How many SFRM thickness measurements are required for a metal deck that uses a flat plate?

In the context of inspecting spray-applied fire-resistive materials (SFRM) on a metal deck utilizing a flat plate, the correct number of required thickness measurements is four. This standard is derived from safety protocols aimed at ensuring adequate fire resistance is provided across the surface.

The rationale behind the requirement for four thickness measurements encompasses the need for a comprehensive assessment of the fireproofing material's uniformity and effectiveness. The measurements are typically taken at various points to account for any irregularities in application, variations in material distribution, or potential surface imperfections. This practice supports the overall performance of the SFRM, ensuring that it effectively meets the fire-resistance rating necessary for the specific structural elements in question.

By adhering to this standard, inspectors can verify that sufficient coverage is present to protect the underlying structural framework during a fire event. This is crucial for maintaining not just safety but also code compliance, as insufficient thickness can lead to structural failures or increased fire risks. Thus, taking four measurements provides an adequate representation of the thickness across the area, enhancing the reliability of the assessment.