What is the minimum nominal thickness of the metal wall for a 16"x24" galvanized duct?

What is the minimum nominal thickness of the metal wall for a 16"x24" galvanized duct?

• A. 0.05 inch (No. 19 Gage)
• B. 0.04 inch (No. 20 Gage)
• C. 0.03 inch (No. 21 Gage)
• D. 0.06 inch (No. 18 Gage)

Answer: (B)

The minimum nominal thickness of the metal wall for a 16"x24" galvanized duct is 0.04 inch, which corresponds to No. 20 gauge. This thickness is in line with industry standards that dictate the appropriate gauge based on the dimensions and intended use of the duct. The choice of 0.04 inch ensures that the duct can handle the necessary air pressure, maintain structural integrity, and comply with regulations for metal ducts.

Selecting a gauge that is too thin could compromise the duct's performance and longevity, leading to issues such as air leaks or deformation under varying pressure levels. In contrast, thicker gauges provide robustness but may be unnecessary and more costly for application in standard duct systems. Therefore, the designation of No. 20 gauge as the minimum ensures a balance between functionality, efficiency, and cost-effectiveness specifically for a duct of these dimensions.