In SFRM testing, what is the acceptable method for measuring thickness?

In SFRM (Spray-Applied Fire-Resistive Material) testing, the most reliable and standardized approach for measuring thickness is through direct measurement with tools. This method involves using measuring devices such as calipers or micrometers to obtain accurate thickness readings from the fireproofing material.

The precision of direct measurement ensures that the thickness complies with the specified criteria, which is critical for assessing the fire resistance of the application. Accurate thickness measurements help in determining whether the application meets building codes and standards for fire safety.

Visual inspection alone lacks the accuracy needed for compliance verification, as it cannot quantify thickness or detect variations in applied materials. Ultrasonic measurement, while a valid technique in certain contexts, may not provide the same level of verification and is generally not the preferred method for SFRM thickness assessment. Random sampling might help in assessing variation across large applications, but without precise measurement, it would not ensure that the entire area conforms to required specifications.

Thus, direct measurement with tools is the most effective and accepted method for ensuring that the thickness of spray-applied fireproofing meets safety and compliance standards.