Which condition is required when applying SFRM based on substrate temperature?

When applying Spray-Applied Fire-Resistive Materials (SFRM), it is crucial for the substrate temperature to be above freezing. This is because when temperatures drop to or below freezing, the SFRM can lose its effectiveness in adhering properly to the substrate. Freezing temperatures can also lead to improper curing and volatility in the material properties, which could ultimately compromise the fire-resistance capability of the application.

Maintaining a substrate temperature above freezing ensures that the SFRM can bind adequately, cure properly, and perform as intended under fire conditions. It's essential for ensuring that the protective layer maintains its integrity and meets safety regulations.

While other conditions like being dry or shaded can impact the performance and application of SFRM, the fundamental requirement related to temperature specifically highlights the importance of avoiding freezing conditions to preserve the material's functional characteristics.