ISO 28921-2:2015

Overview

ISO 28921-2:2015 - Industrial valves - Isolating valves for low-temperature applications - Part 2: Type testing - specifies requirements for type testing isolating valves to verify performance at low temperatures from −50 °C down to −196 °C. The standard defines test procedures, safety provisions and instrumentation needed to confirm valve integrity and operability in low-temperature service. It does not evaluate valve actuators unless they are an integral part of the valve, and it excludes valves designed specifically for cryogenic vessels under ISO 21011.

Key topics and requirements

• Scope of testing: Type testing to demonstrate performance across a temperature range from −50 °C to −196 °C.
• Valve selection: Test a randomly selected production valve representative of a design family; choose a mid-range size to qualify the family.
• Operational cycles: 200 cycles for on-off valves; 3 cycles for check valves.
• Pre-test checks: Valves must be clean and free of water, oils and lubricants (ISO 23208 can guide cleaning). Shell and seat tests follow ISO 5208 (shell test pressure 1.1 × CWP with gas or 1.5 × CWP with liquid/alcohol; seat test pressure ~6 ± 1 bar).
• Cooling and test media: Cooling by liquid nitrogen, nitrogen gas, dry ice with heat-transfer fluid, or other agreed media. Test gas options include nitrogen + 10% helium for temperatures ≥ −110 °C, and ≥97% helium for temperatures down to −196 °C.
• Instrumentation and setup: Use insulated tanks, blind flanges, support brackets and thermocouples (minimum: bonnet area and inside valve plus cooling medium). Continuous temperature and pressure monitoring is required.
• Safety: Emphasizes trained personnel, barriers or protected test areas and remote observation due to hazards of cryogenic testing.
• Documentation: Test procedure in Annex A and a low-temperature type test record example in Annex C.

Applications and users

Who uses ISO 28921-2:2015:

• Valve manufacturers conducting type qualification for low-temperature service
• Independent test laboratories and inspection bodies performing certification tests
• Specifiers, purchasers and end-users (e.g., process plants handling industrial gases, LNG-related piping and low-temperature services) requiring validated valve performance at sub-ambient temperatures
• Engineering and QA teams writing procurement specifications and compliance documentation

Practical value:

• Provides repeatable, auditable type-test methods to reduce risk of valve failure in low-temperature service and to support purchasing and certification decisions.

Related standards

• ISO 28921-1 (Design, manufacturing and production testing)
• ISO 5208 (Pressure testing of metallic valves)
• ISO 21011 (Cryogenic valves for cryogenic vessels - excluded scope)
• ISO 23208 (Valve cleaning guidance)
• ASME B31.3, EN 13480-2 (related piping/materials guidance)

Keywords: ISO 28921-2:2015, isolating valves, low-temperature testing, type testing, −196 °C, valve test procedure, cryogenic valve testing, valve qualification.