ISO 21013-2:2025

Overview

ISO 21013-2:2025 defines international requirements for the design, manufacture, and testing of non-reclosable pressure-relief devices intended for cryogenic vessels. This standard specifically addresses bursting-disc and buckling-pin devices used in cryogenic service, operating with cryogenic fluids and under temperatures ranging from ambient to cryogenic levels. The devices covered have a nominal diameter (DN) up to 200 and are designed to safely relieve single-phase vapors or gases by preventing overpressure in cryogenic systems without the capability of resealing after activation.

This document is critical for manufacturers, engineers, and safety professionals involved in designing and maintaining pressure-relief accessories within cryogenic applications.

Key Topics

• Scope and Application
  The standard focuses on non-reclosable pressure-relief devices such as bursting discs and buckling pins to ensure safety when relieving gases or vapors in cryogenic vessels.

• Design Requirements

  • Rated minimum and maximum temperatures are established based on the coldest fluid and typically a max of +65 °C unless otherwise specified.
  • Coincident temperatures are specified for normal and fire conditions to assure device reliability under different environmental scenarios.
  • Design considerations are given to prevent blockage from sublimating fluids (e.g., CO2) and to control insert materials to avoid failure due to cold flow.

• Materials and Compatibility

  • Materials must be compatible with cryogenic fluids and oxygen service per ISO 21010, ensuring safety and corrosion resistance.
  • Metallic materials must meet toughness requirements at cryogenic temperatures as described in ISO 21028-1 & ISO 21028-2.
  • Non-metallic materials must withstand mechanical stress, weathering, and be appropriate for cryogenic use.
  • Corrosion resistance is emphasized due to low temperatures and high humidity in cryogenic environments.

• Testing and Certification

  • Type approval involves passing mechanical and pressure tests outlined in ISO 4126-2, including burst pressure and operational reliability.
  • Production testing ensures leak tightness using methods like helium mass spectrometry or pneumatic submergence tests.
  • Visual inspection confirms device assembly and compliance to prevent substitution or improper installation.

• Marking and Traceability
  Devices must be clearly marked for identification, including burst pressure and size, to aid in maintenance and verification.

Applications

ISO 21013-2:2025 is essential for industries dealing with cryogenic storage and transportation, including:

• Liquefied Gas Storage: For safely relieving pressure in liquid nitrogen, oxygen, argon, and other industrial gases stored at low temperatures.
• Transport Tanks and Vessels: Ensuring safe overpressure relief in cryogenic tankers and portable containers during transport.
• Petrochemical and Chemical Plants: Where cryogenic fluids are used or produced, reliable safety accessories prevent overpressure incidents.
• Medical and Research Facilities: Handling cryogenic gases such as liquid helium in MRI machines or laboratory equipment requires certified pressure relief devices.

Adopting this standard enhances safety protocols, equipment reliability, and regulatory compliance across sectors handling cryogenic fluids.

Related Standards

• ISO 21013-1: Specifies general requirements for pressure-relief accessories on cryogenic vessels, complementing the non-reclosable devices covered in Part 2.
• ISO 21013-3: Provides methods for determining capacity and sizing of bursting-disc and buckling-pin devices for cryogenic vessels.
• ISO 4126-2: Defines general safety requirements for bursting disc safety devices, used as a normative reference in ISO 21013-2.
• ISO 21010: Focuses on gas/material compatibility specifically for cryogenic vessels, ensuring materials used in pressure-relief devices are appropriate.
• ISO 21028-1 & ISO 21028-2: Define toughness requirements for materials at cryogenic temperatures, critical for selecting materials of pressure-relief devices.
• ISO 23208: Covers cleanliness requirements essential for cryogenic service to prevent contamination and malfunction.

Conclusion

ISO 21013-2:2025 plays a pivotal role in ensuring the safe design and reliable performance of non-reclosable pressure-relief devices in cryogenic systems. By observing stringent material, design, and testing criteria, this standard safeguards critical infrastructure from overpressure hazards in environments dealing with extremely low temperatures and volatile gases. Implementation of this standard benefits manufacturers and end-users by enhancing operational safety and compliance in cryogenic industries worldwide.