Class C fire rating | Thermal Barriers and Ignition Barriers | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

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Posted: Aug 06, 2010 12:05 AM	Class C fire rating Hi Mike, Need a little help! Trying to figure out which coating to use to meet a Class C fire rating. Thanks
Posted: Aug 06, 2010 10:07 AM	Hello tb, There are many coatings that carry Class C or better FLAME SPREAD ratings. However make sure of what is being asked, or required of you. There are TWO ways this can be meant. ONE is to require the COATING ITSELF to carry a Class C Flame Spread rating. The OTHER is to require the "SYSTEM" (SPUF + coating) to carry a Class C rating. (It depends on the code and the situation.) While someone may ask you to provide a Class C coating, they could mean either one of these requirements, and they are worlds apart. The first is fire tested (ASTM E84 Flame Spread test) with just the coating applied to cement board (typical). The other is tested with the coating applied to the intended material. Usually the latter is much more difficult. So, to answer you, I need a little more information. I assume this is to be a coating over SPUF. What density is the SPUF? Where is it being applied? (Type building, wall, ceiling, etc.) Have you been told what code you need to meet? As you probably have seen (or experienced) in other discussions, the codes are complicated sometimes, so I need to know the details of an application in order to be able to do a good job answering your question. By the way, Class C is usually a roofing application. Is that what this is? Mike
Posted: Aug 09, 2010 12:02 AM	Hi Mike, sorry about the delayed response, anyways the State fire marshall said our finished product needs to meet Class C. This in a metal building both wall and ceiling with 2 lb. CC.
Posted: Aug 10, 2010 12:32 AM	OK, now we are in danger of going in a circle, so I have to ask a couple more questions. Most SPUF foams are Class A or at worst Class B, so Class C should be met with any modern SPUF insulation. If the foam is not satisfactory to the FM, then he must not want "exposed" SPUF in the building... is that it? Another way of asking this... Is the Fire Marshal saying that he insists on a coating over the foam? I ask these questions carefully, because so far this sounds very unusual. To me, there must be something more to the story. Mike Kiser
Posted: Aug 10, 2010 12:54 AM	Here's the deal. I believe this is the FM's first experience with SPF. I'm also quite new in the industry. If the SPF meets class C he's happy but our customer wants a white coating over the foam. I think as long as both the SPF and the coating pass Class C it will pas the FM.
Posted: Aug 11, 2010 12:39 AM	Hello tb, Given the situation, all you have to do is go to one of the many resources for a list of Fire Retardant coatings, such as Underwriters' Laboratories. Go to UL, look up fire retardant paints or coatings, and click on "listings". Be warned, most are Class A on their list, and are pricey. HERE IS THE DIRECT LINK TO THAT LIST: http://database.ul.com/cgi-bin/XYV/cgifind.new/LISCANADA/1FRAME/srchres.html?collection=/data3/verity_collections/liscanada&vdkhome=/data3/verity_sw_rev24/common&SORT_BY=textlines:asc,ccnshorttitle:asc&query=BMQXC<IN>CCN+and+not+GUIDEINFO Since you are not after Class A, I suggest first calling your local paint suppliers (Sherwin Williams, ACE Hardware is a good one, or Home Depot) and ask if they have any Class B or C paint or coatings in stock. Might be the best bet for a quick answer. However, if you have time to go through the UL list, and price isn't a big deal, I suggest the Benjamin Moore product, because they have the most robust product in latex, in my humble opinion. Mike Kiser
mason Posted: Aug 11, 2010 01:29 PM	tb, I assume the fire marshall knows that the coating would not be a thermal barrier as required by code.
Posted: Aug 11, 2010 03:57 PM	Mason, Many thanks for chiming in! I answered this in the middle of the night after a long day of travel, and I didn't see the forest for the trees. So busy answering the exact question, I forgot to step back and look at the whole picture! I agree, tb needs to make sure all concerned are aware of the Thermal Barrier requirements and how they affect this metal building. Good save, Mason! Mike

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Comments

Posted: Aug 06, 2010 12:05 AM

Class C fire rating

Hi Mike,
Need a little help! Trying to figure out which coating to use to meet a Class C fire rating. Thanks

Posted: Aug 06, 2010 10:07 AM

Hello tb,

There are many coatings that carry Class C or better FLAME SPREAD ratings. However make sure of what is being asked, or required of you.

There are TWO ways this can be meant. ONE is to require the COATING ITSELF to carry a Class C Flame Spread rating. The OTHER is to require the "SYSTEM" (SPUF + coating) to carry a Class C rating. (It depends on the code and the situation.)

While someone may ask you to provide a Class C coating, they could mean either one of these requirements, and they are worlds apart. The first is fire tested (ASTM E84 Flame Spread test) with just the coating applied to cement board (typical). The other is tested with the coating applied to the intended material. Usually the latter is much more difficult.

So, to answer you, I need a little more information. I assume this is to be a coating over SPUF. What density is the SPUF? Where is it being applied? (Type building, wall, ceiling, etc.) Have you been told what code you need to meet?

As you probably have seen (or experienced) in other discussions, the codes are complicated sometimes, so I need to know the details of an application in order to be able to do a good job answering your question.

By the way, Class C is usually a roofing application. Is that what this is?

Mike

Posted: Aug 09, 2010 12:02 AM

Hi Mike, sorry about the delayed response, anyways the State fire marshall said our finished product needs to meet Class C. This in a metal building both wall and ceiling with 2 lb. CC.

Posted: Aug 10, 2010 12:32 AM

OK, now we are in danger of going in a circle, so I have to ask a couple more questions.

Most SPUF foams are Class A or at worst Class B, so Class C should be met with any modern SPUF insulation. If the foam is not satisfactory to the FM, then he must not want "exposed" SPUF in the building... is that it?

Another way of asking this... Is the Fire Marshal saying that he insists on a coating over the foam? I ask these questions carefully, because so far this sounds very unusual. To me, there must be something more to the story.

Mike Kiser

Posted: Aug 10, 2010 12:54 AM

Here's the deal. I believe this is the FM's first experience with SPF. I'm also quite new in the industry. If the SPF meets class C he's happy but our customer wants a white coating over the foam. I think as long as both the SPF and the coating pass Class C it will pas the FM.

Posted: Aug 11, 2010 12:39 AM

Hello tb,

Given the situation, all you have to do is go to one of the many resources for a list of Fire Retardant coatings, such as Underwriters' Laboratories. Go to UL, look up fire retardant paints or coatings, and click on "listings". Be warned, most are Class A on their list, and are pricey. HERE IS THE DIRECT LINK TO THAT LIST:

http://database.ul.com/cgi-bin/XYV/cgifind.new/LISCANADA/1FRAME/srchres.html?collection=/data3/verity_collections/liscanada&vdkhome=/data3/verity_sw_rev24/common&SORT_BY=textlines:asc,ccnshorttitle:asc&query=BMQXC<IN>CCN+and+not+GUIDEINFO

Since you are not after Class A, I suggest first calling your local paint suppliers (Sherwin Williams, ACE Hardware is a good one, or Home Depot) and ask if they have any Class B or C paint or coatings in stock. Might be the best bet for a quick answer. However, if you have time to go through the UL list, and price isn't a big deal, I suggest the Benjamin Moore product, because they have the most robust product in latex, in my humble opinion.

Mike Kiser

mason

Posted: Aug 11, 2010 01:29 PM

tb,

I assume the fire marshall knows that the coating would not be a thermal barrier as required by code.

Posted: Aug 11, 2010 03:57 PM

Mason,

Many thanks for chiming in! I answered this in the middle of the night after a long day of travel, and I didn't see the forest for the trees. So busy answering the exact question, I forgot to step back and look at the whole picture!

I agree, tb needs to make sure all concerned are aware of the Thermal Barrier requirements and how they affect this metal building.

Good save, Mason!

Mike

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