What is the minimum allowable radius of the test cap used in SFRM bond strength testing?

The minimum allowable radius of the test cap used in Spray-Applied Fireproofing (SFRM) bond strength testing is 1 inch. This specification is crucial for ensuring the accuracy and reliability of the bond strength tests conducted on fireproofing materials. A cap with a radius of 1 inch provides a sufficient surface area that allows for an adequate bond strength measurement. This size also helps to minimize variability in results that could arise from using smaller caps, which may not equally distribute stress across the fireproofing material during testing, leading to inaccurate assessments of its performance.

In essence, adhering to the minimum requirement of a 1-inch radius ensures that the test results will be consistent and reflective of the fireproofing material's true bonding characteristics, which is essential for evaluating its effectiveness in fire resistance applications.