If primer is used on a column beneath SFRM, the column web depth cannot exceed:

The correct answer is 16 inches as it aligns with the guidelines established for applying Spray-Applied Fire-Resistive Material (SFRM) over primed surfaces. When primer is used, it forms a state between the substrate and the fireproofing layer, meaning that specific limitations are required to ensure adequate adhesion and performance of the fireproofing material.

The restriction on the column web depth of 16 inches is typically established due to concerns about how the fireproofing will adhere to the surface and how effectively it provides the intended fire-resistant performance. If the web depth exceeds this dimension, it may challenge the effectiveness of the fire-resistive coating application, potentially compromising the structural integrity and fire safety.

Understanding these parameters is crucial for inspectors to ensure compliance and safety in construction practices involving SFRM and aids in identifying scenarios where additional considerations might be necessary for different configurations or materials.