When flaring aluminum tubing for use with AN fittings, the flare angle must be?

When flaring aluminum tubing for use with AN fittings, the flare angle must be?

• A. 33 degrees
• B. 45 degrees
• C. 30 degrees
• D. 37 degrees

Answer: (D)

Flare angle must be 37 degrees. AN fittings are designed to seal on a 37-degree flare surface, which lets the flare seat evenly against the fitting and form a reliable metal-to-metal seal under pressure. Using a different angle—33, 30, or 45 degrees—will not mate properly with the AN seating and can cause leaks or a failed connection because the flare won’t seat correctly or bottom properly. So the 37-degree flare is the correct standard for aluminum tubing with AN fittings.

Flare angle must be 37 degrees. AN fittings are designed to seal on a 37-degree flare surface, which lets the flare seat evenly against the fitting and form a reliable metal-to-metal seal under pressure. Using a different angle—33, 30, or 45 degrees—will not mate properly with the AN seating and can cause leaks or a failed connection because the flare won’t seat correctly or bottom properly. So the 37-degree flare is the correct standard for aluminum tubing with AN fittings.