Not sure what you mean about ruptured? I have heard of a rash of Kingspan PU blistering skins because gas had no where to escape. if skin is blistered then it means there is no bond

I found this at http://www.foam-tech.com/products/urethane_foam/ama_toxicity.htm

Excerpt from "Toxicology of Urea Formaldehyde and Polyurethane Foam Insulation"

by John C. Harris, MD; Barry H. Rumack, MD; Franklin D. Aldrich, MD, PhD

As printed in the Journal of The American Medical Association, Jan. 16, 1981, Vol. 245, No. 3 (Copy of complete study available upon request)
Polyurethane Foams
Background

When toxicity from urea formaldehyde foam insulation became publicly known, the Rocky Mountain Poison Center received numerous calls regarding polyurethane foam. Toxicity of polyurethane foams is restricted to the manufacturing process, except during fires. Each year, many thousands of tons of polyurethane foams are produced for applications ranging from structural members to pillows. When used as structural insulation, polyurethane foam "sandwiches" of outer paneling, foam core, and inner wall are transported to the job site and assembled onto the framework of the building. Because of the high R value of polyurethane forms, this insulation material has become popular for new housing construction.
Technical Aspects

Polyurethane foams may vary in physical state from tough, rigid solids that can be used for insulation, molding, and structural applications to very soft flexible materials that are suitable for seat cushions. Density of foams may range from approximately 8 kg/L to 1kg/L, depending on the purpose for which the foam is designed. Formation of polyurethane foam involves reacting or difunctional or multifunctional alcohol (polyol) with an aromatic isocyanate in the presence of a blowing agent, catalyst, and surfactant.

A fully cured polyurethane foam contains no residual isocyanate or polyol and, in contrast to the urea formaldehyde foams, presents no problems of bleed-off of toxic products. Only fully cured panels are used in home insulation, and there have been no reports of human toxicity caused by this insulation material. For more information about toxins released from insulation during a fire, click here.

So, JeffD, I'm curious as to what you think the snippet that you posted actually says?

The foam industry uses the term off-gassing to describe the gradual release of the blowing agent trapped in the cells of some foams. Urethane foam has a very high r-value when it's first manufactured. Unfortunately, many salesman use this day-1 number to describe their product's performance. In reality, foams that are susceptible to off gassing have an r-value that is referred to as the "aged" value. Polyurethane foam has an aged r-value of around 6.3 per inch. The addition of a skin on both sides will minimize this slow bleed of the blowing agent. However, I have yet to see a reputable manufacturer claim that the aged value is the same as at the date of manufacturing.

The term off-gassing in this context is often confused with the fear of "toxic" fumes; as in a fire or the recent formaldehyde problem with Katrina trailers. It is an entirely different issue that uses the same term.

and that's the truth,
AL

Al; 

what is the chemical used for the blowing agent?

Dick Mills,

Is it not clear from the last paragraph? What point would you like to make?

JeffD, that's a good answer. All of the paragraphs preceding that last one are superfluous, and sound as if one is making an argument (or at least intending to leave the impression) that PU foam off-gases formaldehyde - which is absolutely false. There is no formaldehyde in PU foam. But, it now appears clear that we are both on the same page.

In general the topic of PU or PU/PIR or PIR off gassing or more specifically SIPs made with this material is difficult to research. There seems to be a great amount of biased information from the manufacturers and little third party testing reports with conclusive evidence one way or the other.

In my opinion this is the last piece of the puzzle in making PU/PIR metal SIPs the current perfect building material.

Posted By JeffD on 09 Jul 2010 10:17 AM

In my opinion this is the last piece of the puzzle in making PU/PIR metal SIPs the current perfect building material.

Sounds like that gas has gotten to you...

Posted By JeffD on 09 Jul 2010 10:17 AM
In general the topic of PU or PU/PIR or PIR off gassing or more specifically SIPs made with this material is difficult to research. There seems to be a great amount of biased information from the manufacturers and little third party testing reports with conclusive evidence one way or the other.

In my opinion this is the last piece of the puzzle in making PU/PIR metal SIPs the current perfect building material.

Jeff; 

 as you said it is hard to get unbiased  information from manufacturers, it is also not unbiased from distributors, commisioned sales people and people getting finders fees for selling polyurethane metal sips. (you?)

One of our sources that  make both EPS and urethane, recommends that we stay away from PU , not because the offgassing is toxic , but because it cannot permeate the metal skins it blisters and delaminates.

I cannot understand using a core with so much controversy?

Chris,

I presented some documentation and expressed an opinion. One should not have a problem with that.

Could you share any documentation of blistering PU panels? or are you spreading biased information?

Posted By JeffD on 10 Jul 2010 09:37 PM
Chris,

I presented some documentation and expressed an opinion. One should not have a problem with that.

Could you share any documentation of blistering PU panels? or are you spreading biased information?

Jeff;

I have no problem with your opinion, my point is that your opinion is biased just like mine. It is no secret that I favor EPS for reasons I feel are very good. I am not sure why you would conclude that PU is better , other than you have a financial interest in it?

Re blistering , don't take my word for it ........ ask Jelly

Let me revise my stated opinion because it was a personal bias.

The perfect panel is really a balance of the following factors: r-value, strength, thickness, available length, durability, desired material properties, product certification & testing, local availability, quality, price, lead time, shipping cost, erection availability, erection cost, manufacturer reputation, distributor reputation, salesperson reputation, warranty, ease of handling, ease of erection and probably a few more things I can't thick of right now.

well said jeffd....seems there are too many rich people who don't care about cost and even strength,
so the perfect panel means something different to each person. for me, if this industry is ever
to become more than it is, it needs to account for cost as job #1...then worry about all other
'benefits' after that.  steve

So, just to clarify, are you saying that, in your book, "cost" overrides all other considerations in a building project?

structural integrity and performance overrides all

http://www.buildinggreen.com/live/index.cfm/2010/6/1/Avoiding-the-Global-Warming-Impact-of-Insulation

This may be helpful information if you have an interest in information derived from scientific investigation

I attended a seminar recently where the presenter claimed that Polyiso boards shrink and release gas for a considerable time after production. The shrinkage would obviously lead to laps in the insulation and therefore underperformance while the release of gas was considered to be a threat to health. Chris or Jeff can you offer any advice on this? Thanks.

Sorry - that should read 'gaps in the insulation......'

If you don't mind me asking, what was the seminar about and who was presenting it?

The information I have seen supports your statements.

The seminar was aimed at architects and the topic was 'refurbishment of existing housing' with an emphasis on solid as opposed to cavity wall construction. You are probably aware of the trend towards applying PIR/ PUR panels to the internal faces of walls in order to improve thermal insulation performance. It was claimed at the presentation that this material shrinks over time. The manufacturers deny this. I really don't want to give out the name of the presenter - I am confident that he said what he said in good faith and just wanted to follow up and try to verify it. The supposed shrinkage and supposed off gassing are obviously parts of the same process.

The big questions on shrinkage would be "how much" and "how soon". I have seen references to EPS shrinking as well (it was most recently mentioned in a post in the ICF forum about block shrinking). I would think sheet stock would finish any outgassing/shrinking within a reasonably short amount of time (large surface area to volume). Most issues I have seen reported seem to be from foam-in-place products instead of premanufactured sheet/stock.

Bigrig;

I have never heard or seen a reference for EPS shrinking, it is one of the most stable building products out there and it does not loose R-value with age like PU.
Sheet and block PU do continue to offgas for a long period of time. one of our manufacturers produces both EPS and PU laminated panels, they have had a moratorium on the PU panel production for the last 8 months until the offgassing issue is resolved.

Mayhaps he was thinking of XPS shrinkage? (Which is a known phenomenon, but much-improved since the 1970s). All the shrinkage that will ever happen with EPS occurs in the minutes that it cools from molding.

The R-loss of polyurethane is required by FTC rules to be already accounted for in the advertised R value. They might specify R6 or R6.5 per inch, but it'll likely perform to R7-R8 right off the presses, only sinkng to the "aged value" over a decade or more.