familiar with UL-263?

[theo1]

hello, would you explain what is UL-263 say about 1 hour fire rated design for walls and floors? i have a detail from national gypsum to increase the existing 3/4" plaster walls to 1 hour rated walls by installing 1 layer of 5/8" type-X to existing plaster walls. am i missing anything to add? is it sufficiant to use existing plaster walls thats in very good shape and just add one layer of type-X on top of it so it meets the 1 hour fire rate? your help is very appreciated . thanks

 

[boo1]

UL-263 These fire tests are applicable to assemblies of masonry units and to composite assemblies of structural materials for buildings. These requirements are intended to evaluate the length of time that the types of assemblies specified in 1.1 will contain a fire or retain their structural integrity, or both, dependent upon the type of assembly involved, during a predetermined test exposure.

The 5/8"-X is rated by UL for a "1 hour" fire barier. Adding this layer to exixting plaster should provide this rating. Penetrations (doors, cableways, penetrations) should be addressed so the assembly provides required barrier.