What is the lowest allowed individual thickness for a wide flange requiring 2" of SFRM?

The individual thickness of spray-applied fire-resistive material (SFRM) is critical for achieving the desired fire protection performance for wide flange beams. In this case, when a wide flange structural member requires a total thickness of 2 inches of SFRM, the minimum allowable thickness that can be applied in a single pass is typically governed by the manufacturer's recommendations and the building code requirements.

The correct choice indicates that an individual thickness of 1-¾ inches can be applied effectively, allowing for a total of 2 inches when accounting for possible thickness loss due to application techniques or settling over time. This means that when applying the SFRM, the thickness in a single layer should not be less than this amount to ensure adequate coverage and performance standards are met.

If the application were to use less than 1-¾ inches on a wide flange, it could result in inadequate fire protection, as it would not provide enough insulation against heat and flames in the event of a fire scenario. Thus, the answer highlights a minimum standard that must be adhered to in order to maintain the effectiveness of the fire-resistive coating, ensuring safety and compliance with fire safety regulations.