SIST EN 437:2021

SLOVENSKI STANDARD
01-julij-2021
Nadomešča:
SIST EN 437:2019
Preskusni plini - Preskusni tlaki - Kategorije naprav
Test gases - Test pressures - Appliance categories
Prüfgase - Prüfdrücke - Gerätekategorien
Gaz d'essais - Pressions d'essais - Catégories d'appareils
Ta slovenski standard je istoveten z: EN 437:2021
ICS:
27.060.20 Plinski gorilniki Gas fuel burners
91.140.40 Sistemi za oskrbo s plinom Gas supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 437
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 27.060.20; 91.140.40 Supersedes EN 437:2018
English Version
Test gases - Test pressures - Appliance categories
Gaz d'essais - Pressions d'essais - Catégories Prüfgase - Prüfdrücke - Gerätekategorien
d'appareils
This European Standard was approved by CEN on 19 January 2021.

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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 437:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Gases . 7
4.1 Classification in gas families and groups . 7
4.2 Test gases . 8
5 Test pressures . 12
6 Classification of appliances . 14
6.1 Appliance categories . 14
6.1.1 General . 14
6.1.2 Category I . 14
6.1.3 Category II . 15
6.1.4 Category III . 16
6.2 Operations permitted for a change of gas or pressure, adjustment and regulating
devices . 16
7 Choice of test gases and test pressures . 17
8 Marking . 18
Annex A (normative) Conditions for preparation of the test gases . 19
Annex B (informative) National situations . 20
B.1 General . 20
B.2 Categories listed in the body of the standard marketed in the different countries . 20
B.3 Appliance supply pressures corresponding to the categories given in B.1 and B.2 . 23
B.4 Special categories marketed nationally or locally . 27
B.4.1 General . 27
B.4.2 Categories . 33
B.5 Test gases and test pressures corresponding to the special categories given in B.4 . 40
B.6 Special conditions . 47
B.7 National and local gas distribution specifications relevant for defining appliance
categories given in B.4 . 54
Annex C (informative) Guidelines for extension to other categories . 55
Annex D (informative) Relationship between the distributed gases and the corresponding test
gases . 56
Bibliography . 57

European foreword
This document (EN 437:2021) has been prepared by Technical Committee CEN/TC 238 “Test gases, test
pressures, appliance categories and gas appliance types”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2021, and conflicting national standards shall be withdrawn
at the latest by October 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.
This document supersedes EN 437:2018.
EN 437 is intended to provide all the CEN Technical Committees preparing standards on gas appliances with
definitions for test gases, test pressures and categories of appliances for use by these committees within the
limits of the scope defined in Clause 1.
The document seeks to clarify the present situation with respect to test gases, test pressures and appliance
categories.
The concern for clarity has led to the elucidation of numerous categories and national situations or
conditions. The complexity of the document is likely to increase as new members join the Union.
This document can be considered as an important stage in the harmonization of test gases, test pressures and
appliance categories and the quality of information on gas usage in Europe.
In comparison with the previous version, this document incorporates updates of Table 6, Table 7, Table B.4
and some editorial changes.
Annex B gives national situations relating to gases, gas pressures and appliance categories that apply
nationally or locally. The information provided is included under the responsibility of the national
standardization bodies. The tables of Annex B give the available information. Therefore, Annex B is
informative.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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.
1 Scope
This document specifies the test gases, test pressures and categories of appliances relative to the use of
gaseous fuels of the first, second and third families. It serves as a reference document in the specific standards
for appliances.
The document makes recommendations for the use of the gases and pressures to be applied for the tests of
appliances burning gaseous fuels.
NOTE Procedures for tests are given in the corresponding appliance standards. The test gases and the test
pressures specified in this standard are in principle intended to be used with all types of appliances.
However, the use of some test gases and test pressures may not be appropriate in the following cases:
— appliances with nominal heat input greater than 300 kW;
— appliances constructed on site;
— appliances in which the final design is influenced by the user;
— appliances constructed for use with high supply pressures (notably direct use of the saturated vapour
pressure).
In these cases, the specific appliance standards may specify other test conditions in order to establish
compliance with their requirements.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN ISO 3166-1:2020, Codes for the representation of names of countries and their subdivisions - Part 1: Country
code (ISO 3166-1:2020)
EN ISO 6976:2016, Natural gas - Calculation of calorific values, density, relative density and Wobbe indices from
composition (ISO 6976:2016)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
gas appliance
appliance burning gaseous fuels
Note 1 to entry: For the purposes of this standard the term “gaseous fuels” means any fuel which is in a gaseous state
at a temperature of 15 °C under an absolute pressure of 1 bar.
3.2
distributed gas
gaseous fuel used on the territory of a CEN member
3.3
test gas
gases intended for the verification of the operational characteristics of gas appliances
Note 1 to entry: Test gases include reference and limit gases.
3.4
reference gas
test gas with which appliances operate under nominal conditions when they are supplied at the
corresponding normal pressure
3.5
limit gas
test gas representative of the extreme variations in the characteristics of the gases for which appliances have
been designed
3.6
test pressure
gas pressure used to verify the operational characteristics of gas appliances, consisting of normal and limit
pressures
Note 1 to entry: Gas pressure is expressed in millibars (mbar) 1 mbar = 10 Pa.
3.7
normal pressure
p
n
pressure under which the appliances operate in nominal conditions when they are supplied with the
corresponding reference gas
3.8
limit pressure
pressure representative of the extreme variations in the appliance supply conditions
Note 1 to entry: Limit pressures comprise a maximum pressure p and a minimum pressure p .
max min
3.9
pressure couple
combination of two distinct gas distribution pressures applied by reason of the significant difference existing
between the Wobbe indices within a single family or group in which
— the higher pressure corresponds only to gases of low Wobbe index;
— the lower pressure corresponds to gases of high Wobbe index.
Note 1 to entry: The pressure couple is indicated by using the symbol (⇆).
3.10
reference conditions
conditions which correspond to 15 °C, 1 013, 25 mbar, unless otherwise specified
3.11
relative density
d
ratio of the masses of equal volumes of dry gas and dry air under the same conditions of temperature and
pressure: 15 °C or 0 °C and 1 013, 25 mbar
3.12
calorific value
quantity of heat produced by the complete combustion, at a constant pressure equal to 1 013,25 mbar, of a
unit volume or mass of gas, the constituents of the combustible mixture being taken at reference conditions
and the products of combustion being brought back to the same conditions
Note 1 to entry: A distinction is made between:
— the gross calorific value H : the water produced by combustion is assumed to be condensed;
s
— the net calorific value H : the water produced by combustion is assumed to be in the vapour state.
i
Note 2 to entry: The calorific value is expressed:
— either in megajoules per cubic metre (MJ/m ) of dry gas under the reference conditions;
— or in megajoules per kilogram (MJ/kg) of dry gas.
3.13
Wobbe index
ratio of the calorific value of a gas per unit volume and the square root of its relative density under the same
reference conditions
Note 1 to entry: The Wobbe index is expressed in megajoules per cubic metre (MJ/m ) of dry gas under the reference
conditions.
Note 2 to entry: The Wobbe index is said to be gross (W ) or net (W ) according to whether the calorific value used is
s i
the gross or net calorific value.
3.14
heat input
Q
quantity of energy used in unit time corresponding to the volumetric or mass flow rates, the calorific value
used being either the net or gross calorific value
Note 1 to entry: The heat input is expressed in kilowatts (kW).
3.15
nominal heat input
Q
n
value of the heat input declared by the manufacturer
3.16
mass flow rate
M
mass of gas consumed by the appliance in unit time during continuous operation
Note 1 to entry: The mass flow rate is expressed in kilograms per hour (kg/h) or grams per hour (g/h).
3.17
volume flow rate
V
volume of gas consumed by the appliance in unit time during continuous operation
Note 1 to entry: The volume flow rate is expressed in cubic metres per hour (m /h), litres per minute (l/min), cubic
3 3
decimetres per hour (dm /h) or cubic decimetres per second (dm /s).
3.18
gas family
group of gaseous fuels with similar burning behaviour linked together by a range of Wobbe indices
Note 1 to entry: See Table 1.
3.19
gas group
specified range of Wobbe index within that of the family concerned
Note 1 to entry: This range is determined on the general principle that appliances using this gas group operate safely
when burning all gases within this range without adjustment.
Note 2 to entry: Adjustment of the appliance may be permitted in accordance with the special national or local
conditions that apply in some countries (see B.4). For gases corresponding to national or local conditions, see Tables
B.5, B.6 and B.7.
Note 3 to entry: See Table 1.
3.20
appliance category
means of identifying the gas families and/or gas groups for which a gas appliance is designed to operate safely
and to the desired performance level
Note 1 to entry: General appliance categories are described in 6.1. Special appliance categories marketed nationally
or locally are described in B.4.
Note 2 to entry: See individual appliance standards.
4 Gases
4.1 Classification in gas families and groups
Gases are classified into three families, each family may be divided into groups, (themselves being divided
into ranges, see Annex B), as a function of the Wobbe index, according to the values given in Table 1.
NOTE 1 See Annex D for more details.
NOTE 2 The classification given in Table 1 is used for the communication of the types of gases and corresponding
supply pressures of gaseous fuels used on the territories of Member States.
Table 1 — Classification of gas families and groups as a function of the Wobbe indices, dry gas at
15 °C and 1 013,25 mbar
Gas families and groups Gross Wobbe index, dry gas at 15 °C and 1 013,25 mbar
MJ/m
Minimum Maximum
First family
— Group a 22,4 24,8
Second family 39,1 54,7
— Group H 45,7 54,7
— Group L 39,1 44,8
— Group E 40,9 54,7
Third family 72,9 87,3
— Group B/P 72,9 87,3
— Group P 72,9 76,8
— Group B 81,8 87,3
4.2 Test gases
The composition and principal characteristics of the different test gases corresponding to the gas families or
groups are given in Tables 2 and 3.
In particular cases specified in the individual appliance standards, gas G 24, whose characteristics are given
in Table 3, may be used but only at the normal test pressure.
The calorific values of the third family gases, expressed in mega joules per cubic metre in Table 2, may also
be expressed in mega joules per kilogram of dry gas, as shown in Table 3.
The values in Tables 2 and 3, measured and expressed at 15 °C, are derived from EN ISO 6976:2016.
The conditions for the preparation of the test gases are given in Annex A.
NOTE The characteristics of second family gases at reference conditions other than 15 °C for metering and 15 °C
for combustion can be calculated using the coefficients given in EN ISO 13443:2005, Annex A (normative). As an
example, the characteristics of the reference gases of the second family at 0 °C for metering and for combustion and
1 013,25 mbar (dry gas) are given in Table 4.
a
Table 2 — Characteristics of the test gases for the first and second families, gas dry at 15 °C and
1 013,25 mbar
Gas
family Composition
W H W H
Test gases Designation d
i i s s
and by volume
Group
c 3 3 3 3
% MJ/m MJ/m MJ/m MJ/m
b
Gases of the first family
Group a Reference gas G 110 CH = 26
Incomplete  H = 50 21,76 13,95 24,75 15,87 0,411
combustion,
N = 24
flame lift and
sooting limit gas
Light back limit G 112 CH = 17
gas
H = 59 19,48 11,81 22,36 13,56 0,367
N = 24
b
Gases of the second family
Group H Reference gas G 20 CH = 100 45,67 34,02 50,72 37,78 0,555
Incomplete G 21 CH = 87 49,60 41,01 54,69 45,28 0,684
combustion and
C H = 13
3 8
sooting limit gas
Light back limit G 222 CH = 77 42,87 28,53 47,87 31,86 0,443
gas
H = 23
Flame lift limit G 23 CH = 92,5 41,11 31,46 45,66 34,95 0,586
gas
N = 7,5
Over heating G 24 CH = 68 47,01 35,70 52,09 39,55 0,577
d
limit gas
C H = 12
3 8
H = 20
Gas
family Composition
W H W H
Test gases Designation d
i i s s
and by volume
Group
c 3 3 3 3
% MJ/m MJ/m MJ/m MJ/m
Group L Reference gas G 25 CH = 86 37,38 29,25 41,52 32,49 0,612
light back limit
N = 14
gas
Incomplete G 26 CH = 80 40,52 33,36 44,83 36,91 0,678
combustion and
C H = 7
3 8
sooting limit gas
N = 13
Flame lift limit G 27 CH = 82 35,17 27,89 39,06 30,98 0,629
gas
N = 18
Group E Reference gas G 20 CH = 100 45,67 34,02 50,72 37,78 0,555
Incomplete G 21 CH = 87 49,60 41,01 54,69 45,28 0,684
combustion and
sooting limit gas
C H = 13
3 8
CH = 77
Light back limit G 222 42,87 28,53 47,87 31,86 0,443
gas
H = 23
CH = 85
Flame lift limit G 231 36,82 28,91 40,90 32,11 0,617
gas
N = 15
Over heating G 24 CH = 68 47,01 35,70 52,09 39,55 0,577
d
limit gas
C H = 12
3 8
H = 20
a
For gases used nationally or locally, see B.5.
b
For other groups, see B.5.
c
See also Annex A.
d
Limit gas used only for certain types of appliance, specified in the individual appliance standards (e.g. fully
premixed burners, forced draught burners, …).
a
Table 3 — Characteristics of the test gases for the third family, gas dry at 15 °C and 1 013,25 mbar
Gas
family Composition
W H W H
Test gases Designation d
i i s s
and by volume
group
c 3 3 3 3
MJ/kg MJ/kg
% MJ/m MJ/m MJ/m MJ/m
Gases of the third
b
family
Reference  n-C H = 50 80,58 116,09 45,65 87,33 125,81 49,47 2,075
4 10
gas
Groups Incomplete G 30 i- C H = 50
4 10
B/ P combustion
and sooting
limit gas
Flame lift G 31 C H = 100 70,69 88,00 46,34 76,84 95,65 50,37 1,550
3 8
limit gas
and B Light back G 32 C H = 100 68,14 82,78 45,77 72,86 88,52 48,94 1,476
3 6
limit gas
Group P Reference G 31 C H = 100 70,69 88,00 46,34 76,84 95,65 50,37 1,550
3 8
gas,
Incomplete
combustion,
flame lift and
sooting limit
a
gas
Light back G 32 C H = 100 68,14 82,78 45,77 72,86 88,52 48,94 1,476
3 6
and sooting
d
limit gas
a
For gases used nationally or locally, see B.5.
b
For other groups, see B.5.
c
See also Annex A.
d
Limit gas used only for certain types of appliance, specified in the individual appliance standards (e.g. fully premixed
burners, forced draught burners, …).
Table 4 — Characteristics of the reference gases of the second family at 0 °C and 1 013,25 mbar
Composition
W H W H
Gas group Test gas Designation d
i i s s
by volume
3 3 3 3
%
MJ/m MJ/m MJ/m MJ/m
Group H Reference G 20 CH = 100 48,20 35,90 53,61 39,94 0,555
gas
Group L Reference G 25 CH = 86 39,45 30,87 43,88 34,34 0,613
gas, light
back limit
gas
N = 14
Group E Reference G 20 CH = 100 48,20 35,90 53,61 39,94 0,555
gas
5 Test pressures
The values of the test pressures, i.e. the static pressure to be applied at the gas inlet connection to the
appliance whilst in operation, are given in Tables 5 and 6.
NOTE The test conditions are specified in the individual appliance standards.
However:
— for the combustion test in still air with G 21 the appliance is first adjusted on G 20 to give an increase of
5 % in the nominal heat input where a gas pressure governor exists, and an increase of 7,5 % in the
absence of a governor. Gas G 21 is then substituted for G 20 without altering this adjustment;
— tests for ignition and crosslighting should be carried out at an inlet pressure of 0,7 times the normal
pressure (p ) using the reference gas(es) for the first and second families.
n
a
Table 5 — Test pressures where no pressure couple exists
Appliance categories Test gas p p p
n min max
having as index
mbar mbar mbar
st
G 110 8 6 15
1 family 1a
G 112
nd
G 20, G 21, 20 17 25
2 family
2H G 222, G 23
nd
G 25, G 26, 25 20 30
2 family
2L G 27
nd
G 20, G 21, 20 17 25
2 family
2E G 222, G 231
G 20, G 21, 20 17 30
nd
G 222, G 231,
2 family
G 25, G 26,
a
G 27
d
G 25, G 26, 25 20 30
2N
G 27
b
G 30, G 31, 25 35
rd
G 32
3 family
3B/P G 30, G 31, 50 42,5 57,5
G 32
rd
G 31, G 32 30 25 35
3 family, 3P
rd
G 31, G 32 37 25 45
3 family
3P G 31, G 32 50 42,5 57,5
rd
G 30, G 31, 29 20 35
3 family
c
G 32
3B
a
For test pressures corresponding to gases distributed nationally or locally, refer to Table B.5.
b
Appliances of this category may be used, without adjustment, at the specified supply pressures
of 28 mbar to 30 mbar.
c
The tests with G 31 and G 32 are carried out at the normal pressure only (p = 29 mbar), these
n
test gases being more severe than any gas distributed. This condition covers the normal
variations in the gas supply.
d
See definition in 6.1.2.3.
Table 6 — Test pressures where a pressure couple exists
p p p
Appliance categories Test gas
n min max
having as index
mbar mbar mbar
nd
G 20, G 21, G222 20 17 25
2 family: 2E+
a b
(20⇆25 couple) G 231 30
(25) 17
rd c
G 30 20 35
3 family: 3+ 29
(28–30⇆37 couple) G 31, G 32 37 25 45
rd
G 30 50 42,5 57,5
3 family: 3+
(50⇆67 couple) G 31, G 32 67 50 80
rd
G 30 112 60 140
3 family: 3+
(112⇆148 couple) G 31, G32 148 100 180
a
This pressure corresponds to the use of low Wobbe index gas but in principle no test is carried
out at this pressure.
b
See B.6.
c
Appliances of this category may be used without adjustment at the specified supply pressures of
28 mbar to 30 mbar.
6 Classification of appliances
6.1 Appliance categories
6.1.1 General
Appliances are classified into categories defined according to the gases and the pressures for which they are
designed.
The definition of the categories follows from 6.1.2, 6.1.3 and 6.1.4.
In each country, taking account of the local gas distribution conditions (gas composition and supply
pressures), only some of the categories defined in 6.1.2, 6.1.3 and 6.1.4 are marketed. In addition, some of
these categories are used only for certain types of appliances as specified in the individual appliance
standards.
The conditions concerning the marketing of these appliance categories in each country and the corresponding
supply pressures are given in Tables B.1, B.2 and B.3 (see also B.4 for the categories marketed locally and
nationally, corresponding to the gases and specific supply pressures given in Table B.5; B.6 gives the
particular conditions specific to certain countries).
NOTE See also Annex C - Guidelines for extension to other categories.
6.1.2 Category I
6.1.2.1 General
Appliances of category I are designed exclusively for the use of gases of a single family or of a single group.
6.1.2.2 Appliances designed for use on first family gases only
Category I : appliances using only gases of group a of the first family at the prescribed supply pressure (this
1a
category is not used).
6.1.2.3 Appliances designed for use on second family gases only
Category I : appliance using only gases of group H of the second family at the prescribed supply pressure.
2H
Category I : appliances using only gases of group L of the second family at the prescribed supply pressure.
2L
Category I : appliances using only gases of group E of the second family at the prescribed supply pressure.
2E
Category I : appliances using only gases of group E of the second family, and operating with a pressure
2E+
couple without adjustment of the appliance. The appliance gas pressure regulating device, if it exists, is not
operative at pressures in between the two normal pressures of the pressure couple.
Category I : appliances using only second family gases at the prescribed supply pressure and that
2N
automatically adapt to all gases of the second family.
Category I : appliances having a pressure regulator which can be manually adjusted in order to utilize each
2R
of the following gas groups: H, E, L, K and LL (see also Table B.6).
rd
family gases only
6.1.2.4 Appliances designed for use on 3
Category I : appliances capable of using the third family gases (propane and butane) at the prescribed
3B/P
supply pressure.
Category I : appliances capable of using gases of the third family (propane and butane) and operating with
3+
a pressure couple without adjustment of the appliance. However, for certain types of appliances specified in
the particular standards, adjustment of the primary combustion air may be permitted when changing from
propane to butane and vice versa. No gas pressure regulating device is permitted on the appliance.
Category I : appliances using only gases of group P of the third family (propane) at the prescribed supply
3P
pressure.
Category I : appliances using only gases of group B of the third family (butane) at the prescribed supply
3B
pressure.
Category I : appliances having a pressure governor using all the gases of the third family which can be
3R
adjusted manually in order to utilize the various gases of a group of the third family under the local condition
of distribution (see Table B.7).
6.1.3 Category II
6.1.3.1 General
Appliances of category II are designed for use on gases of two families:
6.1.3.2 Appliances designed for use on gases of the first and second families
Category II : appliances capable of using gases of group a of the first family and gases of group H of the
1a2H
second family. The first family gases are used under the same conditions as for category I .The second family
1a
gases are used under the same conditions as for category I .
2H
6.1.3.3 Appliances designed for use on gases of the second and third families
Category II : appliances capable of using gases of group H of the second family and gases of the third
2H3B/P
family. The second family gases are used under the same conditions as for category I . The third family gases
2H
are used under the same conditions as for category I
3B/P.
Category II : appliances capable of using gases of group H of the second family and gases of the third
2H3+
family. The second family gases are used under the same conditions as for category I .The third family gases
2H
are used under the same conditions as for category I
3+.
Category II : appliances capable of using gases of group H of the second family and gases of group P of the
2H3P
third family. The second family gases are used under the same conditions as for category I . The third family
2H
gases are used under the same conditions as for category I .
3P
Category II : appliances capable of using gases of group L of the second family and gases of the third
2L3B/P
family. The second family gases are used under the same conditions as for category I . The third family gases
2L
are used under the same conditions as for category I .
3B/P
Category II : appliances capable of using the gases of group L of the second family and gases of Group P of
2L3P
the third family. The second family gases are under the same conditions as for category I The third family
2L.
gases are used under the same conditions as for category I .
3P
Category II : appliances capable of using gases of group E of the second family and gases of the third
2E3B/P
family. The second family gases are used under the same conditions as for category I . The third family gases
2E
are used under the same conditions as for category I .
3B/P
Category II : appliances capable of using gases of group E of the second family and gases of the third
2E+3B/P
family. The second family gases are used under the same conditions as for category I . The third family
2E+
gases are used under the same conditions as for category I .
3B/P
Category II : appliances capable of using gases of Group E of the second family and gases of the third
2E+3+
family. The second family gases are used under the same conditions as for category I . The third family
2E+
gases are used under the same conditions as for category I .
3+
Category II : appliances capable of using gases of group E of the second family and gases of group P the
2E+3P
third family. The second family gases are used under the same conditions as for category I The third family
2E+.
gases are used under the same conditions as for category I .
3P
Category II : appliances having a pressure governor using all the gases of the second family and/or gases
2R3R
linked to the second family and all the gases of the third family which can be adjusted manually in order to
utilize the various gases of the groups of the second family and third family under the local conditions of
distribution. The second family gases are used under the same conditions as for category I The third family
2R.
gases are used under the same conditions as for category I (see Tables B.6 to B.8).
3R
6.1.4 Category III
Appliances of category III are designed for use on gases of three families.
This category is not used in general.
The categories III accepted in specific countries are given in Annex B (see B.4).
6.2 Operations permitted for a change of gas or pressure, adjustment and regulating devices
The individual appliance standards should specify:
— the operations permitted for a change of gas or of pressure (as far as possible the permitted conversion
operations should be limited so as to ensure that the conversion may be effected without difficulty);
— the conditions applicable to adjustment and regulation devices.
7 Choice of test gases and test pressures
According to the appliance category:
— the tests are carried out with the gases given in Table 7;
— the test pressures are chosen from Tables 5 and 6, as appropriate, as a function of the test gas and in
accordance with the requirements given in the individual appliance standards.
a, b
Table 7 — Test gases corresponding to the appliance categories
Category Reference Incomplete Light back Lift limit gas Sooting limit gas
gas combustion limit gas
limit gas
I G 20 G 21 G 222 G 23 G 21
2H
I G 25 G 26 G 25 G 27 G 26
2L
e
G 20 G 21 G 222 G 231 G 21
I I
2E, 2E+
c d d d d d
I
G 20  G 21 G 222 G 231 G 21
2N
c d d d d d
G 25  G 26 G 25 G 27 G 26
e
I
2R
I , I G 30 G 30 G 32 G 31 G 30
3B/P 3+
I G 31 G 31 G 32 G 31 G 31, G 32
3P
I G 30 G 30 G 32 G 31 G 30
3B
f
I
3R
II G 110, G 20 G 21 G 112 G 23 G 21
1a2H
II2H3B/P, G 20, G 21 G 222, G 23, G 30
II
2H3+ G 30 G 32 G 31
II
G 20, G 21 G 222, G 23, G 31, G 32
2H3P
G 31 G 32 G 31
II G 25, G 26 G 32 G 27, G 30
2L3B/P
G 30 G 31
II G 25, G 26 G 32 G 27, G 31, G 32
2L3P
G 31 G 31
II2E3B/P, G 20, G 21 G 222, G 231, G 30
II2E+3B/P,
G 30 G 32 G 31
II
2E+3+
II G 20, G 21 G 222, G 231, G 31, G 32
2E+3P
G 31 G 32 G 31
g
II
2R3R
Category Reference Incomplete Light back Lift limit gas Sooting limit gas
gas combustion limit gas
limit gas
a
For the test gases corresponding to the categories marketed nationally or locally, see Table B.4.
b
Tests with the limit gases are carried out with the injector and adjustment corresponding to the
reference gas of the group to which limit gas used for the test belongs.
c
The heat inputs shall be equivalent and within the tolerances specified in the appliance standards.
d
Since the adjustment of the burner changes automatically when the appliance is supplied with
different test gases, it may be necessary to examine all phenomena (e.g. incomplete combustion,
sooting, light back, flame lift) with all the test gases.
e
See Table B.6.
f
See Table B.7.
g
See Table B.8.
8 Marking
The marking of a category comprises:
— in Roman numerals, the number of utilizable gas families;
— in an Arabic numeral suffix, the number assigned to the gas family considered, i.e. 1 for the first family, 2
for the second and 3 for the third;
— in the suffix following that numeral, the letter or letters designating the utilizable gas group or groups,
respectively.
The suffix to the Roman numeral denotes all the families with all the gas groups usable by the appliance, with
or without making adjustments and/or adaptations appropriate to each group.
In cases where the appliance is capable of using gases belonging to one of the groups E or B/P that completely
or partially encompass more restricted groups, the breadth of which is expressed by a Wobbe number range,
the supply pressure may be set according to the pressure couple principle. This supply condition for the gas
group considered is symbolised by the “+” sign following the letter E or the digit 3 for group B/P; in the latter
case, the symbol for the group itself is replaced by the digit 3, which denotes the third family.
Annex A
(normative)
Conditions for preparation of the test gases
The composition of the gases used for the tests shall be as close as possible to that in Table 2. For the
preparation of these gases, the following rules shall be observed:
— the Wobbe index of the gas used shall be within ± 2 % of the value indicated in the table for the
corresponding test gas (this tolerance includes the error due to measuring instruments);
— the constituents used for the preparation of the mixtures shall have at least the following purity:
nitrogen N 99 %  with a total content of hydrogen, carbon monoxide and
oxygen below 1 % and a total content of nitrogen and
hydrogen H 99 %
carbon dioxide below 2 %
methane CH 95 %
C H
propene 95 %
3 6
C H
propane 95 %
3 8
1)
C H 95 %
butane
4 10
However, these conditions are not mandatory for each of the components if the final mixture has a
composition identical to that of a mixture which would have been made from components satisfying the
preceding conditions. Therefore, in order to make up a mixture, it is possible to start with a gas already
containing, in suitable proportions, several components of the final mixture.
nd
However, for gases of the 2 family:
— for the tests carried out with reference gases G 20 or G 25, a gas belonging respectively to either group H
or group L or group E, may be used even if its composition does not satisfy the above conditions, provided
that after the addition of either propane or nitrogen as appropriate, the final mixture has a Wobbe index
within ± 2 % of the value given in the table for the corresponding reference gas;
— for preparation of the limit gases another gas may be used as the base gas instead of methane:
— for limit gases G 21, G 222, G 23 and G 24, a natural gas of group H may be used;
— for limit gases G 27 and G 231, a natural gas of group H, L or E may be used;
— for the limit gas G 26, a natural gas of group L may be used.
In all cases the final mixture obtained by adding propane or nitrogen shall have a Wobbe index within ± 2 %
of the value given in Table 2 for the corresponding limit gas and the hydrogen content of the final mixture
shall be as given in Table 2.
1)
A mixture of iso/n butane is permitted. Appliance standards may be more precise on the composition of the mixture
and the purity of the gases.
Annex B
(informative)
National situations
B.1 General
In each country in which this standard applies, appliances may be marketed only if they comply with the
particular national supply conditions of that country.
In order to permit, both at the time of testing the appliance and at the time of its sale, the correct choice to be
made from all the situations covered, the various national situations are summarized in Tables B.1, B.2, B.3,
B.4 and B.5.
In accordance with EN ISO 3166-1:2020, the names of countries shall be represented by the following codes:
AT Austria IE Ireland
BE Belgium IS Iceland
BG Bulgaria IT Italy
CH Switzerland LT Lithuania
CY Cyprus LU Luxembourg
CZ Czech Republic LV Latvia
MK Republic of North Macedonia
DE Germany MT Malta
DK Denmark NL Netherlands
EE Estonia NO Norway
ES Spain PL Poland
FI Finland PT Portugal
FR France RO Romania
GB United Kingdom SE Sweden
GR Greece SI Slovenia
HR Croatia SK Slovakia
HU Hungary TR Turkey
B.2 Categories listed in the body of the standard marketed in the different countries
Tables B.1.and B.2 give the national situations concerning the marketing in the various countries of the
appliance categories listed in the body of the standard.
The information given in these tables indicates only that these categories may be sold throughout the whole
of the country concerned and B.4 should be consulted for confirmation.
In all cases of doubt, the local gas supplier should be consulted in order to identify the precise category
applicable.
Table B.1 — Category I (single categories) marketed
e a a a a
I I I I I I
Country code
I I I I I
2H 2E 2E+ 2N 3B/P 3+
2L 2R 3P 3B 3R
AT x      x  x
d
BE    x X  x x x
x
BG (NAv)
CH x      x x x
CY       x x  x
CZ x     x x x x  x
a, c c c
DE   x  x  x
x  x x
a, c c c
DK x    x
x  x x
EE x     x x    x
a
ES x    x  x x x x
x
FI x      x
b b a a
FR  x  x x x x
x x x x
d
GB x     x x x x x
x
a
GR x    x x x x x x
x
HR x      x  x
c
HU      x  x x
x
IE x       x x x
IS (NAv)
IT x     x x x x  x
LT x      x x x  x
LU (NAv)
LV x
MK (NAv)
MT (NAv)
NL     x  x  x
NO x     x x    x
PL   x  x x x  x  x
a
PT x    x  x x x x
x
c
RO x x    x  x
x
SE x      x
a
SI x    x x x x  x
x
SK x     x     x
e a a a a
Country code I I I I I I
I I I I I
2H 2E 2E+ 2N 3B/P 3+
2L 2R 3P 3B 3R
TR x      x x
The mention NAv (“Not Available”) placed alongside the names of the countries means that the country

concerned has not indicated its choice of category.
a
Categories applicable only to certain types of appliances, specified in the individual appliance standards.
b
Categories applicable only to certain types of appliance for which the conformity is based on unit
verification, (see the Gas Appliances Regulation) (see the Gas Appliances Regulation).
c
See B.6.
d
Category applicable only for appliances installed in Touring and Motoring Caravans.
e
Category I is a historic category of which there is a number of appliances still in use.
2L
Table
...