Standardization and quality control of hydrogen in dedicated gas networks: European and international practices

STANDARDIZATION AND QUALITY CONTROL OF HYDROGEN IN DEDICATED GAS NETWORKS: EUROPEAN AND INTERNATIONAL PRACTICES 

ABSTRACT. This report presents an analysis of the development of the hydrogen economy, which is considered a key element of the energy transition toward a low-carbon energy system. The widespread integration of hydrogen into energy infrastructure requires the development and implementation of reliable technical standards to ensure safety, interoperability, and effective control of gas quality. The report provides an overview of existing standardisation activities in Europe and at the international level, with a focus on hydrogen networks and the quality of gaseous hydrogen. The main topics addressed include leak detection and emission monitoring, hydrogen odorisation (including the use of sulfur-free odorants), safety and explosion prevention, hydrogen purification systems, as well as gas quality parameters. Based on the analysis, conclusions are drawn regarding existing gaps and priority directions for the future development of standardisation in the field of hydrogen technologies. 

Keywords: hydrogen, infrastructure, standardisation, safety, leakage detection 

Introduction 

Technical standards provide the foundation for the design, construction, operation and maintenance of engineering systems. They establish requirements for products, materials and processes, as well as responsibilities of infrastructure operators, with the aim of ensuring functionality, interoperability and safety. Standards are particularly important for integrating hydrogen into the European energy system because of the specific properties of H₂, including its high diffusivity, wide flammability range and low ignition energy. 

In this review, the term “grid” refers to a pipeline system conveying hydrogen to end-use applications or downstream systems, including underground hydrogen storage. The analysis focuses on standardisation activities within CEN, CENELEC, ISO, IEC and national standardisation bodies. 

Standardisation framework and types of deliverables 

Standardisation deliverables are developed by expert groups comprising system operators, manufacturers, end-users, public authorities, industry associations and scientific and technical organisations. At European and international levels, CEN/CENELEC and ISO/IEC play central roles. 

The principal types of standardisation deliverables include European Standards (EN), adopted at national level; Technical Specifications (TS), which may address subjects for which full standardisation is not yet sufficiently mature; Technical Reports (TR), which provide informative technical material; and CEN Workshop Agreements (CWA), which facilitate stakeholder and industry consensus. 

International cooperation is supported by the Vienna Agreement (CEN–ISO) and the Frankfurt Agreement (CENELEC–IEC), which provide mechanisms for parallel standards development and voting, and for adopting international standards as European standards. 

Key standardisation topics for hydrogen grids 

In practice, the principal topics affecting the safety and interoperability of hydrogen grids include: 

Hydrogen leakage detection and emissions monitoring. 

Hydrogen odorisation, including sulfur-free odorants, and leakage detection with and without odorisation. 

Safety protocols and technical solutions for ignition and explosion prevention. 

Hydrogen purification systems and impurity control. 

Hydrogen quality parameters for grid operation and end-use applications. 

Leakage detection and monitoring related to emissions 

Leakage detection and emissions monitoring are essential both for safety and for environmental reporting (Table 1). Depending on system scale, bottom-up approaches (local measurements and inspections) and top-down approaches (aggregate measurement methods for extensive grids and storage facilities) may be applied. Within safety management systems, these activities should be integrated into operational procedures and maintenance plans. 

Table 1. Identified standards relating to leakage detection and monitoring of emissions 

Leakage detection with and without odorisation; sulfur-free odorants 

Odorisation is an established safety measure in gas networks. For hydrogen, conventional sulfur-containing odorants used in natural gas systems may be unsuitable for some applications, particularly fuel cells and sensitive catalytic processes. This has encouraged the development of sulfur-free odorants and selection criteria covering chemical stability, material compatibility, effects on purification and reliable human odour perception. 

Table 2. Identified standards relating to leakage detection and monitoring 

Safety and explosion prevention 

Given hydrogen’s low ignition energy and wide flammability range, risk management should combine engineering safeguards (gas detection, automatic isolation valves and ventilation), procedural measures (inspection and maintenance) and standardised methods for hazardous-area classification and equipment selection (Tables 3 and 4). 

Table 3. Standards relating to safety protocols 

Table 4. Standards for technical solutions for explosion prevention and management 

Hydrogen purification systems 

Produced hydrogen may contain impurities such as H₂O, O₂, N₂, CO, CO₂, CH₄ and traces of sulfur compounds. Controlling these impurities is critical to the reliability of infrastructure and downstream applications. Standardised purity specifications and analytical methods are therefore required (Tables 5 and 6). 

Table 5. Identified standards for hydrogen quality parameters 

Table 6. Identified standards for hydrogen quality control and monitoring 

Hydrogen quality parameters for use in grids 

Hydrogen quality parameters for grids should reflect infrastructure compatibility and downstream application requirements. Standards specify permissible impurity levels, sampling procedures, measurement methods and monitoring requirements. 

At present, most existing hydrogen quality standards are application-oriented. A dedicated European or international standard defining gaseous hydrogen quality throughout dedicated hydrogen grids has not yet been established in the framework examined by the source report. 

At international level, ISO 14687:2025 is a key reference. The following Type I grades are identified: 

Type I, Grade A (98% purity): residential and commercial combustion appliances. 

Type I, Grade B (99.90% purity): industrial fuel applications. 

Type I, Grade C (99.995% purity): aerospace PEM fuel-cell applications. 

Type I, Grade D (99.97% purity): PEM fuel cells for road vehicles. 

Type I, Grade E: stationary PEM fuel-cell applications. 

Type I, Grade F: hydrogen internal combustion engine applications. 

Identification of standardisation needs 

The analysis confirms the need for a new gaseous hydrogen quality standard for dedicated hydrogen grids, covering hydrogen entering the grid from production facilities or terminals and hydrogen delivered at grid exit points to connected applications. 

In view of the emerging European hydrogen network, the development of a single hydrogen quality standard for gaseous hydrogen grids is recommended, irrespective of grid type. CEN/TS 17977 on repurposed gas systems should be linked to the proposed new standard. 

The need for new or adapted standards for hydrogen quality control and monitoring warrants further detailed analysis. 

Conclusion 

Existing standards provide a valuable basis, but a substantial proportion originate in the natural gas sector. Hydrogen requires specific provisions for leakage and emissions monitoring, selection criteria and test methods for sulfur-free odorants, and harmonised approaches to gas quality control. Priority should be given to standardised hydrogen leakage measurement methods and their integration into safety management systems. 

References 

ISO 14064-1:2019. Greenhouse gases — Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals. 

ISO/TS 19870:2023. Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the production, conditioning and transport of hydrogen to consumption gate. 

ISO 19880-1:2020. Gaseous hydrogen — Fuelling stations — Part 1: General requirements. 

ISO 24367:2023. Non-destructive testing — Acoustic emission testing — Metallic pressure equipment. 

EN 13306. Maintenance — Maintenance terminology. 

Regulation (EU) No 1025/2012 on European standardisation. 

HyQUAL NET. Deliverable D3.1: Report on existing standardisation activities in Europe and internationally — Interim report, December 2025.