ISO 22734-1:2025 PDF

Overview

ISO 22734-1:2025 - Hydrogen generators using water electrolysis - Part 1: Safety specifies safety requirements for appliances and systems that produce hydrogen by electrochemical water electrolysis. The standard covers generator-level safety for hydrogen and oxygen handling, electrochemical cells and stacks, mechanical and electrical equipment, control and safety systems, enclosure design, and required tests and markings. It applies to hydrogen generators using applicable ion-transport media and defines how the safety provisions relate to different sizes and subassemblies (see clauses on applicability and exclusions).

Key topics and requirements

The standard focuses on practical safety controls across these technical areas:

• Operating conditions
  • Energy input, feed water quality, ambient environment, protective gas, hydrogen/oxygen delivery and venting.
• Risk management
  • Hazard identification and mitigation for fire/explosion, pressure, temperature, spillage/overflow and personnel protection.
• Chemical reaction equipment
  • Requirements for electrochemical cells/stacks, oxygen/hydrogen catalytic reactors, and gas drying systems.
• Mechanical requirements
  • Materials selection, pressure-bearing components, pressure relief devices, fans/ventilation and heat transfer systems.
• Electrical equipment & wiring
  • Grounding/bonding, overcurrent protection, heaters, power conversion and hazardous-area considerations.
• Control systems
  • Safety control circuits, programmable electronics, start/stop and emergency-stop functions, alarms, remote control, and failure-mode behavior.
• Enclosure and containment
  • Strength, ingress protection, fire resistance, ventilation openings and containment of hazardous liquid leakage.
• Testing and verification
  • Type (qualification) tests and routine tests including electrical, pressure, leakage, dilution, fire-spread, temperature, environmental and combustible gas mixture safety tests.
• Marking and documentation
  • Requirements for labelling, instructions and conformity evidence.

Applications and who should use it

ISO 22734-1:2025 is essential for:

• Manufacturers and designers of hydrogen generators and electrolyser systems
• System integrators and OEMs producing on-site hydrogen solutions
• Safety and compliance engineers preparing risk assessments and technical documentation
• Test laboratories and certification bodies conducting type and routine testing
• Facility owners, operators, and maintenance personnel implementing safe installation, operation and service procedures
• Regulators and procurement teams specifying safety requirements in tenders

Typical use cases include on-site hydrogen production for industrial processes, research labs, fuel-cell refuelling stations and distributed energy applications where safety of hydrogen and oxygen handling is critical.

Related standards

This document is Part 1 (Safety) of the ISO 22734 series. Users should consult related parts, national regulations, and standards on hydrogen safety, pressure equipment, electrical installations and gas detection for complete compliance.