Introduction to Valve Standard Organizations and Common Standards

American Society of Mechanical Engineers (ASME)

The American Society of Mechanical Engineers (ASME), founded in 1880, is a globally recognized authority in mechanical engineering. It develops a wide range of technical standards widely adopted in more than 100 countries.

Common ASME valve standards include:

1. ASME B16.34: Valves—Flanged, threaded, and welding end
2. ASME B16.5: Pipe flanges and flanged fittings (NPS 1/2–24)
3. ASME B16.10: Face-to-face and end-to-end dimensions of valves

American Petroleum Institute (API)

The American Petroleum Institute (API), founded in 1919, is a key organization in the oil and gas industry responsible for developing equipment standards ensuring safety, reliability, and interchangeability.

Common API valve standards include:

1. API 6D: Pipeline valves specification
2. API 600: Steel gate valves
3. API 602: Small forged steel valves
4. API 6A: Wellhead and Christmas tree equipment

Among them, API 6D is the most widely used pipeline valve standard.

 Key Application Points and Comparison of Valve Standards

Core Valve Parameters

The three most important valve parameters are:

1. Valve size
2. Pressure class
3. Material

Example marking:

2" 150 WCB

means:

1. Size: 2 inches
2. Pressure class: Class 150
3. Material: WCB

 ASME B16.34 Standard

Actual Valve Bore

ASME B16.34 provides valve bore tables for different NPS and pressure classes (Non-mandatory Appendix A, Table A-1).

Key points:

1. Valve bore ≠ pipe nominal size
2. Higher pressure class → smaller bore

 Pressure Class

ASME B16.34 defines pressure classes including:

1. Class 150
2. Class 300
3. Class 600
4. Class 900
5. Class 1500
6. Class 2500
7. Class 4500

These values are class designations, not actual pressure values.

 Material and Pressure-Temperature Relationship

ASME B16.34 Table 2 defines:

1. Material groups
2. Temperature effects
3. Pressure ratings

For example:

• Class 150 pressure varies from approximately 284 PSI to 20.3 PSI depending on temperature.

ASME B16.5 Flange Standard

 Flange Sealing Face Types

ASME B16.5 defines five main sealing types:

1. RF (Raised Face)
2. FF (Flat Face)
3. MF (Male & Female)
4. TG (Tongue & Groove)
5. RJ (Ring Joint)

 Application by Pressure Class

1. Class 150 / 300 → RF or FF
2. Class 600 / 900 → MF
3. Class 1500 → TG
4. Class 2500 → RJ (metal gasket)

 ASME B16.10 Valve Length Standard

Defines:

Face-to-Face

Used for:

1. RF
2. FF
3. MF
4. TG

End-to-End

Used for:

1. RJ
2. recessed face
3. groove face

Conclusion:
 RJ valves are generally longer in structure.

API 6D Pipeline Valve Standard

 Valve Bore

API 6D requires full bore design to ensure pigging capability.

Key difference:

1. API 6D bore > ASME B16.34 bore
2. Designed for piggable pipeline systems
3. Automatic Cavity Pressure Relief

Requirements:

1. Cavity pressure ≤ 1.33 × pipeline pressure
2. Automatic pressure relief system required
3. Uses SPE seat design

Materials

1. Same ASTM material system as ASME
2. Requires fire-safe design
3. Composite metal + non-metal seat structure Valve Seats (DBB / DIB)

Single Direction Seat (SPE)

1. Single piston effect
2. Enables DBB (Double Block & Bleed)

Double Direction Seat (DPE)

1. Double piston effect
2. Enables DIB (Double Isolation & Bleed)

Summary

ASME and API standards form the core framework of valve design in the oil and gas industry:

1. ASME standards focus on dimensional and structural design
2. API 6D focuses on pipeline safety and operating conditions

Both standards are essential and should be applied together in engineering practice.