/ Field knowledge · IMC 801.1
A perfectly drawn 801 detail is still wrong if the fuel is gas.
Chapter 8 opens with a boundary, not a pipe size. What is being reviewed, and which code actually governs it? Get that wrong and every downstream decision — material, sizing, clearance, termination — is reviewed against the wrong standard. A perfectly drawn IMC 801 detail is still wrong if the appliance is gas-fired and belongs under the International Fuel Gas Code (IFGC).
Educational 2024 International Mechanical Code (IMC) 801.1 from Daily Code Talk. Confirm the adopted edition. Distinct from oil / NFPA 31 (801.2) and Section 804. This is not a vent selection.
- Chapter 8 covers factory-built chimneys, chimney liners, vents, vent connectors, and the utilization of masonry chimneys — installation, maintenance, repair, and approval.
- Hard line: gas-fired appliances vent under the IFGC, not directly through Chapter 8. Confirm appliance type and fuel first.
- Chimney, vent, connector, and liner are not interchangeable terms. Check Section 804 before assuming a direct-vent or mechanical-draft appliance falls outside Chapter 8.
On the set: fuel type, venting method, and governing standard on the appliance schedule (IMC 801, NFPA 31, or IFGC). Cross-check that schedule against every vent detail. If those three columns are blank, the design is incomplete — not just under-detailed.
A connector labeled “chimney,” or a direct-vent unit run as full Chapter 8
Scope errors are expensive because they are invisible until someone checks the fuel type. Escalate mixed-fuel rooms (gas and oil sharing a space), listings that do not name a venting category, and conversions from gas to oil or solid fuel.
Source: Daily Code Talk — IMC 801.1 · tool: Governing-code screen · oil: 801.2 / NFPA 31 · 804: direct-vent.
What to send
The appliance schedule (fuel and venting method), and which code is cited on the vent notes.
If the note says IMC 801 and the schedule says gas
Send the schedule. Masterbuild will say whether 801.1 still has the wrong governing code — or 804 still has no listed 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. Confirm the adopted edition. The IFGC vs IMC Chapter 8 split is 2024 IMC 801.1 education from Daily Code Talk — not a fuel-gas design. This page is not legal advice.