Determination of explosion points of flammable liquids

This European Standard specifies a test method to determine the explosion points of flammable liquids in air. This European Standard applies to flammable liquids at atmospheric pressure and at temperatures in the range from ­ 50 °C to 300 °C.
This European standard must not be applied to explosives or materials which, under the test conditions, are thermally unstable liquids (e.g. polymerizing/oxidizing materials).

Bestimmung von Explosionspunkten brennbarer Flüssigkeiten

Diese Europäische Norm legt ein Prüfverfahren zur Bestimmung der Explosionspunkte in Luft von brennbaren
Flüssigkeiten fest. Diese Norm gilt für brennbare Flüssigkeiten bei Umgebungsdruck und für Temperaturen
von –50 °C bis 300 °C.
Diese Europäische Norm gilt nicht für Sprengstoffe oder Produkte, die unter den Prüfbedingungen thermisch
instabil sind (z. B. polymerisierende/oxidierende Flüssigkeiten).

Détermination des points d'explosion des liquides inflammables

La présente norme prescrit une méthode d’essai permettant de déterminer les points d’explosion des liquides inflammables dans l’air. La présente norme s’applique aux liquides inflammables ) à la pression atmosphérique et à des températures comprises entre ­ 50 °C et 300 °C.
La présente norme ne s’applique pas aux explosifs ou matériaux qui, dans les conditions d’essai, sont des liquides thermiquement instables (par exemple les matériaux polymérisables/oxydants).

Ugotavljanje točk eksplozije vnetljivih tekočin

Ta evropski standard opredeljuje preskusno metodo za ugotavljanje točk eksplozije gorljivih tekočin na zraku. Ta evropski standard velja za gorljive tekočine pri pritisku atmosfere in pri temperaturi v razponu od 50°C do 300°C. Ne sme se uporabljati za eksplozive ali materiale, ki so pod preskusnimi pogoji toplotno nestabilne tekočine (npr. polimerizacijski/oksidacijski materiali).

General Information

Status
Published
Publication Date
23-Dec-2009
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
23-Dec-2009
Due Date
27-Feb-2010
Completion Date
24-Dec-2009

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Bestimmung von Explosionspunkten brennbarer FlüssigkeitenDétermination des points d'explosion des liquides inflammablesDetermination of explosion points of flammable liquids13.230Varstvo pred eksplozijoExplosion protectionICS:Ta slovenski standard je istoveten z:EN 15794:2009SIST EN 15794:2010en,fr,de01-februar-2010SIST EN 15794:2010SLOVENSKI

STANDARD
SIST EN 15794:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15794
October 2009 ICS 75.160.20 English Version
Determination of explosion points of flammable liquids
Détermination des points d'explosion des liquides inflammables

Bestimmung von Explosionspunkten brennbarer Flüssigkeiten This European Standard was approved by CEN on 22 September 2009.

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 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 Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15794:2009: ESIST EN 15794:2010

EN 15794:2009 (E) 2 Contents Page Foreword ..............................................................................................................................................................4Introduction .........................................................................................................................................................51Scope ......................................................................................................................................................62Normative references ............................................................................................................................63Terms and definitions ...........................................................................................................................64Principle of the test method .................................................................................................................65Test equipment ......................................................................................................................................65.1Reagents and Materials .........................................................................................................................65.1.1Flammable liquid: ..................................................................................................................................65.1.2Sampling and Storage ...........................................................................................................................65.2Apparatus ...............................................................................................................................................75.3Test vessel ..............................................................................................................................................85.4Heating / cooling chamber ....................................................................................................................85.5Ignition source .......................................................................................................................................85.6Stirrer ......................................................................................................................................................85.7Barometer ...............................................................................................................................................95.8Safety advice ..........................................................................................................................................96Test procedure .......................................................................................................................................96.1General ....................................................................................................................................................96.2Details .....................................................................................................................................................96.2.1Step 1 ......................................................................................................................................................96.2.2Step 2 ......................................................................................................................................................96.2.3Step 3 ......................................................................................................................................................96.2.4Step 4 ................................................................................................................................................... 106.2.5Step 5 ................................................................................................................................................... 107Expression of results ......................................................................................................................... 108Verification of the apparatus ............................................................................................................. 119Test report ........................................................................................................................................... 11Annex A (informative)

Safety advice .............................................................................................................. 12Annex B (informative)

Estimation of explosion points ................................................................................. 13B.1General ................................................................................................................................................. 13B.2Pure substances ................................................................................................................................. 13B.3Mixtures of flammable components only ......................................................................................... 13Annex C (normative)

Criteria for flame detachment .................................................................................... 15Annex D (normative)

Verification ................................................................................................................... 16Annex E (informative)

Example for a form expressing the results ........................................................... 17Annex ZA (informative)

Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC ............................................................................................. 18Bibliography ..................................................................................................................................................... 19

SIST EN 15794:2010
EN 15794:2009 (E) 3

Figures Figure 1 — Explosion point apparatus; schematic ......................................................................................... 7Figure C.1 — Flame detachment ..................................................................................................................... 15Figure C.2 — Halo (UNDETACHED FLAME) .................................................................................................. 15 Tables Table D.1 — Data for verification of the apparatus ....................................................................................... 16Table ZA.1 — Correspondence between this European Standard and Directive (Add the reference and title of the Directive) .......................................................................................................................... 18 SIST EN 15794:2010

EN 15794:2009 (E) 4 Foreword This document (EN 15794:2009) 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 April 2010, and conflicting national standards shall be withdrawn at the latest by April 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. 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, which is an integral part of this document. 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

SIST EN 15794:2010

EN 15794:2009 (E) 5 Introduction Flammable liquids can give rise to an explosion hazard as a result of evaporation generating an explosive gas and/or vapour mixture with air. One way of eliminating the explosion hazard is to prevent explosive mixtures of gases and/or vapours with air from being formed. In order to assess the likelihood of an explosive mixture being formed the explosion point of the flammable liquid is required. The explosion point depends mainly on:  the properties (e.g. explosion limits, vapour pressure, chemical composition including impurities of the flammable liquid;  pressure;  size, shape, and percentage fill of the test vessel;  ignition source (type, energy);  the criterion for self-propagating combustion. The explosion point of a liquid is normally lower than its flashpoint. For pure substances the difference can be up to 10 K. In the case of mixtures the difference can be up to 25 K. Some liquids which do not exhibit a flash point may have explosion limits and thus have an explosion point. To obtain reliable and comparable results it is therefore necessary to standardize the conditions (apparatus and procedure) under which the explosion points are to be determined. SIST EN 15794:2010

EN 15794:2009 (E) 6 1 Scope This European Standard specifies a test method to determine the explosion points of flammable liquids in air. This European Standard applies to flammable liquids at atmospheric pressure and at temperatures in the range from - 50 °C to 300 °C. This European standard must not be applied to explosives or materials which, under the test conditions, are thermally unstable liquids (e.g. polymerizing/oxidizing materials). 2 Normative references The following referenced documents are indispensable for the application 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 13237:2003, Potentially explosive atmospheres – Terms and definitions for equipment and protective systems intended for use in potentially explosive atmospheres 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 13237:2003 apply. 4 Principle of the test method The test sample is placed in a cylindrical vessel and heated up to a specified temperature. After having reached equilibrium conditions between the liquid phase and the gas phase at the set temperature ignition is initiated using a series of induction sparks. It is observed whether a flame detachment or a temperature rise occurs. The temperature of the test apparatus is raised or lowered stepwise, until just no ignition is observed. 5 Test equipment 5.1 Reagents and Materials 5.1.1 Flammable liquid:

The flammable liquid may be:  a single liquid or a defined mixture of liquids;  a process sample (of known or unknown composition). When a pure liquid or a mixture of defined composition is used, the purity of each liquid shall be 99,8 % mol. or better. In the case of a mixture or a process sample of undefined composition the sample should be characterised so that the origin as well as the related process conditions can be identified. 5.1.2 Sampling and Storage Sampling should be carried out if possible according to the procedures given in EN ISO 3170, EN ISO 3171, EN ISO 15528 or an equivalent National Standard. SIST EN 15794:2010

EN 15794:2009 (E) 7 Sufficient sample volume for testing shall be placed in a tightly sealed container appropriate to the material being sampled. At the beginning of the tests, the sample container shall be filled to between 85 % and 95 % of its capacity. The samples shall be stored in conditions that minimize vapour loss and pressure build up to avoid losing volatile components. If possible, the sample should be stored in its container either at ambient temperature, or about 5 K below the test starting temperature (expected explosion point), whichever is the lower temperature. The sample shall be maintained at this temperature, or lower, until all tests on the sample are completed. Viscous liquids, liquids which crystallise on cooling, polymerize or separate are to be stored at just above the temperature at which this occurs.

Sample containers are to be kept closed before and after sampling to avoid alterations of the sample (e.g. evaporation of volatile constituents/impurities). 5.2 Apparatus Apparatus see Figure 1 Dimensions in millimetres

Key 1 Heating chamber with air circulation and temperature regulator6 Thermocouple determining the explosion point and checking the equilibrium2 Test vessel

7 Thermocouple for ignition detection and checking equilibrium3 Ignition source (spark)8 Tightly fitting lid allowing for pressure relief4 Electrodes 9 Inlet valve5 Stirrer 10 Outlet valveFigure 1 — Explosion point apparatus; schematic SIST EN 15794:2010

EN 15794:2009 (E) 8 5.3 Test vessel The test vessel is an upright cylindrical vessel made of pressure-resistant (10 bar) glass with an inner diameter of between 80 mm to 100 mm and a height of between 300 mm to 500 mm. It is covered with a tightly fitting lid allowing for pressure relief (e.g. smooth metal plate on a ground glass surface). The electrodes of the ignition source shall be mounted in the lid in a way that the tips are positioned in the centre (10 ± 2) mm above the surface of the liquid, or with a sufficient distance to avoid wetting. The thermocouple for monitoring the gas phase temperature shall be mounted (20 ± 2) mm below the top of the vessel in the vertical axis. If this thermocouple is also used for ignition detection, it has to have a maximum diameter of 0,5 mm and an uncertainty of measurement of 1,0 K. The thermocouple for measuring the temperature of the explosion point should penetrate the liquid phase by at least 20 mm. For purging the vapour phase, an inlet and an outlet valve should be mounted in the lid. 5.4 Heating /

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