Engineering Reference

Piping Class Valve Specifications

Valve schedules, material specs, and end-connection requirements for common industrial piping classes. Vajra supplies complete valve packages to your project's piping material specification (PMS).

Carbon Steel (Sweet Service)

A1A

ASME Class 150

General Service — Water, Air, Steam up to 16 bar

P: 16 bar
T: Up

Carbon Steel ASTM A216 WCB

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A2A

ASME Class 300

Medium Pressure — Process, Steam, Hydrocarbons to 50 bar

P: 50 bar
T: Up

Carbon Steel ASTM A216 WCB

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A3A

ASME Class 600

High Pressure — Refinery, HP Steam, Oil & Gas to 100 bar

P: 100 bar
T: Up

Carbon Steel ASTM A216 WCB

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Stainless Steel (Corrosive Service)

B1A

ASME Class 150

Stainless Steel — Chemical, Corrosive, Pharmaceutical Service

P: 19.6 bar
T: Up

Stainless Steel ASTM A351 CF8M (SS 316)

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B2A

ASME Class 300

Stainless Steel Medium Pressure — Corrosive Process to 51 bar

P: 51.1 bar
T: Up

Stainless Steel CF8M / A182 F316L

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Alloy Steel (High Temperature)

C1A

ASME Class 150

Alloy Steel — High Temperature Steam and HP Service

P: 19.6 bar
T: Up

1¼Cr-½Mo (ASTM A217 WC6) or 2¼Cr-1Mo (A217 WC9)

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NACE (Sour / H₂S Service)

D1A

ASME Class 150

Sour Service — H₂S Containing Hydrocarbons, NACE MR0175

P: 16 bar
T: Up

Carbon Steel WCB / ASTM A216 with NACE MR0175 hardness control

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Cryogenic (LNG / LOX)

E1A

ASME Class 150 (Cryogenic)

Cryogenic — LNG, Liquid Nitrogen, LOX Service to -196°C

P: Up bar
T: -196°C

Austenitic SS ASTM A351 CF8M / A182 F316L

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What is a Piping Class?

A piping class (also called a piping material class or piping spec) is a structured set of rules that defines which valves, pipes, fittings, and flanges can be used for a given fluid service at given pressure and temperature conditions.

Engineering companies (EPC contractors) and operating companies (owner/operators like IOCL, ONGC, NTPC, SABIC) maintain their own piping class documents. A typical designation like A1A encodes the pressure rating (A = Class 150), fluid group (1 = general), and material (A = carbon steel WCB).

When ordering valves for a project, procurement always quotes the piping class — e.g., “Gate valve, 6", Class A1A, per EIL standard 6-44-0001”. Vajra can supply to any project piping class specification.

Reference Disclaimer

Piping class definitions shown are general industry references. Project-specific piping classes (per EIL, PDIL, SABIC, Fluor, KBR, Jacobs, or owner standards) may differ in material, end connection, trim, and documentation requirements. Always verify against the project's official Piping Material Specification (PMS) before ordering.