If a duct is listed for zero clearance or protected to reduce clearance to zero, it may do what with respect to contact limits without additional corrosion protection?

If a duct is listed for zero clearance or protected to reduce clearance to zero, it may do what with respect to contact limits without additional corrosion protection?

• A. meet
• B. exceed
• C. ignore
• D. comply

Answer: (B)

When a duct is listed for zero clearance or protected to reduce clearance to zero, the listing guarantees it can be placed in direct contact with adjacent surfaces without needing extra corrosion protection. Because of that certification, you may exceed the usual contact limits and still be compliant, since the duct is engineered to tolerate that close proximity without additional coatings or barriers. This doesn’t override all rules—the installation must follow the specific listing conditions. If you deviate from what the listing allows, then you’d need the extra corrosion protection.

When a duct is listed for zero clearance or protected to reduce clearance to zero, the listing guarantees it can be placed in direct contact with adjacent surfaces without needing extra corrosion protection. Because of that certification, you may exceed the usual contact limits and still be compliant, since the duct is engineered to tolerate that close proximity without additional coatings or barriers. This doesn’t override all rules—the installation must follow the specific listing conditions. If you deviate from what the listing allows, then you’d need the extra corrosion protection.