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Matt Kenner
Posted: Jul 28, 2009 10:36 AM
surface burn testing
surface burn.... testing was done on .5lb spray foam at 4" for astm e-84. Can I spray 9" of foam? The irc 314.3 states only to maximum thickness tested. Then I read an exception below that paragraph for applications more than 4" with regards to irc 314.6. What am I allowed to do?
mason
Posted: Jul 28, 2009 11:07 AM
Check with your supplier to see if they have performed a NFPA 286 test on the foam at greater thickness. The E 84 apparatus can only measure up to 4 inches of foam for flame spread and smoke. So the building codes allow a manufacturer to use other fire tests to determine the relative safe use of foam plastics that are thicker than 4 inches.

The NFPA 286 test is the one most commonly used. The foam is sprayed to the outside of a room with drywall on the inside. The test runs 15 minutes (it can run longer if the manufacturer wants additional data). The foam passes if flames are not observed coming through the ceiling or out the front. Most sprayfoam will pass this test if they have a class 1 rating at 4 inches using ASTM E 84.

Some building code officials will allow the use of foam at thickness greater than 4 inches without the additional testing, but it is up to them whether to accept it or not.

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