A fitting is used in pipe plumbing systems to connect straight pipe or tubing sections, to adapt to different sizes or shapes, and for other purposes, such as regulating or measuring fluid flow. The term plumbing is generally used to describe conveyance of water, gas, or liquid waste in ordinary domestic or commercial environments, whereas piping is often used to describe high-performance (e.g. high pressure, high flow, high temperature, hazardous materials) conveyance of fluids in specialized applications. The term tubing is sometimes used for lighter-weight piping, especially types that are flexible enough to be supplied in coiled form.
For example pipes need to conform to the dimensional requirements of :
ASME B36.10M - Welded and Seamless Wrought Steel Pipe ASME B36.19M - Stainless Steel Pipe ASME B31.3 2008 - Process PipinG ASME B31.4 XXXX - Power Piping The B31.3 / B31.4 code has requirements for piping found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. This code specifies requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. This Code is applicable to piping for all fluids including: (1) raw, intermediate, and finished chemicals; (2) petroleum products; (3) gas, steam, air and water; (4) fluidized solids; (5) refrigerants; and (6) cryogenic fluids.