Category
Valves
Subcategory
Control Valve
Applicable standards
5
Issuing bodies
5
Description
Pneumatic / electric control valve — globe, rotary, segmented ball or eccentric plug.
Applicable Standards (5)
API — 1 standard
API 598
Valve Inspection and Testing
Inspection, examination, supplementary examinations and pressure-test requirements for valves.
Key requirements (5)
- Valve inspection and testing — covers the test requirements referenced by other valve standards.
- Tests: shell (high-pressure water), backseat (where applicable), low-pressure pneumatic seat, high-pressure hydrostatic seat, optional high-pressure pneumatic seat.
- Allowable leakage: zero for resilient-seated; small allowable rate for metal-seated (Table 6).
- Test duration: minimum hold times by valve size.
- Visual examination during pressurization.
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.
ISA — 1 standard
ANSI/ISA 75.01.01 / IEC 60534-2-1
Industrial-Process Control Valves — Flow Equations for Sizing Control Valves
Sizing equations for control valves (incompressible and compressible service).
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).
BIS — 1 standard
IS 13049
Diaphragm-actuated, Single Seated Top Guided Globe Type Pneumatic Control Valves
Indian control valve standard.
Key requirements (6)
- Specification for diaphragm-operated control valves.
- Indian counterpart of ISA 75 / IEC 60534 family.
- Cv calculation, leakage classes (I–VI), inherent characteristics.
- Hydrotest per IS 4733 / API 598.
- Pressure classes per IS 4853 (PN 16 to PN 250 typical).
- Used for compliance in Indian refineries and process plants.