Red Seal Sheet Metal Worker Practice Exam

What is the procedure for caulking duct seams?

1. Using a heat gun to melt the caulk

2. Applying caulking evenly along the joint to create an airtight seal

3. Only applying caulk on the outer edge of the duct

4. Mixing caulk with adhesive for better sealing

The correct answer is: Applying caulking evenly along the joint to create an airtight seal

Applying caulking evenly along the joint is essential for creating an airtight seal in duct seams. When properly applied, caulk fills gaps and prevents air leakage, which improves the efficiency of the HVAC system and ensures that conditioned air is distributed effectively. An even application guarantees that the caulk adheres well to both surfaces of the duct, maximizing its sealing capabilities. This technique is crucial for minimizing energy loss and enhancing overall performance. The other approaches do not address the primary goal of sealing duct seams effectively. For example, using a heat gun to melt caulk is not a standard practice and could damage the duct material, while applying caulk only on the outer edges would leave gaps that could compromise the seal. Mixing caulk with adhesive might seem like it could strengthen the bond, but this could lead to inappropriate curing and possibly reduce the intended function of the caulk, which is to fill and seal joints.