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scott moss Posted: Sep 02, 2009 09:20 PM	intumescent coatings I've been reading about having to install intumescent coatings over foam in attics and crawl spaces and I'm not familiar with the process or the way you install the coatings, and different ways of covering the foam.
mason Posted: Sep 03, 2009 08:39 AM	All foam plastics in attics and crawl spaces where entry is for service of utilities requires an ignition barrier. The ignition barriers listed in the code include; 1-1/2 inches of mineral fiber (rockwool or unfaced fiberglass) 1/4 inch wood sheathing 0.016 inches corrosion resistant steel 3/8 inch gypsum drywall If you use any of these materials, no other covering is required. But if a foam supplier does not want to use a prescriptive ignition barrier there are options. The code allows exceptions to the thermal barrier and ignition barrier requirement based on full scale fire tests specific to the applicaton and end use configuration. such as NFPA 286, UL 1715, FM 4880, etc. Recently many sprayfoam suppliers have tested their foams with a variety of intumescent coatings to achieve approvals with ICC Evaluation Services as exceptions to the thermal barrier or ignition barrier rules. So, it is not a case of one intumescent coating that would be universally accepted with all foam plastics. Each coating requires testing with each foam to be able to used it. But to answer your question about intumescent coatings. Most of these coatings are single component and can be sprayed with airless coating equipment. They come in a variety of physical properties that would dictate what specific type of coating pump, hoses and sprayguns that would be required. ASk your sprayfoam supplier about which coating they use with their foam and what options are available going into the future.
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Sep 03, 2009 10:10 PM	Don't forget to take note that you will now have to navigate the attic or crawlspace 3 times now where we only had to once before. That's once to spray the foam, and two separate coatings of the intumescent coating. And by the way, make sure that you cover all areas of the foam with two coats evenly over that uneven foam surface in an 18" crawlspace. Mason's right about the prescriptive ignition barriers specified in the codes, but the real question is what/who determined that these were acceptable? This question has yet to be answered with other than "These were materials on the jobsite that someone felt were appropriate!" June 1st will be a sad day for us installers and the coating manufacturers will be rolling in the cash. It's sad how this is so far from a scientific data based decision and so many people are just turning the other way! Will you?
Posted: Sep 03, 2009 10:36 PM	jim,,, i have a couple of hard core believers that tell me they will make this work,,they KNOW the spf makes their design/build system work...most though,,will opt for sealing the dry walled lid and topping with filterglass or shredded paper...provideing a vented attic assembly with the definition of the builing envelope at the drywall ceiling instead of the roof line... compromise,,you bet,,other negs,,you bet,,but if you cant beat em buy em,,,or sumpin like that...economics will overrule physics,,as it does now,,

Author

Comments

scott moss

Posted: Sep 02, 2009 09:20 PM

intumescent coatings

I've been reading about having to install intumescent coatings over foam in attics and crawl spaces and I'm not familiar with the process or the way you install the coatings, and different ways of covering the foam.

mason

Posted: Sep 03, 2009 08:39 AM

All foam plastics in attics and crawl spaces where entry is for service of utilities requires an ignition barrier.

The ignition barriers listed in the code include;
1-1/2 inches of mineral fiber (rockwool or unfaced fiberglass)
1/4 inch wood sheathing
0.016 inches corrosion resistant steel
3/8 inch gypsum drywall

If you use any of these materials, no other covering is required.

But if a foam supplier does not want to use a prescriptive ignition barrier there are options. The code allows exceptions to the thermal barrier and ignition barrier requirement based on full scale fire tests specific to the applicaton and end use configuration. such as NFPA 286, UL 1715, FM 4880, etc. Recently many sprayfoam suppliers have tested their foams with a variety of intumescent coatings to achieve approvals with ICC Evaluation Services as exceptions to the thermal barrier or ignition barrier rules.

So, it is not a case of one intumescent coating that would be universally accepted with all foam plastics. Each coating requires testing with each foam to be able to used it.

But to answer your question about intumescent coatings. Most of these coatings are single component and can be sprayed with airless coating equipment. They come in a variety of physical properties that would dictate what specific type of coating pump, hoses and sprayguns that would be required. ASk your sprayfoam supplier about which coating they use with their foam and what options are available going into the future.

jimcoler

I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs.

I've expanded my knowledge into t

Posted: Sep 03, 2009 10:10 PM

Don't forget to take note that you will now have to navigate the attic or crawlspace 3 times now where we only had to once before. That's once to spray the foam, and two separate coatings of the intumescent coating. And by the way, make sure that you cover all areas of the foam with two coats evenly over that uneven foam surface in an 18" crawlspace.

Mason's right about the prescriptive ignition barriers specified in the codes, but the real question is what/who determined that these were acceptable? This question has yet to be answered with other than "These were materials on the jobsite that someone felt were appropriate!"

June 1st will be a sad day for us installers and the coating manufacturers will be rolling in the cash. It's sad how this is so far from a scientific data based decision and so many people are just turning the other way! Will you?

Posted: Sep 03, 2009 10:36 PM

jim,,,
i have a couple of hard core believers that tell me they will make this work,,they KNOW the spf makes their design/build system work...most though,,will opt for sealing the dry walled lid and topping with filterglass or shredded paper...provideing a vented attic assembly with the definition of the builing envelope at the drywall ceiling instead of the roof line...
compromise,,you bet,,other negs,,you bet,,but if you cant beat em buy em,,,or sumpin like that...economics will overrule physics,,as it does now,,

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