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Valve Standard Reference

ASME B16.5

American

Pipe Flanges and Flanged Fittings NPS 1/2 through NPS 24 Metric/Inch Standard

ASME B16.

What is ASME B16.5?

ASME B16.5 (Pipe Flanges and Flanged Fittings NPS 1/2 through NPS 24 Metric/Inch Standard) is an industrial valve standard issued by American Society of Mechanical Engineers (ASME). Covers raised face (RF), ring-type joint (RTJ), flat face (FF), and tongue-and-groove flanged valves and fittings, NPS ½" through NPS 24", in all standard ASME pressure classes.

Issuing Body:
American Society of Mechanical Engineers (ASME)
Category:
design

Overview - ASME B16.5

ASME B16.5 is the fundamental flange standard that establishes pressure-temperature (P-T) ratings, materials, dimensions, tolerances, marking, and testing requirements for flanged fittings and flanged valves in sizes NPS ½" through NPS 24". It defines seven pressure classes (150 through 2500) across 33 material groups, making it the universal reference for valve end flange selection and procurement worldwide. Any valve with flanged ends ordered for ASME-governed piping systems must comply with B16.5 for proper mating.

Scope

Covers raised face (RF), ring-type joint (RTJ), flat face (FF), and tongue-and-groove flanged valves and fittings, NPS ½" through NPS 24", in all standard ASME pressure classes. Applies to carbon steel, alloy steel, and stainless steel body materials across seven pressure classes.

Vajra Industrial Solutions manufactures and supplies valves engineered to comply with ASME B16.5, each delivered with ASME B16.5 compliance marking on valve body flange and Material Test Reports (MTR) per EN 10204 3.1 as standard.

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Applicable Valve Types

Ball Valves - flanged end

Gate Valves - flanged end

Globe Valves - flanged end

Butterfly Valves - double-flanged

Check Valves - flanged end

Plug Valves - flanged end

Applicable Pressure Classes

Class 150Class 300Class 600Class 900Class 1500Class 2500

Key Requirements - ASME B16.5

01.

Seven pressure classes defined: Class 150, 300, 600, 900, 1500, and 2500

02.

Thirty-three material groups (1.1 through 3.3) each with its own P-T rating table

03.

Class 150 WCB carbon steel rated 285 psi at ambient; Class 2500 rated 4500 psi

04.

Flange facing options: raised face (RF), flat face (FF), ring-type joint (RTJ), tongue-and-groove

05.

Bolting dimensions and bolt circle specified per class and nominal size

06.

Material marking on flange body: material designation, pressure class, size, heat code

07.

Hydrostatic shell test per manufacturer's standard (minimum 1.5× rated pressure)

08.

End flange dimensions must match piping flanges for leak-free bolted assembly

Testing Requirements - ASME B16.5

Shell hydrostatic test: 1.5× rated pressure per class and material group

Flange facing dimensional inspection to B16.5 tolerances

Positive material identification (PMI) for alloy and stainless steel flanges

Documentation Required for ASME B16.5 Compliance

ASME B16.5 compliance marking on valve body flange

Material Test Reports (MTR) per EN 10204 3.1

Pressure-temperature rating data sheet referencing B16.5 material group

Hydrostatic test certificate

Related Standards

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Part of the Vajra Valve Standards Library
Reviewed by Valve Standards Engineering, Vajra Industrial SolutionsDiscipline: Industrial Valve Standards & ComplianceLast reviewed: 20 June 2026

Connected Engineering

Need ASME B16.5 Compliant Valves?

We supply valves to ASME B16.5 with full certification documentation. Share your requirements for a 24-hour quote.