EN 1839:2003
(Main)Determination of explosion limits of gases and vapours
Determination of explosion limits of gases and vapours
This standard specifies a test method to determine the explosion limits of gases, completely evaporated liquids (vapours) and their mixtures mixed with air. An air/inert gas mixture (volume fraction of the oxygen <21%) can be used as oxidizer in the place of air. This standard applies to gases, vapours and their mixtures at atmospheric pressure and at temperatures from ambient temperature to 200 °C.
Bestimmung der Explosionsgrenzen von Gasen und Dämpfen
Diese Europäische Norm legt zwei Verfahren (Methode T und Methode B) zum Bestimmen der Explosionsgrenzen von Gasen, Dämpfen und deren Gemischen in Mischung mit Luft fest. An Stelle von Luft kann als Oxidator auch ein Luft/Inertgas-Gemisch (Volumenanteil des Sauerstoffs < 21 %) verwendet werden. In dieser Europäischen Norm subsumiert der Ausdruck �Luft" auch solche Luft/Inertgas-Gemische.
Dieses Verfahren gilt für Gase, Dämpfe und deren Gemische bei Umgebungsdruck und Temperaturen von Raumtemperatur bis 200 °C.
Determination des limites d'explosivité des gaz et des vapeurs
La présente Norme européenne spécifie deux méthodes d'essai (méthode T et méthode B) pour déterminer les limites d'explosivité dans l'air des gaz, des vapeurs et de leurs mélanges. Un mélange d'air et d'un gaz inerte (fraction volumique de l'oxygène inférieure à 21 %) peut être utilisé comme comburant, au lieu de l'air. Dans cette norme, le terme " air " comprend également les mélanges air/gaz inerte.
La présente norme s'applique aux gaz, aux vapeurs et à leurs mélanges à la pression atmosphérique et à des températures comprises entre la température ambiante et 200 °C.
Ugotavljanje mej eksplozivnosti plinov in hlapov
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Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2003
Ugotavljanje mej eksplozivnosti plinov in hlapov
Determination of explosion limits of gases and vapours
Bestimmung der Explosionsgrenzen von Gasen und Dämpfen
Determination des limites d'explosivité des gaz et des vapeurs
Ta slovenski standard je istoveten z: EN 1839:2003
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 1839
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2003
ICS 13.230
English version
Determination of explosion limits of gases and vapours
Determination des limites d'explosivité des gaz et des Bestimmung der Explosionsgrenzen von Gasen und
vapeurs Dämpfen
This European Standard was approved by CEN on 7 August 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1839:2003 E
worldwide for CEN national Members.
Contents page
Foreword.3
1 Scope .5
2 Normative references .5
3 Terms and definitions.5
4 Test Methods.6
4.1 Method T (”tube” method) .6
4.1.1 Principle.6
4.1.2 Reagents and Materials.7
4.1.3 Apparatus .7
4.1.4 Preparation of the test mixture.10
4.1.5 Procedure .10
4.2 Method B ("bomb" method).11
4.2.1 Principle.11
4.2.2 Reagents and materials.11
4.2.3 Apparatus .11
4.2.4 Preparation of the test mixture.14
4.2.5 Procedure .15
4.3 Expression of results .16
4.4 Test report .16
Annex A (informative) Examples to describe flame detachment .18
Annex B (informative) Example for a recommended evaporator equipment.19
Annex C (normative) Safety advice .21
Annex D (informative) Example for a form expressing the results .22
Annex E (normative) Verification.23
Annex F (informative) Conversion of the values for the explosion limits .25
Annex ZA (informative) Clauses of this European Standard addressing essential requirements or other
provisions of EU Directives .29
Foreword
This document (EN 1839:2003) has been prepared by Technical Committee CEN/TC 305 “Potentially explosive
atmospheres — Explosion prevention and protection”, the secretariat of which is held by DIN.
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 March 2004, and conflicting national standards shall be withdrawn at the latest by
March 2004.
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, B, C or D, which is an integral part of this
document.
In this European Standard the annexes A, B, D and F are informative and the annexes C to E are normative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
To avoid the hazard of explosion, an appropriate measure is to prevent explosive mixtures of gases and/or vapours
being formed. To do so, the explosion limits (also known as ”flammability limits”) of the flammable substance have
to be known. These limits depend mainly on:
the properties of the flammable substance,
temperature and pressure,
size and shape of the test vessel,
ignition source (type, energy),
the criterion for self-propagating combustion.
To obtain reliable and comparable results it is therefore necessary to standardize conditions (apparatus and
procedure) under which the explosion limits are to be determined. It is however not possible to propose one
method that is suitable for all substances. The use of an apparatus that can also be used for the determination of
other explosion characteristics would also be a benefit. To these practical reasons the standard offers two
methods, tube method (method T) and bomb method (method B). In general the tube method gives a wider
explosion range. Differences in the explosion limits determined by the two methods can differ by up to 10 %
relative.
1 Scope
This European Standard specifies two test methods (method T and method B) to determine the explosion limits of
gases, vapours and their mixtures mixed with air. An air/inert gas mixture (volume fraction of the oxygen < 21 %)
can be used as oxidizer instead of air. In this standard the term “air” includes such air/inert mixtures.
This European Standard applies to gases, vapours and their mixtures at atmospheric pressure and at temperatures
from ambient temperature to 200 °C.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).
EN 1127-1:1997, Explosive atmospheres — Explosion prevention and protection — Part 1: Basic concepts and
methodology.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
explosion range
range of the concentration of a flammable substance in air, within which an explosion can occur, respectively range
of the concentration of a flammable substance in mixture with air/inert gas, within which an explosion can occur,
determined under specified test conditions
NOTE Adapted from EN 1127-1.
3.2
explosion limits
limits of the explosion range
[EN 1127-1:1997, 3.7]
3.3
lower explosion limit
LEL
lower limit of the explosion range
3.4
upper explosion limit
UEL
upper limit of the explosion range
[EN 1127-1:1997]
NOTE 1 The values of the explosion limits vary with type and amount of inert gas added.
NOTE 2 In English literature the term ”flammability limits” is also used for describing the limits determined according to this
standard. The term ”explosion limits” is chosen here to designate the same safety characteristics. This is done, because new
regulations now use this term.
3.5
explosion criterion — flame detachment
in method T, the criterion of an explosion (self-propagating combustion) is the upward movement of the flame from
the spark gap for at least 100 mm. This process which is referred to as "flame detachment" is visually observed
(examples see annex A). If a halo reaches the top of the tube or has at least a height of 240 mm this shall be also
counted as an ignition
NOTE During the duration of the ignition spark, test mixtures whose test substance content lies slightly outside the
explosion range exhibit a luminous phenomenon (which is referred to as ”halo”) above the spark gap which does not, however,
detach from the latter (see annex A). In the case of certain test substances (e.g. halogenated hydrocarbons), this luminous
phenomenon occupies a large portion of the test vessel. The formation of an halo exclusively is not yet considered to be an
ignition of the test mixture unless it reaches the top of the tube or a minimum height of 240 mm.
3.6
explosion criterion — pressure rise
in method B, the criterion of an explosion (self-propagating combustion) is the amount of the measured explosion
overpressure. The test mixture is considered explosive if the measured explosion overpressure is equal to or
greater than the overpressure created by the ignition source alone in air, plus (5 ± 0,1) % of the initial pressure
3.7
vapour
gaseous phase emanating or being emanated from a liquid. If not otherwise mentioned, the term ”gas” in this
standard also includes such vapours but not mists
NOTE The special features of vapours (possible condensation, difference in mixture composition between liquid and
vapour phase, change in mixture composition when taking out vapour phase from a closed volume) have to be considered
carefully when determining explosion limits for vapours of flammable liquids.
3.8
oxidizer
air or an air/inert gas mixture (volume fraction of the oxygen < 21 %)
3.9
sample
a substance or a mixture of substances for which explosion limits are to be determined
3.10
test substance
the sample in the gaseous state — in the case of liquid samples, after complete evaporation
3.11
test mixture
the mixture of test substance and air
4 Test Methods
4.1 Method T (”tube” method)
4.1.1 Principle
The test mixture is led through the cylindrical test vessel from below towards the top until the mixture being in the
test vessel before has been completely replaced. Then in the quiescent test mixture an ignition is initiated using a
series of induction sparks, and it is observed whether or not a flame detachment occurs. The test substance
content of the test mixture is varied step by step until the LEL or the UEL (explosion criterion — flame detachment)
have been determined or until it is certain that there exists no explosion range.
4.1.2 Reagents and Materials
air: the air shall be free of water and oil. If synthetic air is used, it has to be stated in the report.
inert gases: the purity of the inert, or the mixture of inerts, shall be 99,8 % mol. or better. If a mixture of inerts is
used, the composition of the mixture shall be stated in the test report.
flammable substance: the flammable substance may be:
a single substance or a defined mixture of substances,
a process sample (of known or unknown composition).
When a single substance or a mixture of substances is used, the purity of each substance shall be 99,8 % mol.
or better. In the case of a mixture of sub
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