Maybe someone at NASA knows the answer, but I haven’t been able to get anywhere figuring this out. There are several ways that heat can be lost from a storage tank of the type we’re concerned with:

1) Conduction. That’s want U-value and R-value measure.
2) Radiation. That’s what an air gap with reflective foil is goos at stopping.
3) Convection. That’s when warm air or water is able to move up and/or out, being replaced with cooler air/water.
4) Evaporation.

R-value doesn’t address the last three. To me, there are two basic questions:

1) If you have a limited amount of space for insulation, what material or combination of materials will provide the lowest total heat loss?

2) Same question, if your budget is limited.

I called the manufacturer today and asked them about direct contact with 200 degree temps. He stated that the 180 degree rating on the bags is to insure that when it is installed, the cellulose is kept a minimum of 3 inches away from light fixtures and chimneys. Prolong exposures to 200 degrees will have no affects on the quality, nor will it cause added settling of the cellulose.  I guess I have finally decided on how I will insulate - one more decision down!!

good to know, and thanks for passing the information back.  one thing, when you go to install the cellulose, even though it’d seem like you could open the “bales” and shred it up and toss it in by hand- rent a blower instead (tool rental places seem to have them)-- the blower shreds the stuff and mixes it with air, so that it’s uniform- otherwise it goes in in mats and chunks, which (A) uses more material; and (B) has a lower R-value.

How are you insulating underneath the propane tanks with all the weight.  I’m trying to figure out a good design for a shed to store 2 -500 propane tanks, EKO60, and 8 cords of wood.  The insulation space is the main question on the side if you could have any width of side insulation and how to insulate the bottom.  The shed will have a concrete floor.  Any help would be appreciated.

I’m standing the tanks on end with semi truck rims for a base welded on the ends. I built the “box” to be a little over two ft larger than the tanks so I’ll have more than 12” of insulation on the sides. The bottom sits on the rims and I did not insulate the floor but I will fill the inside of the rims with insulation so I’m not sure how much I’ll lose but I think it will be minimal.  The problem I see is that the heat will want to travel through the rims to the concrete but with all that weight, I want a good base.

doesn’t seem like you should lose all that much heat, relatively speaking, downward.  If you wanted to, you could cut circles of polyiso foam board the inside diameter of the truck rims and set the tank/ bases down over that- at that point, your only real loss would be conduction via the rims, which should be minimal-- and I agree, with the weight that you’re dealing with, you want sturdy and stable!