ASME B31.3, also known as the “Process Piping Code,” is a technical standard and code of practice published by the American Society of Mechanical Engineers (ASME) that provides requirements and guidelines for the design, fabrication, installation, inspection, and testing of process piping systems. Process piping systems are used to transport fluids, gases, and other materials in various industries, such as chemical, petrochemical, oil and gas, and power generation.

ASME B31.3 is one of the most widely used codes for process piping, and is recognized and adopted by many national and international organizations, including the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO). ASME B31.3 is regularly updated and revised to reflect the latest developments and best practices in the field of process piping, and is available in print and electronic formats.

ASME B31.3 consists of several sections and appendices, which cover various aspects of process piping design, fabrication, installation, inspection, and testing. Some of the key sections and appendices of ASME B31.3 include:

• Section A: General Requirements: Provides general requirements and definitions that apply to the design, fabrication, installation, inspection, and testing of process piping systems. This section defines important terms and concepts, such as process piping, design basis, material specification, and hydrostatic testing.

• Section B: Materials: Specifies the materials and grades that are acceptable for use in process piping systems, and provides requirements for material identification, marking, and testing. This section includes tables of materials, their properties, and their allowable stresses, as well as requirements for material traceability and testing.

• Section C: Design: Provides requirements and guidelines for the design of process piping systems, including pipe sizing, pressure and temperature ratings, material selection, stress analysis, and joint design. This section covers the design of process piping systems, including the determination of pipe size, pressure and temperature ratings, and material selection, as well as the calculation of pipe wall thickness and joint design.

• Section D: Fabrication: Specifies the requirements and procedures for the fabrication of process piping systems, including cutting, bending, welding, nondestructive testing (NDT), and hydrostatic testing. This section covers the fabrication of process piping systems, including the cutting, bending, and welding of pipe and fittings,