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Marc French Posted: Aug 20, 2010 04:39 PM	Attic & crawl Ignition barrier Mike, I have really enjoyed your forum so far. Your explanation of thermal barriers (though long) brought new light to helping me understand why TB's are important. I did not understand the impact that high heat had on the whole situation. In my head I was protecting the foam from the actual flame. I am discussing the topic of SPF next week with a group of DOE and Weatherization officials in Anchorage. I was wondering if you could give an explanation of how and why Ignition barrier is used in the attic and crawl areas. I use BASF spray seal when I need to, and it looks like latex paint. It doesnt cost like latex paint $$$ so what is the magic in these products? and what is the purpose.
Posted: Aug 20, 2010 06:27 PM	mfrencher, Thanks for the comments... glad to help. As for Ignition Barriers, you'll be glad to know I don't have to write a "book" on it. The issues are simpler, and I can get it done pretty quickly, but I am tied up in meetings this evening, so I can't answer it completely right now. I promise to get this answered over the weekend, in time for your meetings next week. I will say this for now... I happen to agree with many, like foamdude, in that the codes have drifted from the original intent of the term "ignition" barrier, so I will discuss that a little bit, but that will be my "opinion". Most importantly, we all have to deal with the realities of how the code reads today, so I will address that first and foremost so you will be in line with the written code. Mike Kiser
Posted: Aug 23, 2010 03:49 PM	mfrencher, First of all, the “explanation” of how and why ignition barriers are used: HOW TO USE IGNITION BARRIERS... For “coatings”, they must be used exactly in the same manner as they were used in the Ignition Barrier test associated with the particular coating. In your case, the BASF coating must be applied at the same thickness (measured in mils or square feet per gallon) and in the same manner as stipulated in their ICC-ES report. The meaning of “Manner” includes application method (spray, roller, etc.), Number of coats, curing requirements, and any “limitations” noted in the conditions of application. ALWAYS READ THE REPORTS CAREFULLY. “ICC-ES REPORTS” are preferred because they are the most consistent and reliable certifications. ICC-ES reports ALWAYS require proof that the product you buy and apply is the SAME as the one that was used in the fire test. Others, such as Warnock-Hersey / Intertek / Underwriters Laboratories MAY have the same stipulations, but unlike ICC-ES reports, they also might NOT. Always make sure there are two things that are part of the testing/certifying documents: (1) Engineering reports that declare that everything was “witnessed” by engineers, including all aspects of production, delivery, application, and burn testing of the coating, on a foam that also is “witnessed” in the same way. This is to PROVE that a company actually produces the product that was tested. (2) A follow-up services program which “witnesses” and verifies that what the company produces and sells on a daily basis is the exact same product as that used in the test. BOTH are critical to ASSURE all “life and safety” requirements are met, and that you have done everything on your part to assure your client that his project is proper and safe. WHY USE IGNITION BARRIERS?... (This part of the answer is a long one, so if you are in a time crunch, there is a short “summary” at the end of this.) The code organizations have the difficult task of making sure the codes provide maximum safety to the public, with materials and methods that are as practical and cost effective as possible. (If it isn’t feasible, it won’t get used widely, which would be self defeating.) A tough job indeed! And they have the unenviable task of writing codes that they know will never be agreeable to everyone. Keep that in mind as we discuss this. As we know, the original code stated that an “ignition barrier” must be installed over plastic foam insulation, and in the early days, it was decided that several materials (including ¼” thick wood panels, 0.016” sheet metal, etc.) may be used as “ignition barriers”. The fact that they chose plywood, which is flammable, shows that the original “intent” was simply to resist “quick” ignition by a small flame. This was because OLD SPUF “BACK THEN” WAS SO FLAMMABLE THAT A SMALL FLAME COULD START IT BURNING OUT OF CONTROL! Therefore, this was “originally” truly meant as an IGNITION ‘RESISTANT’ BARRIER. Now comes the complicated part... Since SPUF formulations have become much more flame resistant than the original formulas, the codes had to adjust to this. KEEP IN MIND THE DISCUSSION OF HOW HEAT AFFECTS FOAM TO THE POINT OF “FLASH OVER”. Since the code organizations were keenly aware of this aspect of SPUF, they HAD to keep it in mind in the writing of the codes. As foams became better at FLAME SPREAD (as I have discussed on other threads), the fact that, with exposure to excessive HEAT, the “flash over” issue remains, this forces code organizations to lean toward the “conservative” side of things in writing code requirements. In “my opinion”, they went TOO FAR in the conservative direction the first time they stipulated a new test requirement, that being the SWRI99-02 test. This test included a HUGE fire, with only a 4 ft. tall room (ceiling), which was, again, “in my opinion” too aggressive of a fire to represent something called an “ignition barrier”. This test was recently replaced by a “version” of the NFPA 286 test, using ONLY THE LOW FLAME LEVEL of that test. In my opinion, even though this is still NOT in line with the original ideals of “ignition” barriers (small flame “ignition” protection), it IS a step in the right direction, because the pass/fail criteria was set by burning 1/4" plywood, so the result would match one of the original “ignition barrier” materials. Although many disagree with this test for “ignition barriers”, they need to realize that those who were given the responsibility of designing the new test HAD to keep in mind the inherent risk of “flash over” with SPUF... even with the “new” formulations. They had to consider the “life and safety” issues and therefore “err” on the side of caution. THAT (in my humble opinion) is why a fairly aggressive flame source was used as a MEANS to compare ¼” plywood with new proposed materials. As I said, in MY OPINION, this does not embrace the ORIGINAL intent of “ignition” barriers, but it DOES take into consideration the fact that even new “low flame spread” formulas of SPUF are at risk of FLASH OVER, and therefore must be tested more aggressively than the original “idea” of ignition barriers. Bottom line: The code requires that any foam, or foam + ignition barrier, must pass the new “version” of NFPA-286. The REASON for this is, the risk of FLASH OVER forces the code officials to write conservative code requirements that take this into account. While the new test is not “exactly representative” of attic spaces, it DOES pretty much guarantee that any material that meets the code will be safe in an attic or crawl space, in most scenarios. As I keep saying, these are Life and Safety issues, and the “off gassing” and “flash-over” issues of SPUF create a situation whereby the codes need to err on the side of caution. Just an analogy to demonstrate why I say this. Imagine if the code actually only required a small scale “ignition” test that exposes the foam to a small flame similar to a cigarette lighter or match for five minutes (or 15 for that matter). Then suppose someone approves a light weight Polystyrene foam, because it passed this test (by melting back away from the flame during the test). Then a major fire occurs because a few boxes stored in the attic caught on fire due to a leak in a gas line connected to a heater unit. The boxes could easily create a big enough fire and heat to start off-gassing of the foam. Then, a major fire. This “possibility” becomes the problem for someone who is responsible for writing a code for this. When you are dealing with plastics, the realities of what MIGHT happen are a very big deal. The new tests are the result of this burden on the code writers, PLUS the fact that we know a lot more about the risks of foam than when the ignition barrier codes were first written. Bottom line here... it’s not perfect, never will be. BUT, the way it is written, the above is very unlikely to happen… and that’s good. By the way, I have gotten long winded again, so I should explain why I tend to do that. I have personal experience with tragedy that takes a life, when the “worst case” happens. As a result, I am spending my life doing everything I can to remove “worst case” scenarios. That’s why I am in Fire Protection, and that’s why I insist everyone does a good job for the customer. It could be their loved one that we save. As for your last questions: There is no “magic” in these ignition barrier products. They simply need to be a good quality flame resistant coating to help foam pass the new Ignition Barrier test. It is not terribly difficult to pass as it is written now. (compared to the previous SWRI99-02 test.) This is why some good fire resistant foams are now passing without any coatings. A SHORT SUMMARY: (a) The WAY you use new ignition barrier coatings is to apply and cure them exactly as stipulated in the ICC-ES report (or equal test report). It is safest to use products with ICC-ES report. (b) The REASON ignition barriers are required in attics and crawl spaces is because earlier codes required certain materials as true “ignition barriers”, so the newest codes compare one of those early qualified ignition barrier materials (plywood) with new materials by using a large enough fire test to at least “partially” account for the FLASH OVER issues that still exist with new flame resistant foams. (c) Certified ignition barrier coatings are typically good quality fire resistant paints or coatings that resist flames / heat long enough to pass the new version of the NFPA 286 test. Some are more reasonable priced than others, so I suggest you do your due diligence to find the best priced “certified” coatings. Let me know if any questions remain, or if anything is not crystal clear! I will be glad to clarify. Good luck with your presentations! Mike Kiser
Marc French Posted: Aug 31, 2010 09:15 AM	Mike, Thank you for all the information. In my role as a Tech advisor for low income weatherization in the Northwest I find this information to be the best around. It one thing to teach others the codes and how to comply but another to be able to explain the why of it all. I promise to try and credit you and sprayfoammagazine.com with as much of this material as possible as I share it with others in my area. Thanks again for all your help.
Posted: Sep 03, 2010 11:28 AM	You are very welcome! I am glad the info was helpful.