Emilio's steam pipe insulation journey

Emilio

So, I've got the books, I've had a pro out to review my system (Charles Gerrity) and replace all radiator valves and now it's time to reinsulate my pipes. As Charles pointed out some issues with the near boiler piping of my system which I plan to have him remedy in the near future I won't be insulating most of that section until the work is completed. With winter upon us here in MA I did want to get the sections that won't be seeing major changes insulated.



I'll be documenting the progress and using this thread as a place to ask questions. The first of which is about the snugness of the insulation on my pipes. I test fit two different 2" pipe sections and a 1.5" section. From what I've read I assumed they would have been really snug but they aren't. They fit well enough but there is a gap as seen in the photos. I measured my pipes with a mini rocket I bought here so I'm pretty confident in my measurements. Does the gap in the pictures look acceptable to you?

Bob Gagnon plumbing and heating

The Insulation

Is the right size, don't worry about the air space, insulate away.



Thanks, Bob Gagnon

icesailor

Air spaces:

The air spaces are part of the insulation. It's the air trapped in the fiberglass that give the majority of heat transfer resistance.

Charlie from wmass

Yes the thing that stops the transfer of heat is the air

Keep the joints nice and tight to prevent air flow and all will be great.

Emilio

Thanks!

Thanks for the confirmation.



What do you guys do in a situation like the one pictured? I've got a pipe passing above the steam line. I have about 3/4" of an inch clearance. Do I notch or let the insulation rest against the pipe. I am leaning towards notching as crushed insulation is a no-no. If I notch do I tape over the exposed fiberglass?



What about when going around the hangers in the second picture? Just notch a hole on top?

Emilio

Made some progress tonight

Tossed up some more sections tonight. Did a couple elbows as well. The 90's were simple to get on and tacked/taped but the tees were a bit of a pain in the neck. Pictures attached.



I also took a picture of a hole in the cover that was opened by the installer I assume and never closed up. Any advice as to how to plug it? I popped the top off a while back to clean out the remains of a mouse nest after I bought the house last fall. I was thinking of putting some fiberglass in the hole and sealing it with a foil tape. The previous owner left a can on top, I assume he hoped it would reduce the heat loss. I can feel plenty of heat radiating from the hole so I'm assuming it'd be wise to close it up.

Charlie from wmass

That's just fine for sealing that.

also notching the insulation will be fine for around other pipes and hangers. If I do the insulation I grove the inner face to accomodate the hanger but that is just me being fussy. Tape at openings to prevent the air from flowing is important as the air currents will carry off BTU's, like little drafts.