What is the purpose of maintaining specified substrate temperatures during SFRM application?

Maintaining specified substrate temperatures during the application of Spray-Applied Fire-Resistive Material (SFRM) is essential primarily to enhance the adhesion of the material. Proper temperature control ensures that the substrate surface is conducive to bonding with the fireproofing material. When the substrate is within the recommended temperature range, it allows for better mechanical interlocking and chemical adhesion between the SFRM and the surface to which it is applied. This is crucial because strong adhesion leads to improved performance of the fireproofing system, ensuring that it adequately protects structural elements during a fire incident.

Other objectives such as reducing application time, increasing the thickness of the fireproofing layer, or minimizing the overall weight of the column do not directly pertain to the critical function of substrate temperature in ensuring effective adhesion of the fireproofing material. Therefore, the correct answer emphasizes the importance of temperature regulation for optimal bonding of SFRM during its application.