What is considered a high-density SFRM?

High-density spray-applied fire-resistant materials (SFRM) are typically defined by their density, as this is a crucial factor that influences their thermal performance and overall fire-resistance characteristics. Generally, materials with a density greater than 1.7 lb/ft³ would be classified as high-density SFRM. Such materials tend to provide better insulation and fire-resistive performance compared to lower-density counterparts due to their thicker application and greater mass, which helps to delay the transfer of heat.

In the context of the provided choices, while options like 1.5 lb/ft³ and 2.0 lb/ft³ indicate different density levels, only a density greater than 1.7 lb/ft³ unequivocally aligns with the accepted definition of high-density SFRM. This distinction is important not only for compliance with building codes but also for ensuring adequate fire protection in structures. Thus, citing the threshold of 1.7 lb/ft³ serves to define high-density SFRM accurately within the field of fireproofing materials.