Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: coolidge on March 07, 2014, 06:29:42 PM
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If you could, would you use sprayfoam and make your own lines instead of using Thermopex or Logstor. I figure I could save roughly 2500 bucks and have a much higher r value
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I'm obviously in the minority on this subject, but I spray foamed in place with no ill results and 0* heat loss between boiler and house. I dug the trench, lined it with plastic sheeting, laid my lines, and spray foamed lifting the lines a couple inches as I went for full surround on the pipes. I wrapped the extra plastic over the top of the foam and left it. When I buried the foamed pipe, I had about a 1' diameter glob of foam around two 1-1/4" pipes for a super insulated package.
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No I would not.
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Whats going to protect your foam from heaving or tree roots?
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Tree roots follow water, if no water no roots, many have used this method with very well documented results. Spray foam isn't just water resistant but water proof.
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If you could, would you use sprayfoam and make your own lines instead of using Thermopex or Logstor. I figure I could save roughly 2500 bucks and have a much higher r value
I too, am looking into the spray foamed method of lineset encapulation as I do NOT have any trees growing in the general area where my runs will be located! I might be concerned if I had any Willow trees close by-they will find a way to break into black cast-iron sewer pipes to find moisture! From what I have gathered from reading on this and other forums-Frost and heavy equipment/Truck traffic might be a problem?? The H.D. version of the closed cell foam to use has a 26 PSI rating and is completely waterproof as previously stated. I plan on putting mine down below the 4' mark due to high frost concerns in a very cold area. The less amount of heat loss the better and $$$ savings can be used in the rest of the Install. Cranky
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I am thinking I am going to go this root ( not tree root) if I move my boiler. I am going to try and center the lines in sch 40 pipe and fill it with closed cell. I have a silicone coating I could run through my airless sprayer to seal any and all joints. Still in the planning process, will lost picks if this happens.
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found on the net....true or not, it is worth asking around more before you do this
Polyurethane foams can be made ‘open cell’ or ‘closed cell’ Open cells foams are not water proof and allow water to permeate via the open cells. Twin component foam is designed to be closed cell. However, scientifically, no polyurethane foam is ever 100% closed cell as the cells sacs making up the foam can and do rupture and this will leaves a percentage of open cells. The percentage of open cells is, however, quite low. A ‘closed cell’ foam is best described as water resistant rather than water proof in much the same way as timber is water resistant but not technically water proof. In practice, closed cell foams afford excellent water resistance and can be applied under roof slates and tiles to prevent the ingress of rain and snow. A depth of foam of 90 mm will give a vapour permeability of less than 1 perm (55ng/m2.s.Pa) which affords vapour barrier protection.
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I don't think it is worth the gamble of doing your own. Sure some have done it with no problems and saved ton's of money. Others have done it, found out it didn't work and then bought the good stuff.
It's your money so I would suggest you do with it whatever you would like and keep us posted!
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They swear by the foam in trench method at Hearth.com.
I'm however going a different route. I already have 6 inch PVC buried to the house. I'm going to dig the two corners up, pull the line out I have then most likely go with the 3 wrap from Zsupply. From the boiler to the shop we still have to dig that trench. I'm again, most likely using zsupply again but a 5 wrap as its a longer run. A piece of 6" PVC will just slide over a 5" tile from experimenting. I also have to cross the driveway twice. Semi's and tandem grain trucks dive over both places it has to cross. I'll most likely get a piece of 8" culvert to run the PVC thru at each drive crossing.
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The MOST important thing to remember when burying lines for energy transfer, is to get a good seal all the way around. Because water infiltration KILL efficiency and steals BTUs.
I personnally would not build my own, but hey what do I know. ::) Its nice to know that in most cases if I install a premade product from a supplier I have some sort of warrenty/guarentee for a period of time. Plus how much is spray foam going to cost vs. Thermopex, Logstor or other under ground pipe manufacturer??
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It all depends on your local spray foam contractors cost, it's the long runs and or using larger than 1" pipe when the foam in trench is much cheaper. You would literally have to submerge the line set and expose it to enough ground movement to crack the foam for it to fail. And I don't think the soil will be bending line sets past 30 degrees in a short length to crack. With the foam there are no air spaces for water to fill.
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Here is a test they did in Canada, it is not the SAME but it is still buried foam, I do agree you need to get a good seal.
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Very good results for direct burial, a lot better way than how we were using the 2" foam board on all the houses. Nailed up and seams untreated.
That's pretty cool how the r value went up on the second year.
I've seen the purple treated spray foam used a few times where direct weather exposure or fire exposure was.
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The "problem" with spray polurethane and foam board exposed directly to soil is...........
BUGS.
Citronella ants, carpenter ants, and,,,, termites can all live in this foam. :o
I would be hesitant to use "foam in the ditch" method or foam board without treating the dirt/foam interface with termite pesticide (in particular, fipronil aka Termidor; simply put, nothing works much better on termites and ants than fipronil at this point in time). :)
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Closed cell foam is not water proof, it may be water proof in its intended application as a wall insulation but when buried in the ground it can break down and absorb water. I have seen it recently, the customer said it worked great for 4 years and this winter he started having growing issues as winter went on.
The gas inside the bubbles that make up closed cell foam do try to escape over time, this is one of the reasons logstor uses a membrane inside there pipe to stop this flow of gas out of the bubbles, this made for a much better and longer lasting product.
There is absolutely no way to ever achieve 0 heat loss.
The customer that had the spray foam had it probably 8 inches around his line set, the outside of the foam is Def breaking down and absorbing water and in places it has cracks that go down to the pipes
With that being said, customer double checked with installer to make sure he used closed cell foam, of course he did. They contacted the manufacturer and later so did I, the manufacturer which is one of the largest, said that the foam can't handle any temps over 180 degrees and that it was never designed to be placed in the ground.
Soooo.... take it for what it's worth
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Question remains here-did he have the foam encapulated in plastic? If sprayed into visquine(4 mil) and adheres to the plastic would this NOT be the same as the liner in the logstor? Has anyone seen a foam line dug up to verify the cracks and intrusion? Not trying to stir the pot here-just questioning-as it seems that this is a new option to use in lieu of the more expensive logstor and is of some merit??
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You would have to wrap the foamed line with plastic after, wich could be a pain in the butt. Closed cell foam will stick to plastic but not very well.
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What would it matter if u did wrap it in plastic? U can't possibly seal that plastic, 4 mil plastic is nothing compared to the case thickness of logstor
Also, logstor isn't depending on there case to stop the gas, that's why they added the membrane layer inside the pipe itself
I've yet to see a spray foam manufacturer say there product would be good underground or that it would handle temps over 180 degrees, this isn't the designed purpose of the foam some folks are trying to use
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Question remains here-did he have the foam encapulated in plastic? If sprayed into visquine(4 mil) and adheres to the plastic would this NOT be the same as the liner in the logstor? Has anyone seen a foam line dug up to verify the cracks and intrusion? Not trying to stir the pot here-just questioning-as it seems that this is a new option to use in lieu of the more expensive logstor and is of some merit??
i have seen a faom line about 12 inches square and wrapped in plastic dug up......a section 12 feet long could not be lifted by one man!
that being said i can not say for certain if it was closed or open celll faom as it was not mine
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For those who are thinking of using spray foam why don't you buy a can of closed cell foam, cover a 2' long piece of pipe and set the whole thing in a 5 gallon pail of water for awhile and see what happens. If it leaks right away or within a few days you will know it will definitely fail over time.
Then I would buy Logstor, again.
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The can stuff isn't exactly the same as what's sprayed from a rig. There are many options, and blends. I do know great stuff and the professional sprayed in foam will float in sumps, cisterns, or submerged in tanks for decades without absorbing more than .10%. That being said, I know if the pex pipe itself leaks in the underground pipe closed package, it will pressurized the whole line set and under pressure and direct hot water contact will break down and hold water.
There are blends that are more flexible, insect repellent, NIFPA fire retardant and stuff made for direct burial. Which what was used in the article previously posted to insulate basement walls below grade. Anything is possible, especially when we see youtube videos of the guy redoing his failed lines with garbage bags , duct tape and pink batting insulation.
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I seen that video too, they didn't appreciate my comments lol
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Sometimes the truth is hard to swallow
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Just looking on Pex Supply, 300 ft roll of 1.25" hePex is about 1700. If Logstor is even $14 a foot its only $400 and change more. Logstor it is then.
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HAVE ANY OF YOU GUYS USED THIS PRODUCT BEFORE
http://www.insulseal.com/index.html (http://www.insulseal.com/index.html)