ASME B31.3 Limitations on Valves

Most valves in ASME B31.3 piping systems are in accordance with the following listed standards:

• ASME B16.10, Face-to-Face and End-to-End Dimensions of Valves

• ASME B 16.34, Valves—Flanged, Threaded, and Welding End

• API 526, Flanged Steel Pressure Relief Valves

• API 594, Wafer and Wafer-Lug Check Valves

• API 599, Metal Plug Valves—Flanged, Threaded and Welding Ends

• API 600, Bolted Bonnet Steel Gate Valves for Petroleum and Natural Gas Industry

• API 602, Compact Steel Gate Valves—Flanged, Threaded, Welding and Extended Body

• Ends

• API 603, Class 150, Cast, Corrosion-Resistant, Flanged-End Gate Valves

• API 608, Metal Ball Valves—Flanged, Threaded, and Welding Ends

• API 609, Butterfly Valves: Double Flanged, Lug- and Wafer-Type

• AWWA C500, Metal-Seated Gate Valves for Water Supply Service

• AWWA C504, Rubber-Seated Butterfly Valves

• MSS SP-42, Class 150 Corrosion-Resistant Gate, Globe, Angle, and Check Valves with

• Flanged and Buttweld Ends

• MSS SP-70, Cast Iron Gate Valves, Flanged and Threaded Ends

• MSS SP-71, Cast Iron Swing Check Valves, Flanged and Threaded Ends

• MSS SP-72, Ball Valves with Flanged or Buttwelding Ends for General Service

• MSS SP-80, Bronze Gate, Globe, Angle, and Check Valves

• MSS SP-81, Stainless Steel, Bonnetless, Flanged, Knife Gate Valves

• MSS SP-85, Gray Iron Globe and Angle Valves, Flanged and Threaded Ends

• MSS SP-88, Diaphragm Type Valves

• MSS SP-105, Instrument Valves for Code Applications

Listed valves are accepted for their specified pressure ratings. Some of these pressure ratings are tabulated in Appendix I. Valves that are not in accordance with one of the listed standards can be accepted as unlisted components in accordance with para. 302.2.3. Two options are permitted for establishing pressure-temperature ratings for unlisted valves. These are per para. 304.7.2 or ASME B 16.34, Appendix F.

Two additional requirements are provided in para. 307. Bolted bonnet valves must be secured by at least four bolts, except in Category D Fluid Service. Bonnets secured with fewer than four bolts or with U-bolt bonnets are only permitted in Category D Fluid Service.

A requirement for positive stem retention was added to the 2006 edition. The requirement is that the valve stem cannot be removed from the valve, while it is under pressure, by simply removing the stem seal retainer (e.g., packing gland fasteners). #Little_PEng.

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