Indoor Firing Range 1

I went through that painful learning curve about 15 years ago. What I learned was that the Owner has to spend more money on a proper bullet trap to save mechanical ventilation and operating costs. Look at the Savage Scroll type bullet trap - those types of traps, as well as the lighter pistol type "used rubber" backstops, or sand beds generate a whole lot less lead particulates, which saves filter costs and air unit motor hp. The type of bullet trap is also important for making the waste lead harvesting easier.

American Air Filter (AAF) had a good basic indoor gun range design manual way back when I did my first indoor gun range. I'm sure there are updated materials on the Web by now. Basics are: laminar flow downstream(downrange) airflow with low velocity (<30fpm) air supply behind the shooting positions, use an intermediate exhaust pickup about 3-5 meters downrange of the shooting positions to capture gunsmoke, and about 2/3 to 3/4 of the main range exhaust picked up over the bullet trap. The airflow is usually based on a nominal 50fpm to 70fpm laminar downrange air velocity, so whatever the range "face area" is, that will determine minimum range airflow.

So say you have a range that has a width of 50 feet, a room height of 9 feet, then your minimum airflow will be [(50x9) x 50fpm] = 22,500 cfm. The air may be a mix of recirculated air (check filter requirements and NIOSH/OSHA regs) or 100% outdoor air with no recirc, in which case you'd want to use a heat/energy recovery ventilator for sure.

Thank you GMcD,

I have done some research and your "Basics" are right on.

I cant find any requirement for HEPA filters, although NIOSH does recommend them. OSHA requires the working environmnet to be less than 50ug/m3, and since I am not using a recirculation system, I should be covered. The EPA does not require HEPA filters, but does require the lead exposure rate of the exhaust air be less than 1.5ug/m3. So if I use a good bullet trap, hopefully that will not require HEPA filters.

The exhaust above the trap, I was going to move the existing exhaust duct that is over the shaft to about 5 feet before the trap. My thinking is it will give the bullet fragments time to settle and fall in the trap, and not be exhausted outside, possible putting me over the EPA requirements and requiring HEPA filters.

I ended up having to use the 99.5% HEPA filters on my exhaust air discharge (I had a 100% outdoor air IN/100% Exhaust air OUT system), plus a discharge stack because our local Building Code Authorities deemed that the exhaust air content was still going to be entraining fine particulates and molecular pollutants from the gunsmoke, and they considered that exhaust air to be "contaminated" air, and had to be dealt with like some kind of noxius fume exhaust.

The roll-your-eyes part of this was the fact that the building is located on the corner of of two main roads that see a huge amount of traffic with their auto exhaust spewing out. The filtered exhaust air quality was actually better than the ambient air quality....

The bullet fragments are not the source of the airborne lead polluton in a gun range - there is molecular particulates from the gun itself, and the particulates from the bullet trap- the particulates are fine enough that they don't "settle" at the bullet trap. If a lead particle is big enough to settle out, then it's not part of the airborne particulates.