Which statement is true about TFIFRM thickness determinations for a column specified at 65 mils?

• A. An individual thickness determination may be as low as 50 mils
• B. An individual thickness determination may be as low as 52 mils
• C. An individual thickness determination may be as low as 60 mils
• D. An individual thickness determination may be as low as 65 mils

Answer: (B)

TFIFRM thickness determinations have a lower tolerance tied to the specified thickness. The minimum acceptable reading is 80% of what’s specified. For a column specified at 65 mils, 80% equals 52 mils, so the smallest permissible individual thickness is 52 mils. A measurement like 50 mils would be outside the tolerance, while 60 or 65 mils are acceptable since they meet or exceed the minimum.