/ Field knowledge · IMC 303
The room name is a code section.
IMC 303 starts with the type: appliance vs equipment. Fuel-fired appliances are not in sleeping rooms, bathrooms, toilet rooms, storage closets, or surgical rooms unless an exception in 303.3 actually applies — and is drawn.
Educational 2024 IMC 303. Confirm the adopted FBC Mechanical edition and the listing. This is not a location approval for your water heater.
- Type first. Appliance = listed device that conditions air/water/space. Equipment = ducts, dampers, louvers, piping, controls. The location rules follow the type.
- 303.3. Fuel-fired appliances not in (or taking combustion air from) sleeping rooms, bathrooms, toilet rooms, storage closets, surgical rooms — except direct-vent, solid-fuel per MI, or a sealed dedicated enclosure taking all outdoor air with a solid, weather-stripped, self-closing door.
- Closet / outdoor / pit. Closet or alcove only if listed. Outdoor only if outdoor-listed. Pits have floor, side, curb, control-side, and flood rules — draw them.
- 303.8. No mechanical in elevator shafts.
The closet that used to be a bathroom
Field substitutions put water heaters where 303.3 does not. M-001 has to say the prohibition; M-101 has to show the room name. A note without a room is a comment.
Source: DCT 303 · combustion air: Chapter 7 · access: 306.
What to send
The room the appliance sits in (or the photo), the cut sheet, and whether it is replacement or new. Direct-vent vs atmospheric matters.
If the appliance is in a closet that used to be something else
Send the room name and the cut sheet. Masterbuild will say whether 303.3 is even on the path.
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.