these limitations, at least one gallon of liquid hazardous material spilled anywhere in either aisle portion  122 ,  222  or either storage portions  124 ,  224  will result in a detectable amount of liquid gathering of the lowest point  154  of channels  152 ,  252 . A facility  10  according to this invention with more than two legs can be constructed. 
     An alternative embodiment of this invention can be constructed wherein the lower floor  50  does not include a channel  52 . As shown in FIGS. 8A, in an embodiment having a single storage area  24  disposed adjacent to an aisle  22 . Thus, the lowest point  54  (not shown) will be located at one end of facility  10  adjacent to member  32 . Alternatively, in an embodiment having two storage portions  24  located on either side of aisle  22 , as shown in FIG. 8B, but without a channel  52 , the lower floors  50  meet at a vertex  56  generally below aisle  22 . Thus, the lowest point  54  (not shown) will be located at one end of facility  10  at vertex  56 . In either of these embodiments, sensor  60  (not shown) is disposed at the lowest point  54 . 
     As shown on FIGS. 9A,  9 B,  9 C and  9 D, the sloped surface  51  of lower floor  50  may be constructed using a support members  301  having a variable height that are disposed on a flat foundation  300 . The support members  301  include C-beams  302  with attached inverted L-shaped members  304 . The inverted L-shaped member  304  includes a long member  306  and a short member  308  attached at a vertex and disposed generally at a right angle. C-beams  302  include a generally horizontal top and bottom members  310 ,  314 , connected to each other by a generally vertical member  312 . L-shaped members  304  are inverted and attached at a descending angle to C-beams  302  by long member  306 . At a first end  320  of C-shaped beam  302 , L-shaped member  304  extends a maximum height above top member  310 . At a second end  322  of C shaped beam  302  short member  308  of L-shaped member  304  is substantially even with top member  310 . L-shaped members  304  may be attached to C-beams  302  by any method such as fasteners or welding. 
     As shown in FIG. 2, to create sloped surface  21 , the support members  301  are disposed on a foundation  300 . A planar member  320  is placed across support members  301  resting on short member  308 . Planar member  320  is preferably made of steel plate. Planar member  320  can be welded to upper floor support members  30 ,  32 ,  34 , and  36  and to channel  52  thereby creating a seal between the planar member  320  and the support members  30 ,  32 ,  34 , and  36 . Optionally, a polypropylene top surface  322  may be installed over planar member  320 . 
     As shown on FIG. 1, facility  10  further includes lateral walls  11  extending generally vertically from foundation  300 , doors  14  in walls  11 , as well as safety features such as a ventilator fan  16 , warning lights  17  and explosion vents  18 . These elements are well known in the prior art. As noted above, the safety features may be controlled by the spill detection system  70  according to a predetermined protocol. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
A metal hazardous material storage facility where the floor is divided into an upper floor, having passages therethrough, and a lower floor, located below said upper floor and which has a sloped surface. A sensor, which is coupled to a leak detection system is located at the lowest point on the lower floor. Containers of hazardous material are stored on the upper floor. As such, regardless of where the container is stored in the facility, any fluid which leaks from a container will pass through the openings in the upper floor and flow down the sloped surface of the lower floor to the sensor.