Which of the following is NOT a basic type of flange facing?

Flange facings are crucial in ensuring proper sealing and fit between flanged connections in piping systems. The raised face, lap joint, and flat/full face are recognized types of flange facings with distinct characteristics that serve various applications.

The raised face type is commonly employed to improve the sealing capabilities by allowing the gasket to sit on an elevated surface, thereby creating better compression during assembly. The lap joint, on the other hand, features a design that allows for easier alignment and is especially useful when dealing with systems requiring frequent disassembly. Flat/full face flanges, meeting specific criteria, provide a flat gasket surface which is essential for certain applications where a raised face would not be suitable.

In contrast, conical face does not represent a standard or recognized type of flange facing in the industry. While traditional flange facings focus on ensuring a reliable seal and mechanical fit, a conical face is uncommon and not typically found in pipefitting applications. As a result, it is correct to identify conical face as not being a basic type of flange facing.