Daily Code Talk #49: IMC 502 Part 4 (502.11–502.20.1)

🧠 Plain-English Highlights• 502.11 motion picture projectors: If a projector has an exhaust collar, hard-connect it and size per manufacturer. Without a collar: electric arc ≥200 cfm per lamp; xenon ≥300 cfm per lamp and housing ≤130°F. Do not tie projection exhaust into other exhaust/return systems.• 502.12 organic coating: Enclosed Class I organic coating processes: exhaust ≥1 cfm/ft² of solid floor, pick up at floor level, discharge outdoors, and sweep the floor area with clean makeup air.• 502.13–502.15 garages and pits: Public garages exhaust continuously or per IMC 404 + 403. Where Class I liquids or LP-gas can reach basements/pits, provide exhaust to prevent flammable vapor buildup.• 502.14 motor vehicle operation: Areas with operating vehicles need IMC 403 ventilation + source-capture connected to tailpipes where engines run in place. Exceptions: EV-only, 1- and 2-family dwellings, or spaces where engines run only long enough to move vehicles in/out.• 502.16 lighter-than-air fuel repair garages: CNG/LNG/hydrogen/other lighter-than-air fuels: provide mechanical exhaust with inlets low, outlets high, rate based on room volume, and automatic shutdown of fueling on exhaust failure. Hydrogen repair must also meet NFPA 2.• 502.17 tires and dust: Rooms using rubber cement/flammable solvents follow NFPA 91. Buffing machines connect to dust collection to keep dust from accumulating.• 502.18–502.19 special rooms: Specific rooms shall be exhausted per Chapter 4. Indoor firing ranges need ventilation that protects occupants and follows OSHA 29 CFR 1910.1025 where applicable.• 502.20–502.20.1 manicure/pedicure: Provide local exhaust per Table 403.3.1.1 Note h. If no factory exhaust, add inlets within 12 in horizontally and vertically of where chemicals are applied, and run the exhaust whenever the space is occupied.🏗️ Why it matters• These “special” occupancies come with specific rates, pickup locations, and interlocks. 🗺️ Where to show it• M-001: A “SPECIAL EXHAUST – IMC 502.11–502.20” note with key design bases (cfm/lamp, 1 cfm/ft², source capture, pit exhaust, mani/pedi pickup).• M-101 / M-601: Tag special exhaust rooms and match up with the exhaust schedule list EXHAUST TYPE, DESIGN BASIS, and CODE REF.✅ Do• Ask early if the project includes cinemas, coating rooms, pits, gaseous-fuel repair, firing ranges, or salon stations and design to the process, not just the room name.• Call out design bases in the schedule⛔ Don’t• Tie special exhaust into general return or environmental exhaust.🔧 Field tipStandardize a “SPECIAL EXHAUST – IMC 502” so these occupancies are handled consistently on every job.Comment “IMC502” if you want a paste-ready special-exhaust note and starter schedule.DM “ADVISORY” for a quick sweep of your garages, salons, projection rooms, or coating spaces before you submit.