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John P
Q&A Forums Registered User
Posted: 8/30/2009 7:32 AM EST

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Off-gassing
Mason,

It is my understanding that the first wave of foam insulation products that were released in the 1970's for residential construction were urea formeldehyde products that off-gas and ultimately created an unhealthy environment for building occupants. They also lost material composition over time and degraded.

The bad press from this time period is still felt today. I have come across many a customer that asks about off gassing. To my knowledge, all polyurethane foams off gasses. With today's formulas, the quantity of off gassing is typically so low, that it is barely detectable. I this a correct assumption?

When assessing the technical data sheets from Icynene, NCFI, Demilec, Bayer, etc, etc. You find most of the same ASTM tests conducted...density, R-value, compressive strength,etc, etc. Can you explain to me why there is not an ASTM procedure for testing off-gassing? If you look at what happened to Retro-foam in canada you'll see what I am talking about.

Also, why isn't there a test for long term product stability?

With all this concern about fire safety, how has off-gassing and product stability become a non-issue?

To further complicate this question i was hoping you could explain what off gassing is? What gas is being off'ed? Why does it happen? How is it bad for humans?

your bud,
jp

RokonJim

Q&A Forums Registered User
Posted: 8/30/2009 7:56 AM EST

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RE: Off-gassing
If you have the ratio off (don't ask me why I know this) you will have a nasty odor but not if the ratio is correct. I put 2 lb. material on every roof section inside my log house and there is nothing to smell at all, still the old smell of pine logs when I come into the house from the outdoors. I do know the danger of not having it coated with a fire-resistant coat but we're moving into our new log home in 2 weeks and the 3 of us know if there is a fire to get out a window really fast, I've seen the videos of how quickly a fire can spread and overwelm you.

Mason  

Moderator
Posted: 8/30/2009 10:34 AM EST

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RE: Off-gassing
Polyurethane foam never has had formaledhyde in its formula

Spray polyurethane foam has been used in buildings since the early 1960s. In the 1970s a foam plastic called urea formaldehyde foam was introduced. This was not a polyurethane product and had quite distinctively different characteristics and chemistry. The most notable was the formaldehyde used in the product. When the material was injected into wall cavities, frequently the foam off-gassed the formaldehyde fumes. The fumes were very strong (similar to the smell in manufactured houseing some years ago or carpet adhesives). Because of the problems of off-gassing, formaldehyde foams were banned.

But as you suggested the fall out from the urea formaldehyde foam problems hit the growing residential spray polyurethane foam market as well. Consumers had a hard time telling the difference between foam plastics that had similar sounding names.

Now to the present: If spray polyurethane foam is sprayed with a poor mix, or off ratio (B -rich) or with too high a exothermic heat reaction, the catalyst in the foam reacts with the surfactants to create a pungent odor similar to rotten eggs or ammonia. This odor can last quite a while. The best way to prevent this occurace is to install the foam with the correct gun nozzle size and configuration, with the right temperature and pressures and don't spray the foam too thick. Thick applications of foam cause excessive exothermic heat that can affect the cell structure of the foam and cause odors.

The SPF industry recommends no more than 1.5 inches per lift and then wait for the heat to dissipate before the next lift is installed. (this typically takes 10 -15 minutes). However each formula is different and some foams may be installed in thicker applications without problems. Most manufacturers provide information on how thick you can install their foam. But remember this can vary depending on the job site conditions and your equipment.

It is up to the contractor to determine the safe thickness that the foam can be installed. One way to tell is to use a temperature guage to measure the temperature of the foam. For example if the interior temperature of the as it sets up. If the foam does not exceed 200 to 220 degrees F, it is typically all right. But if it goes over 250 to 300 degrees as it is setting up, then the cell structure and physical properties of the foam will be affected. Odors, shrinkage and poor adhesion can result.

Mason  

Moderator
Posted: 8/30/2009 10:49 AM EST

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RE: Off-gassing
Just like ammonia, or chlorine, odors from sprayfoam applications can be strong even when the total air borne amounts are well below the permissible exposure level (PEL) that OSHA and NIOSH require

However, Many folks are very sensitive to odors and will get nauseous, have head aches etc from odors that would eminate from poorly mixed foam. In addition, strong odors (of any type, even coffee) can cause asthmatics to have seizures. So, it is am important issue to consider.

The odors from sprayfoam are typically the catalyst. The amount of catalyst in polyurethane foam is relatively small compared to other ingredients such as the polyol resins, blowing agents and the A side (isocyanate). Blowing agents are not considered harmful, the A side can be harmful but fumes and mists from the A side dissipate rapidly after spray operations have stopped. So what you are smelling is the catalysts or the reaction of the catalyst with the surfactanct in the foam.


There are many ways to test the off-gassing of building products. SPFA has a task group that is working with the Center for the Polyurethane Industry (CPI) to develop a test procedure that is best suited for testing sprayfoam for offgassing. They are pretty far down the road on this project and I expect at the annual conference the test procedure will be unvailed if not sooner at the Polyurethane Conference in October of this year.

Canada requires that all foam plastics (and other building products) be tested for VOC off gassing. So the foams that are sold in Canada must pass that test. I believe no excessive VOC emissions are allowed after 2-3 weeks of testing in the chambers.

The new procedure developed by the joint task group will be specific to spray polyurethane foam and the chemicals that are most common to those products.

Mason  

Moderator
Posted: 8/30/2009 11:09 AM EST

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RE: Off-gassing
In answer to another of your questions on dimensional stability.

The test procedure required in the polyurethane foam ASTM specification C 1029 for dimensional stability is ASTM D 2126. It is a humid aging test that measure the volume change of a foam plastic when subjected to high heat and humidity.

The sprayfoam is installed to a substrate (plywood or OSB) at 1-1/2 inches thick with at least 2 lifts. The top of the foam is cut so that the lift line is in the sample. The foam is placed in a chamber at 97-99% humidity at 158 degrees F. The foam is measured in a linear direction after one day and after 7 days.

ASTM C 1029 classifies sprayfoam into 4 types based on minimum compressive strength and it has a chart to characterize the volume change of the foam by type.

Type 1 min compressive strenth 15 psi. 12% linear change

Type II min compressive strength 25 psi 9% linear change

Type III min compressive strength 40 psi 6% linear change

Type IV min compressive strength 60 psi 5% linear change

Types 1 & II would include closed cell sprayfoam (ccSPF) used for interior insulation and air barrier applications.

Types III & IV would be ccSPF that is used in roofing or exterior applications such as tanks and pipe insulation.

John P
Q&A Forums Registered User
Posted: 8/31/2009 3:58 PM EST

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RE: Off-gassing
I guess I always assumed that off gassing referred to any potentially harmful gaseous discharge from the foam curing - completely unrelated to the smell. According to you both are the same thing.

ASTM D 2126 sounds like a great test. I would like to see longer time period than 7 days, but better than nothing.

What has brought about all of these questions is that I have a recent customer who is internet educated and has been sold on a certain manufacturers product (0.5 lb open cell). I am trying to propose an alternative product with all of the appropriate technical data and ICC ES reports, but they are not biting.

They want to see data and studies that consist of long term testing and off-gassing output. The manufacturer for the product that I am offering has yet to respond to my query for additional data. Open cell SPF manufacturers don't have tests for these 2 parameters. It would seem logical that they should. In the mean time I am looking for ways to convince my product is just as good if not better.

We demoed a house that had the old urea-formeldehyde foam in it well over a year ago. The product completely lost its material composition. When you touched it, it turned to dust. It also shrank away from the studs. How do we know open cell products that are currently available will not do the same thing in 10-20 years? These manufacturers are putting lifetime warranties on products that have been around for 5-10 years.

jp

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