ASME B16.34: Valves - Flanged, Threaded, and Welding End

1.1 Scope
ASME B16.34 Standard applies to new construction and covers pressure–temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless valves of steel, nickel-base alloys, and other alloys shown in Table 1. Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end valves.

1.5 Denotation

1.5.1 Pressure Rating Designation. Class followed by a dimensionless number is the designation for pressure–temperature ratings. Standardized designations are as follows:

Class 150 300 600 900 1500 2500 4500

Class 400, an infrequently used flanged-end valve designation, is regarded as an intermediate class designation.

1.5.2 Size. NPS followed by a dimensionless number is the designation for nominal valve size. NPS is related to the reference nominal diameter, DN, used in international standards. The relationship is, typically, as follows:

NPS DN NPS DN
1/4 8 1-1/2 40
3/8 10 2 50
1/2 15 2-1/2 65
3/4 20 3 80
1 25 4 100
1-1/4 32    

For NPS ≥ 4, the related DN = 25 × NPS number.

1.6 Cryogenic Service

Valves in cryogenic service shall meet the additional requirements specified in MSS SP-134.

 

Related Information

API 6D: Specification for Valves in the petroleum and natural gas industries

API 600: Steel Gate Valves-Flanged and Butt-welding Ends, Bolted Bonnets

API 623: Steel Globe Valves Flanged and Butt-welding Ends, Bolted Bonnets

BS 1868: Steel check valves for the petroleum, petrochemical and allied industries

BS 1873: Steel globe and globe stop and check valves for the petroleum, petrochemical and allied industries

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Valve type (ball, gate, globe, check etc.), valve size, pressure class, valve material, and end connection (flanged, butt welding etc.)