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What is the fire rating on 5/8″ Type X gypsum board?

April 26, 2017gypsum rating type

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What is the fire rating on 5/8″ Type X gypsum board?

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Fire ratings are associated with assemblies rather than a specific board product. For instance, a wall partition assembly built using one layer of 5/8″ Type X board on both sides of a wood or steel frame carries a one-hour fire rating. Many times, people insist on finding out the rating on one layer of 5/8″ Type X board. If the face side of 5/8″ Type X board is exposed to fire, it takes about 25 minutes for the temperature on the back surface to reach failure criteria. This time duration is termed as the “finish” rating. A “finish” rating of 25 to 26 minutes could be safely quoted as the best possible number. This number is displayed for each wood framed assembly in the UL fire resistance directory. Fire Safety Information for Type X Gypsum Board.