Q&A Column

What is the relationship between Class A and hourly-rated ceilings?

Class A is a term that refers to the surface burning characteristics of the ceiling board and grid. These characteristics are the flame spread and smoke developed measurements, based on UL Standard UL723, Test for Surface Characteristics of Building Materials. This is not a fire resistance test.

"Fire rated" is a term that refers to the fire resistant performance of an assembly of materials that has been tested according to UL Standard UL263, Fire Test of Building Construction Materials.

Assembly components are classified; assemblies are hourly rated. The hourly rating is based on the synergism of all of the assembly components.

Answer submitted by Bob Smith, CSI, CDT, Reinke Wholesale