SIST-TS CEN/TS 18173:2026
(Main)Hydrogen applications - Material compatibility evaluation and qualification - Equipment used in commercial, industrial installations including gas burners, gas burning appliances and fuel gas infrastructures
Hydrogen applications - Material compatibility evaluation and qualification - Equipment used in commercial, industrial installations including gas burners, gas burning appliances and fuel gas infrastructures
This document provides guidance to relevant product standards, for compatibility assessment and qualification of materials for equipment used in commercial, industrial installations including gas burners, gas burning appliances and fuel gas infrastructures that are:
— fed by admixture of natural gas and hydrogen (blending) or pure hydrogen;
— operated at pressure greater than 10 bar (1 MPa) and up to 100 bar (10 MPa);
—operated within a temperature range of −20° C to +60 °C;
NOTE 1 Temperature range outside of −20° to +60°C can be considered after risk assessment by the manufacturer, in compliance with relevant product standard and the requirements specified in this document.
Except for critical equipment, where hydrogen requirements and material compatibility are defined by relevant specific, national and international product standard, according to CEN/TR 17924 and CEN/TR 17797, no specific requirements are necessary, as detailed in this document (see also Figure 1), under the following conditions:
— for a homogeneous mixture of natural gas and hydrogen with a hydrogen content not exceeding 10 % by volume, at operating pressures up to 100 bar (10 MPa); or
— for operating pressures up to 10 bar (1 MPa) with a hydrogen content up to 100 % by volume.
— Equipment is classified as critical when it’s subjected to fatigue or specific mechanical stress due to specific operating conditions and applications (i.e. compression and pumping station, specific industrial installations, fuel tanks for vehicles, …).
Figure 1 — Operating conditions
This document represents minimum requirements and does not restrict the use of better procedures or materials.
The following items are detailed in this document:
— metallic materials;
— non-metallic materials;
— validation tests.
H2-Readiness von Gas-Infrastrukturen– Anforderungen und Prüfverfahren für die Materialeignung von Ausrüstung
Dieses Dokument enthält eine Anleitung zu relevanten Produktnormen, für die Beurteilung der Kompatibilität und der Qualifikation von Materialien für Ausrüstung zur Anwendung in gewerblichen und industriellen Anlagen einschließlich Gasbrennern, Gasverbrennungsanlagen und Brenngasinfrastrukturen, die:
- mit einer Mischung aus Erdgas und Wasserstoff (Mischung) oder reinem Wasserstoff gespeist werden;
- mit einem Druck von mehr als 10bar (1MPa) und bis zu 100bar (10Mpa) betrieben werden;
- innerhalb eines Temperaturbereichs von −20°C bis +60°C betrieben werden;
ANMERKUNG Temperaturbereiche außerhalb von −20°C bis +60°C können nach einer Risikobeurteilung durch den Hersteller entsprechend der relevanten Produktnorm und den in diesem Dokument festgelegten Anforderungen berücksichtigt werden.
Mit Ausnahme von kritischer Ausrüstung, wo Anforderungen an Wasserstoff und die Material-Kompatibilität durch relevante nationale und internationale Produktnormen nach CEN/TR17924 und CEN/TR17797 definiert sind, sind keine besonderen Anforderungen erforderlich, wie in diesem Dokument beschrieben (siehe auch Bild1) unter den folgenden Bedingungen:
- für eine homogene Mischung aus Erdgas und Wasserstoff mit einem Wasserstoffgehalt von nicht mehr als 10% nach Volumen, ein Betriebsdruck von bis zu 100bar (10Mpa) oder
- für Betriebsdrücke bis zu 10bar (1Mpa) mit einem Wasserstoffgehalt von bis zu 100% nach Volumen.
- Ausrüstung wird als kritisch klassifiziert, wenn sie Ermüdung oder spezifischer mechanischer Beanspru
chung durch bestimmte Betriebsbedingungen und Anwendungen ausgesetzt ist (d.h. Druck- und Pumpstationen, spezifische industrielle Anlagen, Kraftstofftanks für Fahrzeuge usw.).
Uporaba vodika - Vrednotenje primernosti materialov in kvalifikacija - Oprema, ki se uporablja v komercialnih in industrijskih napeljavah, vključno s plinskimi gorilniki, plinskimi napravami in plinsko infrastrukturo
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 18173:2025
01-maj-2025
Uporaba vodika - Vrednotenje in kvalifikacija združljivosti materialov - Oprema, ki
se uporablja v komercialnih in industrijskih napeljavah, vključno s plinskimi
gorilniki, plinskimi napravami in infrastrukturo za plin kot gorivo
Hydrogen applications - Material compatibility evaluation and qualification - Equipment
used in commercial, industrial installations including gas burners, gas burning appliances
and fuel gas infrastructures
H2-Readiness von Gas-Infrastrukturen– Anforderungen und Prüfverfahren für die
Materialeignung von Ausrüstung
Ta slovenski standard je istoveten z: FprCEN/TS 18173
ICS:
27.075 Tehnologija vodika Hydrogen technologies
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
kSIST-TS FprCEN/TS 18173:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
kSIST-TS FprCEN/TS 18173:2025
kSIST-TS FprCEN/TS 18173:2025
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 18173
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
April 2025
ICS 27.075; 75.180.01
English Version
Hydrogen applications - Material compatibility evaluation
and qualification - Equipment used in commercial,
industrial installations including gas burners, gas burning
appliances and fuel gas infrastructures
This draft Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee
CEN/TC 235.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a Technical Specification. It is distributed for review and comments. It is subject to change
without notice and shall not be referred to as a Technical Specification.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 18173:2025 E
worldwide for CEN national Members.
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FprCEN/TS 18173:2025(E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 8
3 Terms and definitions . 8
4 General Requirements . 8
5 Metallic materials . 9
5.1 General consideration . 9
5.2 Metalworking critical processes . 9
5.2.1 General. 9
5.2.2 Hot working . 9
5.2.3 Cold working . 10
5.3 Types . 10
5.3.1 Carbon steels . 10
5.3.2 Stainless steels . 10
5.3.3 Aluminium alloys . 11
5.3.4 Copper alloys . 11
5.3.5 Zinc alloys . 11
5.3.6 Nickel alloys . 11
5.3.7 Spheroidal graphite cast iron . 11
5.4 Specific applications . 11
5.4.1 Springs . 11
5.4.2 Nut and bolting . 12
6 Non-metallic materials . 12
6.1 General. 12
6.2 Elastomeric materials . 12
6.2.1 General requirements . 12
6.2.2 Specific requirements for diaphragm . 12
6.3 Non-metallic materials other than elastomers . 12
6.2.1 General. 12
6.2.2 Lubricants and adhesives . 13
7 Tests . 13
7.1 Metallic materials qualification . 13
7.1.1 Specimen . 13
7.1.2 Tests . 13
7.1.3 Testing Conditions (medium, pressure and temperature) . 14
7.1.4 Test tolerances . 15
7.1.5 Test Procedure . 15
7.1.6 Acceptance criteria and Material Qualification . 16
7.1.7 Test Report . 17
7.2 Elastomeric materials qualification . 17
7.2.1 General. 17
7.2.2 Specimens . 17
7.2.3 Test medium . 17
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7.2.4 Test temperatures . 17
7.2.5 Test procedure . 18
7.2.6 Acceptance criteria . 18
Annex A (normative) Fatigue validation test method . 19
Bibliography . 22
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FprCEN/TS 18173:2025(E)
European foreword
This document (FprCEN/TS 18173:2025) has been prepared by Technical Committee CEN/TC 235 “Gas
pressure regulators and associated safety devices for use in gas transmission and distribution”, the
secretariat of which is held by UNI.
This document is currently submitted to the Vote on TS.
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FprCEN/TS 18173:2025 (E)
Introduction
This document is the first edition and reflects the current situation. This can be taken into account in
further development of the document.
The criteria provided in this document for the qualification of materials represent the best knowledge
and judgment available at the time of this release, drawing from technical literature and standards related
to materials for hydrogen applications.
kSIST-TS FprCEN/TS 18173:2025
FprCEN/TS 18173:2025(E)
1 Scope
This document provides guidance to relevant product standards, for compatibility assessment and
qualification of materials for equipment used in commercial, industrial installations including gas
burners, gas burning appliances and fuel gas infrastructures that are:
— fed by admixture of natural gas and hydrogen (blending) or pure hydrogen;
— operated at pressure greater than 10 bar (1 MPa) and up to 100 bar (10 MPa);
—operated within a temperature range of −20° C to +60 °C;
NOTE 1 Temperature range outside of −20° to +60°C can be considered after risk assessment by the
manufacturer, in compliance with relevant product standard and the requirements specified in this document.
Except for critical equipment, where hydrogen requirements and material compatibility are defined by
relevant specific, national and international product standard, according to CEN/TR 17924 and CEN/TR
17797, no specific requirements are necessary, as detailed in this document (see also Figure 1), under
the following conditions:
— for a homogeneous mixture of natural gas and hydrogen with a hydrogen content not exceeding 10 %
by volume, at operating pressures up to 100 bar (10 MPa); or
— for operating pressures up to 10 bar (1 MPa) with a hydrogen content up to 100 % by volume.
— Equipment is classified as critical when it’s subjected to fatigue or specific mechanical stress due to
specific operating conditions and applications (i.e. compression and pumping station, specific
industrial installations, fuel tanks for vehicles, …).
For information regarding the compatibility of materials used in Gas Appliances, refer to CEN/TR 17924. For gas
infrastructure, see CEN/TR 17797.
kSIST-TS FprCEN/TS 18173:2025
FprCEN/TS 18173:2025 (E)
Key
H2 hydrogen content, expressed in percentage by volume (vol %)
P operating pressure, expressed in bar (bar)
specific requirements are needed
no specific requirements are needed
Figure 1 — Operating conditions
This document represents minimum requirements and does not restrict the use of better procedures or
materials.
The following items are detailed in this document:
— metallic materials;
— non-metallic materials;
— validation tests.
kSIST-TS FprCEN/TS 18173:2025
FprCEN/TS 18173:2025(E)
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 6892-1, Metallic materials. Tensile testing - Method of test at room temperature(ISO 6892-1)
EN ISO 23936-2:2011, Petroleum, petrochemical and natural gas industries - Non-metallic materials in
contact with media related to oil and gas production - Part 2: Elastomers(ISO 23936-2:2011)
ISO 2782-1, Rubber, vulcanized or thermoplastic – Determination of permeability to gases – Part 1:
Differential-pressure method
ISO 16573-1, Steel - Measurement method for the evaluation of hydrogen embrittlement resistance of high
strength steels
ASME B31.12:2023, Hydrogen Piping and Pipelines
3 Terms and definitions
No terms and definitions are listed in this document.
4 General Requirements
Materials are deemed acceptable if they:
— are recognized as suitable by national or international standards or,
— fulfil the requirements of clause 5 and 6 or,
— are qualified according to tests described in clause 7 and Annex A when specific attention to fracture
toughness and hydrogen embrittlement resistance is required, or;
— are deemed suitable according to published technical literature under the Manufacturer’s
responsibility.
Materials that are not critical to safety and equipment functionality can be used without further
assessment, based on the manufacturer's risk evaluation.
The non-critical equipment’ requirements in this document are based on the following assumptions:
— Vibrations are not relevant: external and internal vibrations are prevented through appropriate
supports and gas velocity restrictions;
— Gas stratification is not relevant: phenomena related to gas density differences and the admixture’s
static state, leading to stratification and subsequent localized hydrogen buildup, are not considered;
including ASME B31.12 and ASME B31.8 for pipeline under high-pressure or pure hydrogen environments.
Reliable technical literature is supported by a solid and rigorous methodology. Research is conducted using valid
and reliable scientific methods. The presence of data, experimental results, detailed analysis and quotes from other
authoritative sources contribute to credibility. Academic and Peer-Reviewed Sources: Trusted technical literature
comes from academic sources such as scientific journals, academic conferences and publications from recognized
institutions. In particular, peer-reviewed publications are subjected to a rigorous review process by industry
experts before publication, ensuring a certain level of quality and accuracy.
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4,5
— Fatigue stress is not relevant as equipment is not concerned by cycling stress from temperature
and pressure when pressure variation frequency < 0.00005 Hz at pressure fluctuations lower than
7,8
2.0 Mpa, considering MOP = 10.0 MPa and service life of 40 years .
For different working condition a calculation of maximum frequency shall be done.
However, in the specific condition where the fatigue definitions are applicable in structures subjected to
cyclic stress, (engineering evaluation on a case-by-case basis), the impact of the hydrogen-pressure on
crack growth (da/dN) due to dynamic mean stress (R-value) can be disregarded if the cyclic stress
0.5 9
intensity ΔK < 6.5 MPa m for materials outlined in the DVGW research project SyWeSt H2 . If this
condition is not met, or if the materials are used in critical systems, specimens and corresponding tests
shall be carried out as specified in Annex A or relevant specific, national and international product
standard that includes hydrogen requirements.
5 Metallic materials
5.1 General consideration
The requirements of this clause apply to the metallic materials of parts that are under pressure and in
contact with gas.
5.2 Metalworking critical processes
5.2.1 General
Processes categorized as critical, such as hot and cold working, induce localized residual stress in the
metal's microscopic structure as a result of the plastic deformation of the material.
5.2.2 Hot working
Operations like welding and surface treatments generate localized residual tensile stresses, potentially
affecting the elastic properties of the metals. These processes typically increase hardness but reduce
ductility. Appropriate heat treatments can mitigate the residual tensile stress.
Post Weld Heat Treatment (PWHT) for all pressurized, gas-wetted welded parts shall be performed in
line with the relevant design code and approved WPS/WPQR.
For PWHT requirements, make reference to ASME B 31.12 – GR-3 regulation.
C. San Marchi - B.P. Somerday, SAND2012-7321 - September 2012, Technical Reference for Hydrogen
Compatibility of Materials: “Fatigue is a material failure mode particular to cyclic loading. The effects of hydrogen
gas on fatigue properties have not been extensively investigated for most alloy classes. Fatigue is arguably the most
important failure mechanism in structures subjected to cyclic stress, therefore this failure mechanism has to be
considered in the design of hydrogen gas ns subjected to pressure cycling. Given the importance of this failure mode,
more efforts are needed to measure fatigue properties of materials in hydrogen gas. Frequency of the load cycle and
the ratio of minimum load to maximum load (R-ratio) are two important variables that have been shown to affect
fatigue properties measured in hydrogen gas”
ASME B31.8-2020 “Gas Transmission and Distribution Piping Systems”. Fatigue: “The process of development of,
or enlargement of, a crack as a result of repeated cycles of stress.”
BMT FLEET TECHNOLOGY LIMITED - Fatigue Considerations for Natural Gas Transmission Pipelines - June 2016
Internal pressure fatigue of pipes, pipelines and cylinders - International Symposium on Microalloyed Steels for
the Oil and Gas Industry - TMS (The Minerals, Metals & Materials Society), 2007.
Ref. EN 13445-3:2021 “Unfired pressure vessels - Part 3: Design”
DVGW research project SyWeSt H2 (G 202006)_Investigation of Steel Materials for Gas Pipelines and Plants for
Assessment of their Suitability with Hydrogen - January 2023
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5.2.3 Cold working
A heat treatment (e.g. annealing at 250 – 400 °C) may be necessary based on the extent of the cold
mechanical operation, especially in rolling, bending, and calendering. This heat treatment shall be
performed according to the applicable design code and material standard.
During chip removal processes (e.g. cutting processes), it is advisable to utilize an appropriate cooling
lubricant and monitor the heat, which could increase the localized temperature on the metal's surface,
potentially leading to oxide formation or microscopic structural changes.
For copper alloys, e.g. brass, it is strong advised to use suitable and compatible lubricating fluids.
5.3 Types
5.3.1 Carbon steels
Carbon steels are approved for use under these specific requirements:
— Chemical properties:
— Carbon content ≤ 0,22 %;
— Sulphur content ≤ 0,01 % for seamless laminated or formed products :
— ≤ 0,003 % for flat rolled products;
— ≤ 0,025 % for forged and cast products;
— Phosphorus content ≤ 0,015 %;
— Nickel content ≤ 1,00 %;
— Maximum hardness shall comply with ASME B31.12:2023 Table IP-10.4.3-2.
Alternatively, materials listed in ASME B 31.12:2023, Table GR-2.1.1-1, are also appropriate.
Carbon steels not fulfilling the above criteria shall undergo evaluation in line with clause 7.1.
Specific allowance could be made for zinc-plated surface protection (without defect penetration),
considering proper machining (e.g. no sharp edges, round corners, etc.), and no risk of abrasion.
5.3.2 Stainless steels
The selection of stainless steel is based on the material's hardness and brittleness. Austenitic steels, due
to their superior ductility and lack of hardening under hot working, are recommended.
All austenitic alloys (e.g. Series 316, 304, S20910 XM-19 etc.) are permitted without restriction up to
100 % H2, subject to the reference product standards.
Ferritic, martensitic, pearlitic, and duplex alloys should be avoided due to the risk of embrittlement.
Additionally, stainless steel processed via cold working shall comply with clause 5.2.2.
These considerations, as listed in ASME B 31.12, table GR-2.1.1-1, can be utilized for other equipment (such as
valves, vessels, etc.), as their structural function doesn't differ. If materials are used differently from the ASME B
31.12 standard, the requirements of any relevant product standard should be considered.
Sulphur (S) requirements are driven by ANSI / NACE MR0175/ISO 15156—2 Clause 8
Conversion between distinct hardness scales should be conducted according to ISO 18625.
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5.3.3 Aluminium alloys
These alloys are permitted without restrictions, in accordance with the requirements of the reference
product standards.
There are no obvious restrictions for using die-cast light alloys, though controlling porosity during the
casting process to limit gas cavities is recommended. The presence of gas cavities can significantly
compromise the structure's gas permeability. In addition, it is advised to generally control the
solidification phase to prevent hardening effects.
5.3.4 Copper alloys
Copper-zinc and copper-tin alloys (such as brass, bronze, and copper-nickel) that do not contain elements
susceptible to hydrogen embrittlement are resistant to this phenomenon. However, certain elements if
present in declared copper alloys material specification, can lead to hydrogen embrittlement.
NOTE Example of embrittlement element: Sulphur (S), Phosphorus (P), Arsenic (As).
5.3.5 Zinc alloys
The zinc alloys (e.g.: ZL3/ZP3 and ZL5/ZP5, …) can be used up to the maximum allowable pressure values
PS ≤ 10 bar (1 MPa), unless specific requ
...
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