EN ISO 2612:2023

SLOVENSKI STANDARD
01-marec-2024
Analiza zemeljskega plina - Biometan - Določanje amoniaka z absorpcijsko
spektroskopijo z nastavljivimi laserskimi diodami (ISO 2612:2023)
Analysis of natural gas - Biomethane - Determination of ammonia content by Tuneable
Diode Laser Absorption Spectroscopy (ISO 2612:2023)
Analyse von Erdgas - Biomethan - Bestimmung von Ammoniakanteil durch
Absorptionsspektroskopie mittels durchstimmbarer Laserdioden (ISO 2612:2023)
Analyse du gaz naturel - Biométhane - Détermination de la teneur en ammoniac par
spectroscopie d'absorption laser à diode accordable (ISO 2612:2023)
Ta slovenski standard je istoveten z: EN ISO 2612:2023
ICS:
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 2612
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2023
EUROPÄISCHE NORM
ICS 75.060
English Version
Analysis of natural gas - Biomethane - Determination of
ammonia content by Tuneable Diode Laser Absorption
Spectroscopy (ISO 2612:2023)
Analyse du gaz naturel - Biométhane - Détermination Analyse von Erdgas - Biomethan - Bestimmung von
de la teneur en ammoniac par spectroscopie Ammoniakanteil durch Absorptionsspektroskopie
d'absorption laser à diode accordable (ISO 2612:2023) mittels durchstimmbarer Laserdioden (ISO
2612:2023)
This European Standard was approved by CEN on 20 November 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 2612:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 2612:2023) has been prepared by Technical Committee ISO/TC 193 "Natural
gas" in collaboration with Technical Committee CEN/TC 408 “Natural gas and biomethane for use in
transport and biomethane for injection in the natural gas grid” the secretariat of which is held by
AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2024, and conflicting national standards shall be
withdrawn at the latest by June 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: 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 the
United Kingdom.
Endorsement notice
The text of ISO 2612:2023 has been approved by CEN as EN ISO 2612:2023 without any modification.

INTERNATIONAL ISO
STANDARD 2612
First edition
2023-12
Analysis of natural gas — Biomethane
— Determination of ammonia content
by tuneable diode laser absorption
spectroscopy
Analyse du gaz naturel — Biométhane — Détermination de la teneur
en ammoniac par spectroscopie d'absorption laser à diode accordable
Reference number
ISO 2612:2023(E)
ISO 2612:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 2612:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Safety precautions. 3
5 Principle . 3
6 Apparatus . 3
6.1 NH analyser . 3
6.2 Gas delivery system . 3
6.3 Temperature sensor . 4
6.4 Pressure sensor . 4
6.5 Calibration equipment . 4
6.5.1 General . 4
6.5.2 Pressure regulators for the NH cylinders . 4
6.5.3 Flow controller . 4
6.5.4 Flow meter . 4
6.5.5 Dilution device. 4
6.5.6 Output manifold . 5
7 Reagents and materials . 5
7.1 Methane . 5
7.2 Calibration gases. 5
7.3 Inert gas . 5
8 Sampling . 5
8.1 General . 5
8.2 Construction materials . 5
8.3 Cleanliness . 6
8.4 Installation of the calibration gas cylinder . 6
8.5 Pressure control . 6
8.6 Purging of reduction valve and transfer lines . 6
8.7 Flow control . 6
8.8 Leak control . 7
9 Calibration .7
9.1 Calibration procedures . 7
9.2 Frequency of calibration . 7
9.2.1 Multipoint calibration . 7
9.2.2 Zero and span point calibration . 7
10 Interferences . 7
10.1 Interfering absorbers. 7
10.2 Matrix gas . 7
10.3 Secondary level spectroscopic effects: Gas temperature, gas pressure, spatial
homogeneity . 8
10.4 Humidity and carbon dioxide . 8
11 Measurement procedure . 8
12 Expression of results .8
12.1 Quantities and units . 8
12.2 Uncertainty . 8
13 Test report . 9
iii
ISO 2612:2023(E)
Annex A (informative) Spectroscopic analyser performance characteristics for NH
analysis in biomethane .10
Bibliography .11
iv
ISO 2612:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 1,
Analysis of natural gas, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 408, Natural gas and biomethane for use in transport and biomethane for
injection in the natural gas grid, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO 2612:2023(E)
Introduction
Ammonia is a common trace impurity found in biomethane. It is a product from the anaerobic digestion
of biomass, formed from the breakdown of amino acids during the production of biogas. As an impurity
in biogas and biomethane, ammonia is corrosive when it dissolves in the presence of water, damaging
process equipment and leads to an increase in anti-knock processes in combustion engines when
used as a fuel for vehicles. Ammonia is detrimental to the environment and as an air pollutant forms
particulates which are damaging to public health. Additionally, when present in the combustion of
biomethane, ammonia can lead to the formation of nitrogen oxides (NO ), which are regulated pollutants
x
as they are toxic and affect air quality. Therefore, the presence of ammonia in biogas and biomethane is
undesirable to gas distributers and their customers.
-3
Measuring ammonia content in mixtures of methane at the trace level (i.e. mg m ) is technically
difficult due to the adsorptive nature (i.e. “stickiness”) of ammonia. Particularly spectral NH
measurements can be severely hampered by spectral interferences from the matrix gas components,
which further increases the complexity of these measurements. Measurements in biogas or biomethane
are also dangerous due to the potentially explosive nature of methane, when mixed with an oxidizer
like ambient air.
This method supports the implementation of specifications for biomethane and biogas such as EN 16723-
[8] [9]
1 and EN 16723-2 when used in the natural gas grids and when using it as a transportation fuel.
Implementation of these specifications require fit-for-purpose measurement methods with known
performance and acceptable metrological traceability to support the trade of renewable gases as well
as conformity assessment. Currently, methods are referenced in standards such as EN 16723-1 which
have not been validated for use with biomethane and biogas. This document describes measurement
methods that meet these requirements and can be implemented by laboratories and industry, also
those seeking accreditation on the basis of, e.g. ISO/IEC 17025.
The methods described are based on commercially available spectroscopic analysers, specific to the
measurement of ammonia. They have been shown to perform at an acceptable level when quantifying
-3
the ammonia content of biomethane at the 10 mg m level, as specified in, e.g. EN 16723-1.
vi
INTERNATIONAL STANDARD ISO 2612:2023(E)
Analysis of natural gas — Biomethane — Determination
of ammonia content by tuneable diode laser absorption
spectroscopy
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not aim to address all of the safety problems associated with the
materials specified. It is the responsibility of the user of this document to establish appropriate
safety and health practices and to determine the applicability of any other restrictions prior to
use.
1 Scope
This document describes several test methods for measuring the ammonia amount fraction in natural
-1
gas and biomethane at the trace level (µmol mol ). The suitable handling and sampling of pressurised
mixtures of ammonia in methane that are applied to several different ammonia measurement systems
are described. The measurement systems are comprised of readily available commercial spectroscopic
analysers that are specific to ammonia. These NH analysers are considered as a black box in terms of
their operation, which is dependent on the instructions of the manufacturer. The document describes
suitable calibration and measurement strategies to quantify ammonia in (bio)methane around and
-3 -1
above the 10 mg m (14 µmol mol ) level and applies to analysis within absolute pressure ranges of
1 bar – 2 bar, temperatures of 0 °C – 40 °C and relative humidity <90 %.
References are also made to additional standards that are applied either to natural gas analysis or
air quality measurements. In this document the matrix gas is always methane or biomethane and the
measurand is the amount fraction NH .
5 2
NOTE 1 bar = 0,1 MPa =10 Pa; 1 MPa = 1 N/mm .
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.
ISO 6143, Gas analysis — Comparison methods for determining and checking the composition of calibration
gas mixtures
ISO 6145-1, Gas analysis — Preparation of calibration gas mixtures using dynamic methods — Part 1:
General aspects
ISO 7504, Gas analysis — Vocabulary
ISO 9169, Air quality — Definition and determination of performance characteristics of an automatic
measuring system
ISO 10715, Natural gas — Gas sampling
ISO 10723, Natural gas — Performance evaluation for analytical systems
ISO 14912, Gas analysis — Conversion of gas mixture composition data
ISO 14532, Natural gas — Vocabulary
ISO 16664, Gas analysis — Handling of calibration gases and gas mixtures — Guidelines
ISO 2612:2023(E)
IEC 61207-7, Expression of performance o
...