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Insulation Question

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by dogwood, Feb 7, 2010.

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  1. Fred61

    Fred61 Minister of Fire

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    I'm the guy that posted that link but I didn't do it to cause controversy. Perhaps we're reading this wrong and maybe the
    word "charring" has nothing to do with approaching the flash point of the material. Several people have used spray on foam on their tanks with much success and would have found darkening, cracks or degradation by now. In my own case, I attached Isocyanurate panels to my tank and actually used Great Stuff as the adhesive and have found no problems. Of course mine is unpressurized and routinely only reaches 185 to 190 at the top.
    To feel more secure you could purchase a DIY kit of high temp. foam, the smallest number of board feet that they offer and apply a thin coat to the tank and then call in your foam application contractor to finish it to the full thickness desired. Do I think you need to do this? No.

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  2. dogwood

    dogwood Minister of Fire

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    Say Coolidge, what constitutes an "approved 15 minute thermal barrier"? It's encouraging your foam didn't fail at 230 degrees. Maybe the regular 2 lb. "off-the-shelf" foam will do the trick after all. Anybody here burned any foam sprayed over a 200 degree pressure tank? Thanks for the input. We'll sort this out yet.

    Mike
  3. coolidge

    coolidge Member

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    You would want to check with the local building code official to see what his interpretation would be for the fifteen minute thermal barrier. But you could get some latex based paint from the link i provided and paint it on yourself, it will provide you with the proper protection( as usual follow the manufacturers recommendations). Otherwise just a half inch sheetrock will do also. As for the tank and charring, use the two pound that your installer has, you will be fine with that. "Charring" could occur if the hot water did in fact go over the intanded rate of the foam, but it would have to be for a prolonged time. It is not uncommon for the internal temp of the foam being sprayed to reach 275 degrees so if there was going to be failure it would be then.Foam could be alot hotter if spray at too thick of a pass. By alot hotter i mean actualy catch on fire. Two inch pass is the recommended thickness.
  4. jdew1920

    jdew1920 Member

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    I think in a climage like Va you can definately hit a point of diminishing returns. If you you want to add some extra insulation to the attic I would recommend blown in cellulose. One of the main benefits that cellulose gives you is that it seals up pretty well and really limits the air flow through the insulation and around things like electrical boxes and other penetrations. Like someone else mentioned fiberglass performance actually goes down with decreasing temperature. I added about 8" of cellulose (about R24) ontop of the fiberglass that was already in our attic - huge difference. One thing to keep in mind is that you can't pile it too deep - there are weight limits depending on the rafter spacing and drywall thickness.
  5. dogwood

    dogwood Minister of Fire

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    Thank you Coolidge. I was going to frame and box in the tank with sheetrock, so sounds like I should be okay in this regard. I'm starting to feel reassured about spray foaming the tank. Sounds like you have a bit of experience using it.

    Mike
  6. Piker

    Piker Minister of Fire

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    I do not hesitate to recommend spray foam to customers. The red herring comment made earlier is well placed in my opinion. You will certainly not be dissatisfied with the performance of a spray foam insulation job on your storage tanks.

    cheers
  7. Como

    Como Minister of Fire

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  8. dogwood

    dogwood Minister of Fire

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    Coolidge and Piker, I will take your advice on second thought, and go with foaming in the tank, since you seem to have practical experience with the material. Thanks for your help. Maybe I'll try an experiment. I'll see if I can get a small bit of the stuff and put it the oven to test at what temp it melts or combusts. Any idea if the spray foam you get in the can at Lowes is the same as the two pound stuff normally sprayed in for insulating? I think I might have some left over out in the garage to experiment with.

    Mike
  9. Fred61

    Fred61 Minister of Fire

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    I was thinking about applying some to the outside of a pot and then boil some water in it but the heat wafting up from the burner could skew the experiment.
  10. coolidge

    coolidge Member

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    I would not recommend any INSIDE experiments. Once the foam is fully cured it is catotgorized as a plastic, thus some really bad fumes for an inside experiment if exposed to an open flame. If you have a can from Lowes or elswhere spray some on a piece of scrap wood and then use a torch to try your experiment(OUTSIDE). You wont be able to get a two pound foam at a bigbox retailer, the stuff in the cans are more like a half pound foam.
  11. dogwood

    dogwood Minister of Fire

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    Coolidge, Thanks for more good advice. If I had stunk up the oven of my wife's brand new stove with the smell of burning plastic, there would have been hell to pay. I was thinking only about how I could control the oven's temperature fairly closely, but you thought this through more clearly than I, and saved me from myself. I was going to put a one inch cube of foam next to an oven thermometer near the glass window to the oven, and watch what happened as the oven temperature rose. Maybe there's a single guy out there with an old stove who would care to try this experiment to determine the actual combustion point of two pound spray foam insulation. It sounded like fun anyway.

    Mike
  12. RobC

    RobC Minister of Fire

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    I sprayed 2 X 500 gallon propane tanks with the Froth Pac product. Has worked fine. Had a bit of a problem with the foam lofting on first coat. Previous post mentioned having tanks at 100F. I would agree that that would be a minimum temp, but no expert. Closed cell form expands from it's own heat, so when sprayed on cool metal that retards the foam expansion. Secondly you want to spray at about a rate that will yield a two inch finish loft for the same reason. There was a post DIY Foam Didn't Loft, dealt with exothermic reaction. Interesting stuff. I have about 2 inches of foam and tanks are fine. I feel there would be no benefit to adding any more foam as they are cool to the touch as is. One benefit to foam is all the heat is inside the tank. If you can get tanks sprayed by a pro I would consider it. I'm into mine for $850 X 2" and I was quoted $1200 for 3". What I know now, the 3" job would been well worth the extra $400. One thing that did factor in was I wanted to get a base coat on tanks and test system before I made a commitment to the finish foam job. I didn't want to get into this $1200 and then get blindsided buy a leak or a cracked weld etc.....
    Rob
  13. dogwood

    dogwood Minister of Fire

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    Good practical information Rob. I will definitely get the tank warmed or maybe spray during the Summer. I didn't realize that getting a tank sprayed would be that costly. I'll have to call around and get some estimates. Now I wonder how much less efficient blown in insulation would be. I hesitate to use blown-in as the tank will be in an unheated space in my garage and I'd like to keep it as insulated from the cold as possible. Worst come to worst, if finances dictate we can't afford to foam in the 1000 gallon tank, one end of the tank will abut the boiler room, so maybe framing it in with that end open will marginally put it in the insulated envelope of the house

    Mike
  14. sdrobertson

    sdrobertson Minister of Fire

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    My tanks are in a uninsulated polebarn. I have them standing on end and I made the walls 14" from the farthest edge of the tanks so in the corners there is about 30"s of insulation. I used dense packed cellous to insulate them and I'm pretty happy with the results. I have about 3 ft of dense pack cellous on top of the tanks and then I placed almost 4 ft of Styrofoam balls (used for block wall fill) on top of that. I do not have any frost or snow melt above the tanks on the roof. It was a very messy job blowing in the insulation down 12 feet while climbing on the 4 tanks but it was allot cheaper to do it this way. The big advantage to spraying them would be a smaller footprint and if I ever have a leak, I'll have a real mess getting back in the box.

    Attached is a pic of the top of two tanks showing them in relation to walls of the box.

    Attached Files:

  15. dogwood

    dogwood Minister of Fire

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    SDRobertson, looks like the spacing to the walls is similar in both our set-ups, although my tank is horizontal to the ground. Youve got the better arrangement there. If you had to venture a guess, how much less expensive do you think dense packed celluose would be price-wise than foam to get similar R-value. (1/2 the amount, more less?). Did you price it both ways? Did you rent the equipment to blow it in? Is the blower something a typical rental yard might carry or did you have to look elswhere? I wonder how much dense pack celluose would have to go around the tank to be equivalent to 3'' of foam? I'm going to box the tank in anyway, and the back and side walls are already insulated to R-26, so I'd have a head start. Thanks for the info and picture.

    Mike
  16. sdrobertson

    sdrobertson Minister of Fire

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    The total expense for insulation was $508.00 for the cellous and foam beads. The place I got the blown insulation threw in the rental for the the machine. I first blew in the box in fall of 2008 and in the fall of 2009 I went back into the top of the box and used a pole and had to push down into the insulation to fill a few voids that developed. It's hard to control the nozzle when filling such a big void trying to get it densely pack and I did have some settling. I was going to use the foam beads but they wouldn't take the 190's I wanted to run at and the cellous manufacture told me it would hold up to those temps. I never did price the spray foam as I new it would be really expensive to spray 4 tanks.
  17. dogwood

    dogwood Minister of Fire

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    Thanks sdrobertson. I'll called several foam insulation places yesterday to get estimates, but no-one answered the phone. Must be everyone's out due to the snow conditions. Sounds like your cost for dense-pack celluolose was in the reasonable range. If anyone else has a foamed tank and would be willing to share their cost I'd be interested. I'm going to call around again today. Maybe someone will be at work since the snow stopped coming down. Thanks

    Mike
  18. Floydian

    Floydian Feeling the Heat

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    Hey Mike-
    I called a company out of Harrisonburg about a year ago. Price was $1.25/BF, so $15 cu. ft. for 2#(I think) closed cell urethane.
    Found them online but I don't remember their name, sorry.

    Noah
  19. patch53

    patch53 New Member

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    A local insulation company here wants $450 to spray my 500 gallon propane tank. That would be for 4" of closed cell stuff. Sounds kinda high to me?
  20. mrhaney

    mrhaney New Member

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    i see all the hot water storage tanks and i know you all have figured this out to be more effiecient but is it for recovery time or less cycling time on your boiler,i burn coal and my boiler has 108 us gal, idont have any problem
    my stove recovers under a load at 1 degree per minute and not loaded at 2 degrees per minute ,i have burnt wood for years but not in a boiler i assume this is for accumalator ?
  21. sdrobertson

    sdrobertson Minister of Fire

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    Storage adds just a little bit to efficiency as the boiler does not idle. Its most pronounced in the shoulder season. Mostly storage adds to the convenience of when you have to have the boiler running. I work twelve hour days so I'm gone for roughly 14 hours on the days I'm on duty so I wanted to be able to go several days without having to tend the boiler and still keep the house warm even in the cold part of the winter.
  22. Hankovitch

    Hankovitch Member

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    Hello,
    Hankovitch here. My wife and I are in the process of converting our 36' X 104' barn into our home. We have spent 5 years researching the best ways to do things and amassing required items for the project. During our search we found the answer to your query. That is, we found the answer for Closed-cell, Sprayed Polyurethane Foam (SPF). By closed-cell we mean 3# per cubic foot density, and by SPF we mean 'sprayed'....not polyurethane board stock.
    See the below two links for the answer.
    First link is the short answer...((((for a house, 3" of SPF is sufficient - your point of 'diminishing returns'))))
    http://www.monolithic.com/stories/foam-chapter-04/photos#6
    Second link, below, is a wonderful read, and expands greatly on the answer.
    http://www.monolithic.com/stories/foam-chapter-04

    Please let me know what our decision is, and how you like it once you've had the spraying done.

    See below for how our experiment is going with SPF.......
    We have dug out around the foundation of the 36’ x 104’ barn, 4 feet down…..pressure-washed the dirt from the foundation/footing……then applied 3” of SPF to the foundation (down 3’ below grade), and applied 3” of SPF up the 8’ high, 12” thick concrete wall of the milking parlor and up another foot……then sprayed a polyurea paint over the foam…..drain tile was put in around the foundation and runs to one of our ditches 300 feet from the barn……then we back-filled where they dug out around the foundation………then we also applied 2” of SPF inside the barn, to the milking parlor ceiling (underside of hay mow floor)………..we put 14 new windows, 3 new doors, and a new 7’x9’ garage door in each end..………
    In this 3,800 sq foot area (the former milking parlor) the only source of heat is passively from mother earth…down 4 feet the temp of the earth is approximately 50 degrees F…..
    Bottom line on how well the insulation is working.
    Since Jan 1, 2010 outside temp has ranged from +39 F to -14 F.
    During that same time period the inside temp of the former milking parlor has ranged from +33 F to +37F.
    The important thing to note is that, even though the outside temp dropped to 14 below zero, the inside temp always stayed above freezing….on some days inside the milking parlor has been as much as 47 degrees warmer than outside!
    Note, this is with PASSIVE geothermal heating…..we do not have a heat pump, there is NO source of ‘heat’ for the barn other than what mother earth supplies by heat passively (and continually) coming up through the concrete slab of the milking parlor floor!
    Furthermore, there is no ‘earth berm’ of the barn, the entire milking parlor is above ground.
    Pretty awesome, I’d say…..

    And, it will only get better as we…
    - put on storm doors (for the three doors we put in),
    - complete the back-filling (in some places the back-fill is over a foot low), and
    - close off the openings of the two stairways with something better-insulating than the 3/4 OSB we now have covering the openings.
  23. dogwood

    dogwood Minister of Fire

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    Thanks for your reply and the links Hankovitch. I will read through both links today. Sounds like you've done a lot of work digging out around your foundation. That had to be back breaking job. Converting a barn to a house is a tremendous project. Sounds as if you're up to it though. I would like to find out what the point of no return is for the pink stuff too. Maybe there is none.

    Mike
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