ISO/TS 16922:2022
(Main)Natural gas — Odorization
Natural gas — Odorization
This document gives the specifications and guidelines for the methods to be used in the odorization of natural gas and other methane rich gases delivered through natural gas networks to gas applications under a safety point of view. This document also specifies the principles for the odorization technique (including handling and storage of odorants) and the control of odorization of natural gas and other methane rich gases. NOTE The general requirements for odorants, and the physical and chemical properties of commonly used odorants are specified in ISO 13734.
Gaz naturel — Odorisation
Le présent document donne les spécifications et les lignes directrices concernant les méthodes à utiliser dans l’odorisation du gaz naturel et d’autres gaz riches en méthane, distribués via les réseaux de gaz naturel aux applications de gaz d’un point de vue de la sécurité. Le présent document spécifie également les principes de la technique d’odorisation (y compris la manutention et le stockage d’odorisants) et le contrôle de l'odorisation du gaz naturel et d’autres gaz riches en méthane. NOTE Les exigences générales pour les odorisants, et les propriétés physiques et chimiques des odorisants couramment utilisés sont spécifiées dans l’ISO 13734.
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TECHNICAL ISO/TS
SPECIFICATION 16922
First edition
2022-09
Natural gas — Odorization
Gaz naturel — Odorisation
Reference number
ISO/TS 16922:2022(E)
© ISO 2022
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ISO/TS 16922:2022(E)
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ISO/TS 16922:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Necessary odorant addition . . 2
4.2 Requirements and parameters for consideration when selecting an odorant . 2
4.3 Public awareness . 3
5 General remarks on odorant behaviour . 3
5.1 Masking and fading of odorants . 3
5.2 Seals and membranes . 3
5.3 Pipelines . 3
5.4 Buried pipeline . 3
6 Safety precautions. 3
6.1 Handling of odorants . 3
6.2 Spill management and remediation . 4
6.3 Transportation and storage . 4
7 Odorization technique .5
7.1 Odorization of pipeline networks . 5
7.1.1 Odorization of transmission pipelines . 5
7.1.2 Odorization of distribution pipelines . 5
7.1.3 Combined odorization of transmission and distribution pipelines . 5
7.2 Odorizer . 6
7.2.1 General . 6
7.2.2 Liquid injection odorizers . 6
7.2.3 Positioning of odorant injectors . 6
7.2.4 Evaporation odorizers . 7
7.3 Design of installation . 8
7.3.1 Odorization rooms . 8
7.3.2 Ventilation . 8
7.3.3 Installation of injection point and injection pipe . 8
7.3.4 Tank design and operations . 8
7.3.5 Spill kit . 8
7.4 Pressure resistance . 9
7.5 Addition of odorant . 9
7.5.1 Control of the addition . 9
7.5.2 Monitoring and control devices . 9
7.5.3 Testing and commissioning . 9
8 Control of odorization .9
8.1 General . 9
8.2 Check of odorization equipment and systems . 10
8.3 Control of odorization of the gas . 10
8.4 Odour complaints . 10
Bibliography .11
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ISO/TS 16922:2022(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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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.
This first edition ISO/TS 16922 cancels and replaces the first edition (ISO/TR 16922:2013), which has
been technically revised.
The main changes are as follows:
— modification of the structure of the Technical Report, new clauses: 4.1, 4.2, 4.3, 5.1, Clause 7, 7.1,
7.1.1, 7.1.2, 7.1.3, 7.3, 7.3.1, 7.3.2, 7.3.3, 7.3.4, 7.3.5;
— modification of 7.2.
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.
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ISO/TS 16922:2022(E)
Introduction
Processed natural gas normally has little or no odour. For safety reasons distributed natural gas is
therefore be odorized, to permit the detection of the gas by smell.
The odorization is predominantly a safety measure for the user of natural gas. Odorized natural gas
needs to be recognized by the characteristic smell.
This document may also be applied to other gases used in gas supply as e.g. biomethane, blends
containing hydrogen, regasified LNG or LBG, LPG for conditioning in gas supply, etc.
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TECHNICAL SPECIFICATION ISO/TS 16922:2022(E)
Natural gas — Odorization
1 Scope
This document gives the specifications and guidelines for the methods to be used in the odorization of
natural gas and other methane rich gases delivered through natural gas networks to gas applications
under a safety point of view.
This document also specifies the principles for the odorization technique (including handling and
storage of odorants) and the control of odorization of natural gas and other methane rich gases.
NOTE The general requirements for odorants, and the physical and chemical properties of commonly used
odorants are specified in ISO 13734.
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 5492, Sensory analysis — Vocabulary
ISO 14532, Natural gas — Vocabulary
3 Terms and definitions
For the purposes of this Technical Specification, the terms and definitions given in ISO 5492 and
ISO 14532 and the following apply:
3.1.1
odorant content
content of the odorant either in the gas or in air expressed as its mass concentration, volume fraction or
mole fraction
3.1.2
odour perception
awareness of the effect of volatile substances by the olfactory organ
3.1.3
odour character
distinctive and identifiable feature of an odour or flavour
3.1.4
odour intensity
magnitude of the perceived odour
3.1.5
masking
phenomenon by which one or more constituents in the gas stream can change or reduce the odour
intensity (3.1.4) and/or the odour character (3.1.3) of the odorized gas
3.1.6
fading of odorant
phenomenon where adsorption, absorption or chemical reactivity of the odorant result in loss of
odorant across the network
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ISO/TS 16922:2022(E)
4 General requirements
4.1 Necessary odorant addition
Because safety is paramount in the gas industry, it could be assumed that the stronger the odour of gas,
the better. However, an upper limit is usually set to avoid unjustified leakage complaints already caused
by the small volume of unburnt gas escaping during ignition of the burner. An excessive odorization
level can also lead to a slight and permanent gas smell related to micro leaks that cannot be localized
and sealed. This could lead to habituation of the customer with the eventuality of a late reaction when
actual leaks occur. Gas odorization is in most countries a legal or regulation requirement that specifies
that natural gas in air be readily detectable by odour at a concentration of 20 % (safety factor of 5) of
the lower flammability limit (LFL). The LFL of natural gas is normally taken as a volume fraction of
natural gas in air of 4 % to 5 %. However, local regulations may specify other odorization rules.
NOTE Consider potential masking issues when blending natural gas with other gases (e.g. biomethane, LPG),
the odour being either naturally present or artificially added.
4.2 Requirements and parameters for consideration when selecting an odorant
Information about different odorants is given in ISO 13734:2013, Annex A.
Various parameters are considered when selecting an odorant:
— Typical odour character that is intense, unpleasant and universally associated with gas
— Physical properties: Freezing point, boiling point, vapour pressure
— Stability:
— Stability with respect to oxidation in network:
Mercaptans being more reactive than sulfides, they tend to form less odorous disulfides in presence
of rust, thus lowering odorization efficiency.
— Stability in storage:
Some chemicals developed for odorization displaying reactive function can undergo hazardous
polymerization reaction if not stabilized adequately. Such reaction could occur in storage tank
or within injection system.
— Toxicity
— Environmental issues
— Gas quality: wet gas, presence of other sulphur compounds or network displaying condensates will
generate odorant scrubbing or cross contamination that may affect odorant efficiency
— Odorization practice in the region:
— Centralized / decentralized
— Odorization technique: (some odorants may not be compatible with Bypass odorizers, etc.)
— Network material (Carbon steel, plastics)
The level of the odorant added, that determines the odour intensity, is based on different factors
whereof not all are based on measurement, as e.g. local experience. The typical objective is that the
population with a functional sense of smell will be able to smell odorized gas before its concentration
reaches the specified limit (typically 20 % LFL) and thus takes the appropriate measures to protect
itself. Different approaches are applied to define and estimate the concentration of odorant required to
achieve this effect.
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ISO/TS 16922:2022(E)
The odour intensity of an odorant for natural gas or a gas is best determined by the human olfactory
organ.
4.3 Public awareness
In some countries, local regulations require the operators to follow a public awareness program, which
may include specific information about the risk of gas and guidance for leak recognition. The use of
scratch-and-sniff cards containing the encapsulated odorant or other carriers is also frequently used in
a number of countries, but other kind of smell samples are also encountered.
In the case of changing the odour character of the gas odorant, the need to provide adequate information
to the members of the public and gas users should be considered.
5 General remarks on odorant behaviour
5.1 Masking and fading of odorants
Temporary fading in a new gas distribution system or after changing the odorant requires specific
monitoring and can need temporary supplemental odorization or other measures (e.g. preconditioning).
Some components, e.g. present in some natural gases or biogases may react on or with the odorant
applied, resulting in a major loss of smell of the odorant either by masking effects or by chemical
reaction.
5.2 Seals and membranes
Liquid odorants may cause severe swelling or even dissolution of organic materials such as plastics,
elastomeric seals and lubricants. Therefore, in odorization equipment and for joints close to the points
where the liquid odorant is injected into the line, only sealing materials should be used which are
compatible with liquid odorants. This information is normally supplied by the manufacturer of the
odorant (see ISO 13734).
5.3 Pipelines
The low odorant concentrations used for odorization of natural gas do not compromise the integrity of
plastic pipes, seals or diaphragms in gas transportation, distribution and utilization.
When starting gas distribution through new gas lines or when changing the odorant it may take
some time to reach the required odorant concentration at the end of the line. This may result from
the odorant being sorbed on the pipe wall, by pipe dust, rust and incrustations or by gas condensates
(odour fading). The degree of sorption depends on several factors, for example the condition of the pipe
grid, the pressure, the temperature, the flow velocity and the physicochemical properties of odorants.
5.4 Buried pipeline
Odorized gases leaking from gas lines in the ground may lose odorants by sorption in the soil. Sorption
and oxidation of odorants may vary with moisture content and the type of soil. Degradation of odorants
by microorganisms may also occur.
6 Safety precautions
6.1 Handling of odorants
WARNING — Odorants should be handled according to their actual characteristics and prevailing
regulations.
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ISO/TS 16922:2022(E)
IMPORTANT — All relevant safety precautions being observed when handling odorants,
employees should be instructed periodically. Odorants are irritating, harmful and flammable.
Therefore, the specific material safety data sheet should be read prior to handling liquid
odorants. All safety precautions should be strictly observed and followed.
A minimum level of safety may be achieved by the following recommendations:
— Concentrated vapours of odorants may cause short-term acute health problems, such as dizziness,
headache, nausea and irritation of throat, nose and eyes. Therefore protection, for example with a
filter containing activated charcoal or a respirator, is common use. Any extended exposure without
respiration protection need to be avoided.
— When handling odorants, suitable personal protective equipment (eye-, face-, body-protection,
gloves) and safe-handling procedures of the odorant are recommended. If, in spite of the use of
personal protection equipment, liquid odorant contacts the skin or the eyes, wash the affected spot
as first aid, immediately with plenty of water. If an eye comes in contact with liquid odorant, consult
a physician immediately.
6.2 Spill management and remediation
WARNING — Undiluted oxidants should never be brought into contact with odorants: RISK OF
EXPLOSION!
There are several possibilities to eliminate the nuisance caused by the strong odour of spilled odorants.
— For odour mitigation, deodorants may be used, which normally do not change the chemical properties
of the odorant. Therefore, health risks will not be eliminated. For larger amounts of spilled odorants
these masking compounds are not suitable.
— Minor quantities of spilled odorants (surface cleaning) can be treated with different options:
— oxidized to less smelling compounds utilizing a procedure incorporating the spraying of diluted
solutions of an oxidant such as 5 % by mass of sodium hypochlorite or 5 % by mass of hydrogen
peroxide, preferably under the addition of detergents. This procedure should account for the
corrosive and reactive nature of these oxidants.
— neutralized with enzymatic solutions, only effective for some odorants (e.g. mercaptans)
— Larger quantities of spilled or leaked odorants should be sorbed by sorbents (activated charcoal)
and disposed of in tightly shut containers. Small remainders should be treated as minor quantities.
These sorbents or soil contaminated by odorants should be treated according to prevailing regulations.
Commercial products are also available to mask and/or mitigate odorant spillage. These products are
generally available through the odorant manufacturer.
For the cleaning of pipework, containers and parts of the odorizing equipment the use of alcohols
(isopropanol, technical ethanol) is an option. The used cleaning solution are to be disposed according to
prevailing regulations.
6.3 Transportation and storage
Odorants are delivered in corrosion-resistant containers suitable for transport and/or storage
according to prevailing regulations. Odorant containers need to be accompanied by a safety data sheet
conforming to the requirements of all prevailing regulations.
The use of the proper sealing materials is according to the type of odorant, sulfurous or acrylic.
To avoid nuisance when stationary odorant tanks are refilled, vapour equalization lines for gas phase
transfer between storage and transportation tanks are recommended. Lines for transfer equipped with
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ISO/TS 16922:2022(E)
automatic shutoff valves are recommended, where possible. Connections and valves preferably have
minimum dead volume.
Storage rooms for odorant containers are best cool, dry and well ventilated. Extended impact of the sun
increase of the internal pressure of odorant containers during transport and/or storage.
Storage containers and the odorizing plant may be in the same room. Odorants jointly with any easily
inflammable substance is best to be avoided.
7 Odorization technique
7.1 Odorization of pipeline networks
7.1.1 Odorization of transmission pipelines
Centralized odorization is performed at the entry point of gas into the transmission network (i.e. LNG
terminal, interconnection points, etc.). Its advantages are:
— the installation, operation and maintenance of sophisticated equipment to automate and monitor
each odorizer is simpler and results in better uniformity of the odorant concentration in the gases;
— it allows a uniform gas odour throughout a region.
Its disadvantages are
— the odorants may have to be removed from the gas supplied to some industrial consumers, and
— odorized gas is delivered to industrial consumers that may not need it because other safety measures
may be provided to recognize gas leaks (e.g. gas sensors for these industrial processes).
7.1.2 Odorization of distribution pipelines
Decentralised odorization is performed typically at the entry points of the distribution networks,
including biomethane injection points. Advantages for decentralized odorization are:
— odorant concentrations can be adjusted to the specific conditions of the local distribution grid (new
pipes or old pipes with deposits),
— the sulfur content of gas for industrial use or the environmental effects of odorants on some types
of underground storage are not increased by odorization by avoiding unnecessary odorization.
Disadvantages of decentralized odorization are
— the multiplicity of odorization stations, generally close to populated areas,
— generation of transportation of odorant on road or rail, and
— handling of odorant by a multitude of personnel,
— low gas flow is more difficult to follow up in odorant dosage.
7.1.3 Combined odorization of transmission and distribution pipelines
In some countries, classification of transmission pipelines is enforced according to the human
occupancy on either side of the pipelines, defining which pipelines have to be odorized. In a number of
countries, odorization is mandatory when the human occupancy is high.
In some cases, minimum odorization levels in transmission and distribution are different. In other cases,
where different odorants are in use and the possibility exists to transfer odorized gas from distribution
to transmission grids (in case of biomethane overproduction) it may be required to deodorize the gas.
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ISO/TS 16922:2022(E)
7.2 Odorizer
7.2.1 General
Odorization is usually performed using one of the following techniques:
— liquid odorant injection;
— evaporation odorizer.
7.2.2 Liquid injection odorizers
To allow for a constant odorization, the necessary amount of odorant is added to the gas stream
continuously or quasi continuously. This is best accomplished by flow proportional odorization by
injection odorizers. Flow proportioning refers to adjusting the odorant injection rate to the flowrate of
the gas flowing in the pipeline. These odorizers are typically the most commonly used nowadays, and
can be sized to fit most flowrates.
Odorant is injected from a storage tank, generally maintained at low pressure, directly into the flowing
gas. In principle, two systems are commonly in use:
a) Systems with injection pumps: the injection rate is related to the volumetric pump displacement
and the stroke frequency. This frequency is adjusted by accounting for the gas flow as measured by
a measurement device. The pump protected by an upstream filter against clogging.
b) Valve-controlled systems: Gas-flow proportional injection from a pressurized storage tank may be
achieved by means of mass-flow or volume-flow controllers.
The injection of odorant may also be regulated by taking into account the actual odorant concentration
present in the gas. The injection system also can produce information regarding the total odorant
injected, injection rate, and alarms regarding the performance of the system.
The liquid odorant can be injected into an injection probe. Designs of these probes vary but are intended
to maximize vaporization of the odorant into the natural gas. Filters are normally installed upstream
to the injection system in order to decrease the required maintenance of the system. A check valve and
isolation valve should be installed in the connection line between the injection system and the injection
point.
All material in contact with liquid odorants should be assessed for compatibility with the specific
odorant in accordance with the odorant manufacturer’s information. Such assessment is therefore also
performed when the type of odorant is changed.
To inhibit the possibility of leakage, lines carrying liquid odorant are made of seamless precision
stainless steel pipe, but for the connection line to the injection point suitable flexible tubing reinforced
by steel fabric may be used. All pipes carrying liquid odorants are indelibly signed.
NOTE To avoid extreme nuisance due to smell, odorizers are equipped for flushing in case of maintenance.
7.2.3 Positioning of odorant injectors
When insta
...
SPÉCIFICATION ISO/TS
TECHNIQUE 16922
Première édition
2022-09
Gaz naturel — Odorisation
Natural gas — Odorization
Numéro de référence
ISO/TS 16922:2022(F)
© ISO 2022
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ISO/TS 16922:2022(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2022
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
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Tél.: +41 22 749 01 11
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Publié en Suisse
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ISO/TS 16922:2022(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d'application .1
2 Références normatives .1
3 Termes et définitions . 1
4 Exigences générales . .2
4.1 Ajout nécessaire d'odorisant . 2
4.2 Exigences et paramètres à prendre en compte lors du choix d'un odorisant . 2
4.3 Sensibilisation du public . 3
5 Remarques générales sur le comportement d’un odorisant . 3
5.1 Masquage et déperdition des odorisants . 3
5.2 Joints et membranes . 3
5.3 Canalisations . 3
5.4 Canalisation enterrée . 4
6 Consignes de sécurité . 4
6.1 Manipulation des odorisants . 4
6.2 Gestion des déversements et assainissement . 4
6.3 Transport et stockage . 5
7 Technique d’odorisation . 5
7.1 Odorisation des réseaux de canalisation . 5
7.1.1 Odorisation pour canalisations de transport . 5
7.1.2 Odorisation pour canalisations de distribution . 6
7.1.3 Odorisation combinée pour canalisations de transport et de distribution . 6
7.2 Odoriseur . 6
7.2.1 Généralités . 6
7.2.2 Odoriseurs par injection de liquide . 6
7.2.3 Positionnement des injecteurs d'odorisant . 7
7.2.4 Odoriseurs par évaporation . 8
7.3 Conception de l’installation . . . 9
7.3.1 Locaux d’odorisation . . . 9
7.3.2 Ventilation . 9
7.3.3 Installation de point d'injection et de canalisation d'injection . 9
7.3.4 Conception et opérations du réservoir . 9
7.3.5 Kit de déversement . 10
7.4 Résistance à la pression . 10
7.5 Ajout d’odorisant . . 10
7.5.1 Contrôle de l’ajout . 10
7.5.2 Dispositifs de surveillance et de contrôle . 10
7.5.3 Essais et mise en service . 10
8 Contrôle de l'odorisation .11
8.1 Généralités . 11
8.2 Contrôle des équipements et systèmes d'odorisation . 11
8.3 Contrôle de l'odorisation du gaz . 11
8.4 Appels pour odeur . 11
Bibliographie .12
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ISO/TS 16922:2022(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes
nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document
a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de
brevets reçues par l'ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l'intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l'Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant: www.iso.org/iso/fr/avant-propos.
Le présent document a été élaboré par le comité technique ISO/TC 193, Gaz naturel.
Cette première édition de l’ISO/TS 16922 annule et remplace la première édition de l’ISO/TR 16922:2013),
qui a fait l’objet d’une révision technique.
Les principales modifications sont les suivantes:
— modification de la structure du Rapport technique, nouveaux paragraphes: 4.1, 4.2, 4.3, 5.1, Article 7,
7.1, 7.1.1, 7.1.2, 7.1.3, 7.3, 7.3.1, 7.3.2, 7.3.3, 7.3.4, 7.3.5;
— modification de 7.2.
Il convient que l'utilisateur adresse tout retour d'information ou toute question concernant le présent
document à l'organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l'adresse https://www.iso.org/fr/members.html.
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ISO/TS 16922:2022(F)
Introduction
Le gaz naturel traité a normalement peu ou pas d'odeur. Pour des raisons de sécurité, le gaz naturel
distribué est donc odorisé, pour permettre la détection du gaz par l'odeur.
L'odorisation est principalement une mesure de sécurité pour l'utilisateur de gaz naturel. Le gaz naturel
odorisé doit être reconnu par l'odeur caractéristique.
Le présent document peut s’appliquer à d’autres gaz utilisés dans l’approvisionnement en gaz, par
exemple le biométhane, les mélanges contenant de l’hydrogène, le GNL ou le BGL regazéifié, le GPL pour
le conditionnement dans l’approvisionnement en gaz, etc.
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SPÉCIFICATION TECHNIQUE ISO/TS 16922:2022(F)
Gaz naturel — Odorisation
1 Domaine d'application
Le présent document donne les spécifications et les lignes directrices concernant les méthodes à utiliser
dans l’odorisation du gaz naturel et d’autres gaz riches en méthane, distribués via les réseaux de gaz
naturel aux applications de gaz d’un point de vue de la sécurité.
Le présent document spécifie également les principes de la technique d’odorisation (y compris la
manutention et le stockage d’odorisants) et le contrôle de l'odorisation du gaz naturel et d’autres gaz
riches en méthane.
NOTE Les exigences générales pour les odorisants, et les propriétés physiques et chimiques des odorisants
couramment utilisés sont spécifiées dans l’ISO 13734.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 5492, Analyse sensorielle — Vocabulaire
ISO 14532, Gaz naturel — Vocabulaire
3 Termes et définitions
Pour les besoins de la présente Spécification technique, les termes et définitions donnés dans l'ISO 5492
et l'ISO 14532 ainsi que les suivants, s'appliquent.
3.1.1
teneur en odorisant
teneur de l’odorisant dans le gaz ou dans l'air exprimée en concentration massique, fraction volumique
ou fraction molaire
3.1.2
perception des odeurs
conscience de l'effet de substances volatiles par l'organe olfactif
3.1.3
caractère d’une odeur
trait distinctif et identifiable d'une odeur ou d’une saveur
3.1.4
intensité d’une odeur
ampleur de l'odeur perçue
3.1.5
masquage
phénomène par lequel un ou plusieurs constituants du flux gazeux peuvent modifier ou réduire
l’intensité d’une odeur (3.1.4) et/ou le caractère d’une odeur (3.1.3) du gaz odorisé
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3.1.6
déperdition de l’odorisant
phénomène où l’adsorption, l'absorption ou la réactivité chimique de l'odorisant entraînent une perte
d'odorisant sur le réseau
4 Exigences générales
4.1 Ajout nécessaire d'odorisant
Parce que la sécurité est primordiale dans l'industrie du gaz, on peut supposer que plus l'odeur de gaz
est forte, mieux c'est. Toutefois, une limite supérieure est en principe définie afin d’éviter les appels pour
fuites injustifiées causés par le faible volume de gaz non brûlé s'échappant lors de l'allumage du brûleur.
Un niveau d'odorisation excessif peut également entraîner une odeur de gaz légère et permanente liée à
des micro-fuites qui ne peuvent être localisées et réparées. Cela pourrait conduire à l'accoutumance du
client avec le risque d'une réaction tardive lorsque des fuites se produisent réellement. L'odorisation du
gaz est dans la plupart des pays une obligation légale ou réglementaire qui spécifie que le gaz naturel
dans l'air soit facilement détectable par l'odeur à une concentration de 20 % (facteur de sécurité 5) de la
limite inférieure d'inflammabilité (LII). La LII du gaz naturel est généralement considérée comme une
fraction de volume de gaz naturel dans l'air de 4 % à 5 %. Toutefois, les réglementations locales peuvent
spécifier d'autres règles d'odorisation.
NOTE Prendre en considération les problèmes potentiels de masquage lors du mélange de gaz naturel
avec d'autres gaz (par exemple, le biométhane, le GPL), l'odeur étant soit naturellement présente, soit ajoutée
artificiellement.
4.2 Exigences et paramètres à prendre en compte lors du choix d'un odorisant
Des informations sur les différents odorisants sont données dans l’ISO 13734:2013, Annexe A.
Plusieurs paramètres sont pris en compte lors du choix d'un odorisant:
— Le caractère typique de l’odeur intense, désagréable et universellement associée au gaz;
— Des propriétés physiques: point de congélation, point d’ébullition, pression de vapeur;
— La stabilité:
— La stabilité par rapport à l’oxydation dans le réseau:
Les mercaptans étant plus réactifs que les sulfures, ils ont tendance à former des disulfures
moins odorants en présence de rouille, ce qui diminue l’efficacité de l’odorisation;
— La stabilité au stockage:
Certains produits chimiques développés pour l’odorisation présentant une fonction réactive
peuvent subir une réaction de polymérisation dangereuse s'ils ne sont pas stabilisés de manière
adéquate. Une réaction de ce type pourrait se produire dans le réservoir de stockage ou au sein
du système d’injection;
— La toxicité;
— Les questions environnementales;
— La qualité du gaz: gaz humide, présence d’autres composés de soufre ou réseau présentant des
condensats généreront une épuration de l’odorisant ou une contamination croisée pouvant avoir
une incidence sur l’efficacité de l’odorisant;
— La pratique de l'odorisation dans la région:
— Centralisée/décentralisée;
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— La technique d’odorisation: (certains odorisants peuvent ne pas être compatibles avec les
odoriseurs par dérivation, etc.);
— Le matériau du réseau (acier au carbone, plastiques).
Le niveau d'odorisant ajouté, qui détermine l’intensité d’une odeur, est basé sur différents facteurs
qui ne sont pas tous fondés sur la mesure, par exemple l'expérience locale. L'objectif typique est que
la population avec un sens de l'odorat fonctionnel soit capable de sentir le gaz odorisé avant que sa
concentration n'atteigne la limite spécifiée (généralement de 20 % de la LII) et prenne donc les
mesures appropriées pour se protéger. Différentes approches sont appliquées pour définir et estimer la
concentration d'odorisant nécessaire pour obtenir cet effet.
Le meilleur moyen de déterminer l'intensité de l'odeur d'un odorisant pour le gaz naturel ou un gaz est
d’utiliser l'organe olfactif humain.
4.3 Sensibilisation du public
Dans certains pays, les réglementations locales nécessitent que les opérateurs suivent un programme
de sensibilisation du public, qui peut inclure des informations spécifiques concernant les risques liés
au gaz et des recommandations pour la reconnaissance des fuites. L’utilisation de cartes à gratter pour
sentir contenant l’odorisant encapsulé ou d’autres supports est également fréquente dans un certain
nombre de pays, mais il existe aussi d’autres types d’échantillons d'odeurs.
Dans le cas d’une modification du caractère de l’odeur de l’odorisant du gaz, il convient de tenir compte
de la nécessité de fournir les informations adéquates aux membres du public et aux consommateurs de
gaz.
5 Remarques générales sur le comportement d’un odorisant
5.1 Masquage et déperdition des odorisants
La déperdition temporaire dans un nouveau système de distribution de gaz ou après un changement
d'odorisant requiert une surveillance spécifique et peut nécessiter une odorisation supplémentaire
temporaire ou d'autres mesures (par exemple un préconditionnement).
Certains composants, présents par exemple dans certains gaz naturels ou biogaz, peuvent réagir sur ou
avec l’odorisant appliqué, entraînant une perte majeure de l’odeur de l’odorisant soit par des effets de
masquage, soit par réaction chimique.
5.2 Joints et membranes
Les odorisants liquides peuvent provoquer un gonflement important ou même la dissolution de
matériaux organiques tels que les plastiques, les joints élastomères et les lubrifiants. Par conséquent,
dans l'équipement pour odorisation et pour les joints à proximité des points où l’odorisant liquide est
injecté dans le réseau, il convient d’utiliser uniquement des matériaux d'étanchéité compatibles avec
les odorisants liquides. Ces informations sont en principe fournies par le fabricant de l‘odorisant (voir
l’ISO 13734).
5.3 Canalisations
Les faibles concentrations d'odorisants utilisés pour l'odorisation du gaz naturel ne compromettent
pas l'intégrité des canalisations en plastique, des joints ou des diaphragmes pour le transport, la
distribution et l'utilisation du gaz.
Lors du démarrage de la distribution du gaz dans de nouvelles canalisations de gaz ou lors du
changement de l'odorisant, atteindre la concentration d’odorisant requise à l'extrémité du réseau
peut prendre un certain temps. Cela peut résulter de l’absorption de l'odorisant par la paroi de la
canalisation, par la poussière, la rouille et les incrustations des canalisations, ou par des condensats de
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gaz (déperdition de l’odeur). Le degré de sorption dépend de plusieurs facteurs, par exemple l'état du
réseau de canalisations, la pression, la température, la vitesse d'écoulement et les propriétés physico-
chimiques des odorisants.
5.4 Canalisation enterrée
Les gaz odorisés s'échappant des canalisations de gaz dans le sol peuvent perdre des odorisants par
absorption dans le sol. L’absorption et l'oxydation des odorisants peuvent varier avec la teneur en
humidité et la nature du sol. La dégradation des odorisants par des micro-organismes peut également
survenir.
6 Consignes de sécurité
6.1 Manipulation des odorisants
AVERTISSEMENT — Il convient de manipuler les odorisants selon leurs caractéristiques réelles
et la réglementation en vigueur.
IMPORTANT — Toutes les consignes de sécurité pertinentes étant respectées lors de la
manipulation des odorisants, il convient d’informer les employés régulièrement. Les odorisants
sont irritants, nocifs et inflammables. Par conséquent, il convient de lire la fiche de données
de sécurité avant de manipuler des odorisants liquides. Il convient d’observer et de respecter
strictement toutes les précautions de sécurité.
Un niveau minimal de sécurité peut être atteint avec les recommandations suivantes:
— Les vapeurs concentrées d’odorisants peuvent causer des problèmes de santé aigus à court terme,
tels que des étourdissements, des maux de tête, des nausées et des irritations de la gorge, du nez
et des yeux. Il est donc courant d’utiliser un système de protection, par exemple avec un filtre
contenant du charbon actif ou un appareil respiratoire. Toute exposition prolongée sans protection
respiratoire est à éviter.
— Lors de la manipulation d’odorisants, un équipement de protection individuelle approprié
(protection pour œil, visage, corps, gants) et des procédures de manipulation en toute sécurité de
l'odorisant sont recommandés. Si, en dépit de l'utilisation d'un équipement de protection individuelle,
l’odorisant liquide entre en contact avec la peau ou les yeux, laver immédiatement l'endroit affecté
abondamment avec de l'eau, comme premiers soins. Si un œil entre en contact avec un odorisant
liquide, consulter immédiatement un médecin.
6.2 Gestion des déversements et assainissement
AVERTISSEMENT — Il convient de ne jamais mettre en contact les oxydants non dilués avec des
odorisants: RISQUE D’EXPLOSION!
Il existe plusieurs possibilités pour éliminer la nuisance causée par la forte odeur d’odorisants
renversés.
— Pour atténuer les odeurs, des désodorisants peuvent être utilisés, ce qui, normalement, ne modifie
pas les propriétés chimiques de l’odorisant. Par conséquent les risques pour la santé ne seront pas
éliminés. Pour les plus grandes quantités d’odorisants déversés, ces composés de masquage ne sont
pas adaptés.
— Les petites quantités d’odorisants déversés (nettoyage en surface) peuvent être traitées avec
différentes options:
— oxydation en composés moins odorants en utilisant une procédure comprenant la pulvérisation
de solutions diluées d'un oxydant tel que 5 % en masse d'hypochlorite de sodium ou de 5 %
en masse de peroxyde d'hydrogène, de préférence avec addition de détergents. Il convient que
cette procédure tienne compte de la nature corrosive et réactive de ces oxydants.
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— neutralisation avec des solutions enzymatiques, efficace uniquement pour certains odorisants
(par exemple les mercaptans).
— Pour de grandes quantités d’odorisants déversés ou ayant fui, il convient de les absorber par
des absorbants (charbon actif) et de les évacuer dans des conteneurs hermétiquement fermés. Il
convient de traiter les petits résidus comme de petites quantités.
Il convient de traiter ces absorbants ou sols contaminés par des odorisants conformément à la
réglementation en vigueur.
Des produits commerciaux sont également disponibles pour masquer et/ou atténuer les déversements
d’odorisant. Ces produits sont généralement disponibles auprès du fabricant d’odorisant.
Pour le nettoyage des canalisations, des conteneurs et des parties de l'équipement d’odorisation,
l'utilisation d'alcools (isopropanol, éthanol technique) est une possibilité. La solution de nettoyage
utilisée est à éliminer conformément à la réglementation en vigueur.
6.3 Transport et stockage
Les odorisants sont livrés dans des récipients appropriés résistant à la corrosion pour le transport et/
ou le stockage selon la réglementation en vigueur. Les réservoirs d’odorisant sont accompagnés d'une
fiche de données de sécurité conforme aux exigences de toutes les réglementations en vigueur.
L'utilisation des matériaux d'étanchéité appropriés dépend du type d’odorisant, sulfureux ou acrylique.
Pour éviter les nuisances lorsque les réservoirs fixes d’odorisant sont remplis, des lignes d’équilibrage
de vapeur pour le transfert de la phase gazeuse entre réservoirs de stockage et de transport sont
recommandées. Des lignes de transfert équipées de vannes d'arrêt automatiques sont recommandées,
si possible. Les raccords et vannes ont de préférence un volume mort minimal.
Les locaux de stockage pour les réservoirs d’odorisant sont de préférence frais, secs et bien aérés.
L’exposition prolongée au soleil augmente la pression interne des réservoirs d’odorisant lors du
transport et/ou du stockage.
Les réservoirs de stockage et l’installation d’odorisation peuvent être dans la même pièce. Les
odorisants associés à toute substance facilement inflammable sont à éviter.
7 Technique d’odorisation
7.1 Odorisation des réseaux de canalisation
7.1.1 Odorisation pour canalisations de transport
L’odorisation centralisée s’effectue au point d’entrée du gaz dans le réseau de transport (à savoir le
terminal GNL, les points de raccordement, etc.) Ses avantages sont les suivants:
— l'installation, l'exploitation et la maintenance des équipements sophistiqués pour automatiser et
contrôler chaque odoriseur est plus simple et permet une meilleure uniformité de la concentration
d’odorisant dans les gaz;
— elle permet une odeur de gaz uniforme dans toute une région.
Ses inconvénients sont les suivants:
— les odorisants peuvent avoir à être retirés du gaz fourni à certains consommateurs industriels;
— le gaz odorisé est livré à des consommateurs industriels qui peuvent ne pas en avoir besoin parce
que d'autres mesures de sécurité peuvent être utilisées pour détecter les fuites de gaz (par exemple
des capteurs de gaz pour ces procédés industriels).
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7.1.2 Odorisation pour canalisations de distribution
L’odorisation décentralisée est effectuée généralement au niveau des points d'entrée des réseaux
de distribution, y compris aux points d’injection de biométhane. Les avantages de l'odorisation
décentralisée sont les suivants:
— les concentrations d’odorisants peuvent être adaptées aux conditions spécifiques du réseau de
distribution local (canalisations neuves ou anciennes canalisations avec des dépôts);
— en évitant toute odorisation inutile, la teneur en soufre du gaz à usage industriel ou les effets
environnementaux des odorisants sur certains types de stockage souterrain ne sont pas augmentés
par l'odorisation.
Les inconvénients de l'odorisation décentralisée sont les suivants:
— la multiplicité des stations d'odorisation, généralement situées à proximité de zones habitées;
— la création de transport d’odorisant par la route ou le rail; et
— la manipulation d’odorisant par une multitude de personnes;
— un faible débit de gaz est plus difficile à suivre dans le dosage des odorisants.
7.1.3 Odorisation combinée pour canalisations de transport et de distribution
Dans certains pays, la classification des canalisations de transport est appliquée en fonction de
l’occupation humaine de part et d’autre des canalisations, en définissant les canalisations qui doivent
être odorisées. Dans un c
...
ISO/TC193/WG5
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ISO/DTSPRF TS 16922:2022(E)
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ISO TC 193/WG 5
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Date: 2022-07-27xx
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Secretariat: NEN
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Natural gas — Odorization
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Gaz naturel — Odorisation
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ISO/DTSPRF TS 16922:2022(E)
© ISO 2022
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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
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ISO/DTS PRF TS 16922:2022(E)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Necessary odorant addition . 2
4.2 Requirements and parameters for consideration when selecting an odorant . 2
4.3 Public awareness . 3
5 General remarks on odorant behaviour . 3
5.1 Masking and fading of odorants . 3
5.2 Seals and membranes . 3
5.3 Pipelines . 3
5.4 Buried pipeline. 4
6 Safety precautions . 4
6.1 Handling of odorants . 4
6.2 Spill management and remediation . 4
6.3 Transportation and storage . 5
7 Odorization technique . 5
7.1 Odorization of pipeline networks . 5
7.1.1 Odorization of transmission pipelines . 5
7.1.2 Odorization of distribution pipelines . 6
7.1.3 Combined odorization of transmission and distribution pipelines . 6
7.2 Odorizer . 6
7.2.1 General . 6
7.2.2 Liquid injection odorizers . 6
7.2.3 Positioning of odorant injectors . 7
7.2.4 Evaporation odorizers . 8
7.3 Design of installation. 9
7.3.1 Odorization rooms . 9
7.3.2 Ventilation . 9
7.3.3 Installation of injection point and injection pipe . 9
7.3.4 Tank design and operations. 9
7.3.5 Spill kit . 10
7.4 Pressure resistance . 10
7.5 Addition of odorant . 10
7.5.1 Control of the addition . 10
7.5.2 Monitoring and control devices . 10
7.5.3 Testing and commissioning . 10
8 Control of odorization . 11
8.1 General . 11
8.2 Check of odorization equipment and systems . 11
8.3 Control of odorization of the gas . 11
8.4 Odor complaints . 11
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ISO/DTSPRF TS 16922:2022(E)
Bibliography . 12
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Necessary odorant addition . 2
4.2 Requirements and parameters for consideration when selecting an odorant . 2
4.3 Public awareness . 3
5 General remarks on odorant behaviour . 3
5.1 Masking and fading of odorants . 3
5.2 Seals and membranes . 3
5.3 Pipelines . 3
5.4 Buried pipeline . 4
6 Safety precautions . 4
6.1 Handling of odorants . 4
6.2 Spill management and remediation . 4
6.3 Transportation and storage . 5
7 Odorization technique . 5
7.1 Odorization of pipeline networks . 5
7.1.1 Odorization of transmission pipelines . 5
7.1.2 Odorization of distribution pipelines . 6
7.1.3 Combined odorization of transmission and distribution pipelines . 6
7.2 Odorizer . 6
7.2.1 General . 6
7.2.2 Liquid injection odorizers . 6
7.2.3 Positioning of odorant injectors . 7
7.2.4 Evaporation odorizers . 8
7.3 Design of installation . 9
7.3.1 Odorization rooms . 9
7.3.2 Ventilation . 9
7.3.3 Installation of injection point and injection pipe . 9
7.3.4 Tank design and operations . 9
7.3.5 Spill kit . 10
7.4 Pressure resistance . 10
7.5 Addition of odorant . 10
7.5.1 Control of the addition . 10
7.5.2 Monitoring and control devices . 10
7.5.3 Testing and commissioning . 10
8 Control of odorization . 11
8.1 General . 11
8.2 Check of odorization equipment and systems. 11
8.3 Control of odorization of the gas . 11
8.4 Odour complaints . 11
Bibliography . 12
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ISO/DTSPRF TS 16922:2022(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 documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directiveswww.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patentswww.iso.org/patents).
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
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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
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www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
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This document was prepared by Technical Committee ISO/TC 193, Natural Gasgas.
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This secondfirst edition ISO/TS 16922 cancels and replaces the first edition (ISO/TR 16922:2013),
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which has been technically revised.
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The main changes compared to the previous edition are as follows:
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— modification of the structure of the technical report :Technical Report, new clauses :: 4.1 Necessary
odorant addition, 4.2 Requirements and parameters for consideration when selecting an odorant, 4.3
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Public awareness, 5.1 Masking and fading of odorants, , Clause 7 Odorization technique, 7.1
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Odorization of pipeline networks, 7.1.1 Odorization of transmission pipelines, 7.1.2 Odorization of
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distribution pipelines, 7.1.3 Combined odorization of transmission and distribution pipelines, 7.3
Design of installation, 7.3.1 Odorization rooms, 7.3.2 Ventilation, 7.3.3 Installation of injection point
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and injection pipe, 7.3.4 Tank design and operations, 7.3.5 Spill kit.;
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ISO/DTS PRF TS 16922:2022(E)
Introduction
Processed natural gas normally has little or no odorodour. For safety reasons distributed natural gas is
therefore be odorized, to permit the detection of the gas by smell.
The odorization is predominantly a safety measure for the user of natural gas. Odorized natural gas needs
to be recognized by the characteristic smell.
This technical reportdocument may also be applied to other gases used in gas supply as e.g. biomethane,
blends containing hydrogen, regasified LNG or LBG, LPG for conditioning in gas supply, etc.
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TECHNICAL SPECIFICATION ISO/DTS PRF TS 16922:2022(E)
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Natural gas - Odorization
1 Scope
This Technical Specificationdocument gives the specifications and guidelines for the methods to be used
in the odorization of natural gas and other methane rich gases delivered through natural gas networks to
gas applications under a safety point of view.
This Technical Specificationdocument also specifies the principles for the odorization technique
(including handling and storage of odorants) and the control of odorization of natural gas and other
methane rich gases.
NOTE The general requirements for odorants, and the physical and chemical properties of commonly used
odorants are specified in ISO 13734.
Formatted: Pattern: Clear
Formatted: Pattern: Clear
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute
provisions of this Technical Specification. For dated references, subsequent amendments to, or revisions
of, any of these publications do not apply. However, parties to agreements based on this Technical Report
are encouraged to investigate the possibility of applying the most recent editions of the normative
documents indicated below. For undated references, the latest edition of the normative document
referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 5492, Sensory analysis — Vocabulary
ISO 14532, Natural gas — Vocabulary
ISO 5492, Sensory analysis — Vocabulary
ISO 14532, Natural gas — Vocabulary
3 Terms and definitions
For the purposes of this Technical Specification, the terms and definitions given in ISO 5492 and
Formatted: Pattern: Clear
ISO 14532 and the following apply:
Formatted: Pattern: Clear
3.1.1
Formatted: Pattern: Clear
odorant content
Formatted: Pattern: Clear
content of the odorant either in the gas or in air expressed as its mass concentration, volume fraction or
mole fraction
3.1.2
odorodour perception
awareness of the effect of volatile substances by the olfactory organ
3.1.3
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ISO/DTSPRF TS 16922:2022(E)
odorodour character
distinctive and identifiable feature of an odorodour or flavour
3.1.4
odorodour intensity
magnitude of the perceived odor
3.1.5
masking
phenomenon by which one or more constituents in the gas stream can change or reduce the odorodour
intensity and/or the odorodour character of the odorized gas
3.1.6
fading of odorant
phenomenon where adsorption, absorption or chemical reactivity of the odorant result in loss of odorant
across the network
4 General requirements
4.1 Necessary odorant addition
Because safety is paramount in the gas industry, it could be assumed that the stronger the odorodour of
gas, the better. However, an upper limit is usually set to avoid unjustified leakage complaints already
caused by the small volume of unburnt gas escaping during ignition of the burner. An excessive
odorization level can also lead to a slight and permanent gas smell related to micro leaks that cannot be
localized and sealed. This could lead to habituation of the customer with the eventuality of a late reaction
when actual leaks occur. Gas odorization is in most countries a legal or regulation requirement that
specifies that natural gas in air be readily detectable by odorodour at a concentration of 20 % (safety
factor of 5) of the lower flammability limit (LFL). The LFL of natural gas is normally taken as a volume
fraction of natural gas in air of 4 % to 5 %. However, local regulations may specify other odorization rules.
NOTE Consider potential masking issues when blending natural gas with other gases (e. g. biomethane, LPG), the
odorodour being either naturally present or artificially added.
4.2 Requirements and parameters for consideration when selecting an odorant
[1]
Information about different odorants is given in informative annex A of .
Formatted: Pattern: Clear
Various parameters are considered when selecting an odorant:
— Typical odorodour character that is intense, unpleasant and universally associated with gas
— Physical properties: Freezing point, boiling point, vapour pressure
— Stability:
— Stability with respect to oxidation in network:
Mercaptans being more reactive than sulfides, they tend to form less odorous disulfides in presence
of rust, thus lowering odorization efficiency.
— Stability in storage:
2 © ISO 2022 – All rights reserved
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ISO/DTS PRF TS 16922:2022(E)
Some chemicals developed for odorization displaying reactive function can undergo hazardous
polymerization reaction if not stabilized adequately. Such reaction could occur in storage
tank or within injection system.
— Toxicity
— Environmental issues
— Gas quality: wet gas, presence of other sulphur compounds or network displaying condensates will
generate odorant scrubbing or cross contamination that may affect odorant efficiency
— Odorization practice in the region:
— Centralized / decentralized
— Odorization technique: (some odorants may not be compatible with Bypass odorizers, etc.)
— Network material (Carbon steel, plastics)
The level of the odorant added, that determines the odorodour intensity, is based on different factors
whereof not all are based on measurement, as e.g. local experience. The typical objective is that the
population with a functional sense of smell will be able to smell odorized gas before its concentration
reaches the specified limit (typically 20 % LFL) and thus takes the appropriate measures to protect itself.
Different approaches are applied to define and estimate the concentration of odorant required to achieve
this effect.
The odorodour intensity of an odorant for natural gas or a gas is best determined by the human olfactory
organ.
4.3 Public awareness
In some countries, local regulations require the operators to follow a public awareness program, which
may include specific information about the risk of gas and guidance for leak recognition. The use of
scratch-and-sniff cards containing the encapsulated odorant or other carriers is also frequently used in a
number of countries, but other kind of smell samples are also encountered.
In the case of changing the odour character of the gas odorant, the need to provide adequate information
to the members of the public and gas users should be considered.
5 General remarks on odorant behaviour
5.1 Masking and fading of odorants
Temporary fading in a new gas distribution system or after changing the odorant requires specific
monitoring and can need temporary supplemental odorization or other measures ( e. g. preconditioning).
Some components, e. g. present in some natural gases or biogases may react on or with the odorant
applied, resulting in a major loss of smell of the odorant either by masking effects or by chemical reaction.
5.2 Seals and membranes
Liquid odorants may cause severe swelling or even dissolution of organic materials such as plastics,
elastomeric seals and lubricants. Therefore, in odorization equipment and for joints close to the points
where the liquid odorant is injected into the line, only sealing materials should be used which are
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ISO/DTSPRF TS 16922:2022(E)
compatible with liquid odorants. This information is normally supplied by the manufacturer of the
odorant (see [1]).
Formatted: Pattern: Clear
5.3 Pipelines
The low odorant concentrations used for odorization of natural gas do not compromise the integrity of
plastic pipes, seals or diaphragms in gas transportation, distribution and utilization.
When starting gas distribution through new gas lines or when changing the odorant it may take some
time to reach the required odorant concentration at the end of the line. This may result from the odorant
being sorbed on the pipe wall, by pipe dust, rust and incrustations or by gas condensates (odorodour
fading). The degree of sorption depends on several factors, for example the condition of the pipe grid, the
pressure, the temperature, the flow velocity and the physico-chemical properties of odorants.
5.4 Buried pipeline
Odorized gases leaking from gas lines in the ground may lose odorants by sorption in the soil. Sorption
and oxidation of odorants may vary with moisture content and the type of soil. Degradation of odorants
by microorganisms may also occur.
6 Safety precautions
6.1 Handling of odorants
WARNING — Odorants should be handled according to their actual characteristics and prevailing
regulations.
IMPORTANT - — All relevant safety precautions being observed when handling odorants, employees
should be instructed periodically. Odorants are irritating, harmful and flammable. Therefore, the specific
material safety data sheet should be read prior to handling liquid odorants. All safety precautions should
be strictly observed and followed.
A minimum level of safety may be achieved by the following recommendations:
— Concentrated vapours of odorants may cause short-term acute health problems, such as dizziness,
headache, nausea and irritation of throat, nose and eyes. Therefore protection, for example with a
filter containing activated charcoal or a respirator, is common use. Any extended exposure without
respiration protection need to be avoided.
— When handling odorants, suitable personal protective equipment (eye-, face-, body-protection,
gloves) and safe-handling procedures of the odorant are recommended. If, in spite of the use of
personal protection equipment, liquid odorant contacts the skin or the eyes, wash the affected spot
as first aid, immediately with plenty of water. If an eye comes in contact with liquid odorant, consult
a physician immediately.
6.2 Spill management and remediation
WARNING — Undiluted oxidants should never be brought into contact with odorants: RISK OF
EXPLOSION!
There are several possibilities to eliminate the nuisance caused by the strong odorodour of spilled
odorants.
4 © ISO 2022 – All rights reserved
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ISO/DTS PRF TS 16922:2022(E)
— For odorodour
...
TECHNICAL ISO/TS
SPECIFICATION 16922
First edition
Natural gas — Odorization
Gaz naturel — Odorisation
PROOF/ÉPREUVE
Reference number
ISO/TS 16922:2022(E)
© ISO/TS 2022
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ISO/TS 16922:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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.
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
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ISO/TS 16922:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Necessary odorant addition . . 2
4.2 Requirements and parameters for consideration when selecting an odorant . 2
4.3 Public awareness . 3
5 General remarks on odorant behaviour . 3
5.1 Masking and fading of odorants . 3
5.2 Seals and membranes . 3
5.3 Pipelines . 3
5.4 Buried pipeline . 3
6 Safety precautions. 4
6.1 Handling of odorants . 4
6.2 Spill management and remediation . 4
6.3 Transportation and storage . 5
7 Odorization technique .5
7.1 Odorization of pipeline networks . 5
7.1.1 Odorization of transmission pipelines . 5
7.1.2 Odorization of distribution pipelines . 5
7.1.3 Combined odorization of transmission and distribution pipelines . 6
7.2 Odorizer . 6
7.2.1 General . 6
7.2.2 Liquid injection odorizers . 6
7.2.3 Positioning of odorant injectors . 7
7.2.4 Evaporation odorizers . 7
7.3 Design of installation . 8
7.3.1 Odorization rooms . 8
7.3.2 Ventilation . 8
7.3.3 Installation of injection point and injection pipe . 8
7.3.4 Tank design and operations . 8
7.3.5 Spill kit . 9
7.4 Pressure resistance . 9
7.5 Addition of odorant . 9
7.5.1 Control of the addition . 9
7.5.2 Monitoring and control devices . 9
7.5.3 Testing and commissioning . 9
8 Control of odorization .9
8.1 General . 9
8.2 Check of odorization equipment and systems . 10
8.3 Control of odorization of the gas . 10
8.4 Odour complaints . 10
Bibliography .11
iii
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ISO/TS 16922:2022(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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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.
This first edition ISO/TS 16922 cancels and replaces the first edition (ISO/TR 16922:2013), which has
been technically revised.
The main changes are as follows:
— modification of the structure of the Technical Report, new clauses: 4.1, 4.2, 4.3, 5.1, Clause 7, 7.1,
7.1.1, 7.1.2, 7.1.3, 7.3, 7.3.1, 7.3.2, 7.3.3, 7.3.4, 7.3.5;
— modification of 7.2.
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.
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ISO/TS 16922:2022(E)
Introduction
Processed natural gas normally has little or no odour. For safety reasons distributed natural gas is
therefore be odorized, to permit the detection of the gas by smell.
The odorization is predominantly a safety measure for the user of natural gas. Odorized natural gas
needs to be recognized by the characteristic smell.
This document may also be applied to other gases used in gas supply as e.g. biomethane, blends
containing hydrogen, regasified LNG or LBG, LPG for conditioning in gas supply, etc.
v
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TECHNICAL SPECIFICATION ISO/TS 16922:2022(E)
Natural gas — Odorization
1 Scope
This document gives the specifications and guidelines for the methods to be used in the odorization of
natural gas and other methane rich gases delivered through natural gas networks to gas applications
under a safety point of view.
This document also specifies the principles for the odorization technique (including handling and
storage of odorants) and the control of odorization of natural gas and other methane rich gases.
NOTE The general requirements for odorants, and the physical and chemical properties of commonly used
odorants are specified in ISO 13734.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this Technical Specification. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements based on
this Technical Report are encouraged to investigate the possibility of applying the most recent
editions of the normative documents indicated below. For undated references, the latest edition of the
normative document referred to applies. Members of ISO and IEC maintain registers of currently valid
International Standards.
ISO 5492, Sensory analysis — Vocabulary
ISO 14532, Natural gas — Vocabulary
3 Terms and definitions
For the purposes of this Technical Specification, the terms and definitions given in ISO 5492 and
ISO 14532 and the following apply:
3.1.1
odorant content
content of the odorant either in the gas or in air expressed as its mass concentration, volume fraction or
mole fraction
3.1.2
odour perception
awareness of the effect of volatile substances by the olfactory organ
3.1.3
odour character
distinctive and identifiable feature of an odour or flavour
3.1.4
odour intensity
magnitude of the perceived odour
3.1.5
masking
phenomenon by which one or more constituents in the gas stream can change or reduce the odour
intensity (3.1.4) and/or the odour character (3.1.3) of the odorized gas
1
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ISO/TS 16922:2022(E)
3.1.6
fading of odorant
phenomenon where adsorption, absorption or chemical reactivity of the odorant result in loss of
odorant across the network
4 General requirements
4.1 Necessary odorant addition
Because safety is paramount in the gas industry, it could be assumed that the stronger the odour of gas,
the better. However, an upper limit is usually set to avoid unjustified leakage complaints already caused
by the small volume of unburnt gas escaping during ignition of the burner. An excessive odorization
level can also lead to a slight and permanent gas smell related to micro leaks that cannot be localized
and sealed. This could lead to habituation of the customer with the eventuality of a late reaction when
actual leaks occur. Gas odorization is in most countries a legal or regulation requirement that specifies
that natural gas in air be readily detectable by odour at a concentration of 20 % (safety factor of 5) of
the lower flammability limit (LFL). The LFL of natural gas is normally taken as a volume fraction of
natural gas in air of 4 % to 5 %. However, local regulations may specify other odorization rules.
NOTE Consider potential masking issues when blending natural gas with other gases (e.g. biomethane, LPG),
the odour being either naturally present or artificially added.
4.2 Requirements and parameters for consideration when selecting an odorant
Information about different odorants is given in ISO 13734:2013, Annex A.
Various parameters are considered when selecting an odorant:
— Typical odour character that is intense, unpleasant and universally associated with gas
— Physical properties: Freezing point, boiling point, vapour pressure
— Stability:
— Stability with respect to oxidation in network:
Mercaptans being more reactive than sulfides, they tend to form less odorous disulfides in presence
of rust, thus lowering odorization efficiency.
— Stability in storage:
Some chemicals developed for odorization displaying reactive function can undergo hazardous
polymerization reaction if not stabilized adequately. Such reaction could occur in storage tank
or within injection system.
— Toxicity
— Environmental issues
— Gas quality: wet gas, presence of other sulphur compounds or network displaying condensates will
generate odorant scrubbing or cross contamination that may affect odorant efficiency
— Odorization practice in the region:
— Centralized / decentralized
— Odorization technique: (some odorants may not be compatible with Bypass odorizers, etc.)
— Network material (Carbon steel, plastics)
2
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ISO/TS 16922:2022(E)
The level of the odorant added, that determines the odour intensity, is based on different factors
whereof not all are based on measurement, as e.g. local experience. The typical objective is that the
population with a functional sense of smell will be able to smell odorized gas before its concentration
reaches the specified limit (typically 20 % LFL) and thus takes the appropriate measures to protect
itself. Different approaches are applied to define and estimate the concentration of odorant required to
achieve this effect.
The odour intensity of an odorant for natural gas or a gas is best determined by the human olfactory
organ.
4.3 Public awareness
In some countries, local regulations require the operators to follow a public awareness program, which
may include specific information about the risk of gas and guidance for leak recognition. The use of
scratch-and-sniff cards containing the encapsulated odorant or other carriers is also frequently used in
a number of countries, but other kind of smell samples are also encountered.
In the case of changing the odour character of the gas odorant, the need to provide adequate information
to the members of the public and gas users should be considered.
5 General remarks on odorant behaviour
5.1 Masking and fading of odorants
Temporary fading in a new gas distribution system or after changing the odorant requires specific
monitoring and can need temporary supplemental odorization or other measures ( e.g. preconditioning).
Some components, e.g. present in some natural gases or biogases may react on or with the odorant
applied, resulting in a major loss of smell of the odorant either by masking effects or by chemical
reaction.
5.2 Seals and membranes
Liquid odorants may cause severe swelling or even dissolution of organic materials such as plastics,
elastomeric seals and lubricants. Therefore, in odorization equipment and for joints close to the points
where the liquid odorant is injected into the line, only sealing materials should be used which are
compatible with liquid odorants. This information is normally supplied by the manufacturer of the
odorant (see ISO 13734).
5.3 Pipelines
The low odorant concentrations used for odorization of natural gas do not compromise the integrity of
plastic pipes, seals or diaphragms in gas transportation, distribution and utilization.
When starting gas distribution through new gas lines or when changing the odorant it may take
some time to reach the required odorant concentration at the end of the line. This may result from
the odorant being sorbed on the pipe wall, by pipe dust, rust and incrustations or by gas condensates
(odour fading). The degree of sorption depends on several factors, for example the condition of the pipe
grid, the pressure, the temperature, the flow velocity and the physico-chemical properties of odorants.
5.4 Buried pipeline
Odorized gases leaking from gas lines in the ground may lose odorants by sorption in the soil. Sorption
and oxidation of odorants may vary with moisture content and the type of soil. Degradation of odorants
by microorganisms may also occur.
3
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ISO/TS 16922:2022(E)
6 Safety precautions
6.1 Handling of odorants
WARNING — Odorants should be handled according to their actual characteristics and prevailing
regulations.
IMPORTANT — All relevant safety precautions being observed when handling odorants,
employees should be instructed periodically. Odorants are irritating, harmful and flammable.
Therefore, the specific material safety data sheet should be read prior to handling liquid
odorants. All safety precautions should be strictly observed and followed.
A minimum level of safety may be achieved by the following recommendations:
— Concentrated vapours of odorants may cause short-term acute health problems, such as dizziness,
headache, nausea and irritation of throat, nose and eyes. Therefore protection, for example with a
filter containing activated charcoal or a respirator, is common use. Any extended exposure without
respiration protection need to be avoided.
— When handling odorants, suitable personal protective equipment (eye-, face-, body-protection,
gloves) and safe-handling procedures of the odorant are recommended. If, in spite of the use of
personal protection equipment, liquid odorant contacts the skin or the eyes, wash the affected spot
as first aid, immediately with plenty of water. If an eye comes in contact with liquid odorant, consult
a physician immediately.
6.2 Spill management and remediation
WARNING — Undiluted oxidants should never be brought into contact with odorants: RISK OF
EXPLOSION!
There are several possibilities to eliminate the nuisance caused by the strong odour of spilled odorants.
— For odour mitigation, deodorants may be used, which normally do not change the chemical properties
of the odorant. Therefore, health risks will not be eliminated. For larger amounts of spilled odorants
these masking compounds are not suitable.
— Minor quantities of spilled odorants (surface cleaning) can be treated with different options:
— oxidized to less smelling compounds utilizing a procedure incorporating the spraying of diluted
solutions of an oxidant such as 5 % by mass of sodium hypochlorite or 5 % by mass of hydrogen
peroxide, preferably under the addition of detergents. This procedure should account for the
corrosive and reactive nature of these oxidants.
— neutralized with enzymatic solutions, only effective for some odorants (e.g. mercaptans)
— Larger quantities of spilled or leaked odorants should be sorbed by sorbents (activated charcoal)
and disposed of in tightly shut containers. Small remainders should be treated as minor quantities.
These sorbents or soil contaminated by odorants should be treated according to prevailing regulations.
Commercial products are also available to mask and/or mitigate odorant spillage. These products are
generally available through the odorant manufacturer.
For the cleaning of pipework, containers and parts of the odorizing equipment the use of alcohols
(isopropanol, technical ethanol) is an option. The used cleaning solution are to be disposed according to
prevailing regulations.
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ISO/TS 16922:2022(E)
6.3 Transportation and storage
Odorants are delivered in corrosion-resistant containers suitable for transport and/or storage
according to prevailing regulations. Odorant containers need to be accompanied by a safety data sheet
conforming to the requirements of all prevailing regulations.
The use of the proper sealing materials is according to the type of odorant, sulfurous or acrylic.
To avoid nuisance when stationary odorant tanks are refilled, vapour equalization lines for gas phase
transfer between storage and transportation tanks are recommended. Lines for transfer equipped with
automatic shutoff valves are recommended, where possible. Connections and valves preferably have
minimum dead volume.
Storage rooms for odorant containers are best cool, dry and well ventilated. Extended impact of the sun
increase of the internal pressure of odorant containers during transport and/or storage.
Storage containers and the odorizing plant may be in the same room. Odorants jointly with any easily
inflammable substance is best to be avoided.
7 Odorization technique
7.1 Odorization of pipeline networks
7.1.1 Odorization of transmission pipelines
Centralized odorization is performed at the entry point of gas into the transmission network (i.e. LNG
terminal, interconnection points, etc.). Its advantages are:
— the installation, operation and maintenance of sophisticated equipment to automate and monitor
each odorizer is simpler and results in better uniformity of the odorant concentration in the gases;
— it allows a uniform gas odour throughout a region.
Its disadvantages are
— the odorants may have to be removed from the gas supplied to some industrial consumers, and
— odorized gas is delivered to industrial consumers that may not need it because other safety measures
may be provided to recognize gas leaks (e.g. gas sensors for these industrial processes).
7.1.2 Odorization of distribution pipelines
Decentralised odorization is performed typically at the entry points of the distribution networks,
including biomethane injection points. Advantages for decentralized odorization are:
— odorant concentrations can be adjusted to the specific conditions of the local distribution grid (new
pipes or old pipes with deposits),
— the sulfur content of gas for industrial use or the environmental effects of odorants on some types
of underground storage are not increased by odorization by avoiding unnecessary odorization.
Disadvantages of decentralized odorization are
— the multiplicity of odorization stations, generally close to populated areas,
— generation of transportation of odorant on road or rail, and
— handling of odorant by a multitude of personnel,
— low gas flow is more difficult to follow up in odorant dosage.
5
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ISO/TS 16922:2022(E)
7.1.3 Combined odorization of transmission and distribution pipelines
In some countries, classification of transmission pipelines is enforced according to the human
occupancy on either side of the pipelines, defining which pipelines have to be odorized. In a number of
countries, odorization is mandatory when the human occupancy is high.
In some cases, minimum odorization levels in transmission and distribution are different. In other cases,
where different odorants are in use and the possibility exists to transfer odorized gas from distribution
to transmission grids (in case of biomethane overproduction) it may be required to deodorize the gas.
7.2 Odorizer
7.2.1 General
Odorization is usually performed using one of the following techniques:
— liquid odorant injection;
— evaporation odorizer.
7.2.2 Liquid injection odorizers
To allow for a constant odorization, the necessary amount of odorant is added to the gas stream
continuously or quasi continuously. This is best accomplished by flow proportional odorization by
injection odorizers. Flow proportioning refers to adjusting the odorant injection rate to the flowrate of
the gas flowing in the pipeline. These odorizers are typically the most commonly used nowadays, and
can be sized to fit most flowrates.
Odorant is injected from a storage tank, generally maintained at low pressure, directly into the flowing
gas. In principle, two systems are commonly in use:
a) Systems with injection pumps: the injection rate is related to the volumetric pump displacement
and the stroke frequency. This frequency is adjusted by accounting for the gas flow as measured by
a measurement device. The pump protected by an upstream filter against clogging.
b) Valve-controlled systems: Gas-flow proportional injection from a pressurized storage tank may be
achieved by means of mass-flow or volume-flow controllers.
The injection of odorant may also be regulated by taking into account the actual odorant concentration
present in the gas. The injection system also can produce information regarding the total odorant
injected, injection rate, and alarms regarding the performance of the system.
The liquid odorant can be injected into an injection probe. Designs of these probes vary but are intended
to maximize vaporization of the odorant into the natural gas. Filters are normally installed upstream
to the injection system in order to decrease the required maintenance of the system. A check valve and
isolation valve should be installed in the connection line between the injection system and the injection
point.
All material in contact with liquid odorants should be assessed for compatibility with the specific
odorant in accordance with the odorant manufacturer’s information. Such assessment is therefore also
performed when the type of odorant is changed.
To i
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