/ Field knowledge · IMC 401.5
The brochure mesh is not Table 401.5.
IMC 401.5: the brochure mesh is not Table 401.5. In hurricane-prone regions the louver itself has to show AMCA 550 for the exact model and size. Process exhaust does not go into return or relief.
Educational 2024 IMC 401.5–401.6. Confirm adopted edition. Distinct from 401.4 location. DCV / shutdown sequences belong on ventilation controls. This is not a free-area calc.
- 401.5: outdoor air intakes that terminate outside must have corrosion-resistant screens, louvers, or grilles sized per Table 401.5 and suited to local weather. Intakes in exterior walls must also meet IBC exterior-wall opening protectives. In hurricane-prone regions, louvers must comply with AMCA 550.
- Table 401.5 opening sizes: residential — not less than ¼ in and not more than ½ in. Other occupancies — greater than ¼ in and not more than 1 in. Use the short side for rectangles, the diameter for rounds, any side for squares.
- 401.6: stationary local sources that produce particulates, heat, odors, fumes, spray, vapors, smoke, or gases in irritating or injurious quantities must have an exhaust system per Chapter 5, or equivalent collection and removal. Exhaust must discharge directly to an approved exterior location — never into general return/relief.
Verify actual mesh/slot dimension against the table, not the nominal brochure size. Keep screens removable. Louvers drain away from the wall. Put opening size, AMCA 550 yes/no, and IBC protective note on the louver schedule — not only in the spec.
AMCA 500-L is not AMCA 550
Wrong mesh, no AMCA 550 where required, missing IBC opening-protective note, and routing process exhaust to return are the fast redlines. Miami-Dade is hurricane-prone — the submittal has to show 550 for that model and size.
Source: DCT 401.5–401.6 · tool: mesh screen · location: 401.4 · exhaust discharge: Chapter 5 · exhaust screens: 501.3.2.
What to send
The louver submittal (opening size and AMCA marks) and occupancy (residential vs other).
If the louver submittal has no AMCA 550
Send the cut sheet. Masterbuild will say whether 401.5 even has a 550 path — or the mesh is already outside Table 401.5.
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, or a representation about permit approval. Confirm the adopted edition. Opening sizes below are 2024 IMC Table 401.5 education from Daily Code Talk — not a louver selection. This page is not legal advice.