Strong Insulation

[cve60069]

I am looking for an heat-insulation material that will support a minimum of 20 kN/m2. I am looking at blown glass but was hoping that there may be some other materials about.

Many thanks

 

[Ron]

That's not very much pressure. Almost any rigid foam insulation will do that.

 

[cve60069]

Ron

Are you sure?

 

[Ron]

Yes. A typical urethane foam with medium density has a compressive strength of about 30 psi or a little over 200 kN/m^2 (you probably should check my conversion though!)

 

[SteelPE]

If you are looking for something stronger then you can take a look at this:

http://foamular.com/assets/0/144/172/174/bf64ec70-16f1-4748-abc7-c9dee5100987.pdf

 

[dik]

DOW makes some high compressive insulations... extruded polystyrene, Hi-Load 40, 60, and 100, that I've used with good results for several decades. Your loading is relatively 'light'... They also have load-deformation information.

Dik

 

[Den32]

Yes, there are specific insulation boards rated for compression loads.

We did some of these for Frost Protected Foundation design - it is ASTM C578 and there are various types (can't remember which types are load bearing. ASCE 32-01 doesn't allow Types II and X)

Here are some properties from a manuf.

http://www.diversifoam.com/cfproperties.htm

 

[ajk1]

Be aware though that Dow recommends quite high safety factors because of creep etc. Check the Dow technical literature. Your bearing stress is very low, so even with the high safety factor, you may be ok if you use say Dow HI 60 insulation. But check the Dow technical literature and their recommendations. I assume this will not be in a wet environement (it can under certain conditions become waterlogged - I have seen this happen) and that it will not be subject to temperature in excess of Dow recommendations.

 

[ishvaaag]

Perhaps the more dear failure in one of the projects in which I once intervened was with the introduction in 1979, entirely anew, of a mandatory insulation code in Spain. The senior architect after looking the available literature followed the recommendation of the main firm producing insulation panels choosing panel "Roofing" to be placed under terrazzo tiles; it failed miserably on the slight compressibility of the 2 cm thick board. This had to be corrected for about 100 dwellings; after the customary legal action, insurance had to pay. So be always be wary of the recommendations in paper.

I remember 2 old brands that would do. Styrodur and variants can do that; Vitrisol, that essentially is glass with bubles is rigid as a stone, also will. There must be out there trademarks replicating these materials.

 

[csd72]

If you can walk on it without damaging it then it can take well in excess of 20kN/sqm.

Do the numbers and you will see what I mean.

 

[Ron]

csd72....you just had to throw some common sense in there, didn't ya!!

 

[ajk1]

Just be a little bit careful about the "walk-on" test. That does not account for creep. In Canada, Dow requires a safety factor of 10.0; in U.S. they require safety factor of 4.0). So if you have 20 kPa (400 psf) unfactored bearing stress, then in Canada you need an insulation with at least a 4,000 psf ultimate bearing strength or 37.7 psi. Dow HI 40 should be ok (or Owings Corning equivalent insulation).

 

[dik]

You have freezing conditions in Canada?

Dik

 

[ajk1]

occasionally does get cold here.

 

[BAretired]

A safety factor of 10 seems a bit high.

BA

 

[csd72]

ajk1,

good point, though by my calculations you get a safety factor of about 5 anyhow.