misfires and prevent ejected cartridge cases from hitting/distracting adjacent shooters. Shooting booths are made of partitions or panels which can be acoustically treated to reduce the unpleasant effects of noise on surrounding bystanders. The booths are sometimes equipped with communication or target-operation equipment; target or booth lighting controls; shelves for holding weapons and bullets, or to prevent shooters from going downrange; and equipment for practicing shooting from behind a barrier. The firing line, usually marked red or orange, runs along the downrange edge of the shooting booths. Some ranges have motion detectors that can set off an alarm when a shooter passes this line during shooting. Target systems consist of a target object, a target carrier system, and a target control system. Targets for indoor ranges are usually a paper sheet or piece of corrugated cardboard with a printed image, either a bullseye or a silhouette. The target carrier system allows the range to operate more efficiently and safely by transporting the target between the firing line and the target line in both downrange and uprange directions, so the shooter does not have to wait for a "ceasefire" and physically walk downrange to examine and set up the target. The target control system allows the range master to control the operation and movement of the targets through a central control station in the control booth. Some ranges provide local control modules that can be operated in the shooting booths. Operational components A critical component in the design and proper operation of an indoor ranges is the ventilation system. Proper ventilation reduces shooters’ exposure to airborne lead particles and other combustion byproducts. Ventilation systems consist of supply and exhaust air systems and associated ductwork. Supply air can be provided through a perforated wall plenum or radial air diffusers mounted at ceiling height. Airflow along the firing line should be no more than 0.38 m/s (75 feet per minute, fpm) with a minimum acceptable flow of 0.25 m/s (50 fpm). Air is typically exhausted at or behind the bullet trap. Some firing ranges are designed to have multiple exhaust points downrange to maintain downrange flow and desired velocities at the firing line. The exhaust system should be designed to provide minimum duct air velocities of 12.70 – 15.24 m/s (2,500 – 3,000 fpm). The equipment and designs for the ventilation systems are varied, most firing ranges have one supply and one exhaust