Sheet metal work encompasses the cutting, forming, and joining of metal sheets to create HVAC components including ductwork, plenums, transitions, and equipment housings. This skilled trade requires precision tools and techniques to ensure leak-free, structurally sound installations.
Tools and Techniques
Essential tools include sheet metal shears, brakes for bending, riveting guns, crimpers for duct connection, and measuring instruments. Sheet metal thicknesses range from 24 to 30 gauge depending on application. Common joints include standing seams, Pittsburgh seams, and button punches for low-pressure connections. Slip connections allow thermal expansion without creating stress. Proper edge treatments prevent sharp edges hazardous to personnel.
Application Standards
SMACNA standards specify construction methods for rectangular and circular ducts, with reinforcement requirements based on system pressure ratings (typically 0.5 to 2 inches water column). Ductwork must be sized to maintain target velocities of 400-600 FPM for supply air and 300-450 FPM for return air. Professional sheet metal work prevents leakage exceeding 5 percent system capacity, maintaining efficiency and comfort performance.