IMC 802 starts with two basic plan-review questions: is the vent system listed and labeled, and is that vent type permitted for the appliance being served?
Plain-English Highlights
Section 802.1 requires vent systems to be listed and labeled; Type L vents and pellet vents must be tested in accordance with UL 641. For plan review, the drawings should identify the vent type, listing and labeling basis, appliance type, fuel type, vent manufacturer, and appliance manufacturer's venting requirements - a vent is not acceptable simply because its size matches the appliance outlet, the complete vent system must be approved for the intended appliance and installation.
Section 802.2 requires vent use to comply with Table 802.2: Type L oil vents are permitted for oil-burning appliances listed and labeled for Type L venting, and for gas appliances listed and labeled for Type B venting. Pellet vents are permitted for pellet fuel-burning appliances listed and labeled for pellet venting. The appliance listing controls the application - Type L and pellet vents are not interchangeable, and a generic instruction to provide a listed vent does not establish compatibility.
Permit Proof Chain
Appliance type, fuel type, and appliance listing identified -> Table 802.2 application checked against that listing -> vent type selected (Type L or pellet) and matched to appliance compatibility -> vent-system listing and labeling basis (including UL 641 for Type L and pellet) documented -> vent manufacturer and appliance manufacturer's venting requirements cross-referenced -> vent size confirmed against the appliance outlet and manufacturer instructions, not assumed from diameter alone.
Where To Show It
M-001: vent listing, code criteria, and manufacturer requirements. M-101: appliance location and vent routing. M-501: vent material, joints, supports, penetrations, and termination. M-601: appliance schedule with fuel type and approved vent type. Specifications: vent-system manufacturer and listing requirements.
**Do** - Identify the vent type in the appliance schedule, not only in a general note. - Match the vent application to Table 802.2 by appliance type and fuel. - Coordinate the vent with the specific appliance listing, not the appliance category in general. - Specify a listed and labeled complete vent system, including its UL 641 basis for Type L and pellet vents.
**Do Not** - Select the vent based only on diameter matching the appliance outlet. - Treat Type L, Type B, and pellet vents as interchangeable. - Specify a pellet vent for an appliance not listed for pellet venting. - Leave vent-system approval to field interpretation or the installer's discretion.
Masterbuild QA Lens
Review the appliance data sheet before the vent detail, not after. If the appliance listing does not name the proposed vent type, no amount of correct routing, support, or termination detailing makes the vent design acceptable.
Drawing / Submittal Check
Compare the appliance schedule's fuel type and listing against the vent type shown on the mechanical drawings and Table 802.2. Confirm the vent-system product data includes its UL 641 listing and states compatibility with the specific appliance model, not just the appliance category.
Common Review Risk
A vent detail specifies a listed Type L vent sized to match the appliance outlet, but the appliance data sheet shows it is only listed for Type B gas venting or pellet venting. The vent passes a visual size check and still fails the actual application requirement in Table 802.2.
When To Escalate
Escalate any vent type not clearly matched to the appliance listing, any appliance schedule that does not state fuel type and approved vent type together, mixed Type L, Type B, or pellet vent components on the same run, and any vent product without a documented UL 641 listing basis.
Field Tip
Review the appliance data before the vent detail. If the appliance listing does not support the proposed vent type, the venting design is not acceptable regardless of how well the vent is routed.