Flue Pipe Touching Building Material

[Sam Morris]

Can this type natural gas chimney flue pipe be touching building material ? House is 14 yrs old

[Dom D'Agostino]

Is that some brand of flex B-vent (Duravent)?

Unless listed and labeled otherwise, minimum 1 inch clearance to combustibles, if it is.

[Sam Morris]

Is that some brand of flex B-vent (Duravent)?Unless listed and labeled otherwise, minimum 1 inch clearance to combustibles, if it is.That is correct, fiberglass by itself is not combustible, the paper backing is

[Bob Harper]

Even material having passed ASTM E-136 as noncombustible cannot be in direct contact with any CAT I gas, oil, or solid fuel venting that carry stated clearances to combustibles. I am not aware of any listed flexible vent connector that can be in direct contact with any form of insulation. The only listed flexible aluminum venting for CAT I I'm aware of that's not listed liner is for listed vent connectors. These cannot pass through walls, floors, or ceilings whether combustible or not. You need listed venting for that.

Now, there are some fireplaces that use flexible aluminum venting for sidewall termination but again, those carry clearances and cannot penetrate floors or ceilings. They can only penetrate the termination wall using a listed firestop assembly.

As with ANY combustion appliance, start with the make and model. The listed instructions will state the only approved venting and configurations.

Any combustion venting that carries stated clearances requires an attic insulation shield.

The flex pictured lacks any modicum of proper support.

FYI, fiberglass does not pass ASTM E-136 last I checked so it should be treated as a combustible. The other problem with insulation is, it works. You pull a blanket on you to stay warm, right. Insulation keeps venting temps high--possibly above design parameters. You need that stated air space to cool the outer wall of the pipe.
HTH

[Bruce Low]

If in fact a chimney flue, a fire waiting to happen! There's not much right about that installation (unless it's a fresh/combustion air intake).

[Richard Bushong]

Can this type natural gas chimney flue pipe be touching building material ? House is 14 yrs old
I am going to throw this out there. What is the BTU value of the fireplace? Can you see if it is flex pipe all the way or is it possilble that they are using the flexpipe as a sleeve over B-tyoe gas vent to maintain proper clearance from the installation. If not it is definitely a clearance violation and needs to be corrected.