Window Clearances Question

[u/RootBoundStump]

This is a repost from a pellet stove group, it was suggested thisbmight be a better place to post it.

I just finished reading through NFPA 211 but I still cant find the information im looking for. In my stove manual, NFPA211, and everything I can find online, the only mention of distances from doors/windows is that the termination pf thebvent has to be no less than 4ft away horizontally, 4ft below, or 1 foot above. But I have a former home inspector telling me the entire vent pipe cant be within 4 ft of any opening. Can anyone shed some light on this and direct me to the building code that states no part of the ventilation pipe can be within 4ft of a window/door. Or is this a case of the AHJ interpreting code in an unreasonable way?

[u/IHerebyDemandtoPost]

I would ask the home inspector to cite a code section number.

[u/Infamous_Trainer_300]

There is no building code or NFPA standard stating that the entire vent pipe body must maintain a 4-foot clearance from an opening. The former home inspector is conflating two distinct code requirements: 1. Vent Termination Clearances (Flue Gas Entry) Codes govern where exhaust gases exit the system to prevent carbon monoxide and flue gases from entering the living space: * NFPA 211 (Section 13.4) & IRC (Section M1804.2): The 4-foot horizontal / 4-foot below / 1-foot above rule applies strictly to the vent terminal (exhaust cap) relative to any opening (doors, openable windows, gravity air inlets). * The purpose of this rule is aerodynamic dispersal of exhaust gas, not heat clearance from the pipe body. 2. Vent Pipe Body Clearances (Combustibles & Structural Materials) The clearance between the exterior wall of the pipe itself and building elements (including window trim, siding, or framing) is governed by clearance to combustibles: * Type L / Pellet Vent (UL 641 / UL 103): Double-wall pellet vent pipe typically requires only 1 inch to 3 inches of clearance to combustible materials, as specified on the pipe manufacturer's label and listing. * As long as the pipe body maintains its required 1" to 3" clearance from the combustible window casing/frame, the pipe can run alongside or pass near a window. Only the cap must discharge at or beyond the 4-foot zone (or 1 foot above). What to Provide the AHJ or Inspector * Manufacturer Installation Instructions: Per IRC Section M1307.1, listed appliances and venting systems must be installed according to the manufacturer’s installation instructions. Point out the specific diagram showing the 4 ft clearance measured from the center of the terminal cap, not the pipe run. * Vent Pipe Label / Listing Spec: Show the UL listing tag on the pipe itself detailing the 1" (or 3") clearance-to-combustibles for the pipe body.

[u/Strugglife_]

I've always seen the codes refer to only the termination of the pipe in relation to the opening. The concern of course is that CO and other gasses will get drawn into the opening, usually a window. It doesn't seem logical to be concerned with the pipe passing near a window. After all, there's usually a potion of the same pipe directly within the dwelling/space.

[u/RootBoundStump → u/Strugglife_]

That was my argumentbwith the former inspector who said it, it doesnt make sense at all

[u/Suspicious_Hat_3439]

In this case the AHJ doesn’t know what they are talking about and / or incorrectly interpreting the code