Steam Pipes and Owens Foamular 150 XPS Foam

Marc_J

We have a 1922 home with a one-pipe steam system. We are in the process of insulating the concrete walls in our basement. There are several locations where a steam pipe riser is making contact with the Owens Foamular 150. Owens is saying that their product should not be in contact with surfaces where the sustained surface temp exceeds 150degreesF. I suspect that the exterior surface of a steam pipe may exceed this but having trouble confirming it. Anyone have experience with this? I can leave a gap around the pipe and fill it with Great Stuff (good up to 240degreesF) but would prefer to avoid the extra work if it's not necessary.

Brewbeer

The outside of a steam pipe riser supplying steam to radiators will easily exceed 150 F, but the best way to be sure is to measure it. You can check the actual temp with an IR gun if you have one. you can also use a lb thermometer or a candy thermometer.

Jamie Hall

The outer surface of a steam carrying pipe will be at, or very close to, 212 F. Great Stuff or products like that will survive, but they will degrade very quickly. It would be much better to insulate the steam pipe with an inch of fibreglass insulation made for the purpose, and then bring your foam up against that.

EBEBRATT-Ed

what @Jamie Hall said

Chris_L

Jamie Hall said:

Great Stuff or products like that will survive, but they will degrade very quickly.

This hasn't been my experience. I used Great Stuff to seal between all of my radiator risers and the floor. After at least 10 years, the foam has discolored, but there is no obvious degradation.

I've also used it to fill the gaps in my less-than-expert miters of fiberglass pipe insulation around fittings. While this was only a year ago, I haven't noticed any degradation there, either.

BobC

The heat may discolor or even deform the foam sheet but the effects will be cosmetic.

Bob

Marc_J

Thanks for the info folks!