For SFRM application, substrate temperatures must be maintained at 40 degrees F for how long after application?

• A. 32 degrees F for 12 hours
• B. 40 degrees F for 24 hours
• C. 40 degrees F for 72 hours
• D. 50 degrees F for 24 hours

Answer: (B)

After applying spray-applied fireproofing, it’s essential to cure the material under a controlled temperature to develop strength and adhesion. Keeping the substrate at 40°F for 24 hours provides the proper conditions for the cementitious binder to hydrate and cure without freezing or drying too quickly, which supports a solid bond to the substrate and overall performance of the SFRM. If the temperature drops below 40°F, hydration slows and cure quality can suffer, risking cracks or debonding. Extending the duration to 72 hours isn’t the standard requirement and doesn’t offer additional benefit for this purpose, while a higher temperature like 50°F isn’t the specified condition. Therefore, 40°F for 24 hours is the correct guideline.