Properly Pitched steam pipe reduces heat loss in crawlspace

michaelmiracle

This is just an inform of what I discovered. I work in a 1924 school in Denver that has 2 pipe steam heat. The piping through the crawlspace has had the asbestos insulation removed and not replaced at least 10 years ago. The steam pipe started springing leaks from pinholes. I started to add back in insulation but it's not complete by any means. I recently saw that the hanger straps for the pipe were low or had been broken or taken off. This created a belly in the run, where most of the leaks occurred. I was able to jack up the pipe and rehang the strapping. I could hear the water running down the pipe as I did this.

This morning I came in and the adjacent basement cafeteria that is usually very hot, was cold. Underneath the 1st floor in the crawlspace, usually very overheated (to the point where the wood floor just above the steam and return pipe travel had started to buckle from the heat) was also cold. The only thing I can surmise is that the steam was heating the stagnant water in the pipe and creating a hot water radiator out of the pipe. I assumed the insulation was the culprit for the heat loss but the difference is dramatic compared to when I added some insulation to the pipes.

I'm happy to share this info.

pecmsg

insulation is not going to stop leaks!

Jamie Hall

Sounds to me as though you've analysed that right. Now to figure out how to keep the cafeteria workers happy…

ethicalpaul

I don't think you analyzed it right. A pipe full of steam is hotter than a pipe full of water, by definition. But yes something is going on apparently with the pitch of the pipe and the condensate.

But I agree with @pecmsg — I can't tell if you fixed the leaks before insulating the pipe, you didn't say you did, and if you didn't, that is not good.

109A_5

Hello michaelmiracle,

" I was able to jack up the pipe and rehang the strapping "

Did you inadvertently create a different (new) low spot, so water is trapped somewhere else now cutting off the steam flow that normally heats the cafeteria ? At least that is what I get out of the story.

michaelmiracle

https://forum.heatinghelp.com/discussion/comment/1831150#Comment_1831150

That is possible but the building is heating up just fine. The steam pipe is hot. This run is the closest to the boiler, so if it was cutting off the steam, the rest of the building would be cold, which isn't the case. But I do need to check the pitch for the rest of the run going back to the boiler for the same pitch problem.

The cafeteria was heating from lost heat coming from the adjacent crawlspace. I had the radiator turned off in the cafeteria up until now because it wasn't needed. I turned it back on so the heat is back to as it should be, hopefully more efficiently.

The insulation I have stared to replace but it is by no means complete. I didn't insulate near the leaks. They all are patched and not leaking water or steam at the moment. But yes, I don't let the insulation get wet.

My point was that the added insulation did not do nearly as much to reduce the heat in the crawlspace as pitching the pipe correctly.

ethicalpaul

My point was that the added insulation did not do nearly as much to reduce the heat in the crawlspace as pitching the pipe correctly.

Sorry to be a naysayer but I think there's something else at play here…I have to say "nay"

109A_5

" My point was that the added insulation did not do nearly as much to reduce the heat in the crawlspace as pitching the pipe correctly. "

I guess I'm a bit confused, but I'm not there. Letting the water out of the pipe should make the system perform as designed. With my insulated pipes in the basement, the basement is heated very little.