Insulating storage tanks

[warno]

It has been discussed a bunch but most of the threads are a few to many years old. I'm wondering what today's standards of insulation on storage tanks is. I have a local spray foamer that has done work for me before. I was wondering about going with spray foam alone.

My tanks will be up against a wall in my garage the wall will be insulated but how much should I go with?

How much insulation should I put around my tanks obviously more is better but what would be bare minimum?

And if not Spray foam what should I use?

Thanks for any help in advance.

 

[Tennman]

Hard to imagine better than spray foam. With 180F water in our tanks if you lay your hand on the foam it's nearly room temp. Polyurethane spray foam used on Shuttle External Tank (-425F). Ours is 3.5-4" all over.

 

[maple1]

My tanks are up against 2x4 stairwell framing.

I insulated that conventionally & added a layer of 1.5" foam board. After my tanks were in place I just framed a box around them & insulated that rather conventionally. Made use of stuff I had left over from building the house. Stuffed batts in around the tanks. One thing I think I should have done is a better job under the tanks. I kind of did the best I could after the fact to get 2 layers of 1.5" foamboard under them, but there are little gaps under in places I'm sure. I also stuffed some cellulose underneath where I could reach. I have the ability to crack open one end of the enclosure (it's hinged, sorta - with Tuck Tape) if I think I need more heat in the basement. Haven't done that for a couple years but could if I wanted - tanks make great radiators.

One more thing I did was stuff 2 rolls of 3/4" pex inside the enclosure under, around & mostly on top of the tanks, before I stuffed insulation in. My DHW runs through that before it goes to my DHW heating stuff. Preheats it a lot, and at times of intermittent use likely does all the DHW heating.

I like having the ability to get at my tanks again if needed - like if I want to plumb something else in in the future. Or need to service for some reason. I also added more temp sensors later, was easy to reach in & tape them to the tanks where I wanted.

 

[huffdawg]

I had mine sprayed with closed cell foam approx 4" thick then I framed them in and filled with fiberglass batts.. works very good.

 

[Bad LP]

I would look into a pour-able closed cell foam that is commonly found in marine applications for flotation in hulls. I would of course block out access to all fittings and temp probes. You could make a nice looking box to enclose the tank for not a lot of money or work.

 

[warno]

I'm going to frame and box in the tanks after insulation. I'm liking the idea of getting at the tank again if ever the need arouse. Maybe I'll use spray foam on the bottoms up to a certain point then stuff Batts in around everything else. What R value should I shoot for as a bare minimum?

I looked into the pourable stuff and it is cheap but I couldn't find a R value for it anywhere.

 

[Buzz Saw]

View attachment 176997 View attachment 176998

I had mine sprayed with closed cell foam approx 4" thick then I framed them in and filled with fiberglass batts.. works very good.

Did you spray those in the tanks final location or spray then move?

 

[huffdawg]

Did you spray those in the tanks final location or spray then move?

Yes they were sprayed where they stand. It made it a bit more difficult for the spray application in the back corner. If I was to do it again I would get them sprayed before setting in against the wall.

 

[Karl_northwind]

I've done all sorts of things. spray foam works great, we've dense packed them with fiberglass (can still stick a hand thru to check a fitting or whatever) if you can get the foaming done at a reasonable cost, do that. but you will have to protect it from the dwelling space.

 

[warno]

I'll get a quote from the local foam companies and I'll go from there. I know fiberglass batts are fairly cheap for what they are. Either way there will be a framed and ply wood structure built around it after is all said and done.

 

[Willman]

check out Roxwul for insulation slightly higher r value and denser for forming. Cuts great for a close fit.

 

[warno]

I didn't think of that. I have some on my boiler that was a pretty good deal from Menards. I'll double check the R value on it, it might be good for the "in between" tank spots.

 

[Buzz Saw]

@warno, what did you end up deciding to do?

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[warno]

Once everything is plumbed and I run for a little bit I'm going to build a box around my tanks and use a wooden fiberglass attic batt. It's has a R value of 30 so I'm going to wrap that all around it inside the box.

 

[hondaracer2oo4]

That's r30 though when installed following certain guidelines. No gaps in fiberglass, not compressed al all, no air movement around or through the fiberglass. If you wrap the tanks carefully with the r30 you might be able to get r 10 equivalent.

 

[warno]

It was the best I could think of for the money. I really thought about spray foam but then thought about the nightmare of having a leak and trying to find it. I could go the roxul route but I thought I'd get more r value the other way. Since the R30 rolls are about 40 feet long versus the 5 feet long Batts of roxul. And the R30 was easily half the money for the coverage.

 

[hondaracer2oo4]

Are you really worried about a 3/8 thick propane tank leaking? I would just keep the foam away from any welded bungs or manifolds and spray the rest. You'll never get a leak in the 3/8 in your life time.

 

[warno]

I was worried about the threaded fittings leaking. Since I didn't cut any of the factory fittings out, I just threaded plugs in them.

My tanks are 1/4" steel, but I see what your saying about them not rusting out anytime soon. I guess I could go back and get a quote from the local guy for foam.

 

[huffdawg]

Also a good idea to spray first before you put them in position.. You need a good 3 feet or so to get a nice uniform application.

 

[warno]

My tanks are tight against my wall on one side, well about 1.5" away. So I could just have the guy glue them to the wall with the foam so to speak. The wall is insulated with r13 batts. And I could stuff some fiber glass in behind the tanks as best as possible before application.

 

[Buzz Saw]

So I could just have the guy glue them to the wall with the foam so to speak. .

If you do this I would put plastic on the wall so the tanks could be pulled out without damaging the foam.

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[maple1]

If the tanks are in a place that is heated - or a place that could use a little heat - I don't think I would fret too much over the insulation. Aside maybe from doing the bottom as best as I could to keep heat out of the ground. The exception to that would be if I was going to try to use this to heat DHW in the summer. But even after investing some $$ on a decent setup that I can do that with here (heat DHW all summer from wood fired storage), and doing it a summer or two - I now just let my storage go cold for the summer & heat our DHW with my ordinary electric resistance DHW heater.

I'd just insulate as best I could, as cheaply & easily as I could. Well, I guess that's what I did. My fiberglass-stuffed enclosure isn't pretty (I should finish that one of these years, likely) - but it works pretty good.

 

[woodsmaster]

i built a box around my tanks and dense packed cellulose insulation in the box.

 

[warno]

The tanks are in my garage which is heated, from the tanks, so any heat loss will be in that building. Here's my storage plumbing thread. It has pics of my tanks.

https://www.hearth.com/talk/threads/starting-my-storage-and-replumb-project.155178/

I was a bit concerned about doing the bottom as I still have a slight water seepage in the corner of my tanks. It's enough that it makes the floor look wet after a REALLY heavy rain. Which is fine with nothing, but if I have any kind of absorbent insulation at the bottom it will wick the water up and ruin my day. Is there anything I can put underneath to avoid this? I have about 1.5" to play with.

 

[Buzz Saw]

The tanks are in my garage which is heated, from the tanks, so any heat loss will be in that building. Here's my storage plumbing thread. It has pics of my tanks.

https://www.hearth.com/talk/threads/starting-my-storage-and-replumb-project.155178/

I was a bit concerned about doing the bottom as I still have a slight water seepage in the corner of my tanks. It's enough that it makes the floor look wet after a REALLY heavy rain. Which is fine with nothing, but if I have any kind of absorbent insulation at the bottom it will wick the water up and ruin my day. Is there anything I can put underneath to avoid this? I have about 1.5" to play with.

I think XPS is non absorbant. Another possibme option is to put foil faced polyisocyuanurate down with the foil down to act as a vapor barrier.

FWIW, The newest Garn manual calls for the foil faced polyisocyuanurate to be put under the unit during install.



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