blueboard vs 180*F pipe

[sorethumbs]

Does anyone know if the high density extruded foam insulation board (blueboard) can be used in direct contact with pipes at 180*F? I have an idea to insulate 1" PEX in a homemade blueboard "sandwich." The pipe would be completely encased in the blueboard. There would be direct contact between the entire circumference of the pipe and the blueboard. The run would be approx. 100ft. Will the blueboard survive?

 

[sixroses]

Not for long, I have blue board that has been melted out from direct contact.
Steve

 

[DaveBP]

Several people have posted on this forum that have used a "blueboard" channel to suspend their pipes in and make a form for poured in urethane foam around the pipes. The urethane can take the highest heat of contact and the blueboard adds more insulation at a lower price. You could search previous posts and see photos and detailed descriptions.
More money up front but probably hard to beat for long-term savings.

 

[sorethumbs]

Thanks Dave. I'm trying to find a low-cost way to run PEX to a garage. Now, I know all the reasons not to go low-cost, and I'm usually not one to try in save-a-buck in leau of poor performance, BUT, in my case I think it makes sense. First off, this pipe will be crossing a septic drain field so it needs to be removable in the future and needs to be shallow. secondly, the garage will only be heated a few times a year for various weekend projects. To me, this adds-up to a home-brew, inexpensive, removable or disposable insulation system. I thought I had it nailed with a blue-board sandwich, now I'm back to the drawing board. I finally did find some specs on the extruded PS pink-board. It should not be subject to sustained temps > 155*F and intermittent temps > 165*F.

Anyone happen to know how many feet of 4" drain tile a large can of "great-suff-pro" can fill? (the tile would have two 1" PEX suspended in it).

 

[DaveBP]

If you're thinking about something like a rigid foam sandwich with channels for pipe routed out between them you could try rigid panels of polyisocyanurate (commonly called urethane). It is almost always foil-faced now but easily available at the usual depots. I believe it will take the heat similar to real polyurethane. I've seen it in 2" thickness but more commonly 1". It's not much more money than polystyrene blueboard.

 

[Piker]

There are some high quality products that can actually be left on top of the ground during the winter. You could run your system like this temporarily until you get your septic issues in order... this way you won't have wasted ANY money on a throw away home brew setup... just bury your existing line.

You can get some cheap stuff for $5/foot on ebay. Never used it... probably wouldn't recommend it... but it's probably at least as cheap as making a homebrew setup.

cheers

 

[sorethumbs]

If you're thinking about something like a rigid foam sandwich with channels for pipe routed out between them you could try rigid panels of polyisocyanurate (commonly called urethane). It is almost always foil-faced now but easily available at the usual depots. I believe it will take the heat similar to real polyurethane. I've seen it in 2" thickness but more commonly 1". It's not much more money than polystyrene blueboard.

Dave, THANKS. Urethane just might be the answer; and your onto what I was thinking. I would use the 2" thick sheet and rip it into strips about 8" wide. I'd then take my router with a large box-core bit and route 2 channels. I'd then use 2 strips, foam adhesive and clamps to form the sandwich. I may even add an extra layer to increase R-value. I have also contemplated using asphalt based foundation coating to help reduce moisture. I figure I'd be at about 1.00/ft for the insulation.

 

[Piker]

If you're thinking about something like a rigid foam sandwich with channels for pipe routed out between them you could try rigid panels of polyisocyanurate (commonly called urethane). It is almost always foil-faced now but easily available at the usual depots. I believe it will take the heat similar to real polyurethane. I've seen it in 2" thickness but more commonly 1". It's not much more money than polystyrene blueboard.

Dave, THANKS. Urethane just might be the answer; and your onto what I was thinking. I would use the 2" thick sheet and rip it into strips about 8" wide. I'd then take my router with a large box-core bit and route 2 channels. I'd then use 2 strips, foam adhesive and clamps to form the sandwich. I may even add an extra layer to increase R-value. I have also contemplated using asphalt based foundation coating to help reduce moisture. I figure I'd be at about 1.00/ft for the insulation.

Moisture will be key. If your assembly gets water logged... you will lose massive amounts of heat.

cheers

 

[sorethumbs]

Thanks Piker, I figured that, but will urethane even absorb water? Do you know? It seems to me to be a hydrophobic material. The foil face and the roof-coating should help even more. I could add a wrap of tyvek over the asphalt coating too.

Oh, and as far as buying pre insulated PEX you see I'm from Wisconsin, and we here kind of have an unwritten rule that if we can make something ourselves it will be better than buying it. Heck, you should see the ice-fishing shantys that we build; many have solar panels for lights and satellite TV, wood stoves, and I'm sure in the not to distant future we'll have home-made geothermal loops down in the bottom of the lake for heat! Anyone form Wisconsin reading this will agree. Beer can engineering at it best here in the frozen tundra.

 

[Piker]

Thanks Piker, I figured that, but will urethane even absorb water? Do you know? It seems to me to be a hydrophobic material. The foil face and the roof-coating should help even more. I could add a wrap of tyvek over the asphalt coating too.

Oh, and as far as buying pre insulated PEX you see I'm from Wisconsin, and we here kind of have an unwritten rule that if we can make something ourselves it will be better than buying it. Heck, you should see the ice-fishing shantys that we build; many have solar panels for lights and satellite TV, wood stoves, and I'm sure in the not to distant future we'll have home-made geothermal loops down in the bottom of the lake for heat! Anyone form Wisconsin reading this will agree. Beer can engineering at it best here in the frozen tundra.

I guess I don't know exactly what you are planning here... but if you are going to bury something, even the slightest crack will allow water to enter and pool in any open cavities. If the water gets past the urethane you will be in trouble.

I understand your desire to do it yourself... It's a great american trait.

cheers