How many total SFRM readings should be taken on a joist?

The standard practice for taking SFRM (Spray-Applied Fire-Resistive Material) readings on a joist typically follows a guideline that dictates a sufficient number of measurements to ensure an accurate representation of the fireproofing application. Taking 14 total measurements is considered to be an optimal number as it allows for a comprehensive assessment of the coverage uniformity and thickness of the fireproofing material.

This amount strikes a balance between thoroughness in measuring variations in thickness or application inconsistency and practicality in terms of time and resources. It ensures that any discrepancies can be identified and addressed, thereby enhancing the overall safety of the fireproofing application in protecting structural components.

While fewer measurements could potentially miss localized issues, the 14 total readings provide a robust dataset from which to assess compliance with applicable standards and ensure the desired level of fire protection is achieved.