Written by Michelle Henderson – July 11, 2019
Things to Know When Building an Indoor Gun Range
Building a gun range can be overwhelming and confusing and at times. There’s a myriad of rules, regulations and laws to adhere to. Where do you start? How do you know what to do first? One of the things you must do at the start is figure out how you are going to ventilate your range. Clean air for you, your employees and your customers is a must. Things to know include:
Range Ventilation: An adequate ventilation system accounts for a substantial amount of the cost for interior equipment for a range. Federal and state health standards must be recognized and adhered to when specifying the range ventilation system. Interestingly, the major concern of regulators isn’t as much for the patrons of the range as it is for the employee or range master who will be spending much of their time in the shooting environment. Find out what the regulations are and build to conform. Advice here is to plan for state-of-the-art ventilation equipment rather than risk being forced later to upgrade or totally retrofit an inadequate system at considerable expense.
The Occupational Safety and Health Administration (OSHA) regulation 1910.1025 sets the Permissible Exposure to Lead (PEL) at 0.05 milligrams per cubic meter of air. This standard is based on an eight-hour time weighted average. The National Institute of Occupational Safety and Health (NIOSH) recommends the ventilation system provide an air flow of a minimum of 50 FPM past the shooter toward the bullet trap, with exhaust points located downrange. Range planners must take into account the use of recirculating types of ventilation to provide comfort conditioning or purging-type systems. Meggitt suggests that the range planner utilize the services of a professional HVAC engineer to design the most appropriate ventilation system consistent with current government regulations, and can recommend one on request.
Other ways to mitigate the lead problem include the use of Meggitt’s GranTrap™ rubber bullet trap designed to prevent bullet fragmentation, thus reducing airborne lead dust. Also, by specifying the type of ammunition that may be used in the range, barium pollutants from primers and lead from bullets can be eliminated.
Range Lighting: Two types of illumination are required in the range; general and target lighting. General illumination is normally provided by fluorescent fixtures and target lighting consists of incandescent reflector-type lamps. Typically two swivel fixtures are provided at each target stop. The wattage is dependent upon the length of throw, but usually 150 watt lamps will provide the desired 100 mfc at the target face. The lights are placed in a protected area in the ceiling in banks across the range. All lights for each target stop, (i.e., 21-foot line target stop) are on one bank and controlled by a dimmer switch to provide variable light conditions for law enforcement training.
Noise Abatement: There are two primary noise considerations in a shooting range; lowering the sound level within the range and preventing the transmission of noise outside of the range. Acoustical applications are of some benefit to lowering the noise level. The walls from twelve feet forward of the firing line to the back wall should be covered with acoustical material. In addition, the horizontal ceiling above the firing line and the front surface of downrange baffles should also be treated. The most widely used material for this application is Class 1 acoustical foam. Check with your local fire department for class requirements.
For additional information, range planners can refer to the Indoor Firing Ranges: Industrial Hygiene Technical Guide. This technical manual was produced by The US Navy Environmental Health Center to provide general information on indoor firing ranges to assist users in recognizing, evaluating, and controlling safety and health hazards inherent to indoor ranges. NEHC TM6290.99-10 Rev 1 http://www.med.navy.mil/sites/nmcphc/Documents/policy-and-instruction/ih-indoor-firing-ranges-technical-guide.pdf
The walls, ceiling, and floor surfaces within twenty feet of the bullet trap receive most misdirected shots and should not receive acoustical treatment due to the high frequency of repair that would be required. Any surface downrange of the firing line that does receive acoustical material should have an air-space between the hard and soft surfaces, even if it’s just the thickness of furring strips.
Reducing the transmission of noise to areas outside the range requires close attention to sound leakage. Even small cracks will allow sound to escape, therefore, all openings should be sealed and all doors weather-stripped. Pipes, ducts, conduit, etc. will transmit noise to the outside if not enclosed in heavy masonry. Do not line exhaust air ducts with acoustical material because of accumulating unburned airborne gunpowder.
Doors leading into the firing range are great offenders of noise transmission. For best sound attenuation, two solid-core doors should be installed at right angles to each other to create an air-lock at the range entrance. One of the benefits of installing an environmental rubber bullet trap is the elimination of noise associated with bullet impact and deceleration on steel bullet traps. This is particularly important when the range shares a common wall with other occupants of the building.
Ballistic Security: Air-space baffles, steel guards, and redirective guards are used to protect protrusions in the range, minimize ricochet threats, and close off the paths that may allow shots to escape. Each device has its own particular function in a range. An air-space baffle is composed of a wood or rubber facing, separated from a steel sheet by a wooden or rubber frame. By separating the surfaces, a misdirected shot will penetrate the front wood or rubber surface and traverse the air space. The round strikes the steel sheet backing and loses its velocity so it is less likely to return to the open space of the range.
The area extending from the firing line to twelve feet downrange is one of the most critical areas in a range where a misdirected shot can compromise shooter’s safety. Utilizing an air-space ceiling system reduces the risk of injury or damage from a vertically directed shot by stopping the path of the round and trapping it in an air-space panel. The air-space panels are suspended horizontally from the ceiling. Typically these panels start at the firing line and extend twelve feet downrange. On occasion, coverage is required behind the firing line and beyond the 12-foot expanse downrange. After installation, acoustical material may be applied to the exposed panel surface to assist in noise abatement.
A series of air-space baffles are often required to protect the ceiling, lights fixtures and pipes located further downrange. The baffles are suspended from the ceiling at a described angle to the floor in intervals determined by ceiling height, range length, and shooting activity. The last row(s) of baffles, immediately in front of the bullet trap, take the greatest number of high shots. Rubber air-space guards should be specified for these baffles in range facilities using rubber bullet traps and redirective steel guards for ranges with steel bullet traps.
Steel guards are often used in place of air-space baffles on flat, slab or precast ceilings. The angled steel guards protect downrange protrusions such as light fixtures, conduit, and ducts from impact and deflect bullets in the direction of the trap. If shooters will be allowed to advance downrange beyond the primary firing line, Combat Walls should be considered for the side-walls of the range. Using the proven design of air-space baffles, a misdirected round impacting the Combat Wall will be safely contained or redirected towards the bullet trap.
To learn more about building a gun range, download our Indoor Range Design Guide.