Wood Framing Between Tank and Foam Insulation?

nhtreehouse Posted By nhtreehouse, Dec 3, 2017 at 11:20 AM

  1. nhtreehouse

    nhtreehouse
    New Member 2.
    NULL
    

    Feb 11, 2017
    23
    4
    Loc:
    New Hampshire
    Hi All,

    I've been lurking around for a while, and am working on installing a wood/pellet boiler system in an outbuilding. It's all coming along quite well, and I'll post an install thread once I get it up and running.

    I've converted a propane tank and have insulated between the tank and the wall with 6" of foam board in three layers (2.5" polyiso/1"XPS/2.5"XPS) with staggered seams. That was the easy part - now I need to build out the foam box into the room and one easy way I've thought about accomplishing this is to build some 2x4 framing next to the tank and use long screws to secure the foam boards to the 2x4 framing. This would put the 2x4 framing inside the storage tank insulation box, meaning the 2x4's are going to see the tank temperature. As of right now, I don't see the 2x4's touching the tank, they will just be inside the insulated space between tank and foam board

    Anyone see any problems with this, or with having foam board touching the storage tank? My inner layer of foam is 2.5" foil faced poiyiso. I guess I'm asking because both the x4s and the foam are quite flammable, and I'm just wondering what people think about this from a fire safety point of view.

    Other alternatives would be to use metal. I could easily fabricate up metal brackets and even weld them to the tank. But foam to framing fasteners are a bit more complicated using metal. Might use all thread rod welded to the bracing with nuts on the outside of the box? Just had another thought to use metal studs for the framing. maybe that would solve both problems?
     
  2. Bad LP

    Bad LP
    Feeling the Heat 2.
    NULL
    

    Nov 28, 2014
    452
    139
    Loc:
    Northern Maine
    Your framing and insulation board will never see more than a 200::F temperature or you have much bigger problems. :eek:

    My 2, 300 gal tanks are vertical. I basically built 2X4 walls then filled the bays with 2 layers of 2" foam boards tightly fit between the studs and covered with 1/2 MDO plywood. Everything is numbered and removable. All of my scrap was cut into smaller 6" strips that were placed as tight to the tanks as I could make them filling all voids out to the corners as best I could. I raised the tanks on solid concrete blocks so that I could insulate the floor under them. The top is removable and made out of 2 layers of 3" blue poly. The back wall (foundation) has 6". I did not want the concrete sucking heat from the tanks.

    On top of the tanks I had some extra Roxul blankets that I laid over the tops. In the center section on the front I cut in a 12X12 steel access door. This comes in very handy to shoot my IR gun on the tanks and pipes because I didn't bother insulating between the tanks.

    On the tank with the pressure and thermometer gauge I cut a piece of 3" PVC and brought it out to a 6X6 steel access door. Comes in handy to watch my temps and system pressure plus it helps in learning how much wood I can burn without coming close to over heating.

    It all must work well as the outside of the box is the same temp as the basement when I point the IR at it. Of course I do get loss from 2 openings where some EMT and junction boxes are in the way and also where the pipes exit the box. My next project will be to insulate and box in the 4 tank pipes going to the boiler, make some sort of panel where the EMT and junction boxes are then glue some 2" foam board to the 12X12 door.

    Cutting that foil faced polyiso sucked. Shop vac hooked to the table saw got a workout.
     
  3. JohnDolz

    JohnDolz
    Feeling the Heat 2.
    NULL
    

    Dec 29, 2015
    387
    47
    Loc:
    Burlington, CT
    Same here, My "box" is built with 2x4's with insulation attached to those.
     
  4. nhtreehouse

    nhtreehouse
    New Member 2.
    NULL
    

    Feb 11, 2017
    23
    4
    Loc:
    New Hampshire
    Thank you both for the replies ... I guess as the long project draws closer to actually firing up the boiler I've become a "Nervous Nellie!" :eek:
     

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