/ Field knowledge · IMC 502.18–502.19
A restroom fan over the firing line is not 502.19.
An indoor firing range is not a warehouse with extra exhaust. IMC 502.18–502.19: specific rooms are exhausted per Chapter 4. Indoor firing ranges need ventilation that protects occupants and, where it applies, follows OSHA 29 CFR 1910.1025 — the Occupational Safety and Health Administration lead standard. A toilet fan over the firing line is not that path. Do not invent a feet-per-minute number on this page; put the Chapter 4 / OSHA basis on the exhaust schedule and keep the air from dumping into the house return.
Educational 2024 International Mechanical Code (IMC) 502.18–502.19 from Daily Code Talk. Confirm the adopted edition. Distinct from 404 garage ventilation and 502.14 tailpipe capture. This is not a range design, not a lead-exposure assessment, and not a substitute for 1910.1025. Daily Code Talk does not publish a capture velocity here — so this page does not either. Packet: 502.18–502.19 PDF · ES.
- 502.18: the room is exhausted per Chapter 4 — Table 403 is the start, not a restroom cfm.
- 502.19 indoor firing range: ventilation that protects occupants. Where OSHA 29 CFR 1910.1025 applies, follow it. That is the lead standard — airborne lead from primers and bullets, not “some extra exhaust.”
- Do not tie range exhaust into general return or environmental exhaust. Lead-bearing air does not belong in the corridor plenum.
- Name the basis on the schedule: Chapter 4 row and, if used, the OSHA path. If the range is also a garage or a pit, 502.13–502.15 (Class I liquids / LP-gas in basements and pits) is a separate question.
On the set: tag the room as an indoor firing range, show dedicated exhaust to outdoors, and note 1910.1025 where it applies. If someone wrote “per manufacturer” with no occupant-protection story, that is the comment.
Range exhaust dumped into the house return
Or a restroom fan over the booth. Occupant protection is the test. Lead is the contaminant. Chapter 4 plus OSHA 1910.1025 where it applies — not a hope that Table 403 “storage” covers live fire.
Source: Daily Code Talk — IMC 502.11–502.20 · tool: Occupant-protection screen · Chapter 4: ventilation · 404: garage.
What to send
That it is an indoor firing range (not a gun shop with a locked door), whether exhaust is dedicated to outdoors, and any OSHA / lead or manufacturer ventilation sheet you already have.
If the range exhaust is on the house return
Send the reflected-ceiling plan and the exhaust schedule. Masterbuild will say whether 502.19 still has no occupant-protection / OSHA basis — or 502.19 still dumps into environmental return.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Masterbuild provides engineering services under a written scope. Nothing on this page is project-specific engineering advice, a code interpretation for your project, a lead-exposure assessment, or a representation about permit approval. Confirm the adopted edition. Exhaust per Chapter 4, occupant-protecting ventilation, OSHA 29 CFR 1910.1025 where it applies, and no dump into house return are 2024 IMC 502.18–502.19 education from Daily Code Talk — not a range design and not a capture velocity. This page is not legal advice.