A flare fitting is a mechanical connection that uses a conical sealing surface to join copper, aluminum, or steel tubing without requiring solder or braze. The fitting consists of a body with a cone-shaped seat and a compression nut that forces a flared tube end into the seat, creating a leak-free seal. Flare fittings are commonly used in refrigerant lines, natural gas connections, and hydraulic systems.
Technical Specifications
Flare fittings comply with ASTM B632 standards and are available in 37-degree and 45-degree flare angles. Common sizes range from 1/4 inch to 1 1/8 inch outer diameter. These fittings maintain pressure ratings up to 500 PSI depending on material and size. Proper flaring tools and torque specifications (typically 12-25 foot-pounds) are essential for reliable connections.
HVAC Applications
Flare fittings are widely used in refrigerant line connections for air conditioning and heat pump systems. They allow technicians to connect tubing runs in the field while maintaining system integrity and preventing refrigerant loss. The reusable nature of flare connections makes them cost-effective for service work compared to soldered alternatives.
Installation Considerations
Proper tube preparation, accurate flaring, and correct tightening are critical for preventing leaks. Over-tightening can crack the fitting, while under-tightening allows refrigerant escape.