What is the minimum density required for metal lath used in SFRM?

The minimum density required for metal lath used in Spray-Applied Fire-Resistive Material (SFRM) is 1.7 lb/ft³. This density is essential because it provides the necessary structural support and robustness required for the application of fireproofing materials. A metal lath with a density of 1.7 lb/ft³ ensures proper adhesion and coverage of the SFRM, which plays a critical role in achieving the desired fire-resistance ratings.

The selected density level also complies with industry standards and building codes, ensuring that the fireproofing can withstand various environmental factors without deteriorating or failing to protect the structural elements beneath. Lower densities may not offer adequate support for the fireproofing material, while higher densities could become unnecessarily heavy and may not be cost-effective in construction practices. This balance in density helps ensure both performance and economic feasibility in construction projects involving fireproofing systems.