When testing SFRM thickness on a joist, how many thickness measurements are taken at each end of a specified length?

When testing the thickness of Spray-Applied Fire-Resistive Material (SFRM) on a joist, industry standards and guidelines specify that seven measurements should be taken at each end of a specified length. In this case, the correct length is 12 inches.

This approach is essential because it ensures an accurate assessment of the thickness and uniformity of the fireproofing material application. The choice of taking measurements at both ends of the specified length helps to determine any variations in thickness that may exist along the application surface, thereby allowing for a thorough evaluation of the fire-resistive properties.

Using this method, inspectors can identify any potential inconsistencies that could affect the fire performance of the assembly, which underscores the importance of meticulousness in ensuring that fireproofing requirements are met.