Why must thickness tests be conducted on SFRM applied to metal decking?

Thickness tests on Spray-Applied Fire-Resistive Materials (SFRM) applied to metal decking are essential primarily to verify the fire rating. The thickness of the fireproofing material directly influences its ability to provide the required level of fire resistance as specified by building codes and project design documents. Different fire ratings—such as those required for structural steel—are achieved through specific material thickness; therefore, measuring the thickness ensures that the application meets these standards.

If the SFRM is applied too thinly, it may not perform as intended during a fire event, potentially compromising the safety of the structure. Conversely, excessive thickness may also be unnecessary, leading to increased costs without additional benefits. Therefore, regularly conducting thickness tests is a critical quality control measure in the application process, ensuring that the fireproofing will adequately protect the structure according to its intended fire resistance rating.