What is the significance of achieving a bond strength of half that on steel for SFRM on primer?

Achieving a bond strength of half that on steel for Spray-Applied Fire-Resistive Material (SFRM) on primer is significant primarily because it helps to prevent delamination. Delamination refers to the separation of layers in a material, which can occur when the bond strength between the SFRM and the surface it's applied to is insufficient.

By ensuring that the bond strength is strong enough (at least half that of the bond to steel), the material is more likely to adhere effectively to the surface, reducing the risk of the fireproofing material flaking or peeling off during exposure to heat or fire. This adherence is crucial in maintaining the structural integrity of the building, as effective fireproofing is essential for protecting the underlying structure from fire damage.

While optimal fire resistance, durability, and compliance with regulations are all important factors in fireproofing practices, the bond strength specifically targets the concern of material adherence, pivotal in preventing delamination.