# Pex and spray foam insulation



## Evolve

I was wondering what some of you do when a situation arises where the insulation used is spray foam and you are running pex pipe?

The spray foam can reach up to 200-220 degrees and the max temp pex can handle is 180. Surprisingly enough I haven't encountered this situation yet, even with all the reno's, and was wondering what do you guys do?

I was thinking of using some kind of aluminum sleeve or something of this nature. 

Any insight would be appreciated.


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## Plumberman

I have run pex in a few building with spray foam insulation. Never had to protect it in any way.


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## Evolve

Plumberman said:


> I have run pex in a few building with spray foam insulation. Never had to protect it in any way.


That is what I thought at first but the client seem insists that it should be protected.


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## Plumber Jim

I would say call your Rep, and see what the manufacture has to say.


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## markb

Plumber Jim said:


> I would say call your Rep, and see what the manufacture has to say.


Best idea. Keep in mind that the 180 deg rating is at 100psi. The pex we use here are rated for 200-something psi at 40psi. The sprayfoam should not be a problem. But still call the rep.


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## Plumberman

What kind of foam are they using?

I haven't seen them apply it that hot here.


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## U666A

Plumberman said:


> What kind of foam are they using?
> 
> I haven't seen them apply it that hot here.


What I was told is that it depends on the thickness. The foam generates heat as it cures.

Certain types they cannot apply beyond a certain thickness, or it will spontaneously combust.


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## Plumberman

U666A said:


> What I was told is that it depends on the thickness. The foam generates heat as it cures.
> 
> Certain types they cannot apply beyond a certain thickness, or it will spontaneously combust.


That explains why they put it on so thick. I know from seeing it that it didn't affect the pex in the walls... 

BTW- That sig line is great! 

Winning!


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## U666A

Plumberman said:


> That explains why they put it on so thick. I know from seeing it that it didn't effect the pex in the walls...
> 
> BTW- That sig line is great!
> 
> Winning!


Lol I changed that seconds before that last post! :laughing:

What... I could be referring to anybody!

:blink: :laughing:

Always Winning!


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## Evolve

Well from what I've read it seems to be when the spray foam is wet, there's a chemical reaction with air that helps it expand. The key is when the chemical reaction occurs that the heat level rises from 200-200 degrees.

Good call on calling the rep, I will do that first thing tomorrow.


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## Evolve

U666A said:


> Certain types they cannot apply beyond a certain thickness, or it will spontaneously combust.


Have to say I'd be curious to see that.


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## U666A

Evolve said:


> Have to say I'd be curious to see that.


It's been the same guys on several of the jobs I've been on over the years. From what the guys have told me is that certain compounds can only be applied to certain thicknesses. For example, the blue stuff being used at the job I'm on now can be applied to a maximum of 4". Thicker than that and it will melt itself and not cure properly, and it runs the risk of combusting. 

This guy told me that his trigger on his wand stuck once so he stuffed the nozzle into a nearby garbage pail and ran back to shut offthe pump. When he got back to the pail, he had a massive blaze to extinguish.

I would be weary of installing PEX without speaking to both the insulator and the manufacturer.

Heck, I'd be weary of installing copper with soft soldered joints without speaking to at least the insulator... Can be deadly...


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## U666A

Duplicate post


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## LukeThorkildsen

Any resolve on this one?

Depends on the foam type.

The closed cell type - lease popular in residential is the one that you can't apply over certain thicknesses.

Open cell type - most popular relies on an exothermic reaction to cure. 2 part chemical mixes at the nozzle of the gun and relies on the steam to cure. This is a fast reaction. Will only be 212 for a few seconds. 

I've seen plenty of pex sprayed with Icynene and Demilec open cell foam with no issues.


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