What is the allowable test cap diameter range when testing SFRM bond strength?

The allowable test cap diameter range when testing the bond strength of Spray-Applied Fireproofing Materials (SFRM) is indeed between 2 to 3-1/4 inches. This specified range is essential to ensure that the tests accurately reflect the material's performance characteristics without introducing significant variables.

Using the correct diameter for the test cap contributes to the consistency and reliability of the bond strength measurements, as larger or smaller caps could lead to uneven pressure distributions or failures that do not accurately represent the material's properties. The chosen range has been established based on various considerations, including the need to avoid an excessively large area that could be influenced by surrounding conditions, while also ensuring a sufficiently large bonding area to achieve reliable results.

Testing outside this diameter range could lead to misleading results, therefore adhering to the specified range is vital for maintaining testing integrity and ensuring compliance with industry standards.