ASME B31.3 Fluid Service Categories
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 press