"Class" fire ratings vs hour fire ratings

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TL;DR
Do (USA) fire ratings for wall coverings (Class A,B,C) relate to fire ratings given in hours for materials like drywall?
Do (USA) fire ratings for wall coverings (Class A,B,C) relate to fire ratings given in hours for materials like drywall?

I'm particularly interested in how ornamental ceiling tiles that have a "class A" fire rating ( e.g. https://www.amazon.com/dp/B00319FP8Y/?tag=pfamazon01-20 ) affect the fire resistance of a drywall ceiling when they are applied over it.

My first idea is that the "class" type of fire rating indicates how much a fire would spread over a tiled ceiling but that the spread of the fire on the tile wouldn't have much effect on how long the fire would take to burn through the drywall. It would take very little time for a fire to burn through a wall covering. So, by this theory, people don't bother to fire rate wall coverings in hours.
 
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Stephen Tashi said:
Do (USA) fire ratings for wall coverings (Class A,B,C) relate to fire ratings given in hours for materials like drywall?
Yes, we discuss and specify elements of fire rated walls, partitions and ceilings based on time of resistance to fire.
UL assembly penetrations and fire dampers and ceiling radiation dampers are also rated by time (example: 1-hour dynamic fire damper).

Please, see:
https://codes.iccsafe.org/content/F...smoke-protection-features#FBC2017_Ch07_Sec706

https://www.ruskin.com/model/dfd-lp

:cool:
 
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