How is sheet metal typically joined in HVAC systems?

In HVAC systems, sheet metal is typically joined using a combination of screws, rivets, or adhesive seams. This method is preferred because it provides strong, reliable connections that are necessary to handle the operational pressures and thermal expansion associated with HVAC systems.

Screws and rivets are mechanical fasteners that create a secure bond by physically joining the pieces of metal together, allowing for easy disassembly if maintenance is needed. Adhesive seams offer flexibility and can seal joints to prevent air leaks, which is crucial in maintaining system efficiency.

The other methods mentioned, such as melting edges together or welding, are less commonly used in HVAC installations due to the specific materials and thicknesses of the sheet metal used. While welding may be applicable in some circumstances, it is not the primary joining method for sheet metal in HVAC settings, where ease of assembly and serviceability are key considerations.