The minimum test area for SFRM thickness is 48 square inches. Which of the following represents a correct choice for that area?

• A. 24 square inches
• B. 48 square inches
• C. 72 square inches
• D. 96 square inches

Answer: (B)

When verifying sprayed fireproofing thickness, you need a sampling area that’s large enough to average out any local variations and give a representative measurement. The specified minimum area is 48 square inches, which is just large enough to capture the typical thickness across the surface. A smaller patch, like 24 square inches, wouldn’t reliably reflect the coating’s thickness. Areas larger than the minimum, such as 72 or 96 square inches, also meet the requirement, but the question is asking for the minimum, so 48 square inches is the correct representation.