Closed cell pipe insulation R-value ( s milne)

According to the Grainger catalog...

Page 3421 (#395 version), there's a table of Therma-Cel brand PE closed cell showing varying R-values based on wall thickness and pipe diameter.

They show 3/8, 1/2 and 3/4" wall thicknesses for 1/2" copper tube thru 1-1/4" as being from the lowest R of 1.8 to 5.7.

Tell the plumbing inspector he owes you a beer or one helluva good excuse as to how he got that dumb. His choice(;-o)

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Pipe insulation r values

Check this out:

Arrrrrr Matey!

The k factor (for Conductivity, engineers can't spell) for Armaflex type insulations is between 0.22 and 0.27 while by comparison, moulded fiberglass is between 0.24 and 0.27.

k factors are analogous to u-factors so the represented R values would be all within the 3.7 to 4.55 range.

Functionally, we accept these as equivalent for equal thicknesses of either material although the Armaflex types have better vapor resistance.

If Armaflex types have zero R value then neither does fiberglass. I bet the building inspector will next tell you that Santa Claus is a myth, the brute.

Hey!

I resemble that remark ;-)