IMC 802 establishes the requirements for listed vent systems, permitted applications, installation, termination, support, insulation protection, and door-swing clearance. Across this five-part series, the plan-review path stayed consistent: the vent must be listed, compatible with the appliance, and installed as a complete system.
Series Map
802.1 / 802.2 - General and vent application: vent systems must be listed and labeled. Type L vents and pellet vents must comply with UL 641 and be used only with appliances listed for that vent type; vent selection cannot be based on diameter alone. 802.3 / 802.4 - Installation and termination caps: vent systems must be sized, installed, and terminated according to both the appliance and vent manufacturer's instructions, and Type L vents must terminate with a listed and labeled cap installed per the vent manufacturer's requirements.
802.5 - Type L vent terminations: Type L vents must terminate at least 2 feet above the highest point of the roof penetration and at least 2 feet higher than any building portion within 10 feet - both conditions must be met. 802.6 - Minimum vent heights: vents generally require at least 5 feet of vertical height above the highest connected appliance flue collar, with exceptions for direct-vent appliances, listed outdoor appliances with integral venting, and pellet vents installed per their listings and manufacturer instructions.
802.7 - Support of vents: the full vent path must be adequately supported for the system design and material weight, and supports must maintain alignment, slope, joint integrity, and required clearances. 802.8 - Insulation shield: where vents pass through insulated assemblies, an insulation shield must maintain the required clearance; in attics, the shield must extend at least 2 inches above the insulation and be secured against displacement.
802.9 - Door swing: doors cannot swing within 12 inches horizontally of an appliance or equipment vent terminal, and doorstops or closers cannot be used to create that clearance.
Permit Proof Chain
Appliance and fuel type identified -> vent type confirmed as listed and compatible with the appliance (Type L or pellet vent, UL 641 basis) -> installation, sizing, and termination coordinated with both the vent and appliance manufacturer's instructions -> Type L termination height and the 2-foot/10-foot roof condition confirmed, or the minimum 5-foot vertical height verified for other vent types -> full vent path supported and every insulated-assembly crossing shown with a shield detail -> nearby doors checked against every vent terminal for the 12-inch swing clearance -> complete vent path shown from appliance connection to outdoor termination.
Where To Show It
M-001: general notes, listing basis, and vent system description. M-101: vent routing and terminal locations relative to roof, walls, and doors. M-501: termination details, support details, and insulation shield details. M-601: appliance and vent equipment schedule. A sheets: door location, swing, exterior elevations, and roof plan. Door schedule: door type and operation for doors near vent terminals. Roof / attic plans: vent penetration locations and insulation shield coordination.
**Do** - Confirm the vent is listed and labeled for the specific appliance before it is shown on the drawings. - Trace the vent path continuously from the appliance flue collar to the outdoor termination, checking height, support, and clearance at every transition. - Cross-check the mechanical vent plan against the architectural roof plan and door swings before the set is finalized. - Treat each 802 subsection as one link in a single proof chain, not as five unrelated checks.
**Do Not** - Select a vent based on diameter alone without confirming its listing and appliance compatibility. - Assume a single sheet shows the complete vent path - listing, height, support, insulation protection, and door clearance are often split across different sheets. - Rely on field adjustment, a doorstop, or a closer to fix a clearance or termination problem that should have been resolved in the design. - Review venting in isolation from the architectural plan, roof plan, and door schedule.
Masterbuild QA Lens
Use this series as a single audit trail rather than five separate checks. A vent system can satisfy listing, height, and support requirements individually and still fail permit review if the insulation shield detail is missing or a nearby door swings into the termination clearance. The strongest reviews trace one vent, on one appliance, from the flue collar to the termination cap, confirming every 802 subsection along that single path before moving to the next appliance.
Common Review Risk
Vent requirements are frequently documented in isolation - a termination height noted on one detail, a support requirement assumed rather than shown, an insulation shield omitted from an attic crossing, or a door swing never checked against a wall terminal. Each omission looks minor on its own sheet, but any one of them can fail inspection or create a field conflict that requires rework after the vent is already installed.
When To Escalate
Escalate any vent system not clearly listed for the connected appliance; any termination height or clearance condition that cannot be confirmed from the drawings alone; any insulated-assembly crossing without a shield detail; and any door swing condition within 12 inches of a vent terminal that has not been resolved in the permanent layout.
Field Tip
Start with the appliance schedule, then trace the vent to the termination. If the vent type, listing, size, supports, clearances, and termination cannot be verified from the permit set, the design is not ready for review.