SIST EN ISO 10298:2020
(Main)Gas cylinders - Gases and gas mixtures - Determination of toxicity for the selection of cylinder valve outlets (ISO 10298:2018)
Gas cylinders - Gases and gas mixtures - Determination of toxicity for the selection of cylinder valve outlets (ISO 10298:2018)
ISO 10298:2018 lists the best available acute-toxicity data of gases taken from a search of the current literature to allow the classification of gases and gas mixtures for toxicity by inhalation.
Gasflaschen - Gase und Gasgemische - Bestimmung der Toxizität zur Auswahl von Ventilausgängen (ISO 10298:2018)
In diesem Dokument sind die besten verfügbaren Daten zur akuten Toxizität von Gasen aufgeführt, die in einer Recherche der aktuellen Literatur entnommen wurden, um die Einstufung von Gasen und Gasgemischen hinsichtlich ihrer Toxizität durch Inhalation zu ermöglichen.
Bouteilles à gaz - Gaz et mélanges de gaz - Détermination de la toxicité pour le choix des raccords de sortie de robinets (ISO 10298:2018)
Le présent document dresse la liste des meilleures données de toxicité aiguë disponibles sur les gaz, extraites des ouvrages de référence actuels et permettant de classer les gaz et les mélanges de gaz en termes de toxicité par inhalation.
Plinske jeklenke - Plini in zmesi plinov - Določanje strupenosti za izbiro izhodnega priključka ventila na jeklenki (ISO 10298:2018)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 10298:2020
01-december-2020
Plinske jeklenke - Plini in zmesi plinov - Določanje strupenosti za izbiro izhodnega
priključka ventila na jeklenki (ISO 10298:2018)
Gas cylinders - Gases and gas mixtures - Determination of toxicity for the selection of
cylinder valve outlets (ISO 10298:2018)
Gasflaschen - Gase und Gasgemische - Bestimmung der Toxizität zur Auswahl von
Ventilausgängen (ISO 10298:2018)
Bouteilles à gaz - Gaz et mélanges de gaz - Détermination de la toxicité pour le choix
des raccords de sortie de robinets (ISO 10298:2018)
Ta slovenski standard je istoveten z: EN ISO 10298:2020
ICS:
23.020.35 Plinske jeklenke Gas cylinders
71.100.20 Industrijski plini Gases for industrial
application
SIST EN ISO 10298:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 10298:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 10298:2020
EN ISO 10298
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2020
EUROPÄISCHE NORM
ICS 71.100.20
English Version
Gas cylinders - Gases and gas mixtures - Determination of
toxicity for the selection of cylinder valve outlets (ISO
10298:2018)
Bouteilles à gaz - Gaz et mélanges de gaz - Gasflaschen - Gase und Gasgemische - Bestimmung der
Détermination de la toxicité pour le choix des raccords Toxizität zur Auswahl von Ventilausgängen (ISO
de sortie de robinets (ISO 10298:2018) 10298:2018)
This European Standard was approved by CEN on 28 September 2020.
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, Turkey 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10298:2020 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 10298:2020
EN ISO 10298:2020 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 10298:2020
EN ISO 10298:2020 (E)
European foreword
The text of ISO 10298:2018 has been prepared by Technical Committee ISO/TC 58 "Gas cylinders” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 10298:2020
by Technical Committee CEN/TC 23 “Transportable gas cylinders” the secretariat of which is held by
BSI.
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 April 2021, and conflicting national standards shall be
withdrawn at the latest by April 2021.
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.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 10298:2018 has been approved by CEN as EN ISO 10298:2020 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 10298:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 10298:2020
INTERNATIONAL ISO
STANDARD 10298
Third edition
2018-02
Gas cylinders — Gases and gas
mixtures — Determination of toxicity
for the selection of cylinder valve
outlets
Bouteilles à gaz — Gaz et mélanges de gaz — Détermination de la
toxicité pour le choix des raccords de sortie de robinets
Reference number
ISO 10298:2018(E)
©
ISO 2018
---------------------- Page: 7 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Determination of toxicity . 2
4.1 General . 2
4.2 Test method . 2
4.2.1 Test procedure . 2
4.2.2 Results for pure gases . . 2
4.3 Calculation method . 2
Annex A (informative) Selection of an LC value for a particular gas . 4
50
Annex B (informative) LC50 values for toxic gases and toxic vapours used in gas mixtures .7
Bibliography .12
© ISO 2018 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(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 on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by ISO/TC 58 Gas cylinders, SC 2, Cylinder fittings.
This third edition cancels and replaces the second edition (ISO 10298:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— The Scope and Clause 4 have been clarified.
— The terms and definitions in Clause 3 have been changed and, in particular, the reference to FTSC
codes (that were in ISO 5145) was changed to ISO 14456.
— Some LC50 values have been updated.
iv © ISO 2018 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
Introduction
ISO 5145 specifies the dimensions of different valve outlets for different compatible gas groups. These
compatible gas groups are determined according to practical criteria defined in ISO 14456.
These criteria are based on certain physical, chemical, toxic and corrosive properties of the gases. In
particular, the tissue corrosiveness is considered in this document.
The aim of this document is to assign for each gas a classification category that takes into account the
toxicity by inhalation of the gas. For gas mixtures containing toxic components a calculation based on
the method specified in the GHS is proposed.
Since the publication of the first edition of ISO 10298, this International Standard has been used for other
purposes than the selection of cylinder valve outlets, e.g. providing toxicity data for the classification
of gas and gas mixtures according to the international transport regulations and according to the
classification of dangerous substances regulations, which since 2003 is under the umbrella of the
Globally Harmonized System (GHS).
© ISO 2018 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 10298:2020
---------------------- Page: 12 ----------------------
SIST EN ISO 10298:2020
INTERNATIONAL STANDARD ISO 10298:2018(E)
Gas cylinders — Gases and gas mixtures — Determination
of toxicity for the selection of cylinder valve outlets
1 Scope
This document lists the best available acute-toxicity data of gases taken from a search of the current
literature to allow the classification of gases and gas mixtures for toxicity by inhalation.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online Browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
lethal concentration 50
LC
50
concentration of a substance in air exposure to which, for a specified length of time, it is expected to
cause the death of 50 % of the entire defined experimental animal population after a defined time period
Note 1 to entry: See Annex A for the selection of this LC value.
50
3.2
toxicity level
level of toxicity of gases and gas mixtures
Note 1 to entry: In ISO 14456, the toxicity level is divided into three groups:
— Subdivision 1: non toxic [LC > 5 000 ppm (volume fraction)]
50
— Subdivision 2: toxic [200 ppm (volume fraction) < LC ≤ 5 000 ppm (volume fraction)]
50
— Subdivision 3: very toxic [LC ≤ 200 ppm (volume fraction)]
50
These subdivisions are sometimes used in transport regulations.
where
LC values correspond to 1 h exposure to gas;
50
ppm (volume fraction) indicates parts per million, by volume.
Note 2 to entry: In the GHS, the inhalation toxicity levels are:
© ISO 2018 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
Category 1: Fatal if inhaled 0 ppm < LC ≤ 100 ppm (volume fraction)
50
Category 2: Fatal if inhaled 100 ppm (volume fraction) < LC ≤ 500 ppm (volume fraction)
50
Category 3: Toxic if inhaled 500 ppm (volume fraction) < LC ≤ 2 500 ppm (volume fraction)
50
Category 4: Harmful if inhaled 2 500 ppm (volume fraction) < LC ≤ 20 000 ppm (volume fraction)
50
Note 3 to entry: In GHS, the LC values correspond to 4 hours exposure. Consequently, the LC50 values given in
50
Annex B (see 4.2.2) need to be divided by 2 (i.e. 41/ ). The reasoning behind the division by 2 is given in A.2.
3.3
lethal dose 50
LD
50
amount of a material, given all at once, which causes the death of 50 % of a group of test animals
3.4
lethal concentration low value
LC
LO
lowest concentration of a substance in air, other than the LC , which was reported in the original
50
reference paper as having caused death in humans or animals
4 Determination of toxicity
4.1 General
Toxicity may be determined through a test method (4.2) for gas mixtures where the data for the
components exist, or through a calculation method (4.3).
For reasons of animal welfare, inhalation toxicity tests geared only for the classification of gas
mixtures should be avoided if the toxicity of each of the components is available. In this case, toxicity is
determined in accordance with 4.3.
4.2 Test method
4.2.1 Test procedure
When new toxicity data are being considered for inclusion in this document, an internationally
[43]
recognized test method such as OECD TG 403 should be used.
NOTE For this document, LC is equivalent to 1 h exposure to albino rats.
50
4.2.2 Results for pure gases
The toxicity of pure gases is listed in Annex B, in which LC values correspond to 1 h exposure. Some of
50
these values have been estimated in accordance with Annex A.
4.3 Calculation method
The LC value of a gas mixture is calculated using Formula 1:
50
1
LC = (1)
50i
C
i
∑
LC
50
i
where
C is the mole fraction of the ith toxic component present in the gas mixture;
i
LC is the lethal concentration of the ith toxic component [LC < 5 000 ppm (by volume)].
50i 50
2 © ISO 2018 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
After the LC of the gas mixture has been calculated, this mixture is classified in accordance with 3.2.
50
NOTE Potential synergistic effects are not considered in Formula 1.
© ISO 2018 – All rights reserved 3
---------------------- Page: 15 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
Annex A
(informative)
Selection of an LC value for a particular gas
50
A.1 General
When collecting data from the open literature on the acute inhalation toxicity of gases, some difficulties
are experienced. For example, taking into account the very early years of publication, one cannot expect
to get results of standardized tests. Moreover, data from reporting sources have to be validated with
respect to their details in handling and summarizing information. Furthermore, there is a lack of
information on inhalation toxicity for several gases. Thus, particular attention is needed to incorporate
all the available facts to complete the toxicological characteristics of gases.
A.2 Time adjustment
In inhalation toxicity tests, the dose-response relationship can be described by Formula A.1:
W = c ⋅ t (A.1)
where
W is a constant which is specific for any given effect, e.g. the deaths of 50 % of the animals
exposed;
c ⋅ t is the applied dose expressed as the product of concentration and exposure time.
This equation, called Haber's rule, is applicable as long as the biological half-life of the substance in
question is reasonably longer than the exposure time.
For gases and vapours with appreciable rates of detoxification or excretion over the time in question,
it was found that the relationship between concentration and time is better described by Formula A.2.
0,5
W = c ⋅ t (A.2)
When extrapolating from 4 h to 1 h, Formula A.2 predicts lower LC values than does Haber's rule. To
50
be on the safe side, this principle was applied by the UN Transport Recommendations in adopting the
conversion factor 2 (i.e. 41/ ) to allow classification of materials on the basis of 1 h LC data. On the
50
other hand, Haber's rule predicts a lower LC when going from a 1-h to a 4-h LC . To make use of all
50 50
the available data on acute inhalation toxicity under the different exposure schemes, a more generalized
version was applied.
Using 1 h as the point of reference,
— going up from shorter periods, linear extrapolation was preferred;
— coming down from longer periods, the conversion factor xhh/1 was used.
However, test results for a period less than 0,5 h were not used, as this was deemed unreliable.
4 © ISO 2018 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 10298:2020
ISO 10298:2018(E)
A.3 Choice of animal
Since data on humans, if available, are usually not sufficient to derive any dose-response relationship,
laboratory animals are used to investigate the toxicity of substances on warm-blooded animals.
Unless there are counter indications, such as extraordinarily high or low susceptibility of the rat
compared to other animals or humans, the rat is the preferred species in the most common toxicity
tests. Therefore, LC data in rats are the most likely to be found. If they are missing, data from animals
50
close to the rat in body weight are evaluated.
A.4 Adjustment for effects
Instead of LC , often the term LC is found in the reporting literature and in databases.
50 LO
Unfortunately, the use of this term is not consistent enough to make any assumptions as to whether
the LC is below or above that value. Nevertheless, it seems reasonable to make the same use of the
50
LC as if it were information about an approximate lethal concentration (ALC). For the classification of
LO
gases, no higher precision is required, but the calculation formula for gas mixtures requires a definite
LC value to be set. Another LC value has been taken
...
SLOVENSKI STANDARD
oSIST prEN ISO 10298:2020
01-maj-2020
Plinske jeklenke - Plini in zmesi plinov - Določevanje strupenosti za izbiro
izhodnega priključka ventila na jeklenki (ISO 10298:2018)
Gas cylinders - Gases and gas mixtures - Determination of toxicity for the selection of
cylinder valve outlets (ISO 10298:2018)
Gasflaschen - Gase und Gasgemische - Bestimmung der Toxizität zur Auswahl von
Ventilausgängen (ISO 10298:2018)
Bouteilles à gaz - Gaz et mélanges de gaz - Détermination de la toxicité pour le choix
des raccords de sortie de robinets (ISO 10298:2018)
Ta slovenski standard je istoveten z: prEN ISO 10298
ICS:
23.020.35 Plinske jeklenke Gas cylinders
oSIST prEN ISO 10298:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 10298:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 10298:2020
INTERNATIONAL ISO
STANDARD 10298
Third edition
2018-02
Gas cylinders — Gases and gas
mixtures — Determination of toxicity
for the selection of cylinder valve
outlets
Bouteilles à gaz — Gaz et mélanges de gaz — Détermination de la
toxicité pour le choix des raccords de sortie de robinets
Reference number
ISO 10298:2018(E)
©
ISO 2018
---------------------- Page: 3 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Determination of toxicity . 2
4.1 General . 2
4.2 Test method . 2
4.2.1 Test procedure . 2
4.2.2 Results for pure gases . . 2
4.3 Calculation method . 2
Annex A (informative) Selection of an LC value for a particular gas . 4
50
Annex B (informative) LC50 values for toxic gases and toxic vapours used in gas mixtures .7
Bibliography .12
© ISO 2018 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(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 on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by ISO/TC 58 Gas cylinders, SC 2, Cylinder fittings.
This third edition cancels and replaces the second edition (ISO 10298:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— The Scope and Clause 4 have been clarified.
— The terms and definitions in Clause 3 have been changed and, in particular, the reference to FTSC
codes (that were in ISO 5145) was changed to ISO 14456.
— Some LC50 values have been updated.
iv © ISO 2018 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
Introduction
ISO 5145 specifies the dimensions of different valve outlets for different compatible gas groups. These
compatible gas groups are determined according to practical criteria defined in ISO 14456.
These criteria are based on certain physical, chemical, toxic and corrosive properties of the gases. In
particular, the tissue corrosiveness is considered in this document.
The aim of this document is to assign for each gas a classification category that takes into account the
toxicity by inhalation of the gas. For gas mixtures containing toxic components a calculation based on
the method specified in the GHS is proposed.
Since the publication of the first edition of ISO 10298, this International Standard has been used for other
purposes than the selection of cylinder valve outlets, e.g. providing toxicity data for the classification
of gas and gas mixtures according to the international transport regulations and according to the
classification of dangerous substances regulations, which since 2003 is under the umbrella of the
Globally Harmonized System (GHS).
© ISO 2018 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 10298:2020
---------------------- Page: 8 ----------------------
oSIST prEN ISO 10298:2020
INTERNATIONAL STANDARD ISO 10298:2018(E)
Gas cylinders — Gases and gas mixtures — Determination
of toxicity for the selection of cylinder valve outlets
1 Scope
This document lists the best available acute-toxicity data of gases taken from a search of the current
literature to allow the classification of gases and gas mixtures for toxicity by inhalation.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online Browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
lethal concentration 50
LC
50
concentration of a substance in air exposure to which, for a specified length of time, it is expected to
cause the death of 50 % of the entire defined experimental animal population after a defined time period
Note 1 to entry: See Annex A for the selection of this LC value.
50
3.2
toxicity level
level of toxicity of gases and gas mixtures
Note 1 to entry: In ISO 14456, the toxicity level is divided into three groups:
— Subdivision 1: non toxic [LC > 5 000 ppm (volume fraction)]
50
— Subdivision 2: toxic [200 ppm (volume fraction) < LC ≤ 5 000 ppm (volume fraction)]
50
— Subdivision 3: very toxic [LC ≤ 200 ppm (volume fraction)]
50
These subdivisions are sometimes used in transport regulations.
where
LC values correspond to 1 h exposure to gas;
50
ppm (volume fraction) indicates parts per million, by volume.
Note 2 to entry: In the GHS, the inhalation toxicity levels are:
© ISO 2018 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
Category 1: Fatal if inhaled 0 ppm < LC ≤ 100 ppm (volume fraction)
50
Category 2: Fatal if inhaled 100 ppm (volume fraction) < LC ≤ 500 ppm (volume fraction)
50
Category 3: Toxic if inhaled 500 ppm (volume fraction) < LC ≤ 2 500 ppm (volume fraction)
50
Category 4: Harmful if inhaled 2 500 ppm (volume fraction) < LC ≤ 20 000 ppm (volume fraction)
50
Note 3 to entry: In GHS, the LC values correspond to 4 hours exposure. Consequently, the LC50 values given in
50
Annex B (see 4.2.2) need to be divided by 2 (i.e. 41/ ). The reasoning behind the division by 2 is given in A.2.
3.3
lethal dose 50
LD
50
amount of a material, given all at once, which causes the death of 50 % of a group of test animals
3.4
lethal concentration low value
LC
LO
lowest concentration of a substance in air, other than the LC , which was reported in the original
50
reference paper as having caused death in humans or animals
4 Determination of toxicity
4.1 General
Toxicity may be determined through a test method (4.2) for gas mixtures where the data for the
components exist, or through a calculation method (4.3).
For reasons of animal welfare, inhalation toxicity tests geared only for the classification of gas
mixtures should be avoided if the toxicity of each of the components is available. In this case, toxicity is
determined in accordance with 4.3.
4.2 Test method
4.2.1 Test procedure
When new toxicity data are being considered for inclusion in this document, an internationally
[43]
recognized test method such as OECD TG 403 should be used.
NOTE For this document, LC is equivalent to 1 h exposure to albino rats.
50
4.2.2 Results for pure gases
The toxicity of pure gases is listed in Annex B, in which LC values correspond to 1 h exposure. Some of
50
these values have been estimated in accordance with Annex A.
4.3 Calculation method
The LC value of a gas mixture is calculated using Formula 1:
50
1
LC = (1)
50i
C
i
∑
LC
50
i
where
C is the mole fraction of the ith toxic component present in the gas mixture;
i
LC is the lethal concentration of the ith toxic component [LC < 5 000 ppm (by volume)].
50i 50
2 © ISO 2018 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
After the LC of the gas mixture has been calculated, this mixture is classified in accordance with 3.2.
50
NOTE Potential synergistic effects are not considered in Formula 1.
© ISO 2018 – All rights reserved 3
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oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
Annex A
(informative)
Selection of an LC value for a particular gas
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A.1 General
When collecting data from the open literature on the acute inhalation toxicity of gases, some difficulties
are experienced. For example, taking into account the very early years of publication, one cannot expect
to get results of standardized tests. Moreover, data from reporting sources have to be validated with
respect to their details in handling and summarizing information. Furthermore, there is a lack of
information on inhalation toxicity for several gases. Thus, particular attention is needed to incorporate
all the available facts to complete the toxicological characteristics of gases.
A.2 Time adjustment
In inhalation toxicity tests, the dose-response relationship can be described by Formula A.1:
W = c ⋅ t (A.1)
where
W is a constant which is specific for any given effect, e.g. the deaths of 50 % of the animals
exposed;
c ⋅ t is the applied dose expressed as the product of concentration and exposure time.
This equation, called Haber's rule, is applicable as long as the biological half-life of the substance in
question is reasonably longer than the exposure time.
For gases and vapours with appreciable rates of detoxification or excretion over the time in question,
it was found that the relationship between concentration and time is better described by Formula A.2.
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W = c ⋅ t (A.2)
When extrapolating from 4 h to 1 h, Formula A.2 predicts lower LC values than does Haber's rule. To
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be on the safe side, this principle was applied by the UN Transport Recommendations in adopting the
conversion factor 2 (i.e. 41/ ) to allow classification of materials on the basis of 1 h LC data. On the
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other hand, Haber's rule predicts a lower LC when going from a 1-h to a 4-h LC . To make use of all
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the available data on acute inhalation toxicity under the different exposure schemes, a more generalized
version was applied.
Using 1 h as the point of reference,
— going up from shorter periods, linear extrapolation was preferred;
— coming down from longer periods, the conversion factor xhh/1 was used.
However, test results for a period less than 0,5 h were not used, as this was deemed unreliable.
4 © ISO 2018 – All rights reserved
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oSIST prEN ISO 10298:2020
ISO 10298:2018(E)
A.3 Choice of animal
Since data on humans, if available, are usually not sufficient to derive any dose-response relationship,
laboratory animals are used to investigate the toxicity of substances on warm-blooded animals.
Unless there are counter indications, such as extraordinarily high or low susceptibility of the rat
compared to other animals or humans, the rat is the preferred species in the most common toxicity
tests. Therefore, LC data in rats are the most likely to be found. If they are missing, data from animals
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close to the rat in body weight are evaluated.
A.4 Adjustment for effects
Instead of LC , often the term LC is found in the reporting literature and in databases.
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Unfortunately, the use of this term is not consistent enough to make any assumptions as to whether
the LC is below or above that value. Nevertheless, it seems reasonable to make the same use of the
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LC as if it were information about an approximate lethal concentration (ALC). For the classification of
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gases, no higher precision is required, but the calculation formula for gas mixtures requires a definite
LC value to be set. Another LC value has been taken as LC when additional information proved it
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plausible to do so.
A.5 Read across
Some substances had to be characterized as analogous to chemically related structures with known
physiological properties. Structure-activity relationships have been taken into consideration as far as
possible. Moreover, in several instances, the toxicological impact on the respiratory tract is based on
fundamental reactions such as the hydrolysis of different gases in the presence of moisture leading to
the same reactive principle.
A.6 Other routes of application
This route may only be used as a very last option.
Sometimes the inhalation toxicity of volatile liquids has to be assessed on the basis of other parenteral,
especially intraperitoneal (i.p.), LD values. There is a good correlation between the LC and LD i.p.
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as far as systemically active substances are concerned. Taking toxic pesticides as an example, it could
be shown that an LD i.p. corresponds in aerosol studies by far and large with the same body weight-
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related dose inhaled by rats during a 4-h period. For instance, an LD i.p. of 100 mg/kg can be assumed
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to be equivalent to a 4 h-LC of about 1 mg/litre air.
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A.7 Conclusion
The selection of an LC value for a particular gas follows the logic algorithm shown in Figure A.1. The
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preferred measurement standard is LC RAT for 1 h. Lacking good data for these exact parameters,
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LC RAT values for times different from, but closest to, 1 h were selected, eliminating all data for
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exposures less than 0,5 h. If no reliable LC data from RAT were available, the next animal of choice
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was MUS (mouse), then in the following order: rabbit, guinea-pig, cat, dog, and monkey. Data for 1 h
exposures were preferred. If no reliable LC data were found for any animal, then a search was made
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for a reliable LC value, utilizing the same hierarchy of animals.
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If no reliable LC or LC value was obtainable, a value was provisionally allocated based on any one, a
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c
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