Apartment steam riser, PestBlock foam, and fire

[brador]

I think a bit off topic but maybe someone can help me out.

I live in an urban apartment building that’s over 60 years old. To mitigate a rodent problem, I sprayed Great Stuff Pestblock to seal off the holes around the steam heat risers. Stupidly, I assumed that foam designed to deter pests would take heat risers into account. Not really. Pestblock has a temperature limit of 240F. (Above the 212F boiling point, but I've never checked the actual pipe temperatures.)

Do I need to worry, or do I remove what I sprayed in (no mean feat)? If the latter, advice would be appreciated. Thanks.

 

[Sylvan]

I think a bit off topic but maybe someone can help me out.

I live in an urban apartment building that’s over 60 years old. To mitigate a rodent problem, I sprayed Great Stuff Pestblock to seal off the holes around the steam heat risers. Stupidly, I assumed that foam designed to deter pests would take heat risers into account. Not really. Pestblock has a temperature limit of 240F. (Above the 212F boiling point, but I've never checked the actual pipe temperatures.)

Do I need to worry, or do I remove what I sprayed in (no mean feat)? If the latter, advice would be appreciated. Thanks.

There is something called "pressure temperature relationship."

Steam at 0 PSI = 212 deg F 2 PSI = 218 .5 deg F 6 PSI = 229.8 ETC

Ask the building supt what pressure they use. NORMALLY less then 3 PSI

You should be in good shape

 

[Sponsor]

 

[brador]

Thanks. Not remotely my area of expertise. Here is a blurb from my co-op's website: "A fire-tube boiler, two-pipe up-feed system with vacuum return. Central high-pressure plant 85psi. At each building, steam pressure reduced in a single stage to the five pounds necessary to supply heat to that building’s radiators. Burn either gas or oil to produce a maximum of 60,000 pounds per hour of steam.”

Seems like the 5psi is my key number--is that correct (probably not )? But I will run over (the boiler is huge, in its own building, but relatively new, 2012) and ask about the psi. At least now I know what to ask.

Thanks again.

 

[Fitter30]

Any pressure below 15 lbs is low pressure above high pressure. Never worked on any high pressure steam buildings. The Empire State building was heated with 5 lbs of pressure when built. High pressure autoclaves, process heating and collage or office campuses as soon as it enters the mechanical rooms reduces to low pressure.

 

[Fitter30]

Any pressure below 15 lbs is low pressure above high pressure. Never worked on any high pressure steam buildings. The Empire State building was heated with 5 lbs of pressure when built. High pressure autoclaves, process manufacturing and collage or office campuses as soon as it enters the mechanical room reduces to low pressure.

 

[Fitter30]

Any pressure below 15 lbs is low pressure above high pressure. Never worked on any high pressure steam buildings. The Empire State building was heated with 5 lbs of pressure when built. High pressure autoclaves, process manufacturing and collage or office campuses as soon as it enters the mechanical rooms reduces to low pressure.

 

[brador]

Any pressure below 15 lbs is low pressure above high pressure. Never worked on any high pressure steam buildings. The Empire State building was heated with 5 lbs of pressure when built. High pressure autoclaves, process heating and collage or office campuses as soon as it enters the mechanical rooms reduces to low pressure. Think 60,000 lbs of steam an hour isn't correct if that's right at 60 million btu's. Empire State building before the LEEDS upgrade with 7000 radiators and 54.5 m btu's to heat it.

Thanks, that's good to know. I just don't want the steam risers to light the expansion foam on fire! (I actually like my neighbors.) But I've learned a lot more by asking around.

FYI, our boiler heats about 2,500 apartments in 7 buildings, plus a block of retail spaces, across maybe 6 city blocks. So it's a big, blue thingy. I don't doubt, however, that the person who wrote the blurb about 60000 lbs/hr was mistaken. And yes, there are two additional, older boilers at hand.

Nevertheless, they say outright that pressure is reduced to 5 psi at each building and I doubt they're playing around with the "superheat" tricks I've been told of.

But I think my best bet is to get off my fat butt and walk over and ask. At least I have an idea of what to ask and may even understand the answer! Thanks a ton!

 

[John Gayewski]

So your are not necessarily OK in this situation (which is an odd one) if your at high pressure with a heating plant you could easily be over the 240 max for the foam in the risers. It says on your blurb that the buildings get 5psi, but the risers are possibly at the high pressure/high temp steam in the event of a mechanical malfunction of the prv.

I do not think the riser could ignight the foam. More than likley it would just melt. But you should remove it and replace the foam with S.O.S pads. Mice can't chew through them and they are cheap and can be formed easily.

 

[Sylvan]

Better off with steel wool no soap or better yet go to a hobby store and buy brass /copper wool.