With IMC 801 complete, Chapter 8 moves into the specific requirements for vent systems. IMC 802 focuses primarily on Type L vents and pellet vents. The central plan-review question: is the vent listed, properly matched to the appliance, and installed as a complete system?
Plain-English Overview
IMC 802 addresses vent listing and labeling, permitted vent applications, manufacturer installation requirements, termination caps and heights, vent support, insulation shields, and door swing clearance. A vent is not acceptable simply because it connects to the appliance - the appliance listing, vent type, material, size, route, support, clearances, and termination must work together as one approved system.
What This Five-Part Series Will Cover
Part 1: IMC 802.1 / 802.2 - listing and vent application, including when Type L vents and pellet vents are permitted, the required UL 641 listing, and appliance compatibility. Part 2: IMC 802.3 / 802.4 - installation and termination caps, covering sizing, installation, termination, and listed cap requirements based on the vent and appliance manufacturer's instructions. Part 3: IMC 802.5 / 802.6 - vent termination heights, including the Type L 2-foot / 10-foot roof rule, the minimum 5-foot vertical vent height, and applicable exceptions.
Part 4: IMC 802.7 / 802.8 - vent support and insulation shields, covering structural support, clearance from insulation, sheet-metal shield requirements, and attic installation details. Part 5: IMC 802.9 - door swing, covering the requirement to keep swinging doors at least 12 inches horizontally from appliance and equipment vent terminals.
Permit Proof Chain
Appliance and fuel type identified -> approved vent type confirmed against the appliance listing -> vent-system listing and labeling basis documented -> installation, support, clearance, and termination coordinated with both the vent and appliance manufacturer's instructions -> door swing and other field-clearance conditions checked at termination points -> complete vent path shown from appliance connection to outdoor termination.
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.
Masterbuild QA Lens
Before reviewing any vent detail, confirm the vent type is actually permitted for the appliance - Type L, Type B, and pellet vents are not interchangeable, and a generic provide-listed-vent note does not establish that compatibility. The appliance data sheet, not the vent diameter alone, controls the vent-type decision.
Why It Matters
Incorrect vent selection or installation can cause poor draft, combustion product leakage, condensate damage, overheating of nearby materials, carbon monoxide exposure, and failed inspections. The permit set should clearly identify the appliance and fuel type, approved vent type, listing and manufacturer basis, vent size and route, supports and clearances, and termination height and location.
Field Tip
Start with the appliance schedule. If the approved vent type and manufacturer's venting requirements are not identified, the vent design cannot be fully reviewed regardless of how well the routing is drawn.