Overview
EN ISO 22734-1:2025 - Hydrogen generators using water electrolysis - Part 1: Safety is a CEN-adopted international standard that specifies the safety requirements for hydrogen gas generation appliances and systems that produce hydrogen by electrolysing water. Published July 2025 and prepared by ISO/TC 197 in cooperation with CEN-CENELEC JTC 6, the standard applies to hydrogen generators using electrochemical reactions and covers applicable ion-transport media, operating conditions and limits, and applicability to different sizes and subassemblies.
Key topics and technical requirements
The standard organizes safety requirements across equipment, operation and control. Major technical topics include:
- Operating conditions
- Energy input and feed water specifications
- Ambient environment, protective gas, hydrogen and oxygen delivery and venting
- Risk management
- Hazard identification, fire and explosion protection, pressure and temperature safety
- Spillage, overflow, drainage and protection for service/maintenance personnel
- Chemical reaction equipment
- Requirements for electrochemical cells and stacks, catalytic reactors (oxygen/hydrogen removal), and gas drying systems
- Mechanical equipment
- Materials selection, pressure-bearing components, pressure relief devices, fans/ventilators, heat transfer systems
- Electrical equipment and wiring
- Grounding/bonding, overcurrent protection, power conversion, heating elements
- Control systems
- Safety control circuits, failure-mode behavior, programmable electronic equipment, emergency stop, alarms, remote control, and interconnection safeguards
- Enclosure requirements
- Structural strength, ingress protection, fire resistance and thermal insulation
The standard also contains normative references, terms and definitions and detailed clauses for design, commissioning, operation and maintenance safety controls.
Applications and who should use it
EN ISO 22734-1:2025 is essential for:
- Manufacturers and designers of on‑site and packaged hydrogen generators using water electrolysis
- System integrators and EPC contractors who install electrolysis-based hydrogen systems
- Safety engineers, inspectors and certification bodies assessing compliance with hydrogen safety requirements
- Facility managers and operators responsible for hydrogen production in industrial, laboratory, energy storage or refuelling applications
- Regulators and procurement teams specifying safe hydrogen generation equipment
Use of this standard helps reduce fire/explosion risk, ensures safe pressure and electrical design, and supports conformity assessment and regulatory compliance in EU member states and other adopting organizations.
Related standards
EN ISO 22734-1:2025 includes normative references and should be used alongside applicable national/EU pressure, electrical and industrial gas regulations. For program-level alignment, consult documents from ISO/TC 197 and CEN-CENELEC JTC 6 and relevant standards on gas handling, pressure equipment and electrical safety.