Foam as Pipe Insulation | Ask Mason Knowles - SPF Consultant | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

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Author	Comments
Rob Granger Posted: Dec 14, 2007 07:29 PM	Foam as Pipe Insulation Mason, Does OC or CC perform well as water line insulation in a northern climate. If so in what depth?
mason Posted: Dec 15, 2007 03:53 PM	Most of the Alaskan pipeline is insulated with 2 to 3 lb density polyurethane foam. Some of the pipes are sprayed and some are pour injected. But, yes SPF is great on pipes. It is one of the oldest SPF applications.
mason Posted: Dec 15, 2007 03:56 PM	In zero degree temperature and below, use about 5-6 inches of foam. In freezing degree temperature around 4 inches, and 2-3 inches in more moderate climates. If the foam is going into the ground with a low water table coat it with a low perm rated coating (like asphalt mastic).
Rob Granger Posted: Dec 15, 2007 05:53 PM	Based on your response you are saying that OC does not work, correct? While I am not advocating OC there is much to learn in this business and I want to become an informed advocate of SPF. Thanks
mason Posted: Dec 17, 2007 03:36 PM	You would not be able to bury a pipe insulated with low density open cell foam. The weight of the soil would crush the cell walls. Plus it is easier to work with the closed cell foam when installing to a small surface area like a pipe.
Rob Granger Posted: Dec 17, 2007 04:54 PM	The application is in the floor joist(ceiling) of a garage with an apartment overhead. I would never think of spraying closed cell underground. IN this application where the faom can be filled to the depth of the joist, 10", would it suffice?
mason Posted: Dec 19, 2007 07:42 AM	OK my mistake, I thought this was a commercial application outside. Lets start over: You could use either low density or medium density in the space. If you are only insulating the pipe and not the whole ceiling of the garage, I would use preshaped insulation specific for pipes (typically neoprene or polyiso). This would be preferable to spraying foam all over the pipe in case someone has to come in later to look for a pipe leak. However, if you are insulating the whole space, either foam would work. As for SPF underground, closed cell SPF works great underground. Lots of testing going back to the 60s on 2 lb density SPF buried underground for years. I have observed it personally working. We dug up a large diameter pipe (3 ft)that had been insulated with 2 lb SPF and buried for 10 years around the Houston area. The foam was in great shape. (note: water tables in this area were below the foam, in areas where the foam would be at or below the water table, a waterproofing coating or mastic would be used.)

Author

Comments

Rob Granger

Posted: Dec 14, 2007 07:29 PM

Foam as Pipe Insulation

Mason,
Does OC or CC perform well as water line insulation in a northern climate. If so in what depth?

mason

Posted: Dec 15, 2007 03:53 PM

Most of the Alaskan pipeline is insulated with 2 to 3 lb density polyurethane foam. Some of the pipes are sprayed and some are pour injected. But, yes SPF is great on pipes. It is one of the oldest SPF applications.

mason

Posted: Dec 15, 2007 03:56 PM

In zero degree temperature and below, use about 5-6 inches of foam. In freezing degree temperature around 4 inches, and 2-3 inches in more moderate climates. If the foam is going into the ground with a low water table coat it with a low perm rated coating (like asphalt mastic).

Rob Granger

Posted: Dec 15, 2007 05:53 PM

Based on your response you are saying that OC does not work, correct? While I am not advocating OC there is much to learn in this business and I want to become an informed advocate of SPF.

Thanks

mason

Posted: Dec 17, 2007 03:36 PM

You would not be able to bury a pipe insulated with low density open cell foam. The weight of the soil would crush the cell walls. Plus it is easier to work with the closed cell foam when installing to a small surface area like a pipe.

Rob Granger

Posted: Dec 17, 2007 04:54 PM

The application is in the floor joist(ceiling) of a garage with an apartment overhead. I would never think of spraying closed cell underground. IN this application where the faom can be filled to the depth of the joist, 10", would it suffice?

mason

Posted: Dec 19, 2007 07:42 AM

OK my mistake, I thought this was a commercial application outside. Lets start over:

You could use either low density or medium density in the space. If you are only insulating the pipe and not the whole ceiling of the garage, I would use preshaped insulation specific for pipes (typically neoprene or polyiso). This would be preferable to spraying foam all over the pipe in case someone has to come in later to look for a pipe leak. However, if you are insulating the whole space, either foam would work.

As for SPF underground, closed cell SPF works great underground. Lots of testing going back to the 60s on 2 lb density SPF buried underground for years. I have observed it personally working. We dug up a large diameter pipe (3 ft)that had been insulated with 2 lb SPF and buried for 10 years around the Houston area. The foam was in great shape. (note: water tables in this area were below the foam, in areas where the foam would be at or below the water table, a waterproofing coating or mastic would be used.)

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