/ Field knowledge · IMC 309
A space heater is not a heating system.
IMC 309: interior spaces intended for human occupancy must be capable of maintaining at least 68°F at a point 3 feet above the floor on the design heating day. Portable plug-in heaters are not the compliance strategy.
Educational 2024 IMC 309. Confirm adopted edition and occupancy. This is not a heating-load design. Active or passive systems can satisfy the requirement — the building design has to, not a space heater.
- Exceptions: spaces whose primary purpose is not human comfort, and Group F, H, S, and U occupancies. Do not apply the exception just because a space is “normally unoccupied.”
- Show which rooms are heated, which are exempt, and the exception basis if heat is omitted.
- Existing-building trap: converted storage, offices carved from warehouses, tenant back rooms. The new use can trigger 68°F even when the old space did not.
Source: DCT 309 · loads: IMC 312 · occupancy: change of occupancy.
What to send
Room names / occupancy, whether this is a shell or a conversion, and whether heat is shown at all.
If the back room used to be storage
Send the occupancy and the room. Masterbuild will say whether 68°F is even on the path, or an exception actually applies.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
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