/ Field knowledge · IMC 502.7 / 502.7.7
A box fan alone does not prove 502.7.7.
Check the coating safety data before classifying the process; not every epoxy is a flammable finish. Under the 2024 IMC model, §502.7 covers flammable finishes, including during construction. Section 502.7.7 requires floor-resurfacing mechanical exhaust of at least 1 cfm/ft² of the area being finished, discharged outdoors by approved temporary or portable means. An unverified box fan at a roll-up door does not establish the rate, approval, or discharge path.
Educational 2024 International Mechanical Code (IMC) 502.7 and 502.7.7 from Daily Code Talk. Confirm the adopted edition. Distinct from a spray booth with an interlock, a dip tank or powder booth, and 404 garage ventilation (the parking floor in normal use). This is not a coating specification or project exhaust design. The model-code minimum is 1 cfm/ft² of the area being finished; confirm the adopted edition, product hazard, and approved temporary/portable equipment before applying it. Packet: 502.7 floor PDF · ES.
- Section 502.7 applies to flammable finishes during construction as well as later work. Use the product safety data and process description to establish whether the flammable-finish provisions apply.
- Section 502.7.7 floor resurfacing: calculate at least 1 cfm/ft² of area being finished and provide approved temporary or portable mechanical exhaust that discharges vapors outdoors. Document the operating sequence based on the process and applicable requirements; §502.7.7 does not itself prescribe an after-work purge duration. Verify equipment suitability, makeup air, and discharge location; do not assume an existing §404 garage CO system satisfies this process requirement.
- Do not dump into house return. Do not manifold into toilet exhaust. Recirculating flammable-finish exhaust is the exception that has to be documented — not the default.
- Do not skip the mechanical permit because the work is “just flooring.” Miami-Dade: HB 803 does not exempt mechanical, electrical, plumbing, or structural. More: permit exemptions.
On the work plan: document finish product and SDS, area being finished, 1 cfm/ft² calculation, approved temporary/portable exhaust equipment, outdoor discharge, operating duration, and nearby occupancy. An open roll-up door alone does not document compliance.
A box fan at the roll-up door, occupied offices on the same floor
Or a parking-garage floor recoat with only the §404 CO fans cited. Section 404 addresses ordinary garage ventilation; §502.7.7 addresses resurfacing vapors and has its own rate and approved temporary/portable exhaust path.
Source: 2024 IMC §502.7.7 · Daily Code Talk — IMC 502.2–502.7 · tool: Floor-resurfacing screen · spray: 502.7 spray · dip / powder: other §502.7 processes · 404: garage · permit: HB 803.
What to send
That floor-resurfacing or a flammable finish will be applied (including during construction), whether anyone is occupying adjacent space, and where the exhaust actually goes — outdoors, or a box fan at the door.
If the only exhaust is a box fan at the roll-up
Send the finish product and a photo of the space. MasterBuild can review product classification, the §502.7.7 area and exhaust calculation, outdoor discharge, and whether any existing garage system actually meets that process requirement.
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 coating specification, or a representation about permit approval. Confirm the adopted edition. The 1 cfm/ft² minimum for approved temporary/portable floor-resurfacing exhaust is 2024 IMC §502.7.7 model-code education, not a project calculation or temporary-occupancy approval. HB 803 does not exempt mechanical work. This page is not legal advice.