BS EN ISO 22734-1:2025

1.1 General

This document specifies the safety requirements of hydrogen gas generation appliances or systems that use electrochemical reactions to electrolyse water to produce hydrogen, herein referred to as hydrogen generators.

1.2 Applicable hydrogen generators

This document is applicable to:

• hydrogen generator appliances or systems (containerised, or skid mounted, complete hydrogen generation systems);

• factory-matched modules (supplied by the same manufacturer) that, when connected together, form a complete hydrogen generation system;

• hydrogen generators intended for industrial, commercial and residential applications;

• hydrogen generators intended for indoor or outdoor environments.

NOTE When this document is applied to hydrogen gas generation appliances or systems intended for installation into buildings, additional requirements for the design of the building are likely to apply. These building requirements are not addressed in this document. Additionally, the hydrogen generator enclosure requirements in this document do not necessarily translate to requirements for a building.

Guidance for hydrogen generators that also provide oxygen used for industrial and commercial applications is provided in this document, however additional considerations can apply.

1.3 Applicable ion transport mediums

This document is applicable to hydrogen generators that use the following types of ion transport medium:

• aqueous alkaline (basic) electrolytes, such as solutions of potassium hydroxide or sodium hydroxide;

• aqueous acidic electrolytes, such as dilute sulphuric acid;

• solid polymeric materials with acidic function group additions, such as acid proton exchange membrane (PEM);

• solid polymeric materials with basic function group additions, such as anion exchange membrane (AEM).

1.4 Applicability to large scale hydrogen generators

This document is applicable to large scale hydrogen generators assembled on site.

NOTE 1 Large scale water electrolysis systems typically have a production rate of 100 kg/hour or more and can be assembled using modules or equipment from various manufacturers.

NOTE 2 Building requirements are not addressed in this document and the hydrogen generator enclosure requirements in this document do not necessarily translate to requirements for a building.

1.5 Applicability to certain hydrogen generator subassemblies

This document is applicable to:

• electrochemical cell stacks (as stand-alone products);

• modules (sub-systems) for integration into larger hydrogen generation systems.

In such cases, the entirety of this document will not be applicable, and the specific sections relevant to the product are established in order to develop a product conformance strategy.

1.6 Excluded hydrogen generators

This document is not applicable to the following:

• residential hydrogen generators that also supply oxygen as a product;

• hydrogen generators that can also be used to generate electricity, such as reversible fuel cells (refer to IEC 62282‑8‑101, IEC 62282‑8‑102 and IEC 62282‑8‑201);

• hydrogen generators that use solid oxide electrolyte (refer to IEC 62282‑8‑101 and IEC 62282‑8‑201).