# insulation



## ICE (Jul 11, 2019)

We require that a goodly amount of water pipe be insulated.

The insulation on the right is a tight fit.  The contractor used the insulation on the left which is loose.  An inspector wrote a correction to replace the loose insulation with the tight fit insulation.  I'm not the guy for insulation code and this other inspector is a plumbing guru whereas I'm lucky if I hit the bowl.

So what do you guys think about this?  Was it worth making them do it over.  My first reaction was..... Hey now, the tight insulation has a thermal bridge and the loose insulation barely touches the pipe.  Honestly, I would have never noticed.


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## linnrg (Jul 11, 2019)

trapped air is somewhat of an insulator


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## HForester (Jul 11, 2019)

It is a workmanship issue. I suppose you could really step into it and get the insulation manufacturer involved to ask the question, "does this product, as installed, provide for R3 insulating properties on the pipe?  (R3 is just an example requirement.)


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## Rick18071 (Jul 12, 2019)

Are there manufacturers installation requirements?


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## Inspector Gift (Jul 12, 2019)

What code section did the inspector cite?


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## jeffc (Jul 12, 2019)

Washington State requires R-3 pipe insulation for freeze protection. When I contacted the manufacturer asking about the pipe wrap r-value, she replied with:

 R value on item 3/4"- #P11X - 2.1 and 1" -P12X - 2.0.

Thank you

Cheryl

Thermwell Products

201-684-4400

Interested in hearing someone tell you, "that is what we always use", ask about the pipe wrap r-value.


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## mtlogcabin (Jul 12, 2019)

The insulation should be a snug fit. Chances are the insulation was not properly sized for the piping used.
https://expressinsulation.com/blogs/news/understanding-fiberglass-pipe-insulation-sizing


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## Sleepy (Jul 12, 2019)

I've always thought the insulation was to prevent condensation on the outside of the pipe and would imagine that if the insulation isn't snug to the pipe it wouldn't work for that purpose.


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## mtlogcabin (Jul 12, 2019)

In general, the outside diameter of a copper pipe will be 1/8” bigger than its nominal width. Plastic pipes will be 3/8” bigger, and cast iron pipes will be ¼” bigger. To derive the nominal width, you need to know what the pipe is made of and then subtract the correct amount.


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