Excluded and Optional Piping Systems The fluid services and classes of piping systems listed below are excluded from the specific requirements of API 570 but may be included at the owner’s or user’s (owner/user’s) option. a. Fluid services that are excluded or optional include the following: 1. Hazardous fluid services below threshold limits, as defined by jurisdictional regulations. 2. Water (including fire protection systems), steam, steam-condensate, boiler feed water, and Category D fluid services, as defined in ASME B31.3. b. Classes of piping systems that are excluded or optional are as follows: 1. Piping systems on movable structures covered by jurisdictional regulations, including piping systems on trucks, ships, barges, and other mobile equipment. 2. Piping systems that are an integral part or component of rotating or reciprocating mechanical devices, such as pumps, compressors, turbines, generators, engines, and hydraulic or pneumatic cylinders where the primary design considerations and/or stresses are derived from the functional requirements of the device. 3. Internal piping or tubing of fired heaters and boilers, including tubes, tube headers, return bends, external crossovers, and manifolds. 4. Pressure vessels, heaters, furnaces, heat exchangers, and other fluid handling or processing equipment, including internal piping and connections for external piping. 5. Plumbing, sanitary sewers, process waste sewers, and storm sewers. 6. Piping or tubing with an outside diameter not exceeding that of NPS ½. 7. Nonmetallic piping and polymeric or glass-lined piping