Thread: Insulation touching furnace exhaust vent

I am relatively new to home inspections but I am pretty sure this is a problem and wondering how others would write this up?


There is insulation paper in contact with the HVAC combustion ventilation from the furnace, I know this paper is designed to be very ignition and combustion resistant but I am pretty sure there is a required clearance from the vent that applies to anything, however it looks as though it has been there for very long (50 year old home) and hasn't caught fire yet.


I wrote it up as potential Asbestos paper (that couldn't be confirmed without laboratory testing) that is breaking clearance requirements from the HVAC combustion vent and is a potential fire hazard.

By combustion ventilation from the furnace, I presume you are not referring to combustion makeup air, but are instead referring to the vent for combustion byproducts - looks like single wall vent.

single wall vent requires minimum 6" clearance from combustible material and 6" clearance from insulation - and you have both there.

Also, I would not refer to that paper facing as being ignition and combustion resistant as that paper facing likely has the same warning that is printed on all other paper faced insulation ... WARNING: This facing will burn. This facing must not be left exposed. This facing must be in substantial contact with gypsum board or other approved material. (Wording to that effect. )

Also, I would not raise the asbestos flag for you that facing.

Kyle,

I do not know your experience level so basically it goes as follows: Single Wall flue pipe clearance is 6 inches from any object. Single wall means the flue is only one layer of metal thick.
Dual or double wall flue clearance is one inch from any object and triple wall flue has zero clearance.
I write this exact as I have stated above as insulation will burn and paper will catch fire-its paper.
The key words are: "from any object"!

Larry Sparks-Certified Master Inspector
Sparks Certified Inspections, Inc.
Inspecting Commercially and Residentially since 1999

Thats most likely asbestos sheeting and is non combustible. If the home is 50 or older guaranteed to be asbestos.

Further there appears to be water related problems with the chimney given the stains.

Originally Posted by Kyle Montgomery

I am relatively new to home inspections but I am pretty sure this is a problem and wondering how others would write this up?


There is insulation paper in contact with the HVAC combustion ventilation from the furnace, I know this paper is designed to be very ignition and combustion resistant but I am pretty sure there is a required clearance from the vent that applies to anything, however it looks as though it has been there for very long (50 year old home) and hasn't caught fire yet.


I wrote it up as potential Asbestos paper (that couldn't be confirmed without laboratory testing) that is breaking clearance requirements from the HVAC combustion vent and is a potential fire hazard.

Actually, there is no visible reason that insulation barrier cannot be positioned at least 1 in away from the flu, the same as where the flu protrudes from the plenum. Regardless of what the barrier is made of.

Also doesn't appear to have the proper clearance around the vent at the ceiling. I also noticed what looks like wires near the vent at the ceiling.

Originally Posted by Jimmy Roberts

Actually, there is no visible reason that insulation barrier cannot be positioned at least 1 in away from the flu, the same as where the flu protrudes from the plenum. Regardless of what the barrier is made of.

You would still need to have 6" clearance between the single wall vent to combustible material and insulation.

Now, if all that vent material was replaced with double wall Type B gas vent, then the clearance could be reduced to 1" to combustible material and insulation.