Category
Valves
Subcategory
Specialty Valve
Applicable standards
2
Issuing bodies
2
Description
Self-operated or pilot-operated pressure regulator for gas / liquid service.
Applicable Standards (2)
ASME — 1 standard
ASME B16.34
Valves — Flanged, Threaded, and Welding End
Pressure-temperature ratings, dimensions, materials, NDE, marking and testing for valves.
Key requirements (7)
- Pressure–temperature ratings for valves (steel).
- Pressure classes: 150, 300, 400, 600, 900, 1500, 2500, 4500.
- Body wall thickness: t = (P·d)/(2·S·E − 1.2·P) + c, plus tabulated minimums.
- Hydrotest: shell at 1.5 × Class 100 °F rating; seat at 1.1 × Class 100 °F rating.
- Special class allows 25% above standard rating with stricter NDE (radiography + hardness).
- Materials per ASME II Part D allowable stress.
- End connections: threaded, flanged, butt-weld, socket-weld.
IEC — 1 standard
IEC 60534 (series)
Industrial-process control valves
International control valve series — sizing, terminology, noise, testing.
Key requirements (8)
- Industrial process control valves — sizing and characteristics.
- Cv / Kv calculation: Q = N·Cv·√(ΔP/ρ) for liquid (with corrections for choked flow).
- Choked flow: ΔP_choke = FL²·(P1 – Ff·Pv) for cavitation.
- Compressible flow: choked when P2/P1 ≤ critical pressure ratio (~0.55 for air).
- Noise prediction: aerodynamic (Part 8-3) and hydrodynamic (8-4) — 85 dBA limit typical.
- Inherent flow characteristics: linear, equal-percentage (most common), quick-opening.
- Rangeability: typical 30:1 (globe), 50:1+ (rotary segmented ball).
- Leakage classes: I (no test), II (0.5% Cv), III (0.1% Cv), IV (0.01% Cv) standard, V (very tight), VI (resilient seat / soft-seated).