Overview
EN ISO 4126-5:2013 - "Safety devices for protection against excessive pressure - Part 5: Controlled safety pressure relief systems (CSPRS)" is a CEN-adopted ISO product standard that specifies requirements for controlled safety pressure relief systems (CSPRS) regardless of the fluid handled. It applies to main valves with a flow diameter ≥ 4 mm and for use at pressures ≥ 0.1 bar gauge (no temperature limitation). This standard covers the design, production testing, type testing, performance determination, sizing, marking and sealing of CSPRS. It is a product standard (not an application/installation standard).
Key topics and technical requirements
- Scope and applicability: CSPRS for all fluids; main valve size and minimum pressure thresholds are specified (4 mm and 0.1 bar gauge).
- Definitions and principles: Clear terms for CSPRS, main valve, relieving principle (valve opens when operating force is released) and loading principle (valve opens when operating force is applied).
- Design requirements: Materials, valve end connections and minimum spring requirements are addressed (see clauses on design).
- Production testing: Mandatory hydrostatic and pneumatic tests, seat leakage, pressure seals and adjustment/verification of set pressures during manufacture.
- Type testing and certification: Tests to determine operating and flow characteristics, coefficient of discharge and certification procedures.
- Performance, sizing and marking: Procedures for determining CSPRS performance, sizing methods, plus marking and sealing requirements for traceability and conformity.
- Regulatory linkage: Annex ZA identifies how this standard relates to the EU Pressure Equipment Directive (PED), offering a route to presumption of conformity within the standard’s scope.
Applications and who uses it
EN ISO 4126-5:2013 is intended for:
- Pressure-relief valve and CSPRS manufacturers (design, production and testing)
- Valve and system design engineers specifying CSPRS for equipment and systems
- Safety and compliance engineers preparing documentation for conformity assessment
- Testing laboratories and certifiers performing type and production tests
- Procurement and quality teams ensuring products meet standardized marking/sealing and certification requirements
Typical practical uses: specifying CSPRS components, verifying discharge capacity and operating characteristics, manufacturing quality control, and supplying evidence for conformity with PED-related requirements.
Related standards
- ISO 4126 series (other parts include Part 1 Safety valves, Part 2 Bursting discs, Part 4 Pilot operated valves, Part 7 Common data, etc.)
- Normative reference within the document: ISO 4126-7:2013 (Common data)
Keywords: EN ISO 4126-5:2013, CSPRS, controlled safety pressure relief systems, safety valves, pressure protection, pressure safety devices, PED compliance, industrial valves.
