Overview
EN ISO 20421-2:2017 - "Cryogenic vessels - Large transportable vacuum-insulated vessels - Part 2: Operational requirements" is a CEN-endorsed ISO standard that specifies operational requirements for large transportable, vacuum‑insulated cryogenic vessels. It covers safe use from initial putting into service through filling, product withdrawal, transport within a site, storage, maintenance, periodic inspection and emergency procedures. For public road, rail, waterway, sea and air transport, additional regulatory requirements may apply.
Key topics and requirements
This standard focuses on practical operational controls and safety measures. Major topics include:
- Preliminaries before putting into service
- Marking and labelling, handover documentation and initial checks.
- Personnel and training
- Competence and training requirements for personnel handling cryogenic vessels.
- General safety and site measures
- Safety considerations for location, storage and on-site transport.
- Putting into service and taking out of service
- Procedures for commissioning and decommissioning vessels.
- Filling and withdrawal
- Prefill checks, preparation steps, after-fill checks and safe withdrawal practices.
- Transport within a location
- Safe movement and securing of vessels inside plants or facilities.
- Maintenance, repair and periodic inspection
- Planned maintenance, documented repairs and intervals/requirements for inspections.
- Change of service
- Requirements when changing the cryogenic product or service conditions.
- Emergency procedures
- Required emergency equipment and response processes, including special provisions for flammable gases (electrical equipment, grounding, emergency response).
The document aligns operational procedures with the design/fabrication guidance found in ISO 20421-1 and supports compliance with UN Recommendations on the Transport of Dangerous Goods where applicable.
Applications and who uses it
EN ISO 20421-2:2017 is intended for organizations involved in the lifecycle of large transportable cryogenic vessels, including:
- Vessel manufacturers and suppliers (for handover and marking requirements)
- Plant operators and end-users (for safe operation, filling and withdrawal)
- Maintenance teams and service contractors (for inspection and repair procedures)
- Safety managers and compliance officers (for emergency planning and regulatory alignment)
- Transport coordinators for on-site movement and storage
Use cases include bulk delivery and dispensation of industrial gases (e.g., oxygen, nitrogen, argon, hydrogen), site storage and temporary distribution using vacuum-insulated tanks.
Related standards
- ISO 20421-1 - Design, fabrication, inspection and testing of large transportable vacuum-insulated cryogenic vessels.
- EN 13530-3:2002 - Superseded by EN ISO 20421-2:2017 (historical reference).
- UN Recommendations on the Transport of Dangerous Goods - for public transport regulatory requirements.
EN ISO 20421-2:2017 is essential for ensuring safe, compliant operations of large transportable cryogenic vessels and for integrating operational practices with applicable design and transport regulations.
