SPF closed cell

[allseason]

Does anyone have any info on the clearance of closed cell Spray Polyurethane Foam from a gas supplied metal flue pipe. I encountered some in a basement and it's about 1/2" away in spots, not to mention overspray on the flue itself.

Thanks ahead of time.

[Bill Kibbel]

Well, is the "flue pipe" a vent connector? A B-vent?

[allseason]

Single wall vent connector for a water heater going into a masonry chimney.

[Bill Kibbel]

Since polyurethane foam is not non-combustible, the single-wall connector clearance requirement is 6".

[allseason]

Thanks

[Marc]

Except that all expanding foam in residential is required to be fire retardant treated. Contact permitted, as far as I could determine a year ago when I last checked.

A friend has it in contact with B-vent.

Marc

[Tom Raymond]

The fire retarder is so that the foam meets flame/smoke index to be left exposed, ie band joist applications, not to make it un-burnable. It most certainly would still be flammable in contact with a vent connector. Less so with the b-vent, that's why the clearance is only an inch. They're both wrong.