Pipe insulation

Brad White_159

We had a thread here a month or so ago you may want to search for along these lines. It went sort of like this:

1) Model energy codes usually specify for steam the use of 1.5 inch thickness for piping up to and including 1.5" iron pipe size and 2" thick for piping 2" and up to 4" iron pipe size. That's code and because you are doing an improvement/retrofit, it is really self-policing. (This was my original take and posted accordingly. Professionally I have to uphold code first.)

2) The old engineer's rule of thumb says that the first inch does all the work. Your first half-inch statement is not far off. In fact, compared to bare pipe, the first inch will knock 100% of your bare pipe heat loss down to about 15% (call it 1/6th). The first half inch took it down to 23% (call it 1/4th). 8 percent more for doubling.

3) Cost of the thicker stuff was brought up. Half-inch was available at the box store for a lot less money than the thick stuff. My concern (defending thicker insulation) was that it was better than nothing, but if done would one realistically go back and over-insulate with thicker nested sizes later? I thought not.

My advice? Code thickness if you can afford it, but at least an inch and do the fittings. PVC covers are available but there is also fiberglass wrap with foil that is effective but looks, well, not neat to be polite no matter how well done. There are some cement (wet-applied) preparations but I have never used them.

Near boiler piping? I would do it all. My former thinking was that leaving it bare promoted condensing -it does of course- as a benefit unexplained. The current and I believe correct thinking, is to insulate it all. It minimizes CO2 absorbtion and hence carbonic acid creation.

John Doll

I am a homeowner insulating my 1 pipe steam system in central NJ. I decided to go with the 3 ft fiberglass insulation. Does it matter how thick it is? Some supply houses have 1/2 inch other stock 1 inch. I remember reading that most of the heat loss is prevented by the first 1/2 inch. Also no one has insulation for the elbows and T's. Do I leave these unwrapped or try to rig something. Finally - what do I do with the near boiler piping - equalizer, hartford loop and the pipe connecting the boiler to header?

Dave Miller

Also an HO learning from The Wall.......

I went to the supply house and asked them for steam pipe insulation and they sold me the 3' x 1/2" fiberglass preformed. Not knowing about "the codes" I used it on the near boiler piping (see attached) and will (carefully) replace some of the old asbestos as the spirit moves. I'm sure the 1" to 2" would be better but I think my basement would be too cold. It's just right, with the 1/2" which is just warm to the touch when firing.

For the elbows I cut 2" fiberglass blanket pieces and used 3M spray adhesive to "stick it up" so as to wrap it with the white duct tape. For the tees and unions, I combined partial 1/2" sections, using the spray again to tack them up, then filled the gaps with 'glass, then wrapped with the tape. Found the tape and small bag of fiberglass at Lowes. Not a professional job, but not too bad for an HO..........?

chuckNJ

source

Another NJ HO here. Check out http://www.sandsinsulation.com
then give 'em a call on Monday. I got everything from them for insulation after my new boiler was installed - PVC elbows, Tees, etc. Whatever thickness you decide on (I used 1 inch). Very reasonable prices, UPS ground was a one day delivery from Erie Pa.

gerry gill

I'D use

1'' fiberglass, (cause its the same size as the asbestos) and then do the fittings in high temp insulating cement (todays equivelant of the old asbestos cement) then wrap with chessecloth and coat with insulation mastic..all available at your local insulation supply house or online at mcmaster carr.

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