Which document outlines general requirements for flanges?

The document that outlines general requirements for flanges is ASME B16.5. This standard specifically covers the dimensions, materials, pressure-temperature ratings, and other requirements for pipe flanges and flanged fittings. It is widely recognized and used in the industry for ensuring compatibility and safety in piping systems.

ASME B16.5 provides detailed specifications that help in the proper selection and use of flanges, which are critical components in the assembly of piping systems. Understanding these requirements is vital for engineers and professionals who work with mechanical systems, as improper flange specifications can lead to failures and safety hazards.

In contrast, the other documents mentioned serve different purposes: AWS D1.1 is focused on welding specifications for structural steel, ASNT SNT-TC-1A pertains to the qualifications of personnel involved in non-destructive testing, and SSPC-PA 2 deals with the measurement of paint film thickness in coatings. Therefore, while they are all important standards within their respective fields, they do not specifically address the requirements for flanges as covered in ASME B16.5.