Spray Foam and Steam riser

timbeans78

I am renting an apartment and I noticed the steam radiator risers at the ceiling are plugged with what I think is great stuff expanding foam. I looked it up and saw that this foam is only rated for up to 240F and says not to use with radiators . I heard that steam risers can get to around 220 if working normally. Is this rating for when the foam starts to degrade or does it literally combust at that temperature. I want to know if this is an urgent fire risk I need to worry about or not. Thanks for any help

EdTheHeaterMan

Is there a customer service number on any of the information you have on Great Stuff? That is the number to call for that information?

EdTheHeaterMan

From what I remember about Great Stuff and other polyurethane insulation is that it is combustible and will melt if it catches on fire and supports flame spread.   The operating temperature range should not exceed extended 200° exposure.  Since Steam will be near and above that temperature on a regular basis It is not recommended for insulating stream pipes.  

You probably will not experience spontaneous combustion at 200° to 220°, however the product will dry out, you may experience off gassing, and it will start to turn a darker color.  

The product will ignite if exposed to 700°F to 800°F however so will the rest of the building's combustible components.  

You may be looking at a product that is known as Fire Block which is designed to seal up openings in floors and walls to prevent air movement within a structure.  That product is rated at a slightly higher temperature however it is not designed to insulate pipes.  It is designed to fill gaps. Best practice would be to use fiberglass pipe insulation designed for steam pipes and then use the spray foam so it fills the gap between the fire rated floor or wall and comes in contact with the insulation NOT THE STEAM PIPE ITSELF.

ChrisJ

I had considered using spray foam around my steam piping, but I didn't want a disgusting stinky sticky mess, so I didn't.

I doubt it would burn, but it'll smell and probably offgas and dry out as Ed said.

Spray foam is excellent has it's places, but this isn't one of them.

EdTheHeaterMan

That would look great too @ChrisJ

look closely at this section… Could there be a Wye Strainer that will never get cleaned?

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1888422#Comment_1888422

It's too early for that stuff Ed.

Ugh.