Insulation on mains: How thick should it be?

Wethead7

The mains are on a steam of hot water system?

We like to use 1 inch on hot water, Steam might be better with something thicker. The riser and branch pipes need covering also.

Vito Cavallo

Insulation on mains: How thick should it be?

My uninsulated mains are 2 1/2" diameter, one main is 20 feet long, the other is 12 feet long.

What is the correct thickness for steam pipe insulation?

I can get 3/4" from Big Orange and 1" from a local guy. Both are the round formed with foil backing.

Is 1" enough for my mains? Any websites that sell thicker?

Thank you.

Kal Row

does it cross the basement end-to-end...

and do you want the basement heated? then cut the insulation in half and put it only on top, and let the bottom half "radiant" heat the basement

Vito Cavallo

Insulation

Sorry, I have steam heat.

I wouldn't mind heating the basement. The pipes run basically through the middle of my small basement. The 20' section runs through the "common" area and the 12 ' section runs through my small boiler room.

Thanx

michael_15

more is good

I always figured more was better, unless you want your basement heated -- but I'm not sure it's ideal to have your steam main condensing constantly while you're trying to simultaneously send heat to the rest of your house through the same main. 2.5-inch bare steel pipe I believe should be around 1.05 square feet EDR per linear foot of pipe. If you are unlucky enough to have copper, it's around 0.67 sqft/linear foot.

Compared to bare steel, I believe 1-inch insulation would cut the heat loss through the pipe by about 80%, 1.5 inches would reduce it around 84%; 2 inches would reduce it by around 87%. Roughly speaking.

I spent a long time looking for 1.5 inch insulation online, but ended up finding it was a LOT more expensive than just finding it at the local plumbing supply house. After all, you're shipping an awfully big box for some pretty cheap stuff.

-Michael