a general term concerning the application of a piping system, considering the combination of fluid properties, operating conditions, and other factors that establish the basis for design of the piping system. See Appendix M.
ASME B31.3 Fluid Service Categories:
(a) Category D Fluid Service: a fluid service in which all of the following apply:
(1) the fluid handled is nonflammable, nontoxic, and not damaging to human tissues as defined in para. 300.2 (2) the design gage pressure does not exceed 1035 kPa (150 psi) (3) the design temperature is not greater than 186°C (366°F) (4) the fluid temperature caused by anything other than atmospheric conditions is not less than −29°C (−20°F)
(b) Category M Fluid Service: a fluid service in which both of the following apply:
(1) the fluid is so highly toxic that a single exposure to a very small quantity of the fluid, caused by leakage, can produce serious irreversible harm to persons on breathing or bodily contact, even when prompt restorative measures are taken
(2) after consideration of piping design, experience,service conditions, and location, the owner determines that the requirements for Normal Fluid Service do not sufficiently provide the leak tightness required to protect personnel from exposure
(c) Elevated Temperature Fluid Service: a fluid service in which the piping metal temperature is sustained equal to or greater than Tcr as defined in Table 302.3.5, General Note (b).
(d) High Pressure Fluid Service: a fluid service for which the owner specifies the use of Chapter IX for piping design and construction; see also para. K300.
(e) High Purity Fluid Service: a fluid service that requires alternative methods of fabrication, inspection, examination, and testing not covered elsewhere in the Code, with the intent to produce a controlled level of cleanness. The term thus applies to piping systems defined for other purposes as high purity, ultra high purity, hygienic, or aseptic.
(f) Normal Fluid Service: a fluid service pertaining to most piping covered by this Code, i.e., not subject to the rules for Category D, Category M, Elevated Temperature, High Pressure, or High Purity Fluid Service.