/ Field knowledge · IMC 607.3
“FSD where required” is not a damper schedule.
A generic “FSD” tag is not a damper schedule. IMC 607.3: the reviewer and the contractor need the test standard, fire rating, leakage class, temperature rating, and actuation method. Fire dampers: UL 555. Smoke dampers: UL 555S. Combination: both. Ceiling radiation: UL 555C or tested as part of the rated assembly. Corridor dampers: UL 555 and UL 555S.
Educational 2024 International Mechanical Code (IMC) 607.3–607.3.3 from Daily Code Talk. Confirm the adopted edition. Distinct from 607.2 listing/install and 607.4 access. This is not a damper schedule for your job.
- 607.3.1 testing: UL 555 (fire), UL 555S (smoke), both for combination fire/smoke. UL 555C for ceiling radiation dampers (or tested as part of the rated assembly). Corridor dampers: UL 555 and UL 555S.
- 607.3.2 rating: fire-damper ratings match the required path in Table 607.3.2.1. Smoke dampers: Class I or Class II leakage, elevated temperature rating of at least 250°F. Combination: both the required fire rating and the smoke rating. Corridor dampers: 1-hour fire rating and Class I or Class II leakage.
- 607.3.3 actuation: fire dampers by heat-responsive devices. Smoke dampers close by listed smoke-detector actuation. Combination fire/smoke must satisfy both. Corridor dampers follow the same fire and smoke actuation logic. Do not show local smoke detection where smoke-control logic should govern.
On the set: damper schedule with type, rating, leakage class, temperature rating, actuation, power/control, access. M-603 / fire-alarm: detector interface, command, position monitoring, shutdown, smoke-control mode, reset. Four questions: listing, rating, what makes it close, what system mode controls it.
“FSD where required”
No UL basis, no leakage class, no 250°F, no actuation. The reviewer guesses. The contractor buys the wrong product. Submittal delay, then a field change.
Source: Daily Code Talk — IMC 607.3 · install: 607.2 · access: 607.4 · 607.5: name the assembly.
What to send
The damper schedule (or typical), whether any damper is a smoke or combination damper, and whether smoke-control mode exists.
If the schedule only says FSD
Send it. Masterbuild will say whether 607.3 still has no UL 555 / 555S path — or a smoke damper still has no Class I/II and 250°F rating.
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. UL 555 / 555S / 555C, Class I or II leakage, 250°F, and 1-hour corridor dampers are 2024 IMC 607.3 education from Daily Code Talk — not a damper schedule. This page is not legal advice.