gas pipe clearance to flue?

[Andrew W. Hinz]

Does anyone know the minimum clearnace of gas piping to a flue pipe? I had one today where the gas piping was touching the flue pipe. (see photo) I'm not sure of the proper clearance, but it didn't look good to me. Thanks

[Jeffrey R. Pope]

The flue (B-vents) generally requires clearances to "building materials," which would include piping. But it's not more of an issue simply because it's a gas pipe.

[Barry Adair]

Originally Posted by jpope

The flue (B-vents) generally requires clearances to "building materials," which would include piping. But it's not more of an issue simply because it's a gas pipe.

As in clearance from the insulation and drywall and where is the fire-stop/flue collar?

What is the source of the moisture stain?

May have been trying for pre-ignition

[Andrew W. Hinz]

This is a furnace flue pipe, not a chimney, so I wouldn't think it needs fire stopping, but yes, I did note that is was touching attic insulation. (1 inch minimum to combustible materials) My specific concern was the gas pipe. I have never seen anything that requires a specific distance from a gas pipe, and maybe there isn't one, but it seems like there should be. I suppose I invision a gas leak that catches fire from the hot flue pipe. Yikes!