Which feature is characteristic of AN flare fittings?

Which feature is characteristic of AN flare fittings?

• A. An identifying shoulder between the end of the threads and the flare core
• B. A threadless design with no shoulder
• C. A groove around the flare
• D. A color-coded ring at the base of the flare

Answer: (A)

The feature being tested is the identifying shoulder on AN flare fittings. This shoulder sits between the end of the threaded part and the flare portion, giving a precise reference point for where the flare begins. It serves two key purposes: it identifies the fitting as an AN flare and provides a seating datum so the flare seats correctly when the nut is tightened. As the nut compresses the flare onto the conical seating surface, a tight metal-to-metal seal is formed. The shoulder also prevents the flare from being driven too far in or bottoming out, which helps ensure a reliable seal. The other options don’t fit because AN flare fittings are not threadless, they don’t depend on a groove around the flare, and they aren’t identified by a color-coded ring at the base of the flare.

The feature being tested is the identifying shoulder on AN flare fittings. This shoulder sits between the end of the threaded part and the flare portion, giving a precise reference point for where the flare begins. It serves two key purposes: it identifies the fitting as an AN flare and provides a seating datum so the flare seats correctly when the nut is tightened. As the nut compresses the flare onto the conical seating surface, a tight metal-to-metal seal is formed. The shoulder also prevents the flare from being driven too far in or bottoming out, which helps ensure a reliable seal.

The other options don’t fit because AN flare fittings are not threadless, they don’t depend on a groove around the flare, and they aren’t identified by a color-coded ring at the base of the flare.