Residential Building Inspector B1Wall Construction and Wall CoveringsHard
An inspector is reviewing plans for a residential building utilizing cold-formed steel framing. The exterior load-bearing walls are designed with 350S162-33 studs. What is the minimum base metal thickness (BMT) of these studs, in inches, for a nominal 33 mil stud?
- A0.018 inch
- B0.027 inch
- C0.043 inch
- D0.033 inch
Show answer & explanationAnswer & explanation
Correct answer: D. 0.033 inch
The '33' in the cold-formed steel stud designation '350S162-33' refers to the nominal steel thickness in mils. To find the minimum base metal thickness (BMT) for a 33 mil stud, you convert mils to inches: 33 mils / 1000 mils/inch = 0.033 inches. This is a direct conversion from the common industry designation.
Why the other options are wrong
- A. 0.018 inch (18 mil) is a much lighter gauge steel, not 33 mil.
- B. 0.027 inch (27 mil) is a thinner gauge, but not 33 mil.
- C. 0.043 inch (43 mil) is a heavier gauge steel, not 33 mil.
Cold-Formed Steel BMT
The minimum base metal thickness of cold-formed steel framing members, typically identified by a mil designation in the product code.
- Mil designation directly relates to thickness in inches.
- Product codes indicate nominal thickness.
- BMT is critical for structural calculations.
Memory trick: Steel stud numbers tell you 'Shape, Width, Flange, Thickness'.