When should a drill bit be used for SFRM inspection?

A drill bit is used for thickness testing high density Spray Fire-Resistive Materials (SFRM) because these materials typically have a denser composition, which may require a more precise method for measuring thickness. High density SFRM can be more challenging to evaluate using non-destructive methods like a magnetic gage or ultrasonic testing, as the density of the material can provide less reliable readings or make it more difficult to assess whether the material meets specified thickness requirements.

By using a drill bit for inspection, the inspector can obtain a core sample of the fireproofing material, allowing for accurate measurement of thickness and better evaluation of the material’s integrity. This method is particularly useful in high density applications where specific thickness is critical for ensuring appropriate fire protection performance.