Control Valve / PSV
Sizing, selection, testing, and installation standards for control and pressure-relief valves.
API 576
APIInspection of Pressure-Relieving Devices
Inspection and maintenance practices for pressure-relieving devices (PSV/PRV).
API 520
APISizing, Selection, and Installation of Pressure-Relieving Devices
Sizing, selection, and installation of pressure-relief devices for refineries.
API 521
APIPressure-Relieving and Depressuring Systems
Design of relief and depressuring systems including flare load determination.
API 526
APIFlanged Steel Pressure Relief Valves
Standardized orifice designations and dimensions for flanged steel PRVs.
API 527
APISeat Tightness of Pressure Relief Valves
Seat tightness test methods and acceptance for PRVs.
IEC 60534
IECIndustrial-Process Control Valves
A multi-part standard covering terminology, sizing equations, flow capacity (Cv/Kv), inherent characteristics, and testing of industrial-process control valves.
ISA 75
ISAControl Valve Sizing, Terminology, and Testing (75 Series)
The ISA 75 series covering control valve sizing equations, terminology, inherent characteristics, and flow/capacity testing — the North American counterpart harmonized with IEC 60534.
ISO 4126
ISOSafety Devices for Protection Against Excessive Pressure
A multi-part standard covering safety valves, bursting discs, and other overpressure-protection devices — the ISO/European counterpart to the API 520/526/527 relief-valve family.
ASME Section VIII
ASMERules for Construction of Pressure Vessels (Overpressure Protection)
Rules for the design, fabrication, inspection, and certification of pressure vessels, including the mandatory overpressure-protection (relief) requirements that drive PSV/relief-device selection.