/ Field knowledge · IMC 804.3.3–804.3.4
A clear wall on the mechanical sheet is not a clear termination.
A horizontal power-exhauster termination that fits on the mechanical plan can still point combustion products at a walkway, opening, outdoor-air intake, meter, grade, adjacent building, or lot line. Review needs an overlay — architecture, site, and utilities — not a note alone.
Educational 2024 International Mechanical Code (IMC) 804.3.3 and 804.3.4 from Daily Code Talk. Confirm the adopted edition and the actual system type. Distinct from mechanical draft and interlocks (804.3) and door swing (802.9). This is not a termination layout. Fuel-gas appliances also follow the fuel-gas code.
- 804.3.3 (from Daily Code Talk): chimneys or vents with power exhausters terminate at least 10 feet from lot lines and adjacent buildings and discharge away from the building. Verify the adopted text.
- 804.3.4 identifies horizontal mechanical-draft controls for walkways, forced-air inlets, doors, windows, gravity air inlets, interior corners, oil-tank vents, gas meters, and finished grade. Those dimensions are code-specific — confirm them in the adopted edition. This page does not reprint a clearance table.
- A termination can meet one dimension and still recirculate, stain, corrode, conflict with pedestrians or utilities, or fail inspection. Clear wall space on the mechanical sheet is not compliant space.
On the set: termination location, discharge direction, and dimensions to the controlling conditions — not only to a wall grid. Flag unknown adjacent conditions as a field-verification hold. Do not leave the final location to field judgment.
One view misses the conflict that fails inspection
Plan shows setbacks and intakes. Elevation shows openings, discharge direction, grade, and pedestrian exposure. Use both with the site plan. If an adjacent condition is unknown, say so — do not assume the blank wall is clear.
Source: Daily Code Talk — IMC 804.3.3–804.3.4 · vertical: 804.3.5 · inlet side: 801.14 · mechanical draft: 804.3 · door swing: 802.9 · intake: 401.4.
What to send
Wall elevation with the proposed termination, nearby doors/windows/intakes, lot line if known, and whether this is a power exhauster or a gravity cap.
If the power venter terminates on the wall
Send the elevation and the site photo. Masterbuild will say which receiving condition still has no dimension — before the hole is cut.
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 10-foot lot-line / adjacent-building figure is 2024 IMC 804.3.3 education from Daily Code Talk. Other 804.3.4 dimensions are not reprinted here — verify the adopted text. This page is not a termination design or legal advice.