I was just given this site by Bioheat USA. I have a tarm gassifier with a 1000 gal storage tank with a rubber liner. It is 7 years old and decided to start leaking. The rubber is disintegrating/crumbling. I have been using 180-185 degree water. Bioheat just told me to keep the water at 170-175 degrees. Originally they said 180-185 degrees. They claim the liner should last 10 years at the lower temperature. The question is when I reline the tank should I go with two layers of rubber so if the first one leaks the second one will last maybe a few more years or will the heat also affect the second layer?
Rubber liner
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jebatty
Minister of Fire
If the first liner is leaking, I don't see how leaving it in place and putting the new over the top or removing the old and installing a new will make any difference in water holding ability. EPDM is rated max at 180. Pushing the max is likely to shorten its life. I think the heat will impact both layers.
Dave T
New Member
Welcome to the boiler room Brialin Interesting question, I've never had a EPDM tank but I am a commercial roofer and work with this stuff a lot, Firestone recently allowed applicators to leave EPDM in place on the roof and overlay it..Even with relief cuts in the old membrane, the two condensate between the layers of EPDM with hot and cold temperature changes..I would be happy with the ten years and use a single layer of rubber and not have to worry about a possible mold issue in the near future.. A few things to consider, there are different types of EPDM, some are FR (fire rated) and will take higher temps consistantly which is what you want (do you know if your first liner was FR?) EPDM also comes in different thicknesses .045 and .060 are the most common try to find .060 FR and you should not have to chance a possible mold issue to get years of good performance, use a single pice of EPDM with no seams try to make organized wrinkles or pigears at corners and NEVER cut yourself short it is easy to do, fill the tank compleatly before cutting excessive off of the EPDM, a lot of guys here with first hand experience maybe one of them can chime in with more help for you..Dave
Fred61
Minister of Fire
I have no "first-hand" experience with a lined tank, but I suspect if you double up on the liner, the inside liner will start floating when it springs a leak. Then you'll have a layer of hot water in the center and cooler water on the outside which will be insulated by a layer of EPDM. And a nasty looking mess.
flyingcow
Minister of Fire
a couple of months ago i talked to the STSS guys. they are probably the ones that supplied the tank and liner to Tarm. If I got one I was told to run about 170 for temps. Any higher would be shortening the life of the liner, 180 intermitant, but try to stay at 170. Also you should watch the PH of your water with a rubber liner, I think it was mainly to do with corrosion of the coils. I think this is not a problem with a PVC type of liner. Don't know the science behind it, but I got that tid bit from a reliable source.
tom in maine
Minister of Fire
We have been making tanks for a number of years and presently provide the square tank to Bioheat. We use a PVC alloy liner.
That being said, I would not be concerned about using EPDM again. If you are concerned about longevity, use .060" instead of .045"
It is harder to work with, but gives you 50% more thickness. And, yes, watch your high temp.
Double lining is not going to cause any weird mold or other problems, but is not necessary.
If the foam is wet, it will dry out. It will not mold if the tank is running at "normal" temps.
Polyisocyanurate foam that is saturated will take months to dry out, so do not be alarmed when installing a new liner in a tank that has
been leaking, when you see some seepage. Polyiso can absorb up to 10X its original weight in water. It loses half its R value at that point, but regains
it once dried out.
Tom
That being said, I would not be concerned about using EPDM again. If you are concerned about longevity, use .060" instead of .045"
It is harder to work with, but gives you 50% more thickness. And, yes, watch your high temp.
Double lining is not going to cause any weird mold or other problems, but is not necessary.
If the foam is wet, it will dry out. It will not mold if the tank is running at "normal" temps.
Polyisocyanurate foam that is saturated will take months to dry out, so do not be alarmed when installing a new liner in a tank that has
been leaking, when you see some seepage. Polyiso can absorb up to 10X its original weight in water. It loses half its R value at that point, but regains
it once dried out.
Tom
Dave T
New Member
TOM,
Do the PVC liners get vulconized with leister guns or is a full sheet used similar to EPDM, have you used TPO for any tanks , why is PVC used over EPDM, is it reinforced?? I agree about the insulation it will dry out but I have seen it mold and get whiteish bloches and carry an odor..Dave
Do the PVC liners get vulconized with leister guns or is a full sheet used similar to EPDM, have you used TPO for any tanks , why is PVC used over EPDM, is it reinforced?? I agree about the insulation it will dry out but I have seen it mold and get whiteish bloches and carry an odor..Dave
tom in maine
Minister of Fire
Hi,
Our liners are welded. PVC and PVC alloys can be heat welded.
I have not used TPO. TPO chemists tell me that it will soften in tank applications over time. We use our materials since they can be made to
drop into the tank shell and there is no folding and you don't smell like a skunk like you do after handling EPDM :^)
Of course, we trade off the cost of welding and having seams for the convenience of not fighting with the big sheets of folded material.
PVC and alloys can also be repaired in the field if necessary. We are presently using an alloy that is made specifically for us. It is reinforced.
We have used reinforced and unreinforced. Both have their place.
PVC can last a long time if the tank water is left in place, since the plasticizer in the PVC comes to an equilibrium in the stored water.
Please note that PVC pond liners are not usable for heat storage tanks.
Foil faced foam will get blotched (corrosion of the aluminum in the facer), which is not a big deal. I have had tanks smell, but the odor will dissipate once it dries out.
I have seen mold occur, but it usually will not form if the tank is not left idle for too long. Heat knocks down most nasty stuff in and out of the water.
Tom
Our liners are welded. PVC and PVC alloys can be heat welded.
I have not used TPO. TPO chemists tell me that it will soften in tank applications over time. We use our materials since they can be made to
drop into the tank shell and there is no folding and you don't smell like a skunk like you do after handling EPDM :^)
Of course, we trade off the cost of welding and having seams for the convenience of not fighting with the big sheets of folded material.
PVC and alloys can also be repaired in the field if necessary. We are presently using an alloy that is made specifically for us. It is reinforced.
We have used reinforced and unreinforced. Both have their place.
PVC can last a long time if the tank water is left in place, since the plasticizer in the PVC comes to an equilibrium in the stored water.
Please note that PVC pond liners are not usable for heat storage tanks.
Foil faced foam will get blotched (corrosion of the aluminum in the facer), which is not a big deal. I have had tanks smell, but the odor will dissipate once it dries out.
I have seen mold occur, but it usually will not form if the tank is not left idle for too long. Heat knocks down most nasty stuff in and out of the water.
Tom
henfruit
Minister of Fire
Tom, Have you ever used HDPE as a liner for one of your tanks? I think it would handle the heat. It has a melting point of about 250-300F (plasticized) if I remember correctly. I welded HDPE for a number of years for a large drainage company and have thought about maybe building a tank out of it. Thoughts??
tom in maine
Minister of Fire
We did some custom sizes for local folks and it was a hassle. Right now we are doing two sizes 550g and 820g. We will be adding more stock sizes and doing solar DHW/space heat tanks soon.
We presently sell through BioheatUSA.
There will be a website up soon at www.americansolartechnics.com
I have not used HDPE. It is rather stiff for packaging and shipping it safely.
Anything under 30 mils thickness is going to have permeation issues, especially in heat storage tanks.
I have been asked about supplying liners. At present we are just trying to keep up with demand for stock items, so we are not doing liners nor custom work.
That is apt to change as we get a little further along.
Tom
We presently sell through BioheatUSA.
There will be a website up soon at www.americansolartechnics.com
I have not used HDPE. It is rather stiff for packaging and shipping it safely.
Anything under 30 mils thickness is going to have permeation issues, especially in heat storage tanks.
I have been asked about supplying liners. At present we are just trying to keep up with demand for stock items, so we are not doing liners nor custom work.
That is apt to change as we get a little further along.
Tom
Dave T
New Member
Tom,
I am asking questions in interest only, not to question your product, that being said do you detail the corners with prefoarmed triangular looking nonreinforced corners?, do you use a cut edge sealent so water does not wick into the reinforcement threads?,do you use hand guns only or do you have a trinivar?,how much of your seams are welded 2" minimum?,do you detail angle change blowouts with similar nonreinforced patching material?,do you detail penatrations with boots or do you wrap pipes in unreinforced??
Thanks for the input..Dave
I am asking questions in interest only, not to question your product, that being said do you detail the corners with prefoarmed triangular looking nonreinforced corners?, do you use a cut edge sealent so water does not wick into the reinforcement threads?,do you use hand guns only or do you have a trinivar?,how much of your seams are welded 2" minimum?,do you detail angle change blowouts with similar nonreinforced patching material?,do you detail penatrations with boots or do you wrap pipes in unreinforced??
Thanks for the input..Dave
tom in maine
Minister of Fire
Hi Dave,
Whew!
I guess there will be few trade secrets after I answer this!
The way we fabricate, we do not need precut corners, besides, the liner is 100% supported by the shell.
We seal, if necessary, but cut edges are usually sealed by the way we assemble and weld.
We can usually use both hand welders and machines to weld.
All our seams are welded at least 1". 2" is usually reserved for landfill membranes that might not be supported
properly.
There are no penetrations below the waterline. All plumbing connections to the tank and heat exchangers are above the waterline at the
perimeter of the tank. I do not trust the longevity of penetrations. I have had too many situations where they can
leak or weep, without the user knowing until there was saturation of the foam with water or water vapor and/or a leak.
To me, it is not necessary if properly designed and not worth the risk, once it leaves my hands.
Tom
Whew!
I guess there will be few trade secrets after I answer this!
The way we fabricate, we do not need precut corners, besides, the liner is 100% supported by the shell.
We seal, if necessary, but cut edges are usually sealed by the way we assemble and weld.
We can usually use both hand welders and machines to weld.
All our seams are welded at least 1". 2" is usually reserved for landfill membranes that might not be supported
properly.
There are no penetrations below the waterline. All plumbing connections to the tank and heat exchangers are above the waterline at the
perimeter of the tank. I do not trust the longevity of penetrations. I have had too many situations where they can
leak or weep, without the user knowing until there was saturation of the foam with water or water vapor and/or a leak.
To me, it is not necessary if properly designed and not worth the risk, once it leaves my hands.
Tom
Dave T
New Member
Thanks Tom,
For some of the answers that I was wondering about, there are differences between what you do and what I do but they go hand and hand.. The question that I still have is if you don't have any flaps in your tanks then there has to be a detail in the inside corners, do you have a roll of unsupported material that is used to make a pigear and cover flap for that pigear??Or is the material preformed with all factory edges with the inside corners already made and you drop it in place and weld the seams on the base and up the walls?? I know you can't be perfect every time a angle and seam go in, what if you burn a hole in the PVC at an angle or have a fishmouth do you patch it with field membrane so to speak and make (tee joints) or is unsupported used in these situations and then the edge melted in to seal the tees??It would be fun to do some tank installs as tanks get more popular maybe roofers can have off season full time work indoors LOL just thinking out loud..Dave
For some of the answers that I was wondering about, there are differences between what you do and what I do but they go hand and hand.. The question that I still have is if you don't have any flaps in your tanks then there has to be a detail in the inside corners, do you have a roll of unsupported material that is used to make a pigear and cover flap for that pigear??Or is the material preformed with all factory edges with the inside corners already made and you drop it in place and weld the seams on the base and up the walls?? I know you can't be perfect every time a angle and seam go in, what if you burn a hole in the PVC at an angle or have a fishmouth do you patch it with field membrane so to speak and make (tee joints) or is unsupported used in these situations and then the edge melted in to seal the tees??It would be fun to do some tank installs as tanks get more popular maybe roofers can have off season full time work indoors LOL just thinking out loud..Dave
Down here in the South, There’s always a cheap, abundant supply of used, large plastic containers caged in an aluminum frame so they can be moved with a fork lift....usually with a large 8” lid on the top and a ball valve on the bottom.
They commonly hold 275 gallons and look easily adaptable to a decent storage system but I have no idea if they can withstand 180 degree temps. Anyone know what type of plastic they’re made from or had any experience with them as a storage device?
My apologies for hi-jacking the thread a little.
They commonly hold 275 gallons and look easily adaptable to a decent storage system but I have no idea if they can withstand 180 degree temps. Anyone know what type of plastic they’re made from or had any experience with them as a storage device?
My apologies for hi-jacking the thread a little.
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Robby
Member
I use pressurized 1250 gal. storage, but I always wondered why not make very strong box, then line with copper soldered at edges. 4'x10' sheets folded 2" at edge and soldered. Temperature unimportant, extremley long life, compatible with all fittings etc. and you can insulate to your hearts content. Easy to install fittings at whatever height,and on and on.
I realize maybe cost more but it is almost forever.
Just wondered.
Robby
I realize maybe cost more but it is almost forever.
Just wondered.
Robby
When I was considering unpressurized storage, I spoke to a fellow that made maple sugar boiling pans. We never got to a final quote but I remember that a stainless steel liner wouldn't cost any more than the commercial rubber swimming pool. But I would have to supply the insulated structure to hold it. That was before the price of metal went wild this summer. It's come back down a bit.
tom in maine
Minister of Fire
One can certainly use stainless or copper for a liner or tank, but obviously this becomes a DIY project since shipping and handling becomes an issue.
While these metals are relatively inert, they are not completely corrosion proof.
I view my job as trying to get the best tank together for the least cost. I have to admit that putting together a tank that can stand the rigors
of this application is not as simple as it seems, especially once it leaves my shop. As a business, there is a lot of cost involved in making a tank that is going to last.
You, as a user, do not want a failure whether you built it or we did. There is a lot of risk involved when you install 8,000 pound of hot water in a basement. And if there is an issue, we need to have things simple and serviceable.
We include color photographed directions, which eliminate many of the mistakes that inexperienced people have made in the past.
This is one big reason why I do not like to make any hole in the liner for plumbing penetrations. If it leaks, and you have to deal with it, life gets very complicated.
I missed a question a while back about liners: Our liner design is such that there is very good strength in the areas where required (like corners).
We test each liner for any defects in material or manufacture.
One last thing, when I used to work with Dick Hill testing wood boilers, we never used a closed loop to tie the boiler into the tank.
We circulated tank water into the boiler and back. You do this with the plate heat exchanger concept, since one side of that loop is unpressurized and has the same limitations as a direct loop. This eliminated the big heat exchanger. We also ran tank water through the heating distribution loop.
This is practical in single level homes. The tank water is treated with corrosion inhibitor that we found that was used in nuclear power plants :^)
It was pretty inert, safe and worked well. It was not stupidly expensive, just a little pricey. Corrosion treatment of an unpressurized boiler is not complicated,
the OWB people are doing it.
There are limitations to the concept, but it worked well and you could always tell the system was working since you could hear some water movement in the
heat distribution system.
My 2 cents worth.
While these metals are relatively inert, they are not completely corrosion proof.
I view my job as trying to get the best tank together for the least cost. I have to admit that putting together a tank that can stand the rigors
of this application is not as simple as it seems, especially once it leaves my shop. As a business, there is a lot of cost involved in making a tank that is going to last.
You, as a user, do not want a failure whether you built it or we did. There is a lot of risk involved when you install 8,000 pound of hot water in a basement. And if there is an issue, we need to have things simple and serviceable.
We include color photographed directions, which eliminate many of the mistakes that inexperienced people have made in the past.
This is one big reason why I do not like to make any hole in the liner for plumbing penetrations. If it leaks, and you have to deal with it, life gets very complicated.
I missed a question a while back about liners: Our liner design is such that there is very good strength in the areas where required (like corners).
We test each liner for any defects in material or manufacture.
One last thing, when I used to work with Dick Hill testing wood boilers, we never used a closed loop to tie the boiler into the tank.
We circulated tank water into the boiler and back. You do this with the plate heat exchanger concept, since one side of that loop is unpressurized and has the same limitations as a direct loop. This eliminated the big heat exchanger. We also ran tank water through the heating distribution loop.
This is practical in single level homes. The tank water is treated with corrosion inhibitor that we found that was used in nuclear power plants :^)
It was pretty inert, safe and worked well. It was not stupidly expensive, just a little pricey. Corrosion treatment of an unpressurized boiler is not complicated,
the OWB people are doing it.
There are limitations to the concept, but it worked well and you could always tell the system was working since you could hear some water movement in the
heat distribution system.
My 2 cents worth.
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