1、February 2010DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 75.160.20!$Cc“1573264
2、www.din.deDDIN EN 15794Determination of explosion points of flammable liquidsEnglish version of DIN EN 15794:2010-02Bestimmung von Explosionspunkten brennbarer FlssigkeitenEnglische Fassung DIN EN 15794:2010-02www.beuth.deDocument comprises pages21DIN EN 15794:2010-02 National foreword This standard
3、 has been prepared by Technical Committee CEN/TC 305 “Potentially explosive atmospheres Explosion prevention and protection” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Sicherheitstechnische Grundstze (Safety Design Principles Standard
4、s Committee), Working Committee NA 095-02-05 AA Gase und Dmpfe (Kenngren). 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15794 October 2009 ICS 75.160.20 English Version Determination of explosion points of flammable liquids Dtermination des points dexplosion des liquides inflammables Besti
5、mmung von Explosionspunkten brennbarer Flssigkeiten 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 an
6、y 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
7、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
8、, 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 COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR N
9、ORMUNG 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: EEN 15794:2009 (E) 2 Contents Page Foreword 4Introduction .51 Scope 62 Normative references 63 Terms and d
10、efinitions .64 Principle of the test method .65 Test equipment 65.1 Reagents and Materials .65.1.1 Flammable liquid: 65.1.2 Sampling and Storage .65.2 Apparatus .75.3 Test vessel 85.4 Heating / cooling chamber 85.5 Ignition source .85.6 Stirrer 85.7 Barometer .95.8 Safety advice 96 Test procedure .9
11、6.1 General 96.2 Details .96.2.1 Step 1 96.2.2 Step 2 96.2.3 Step 3 96.2.4 Step 4 . 106.2.5 Step 5 . 107 Expression of results . 108 Verification of the apparatus . 119 Test report . 11Annex A (informative) Safety advice 12Annex B (informative) Estimation of explosion points . 13B.1 General . 13B.2
12、Pure substances . 13B.3 Mixtures 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 Es
13、sential Requirements of EU Directive 94/9/EC . 18Bibliography . 19DIN EN 15794:2010-02 EN 15794:2009 (E) 3 Figures Figure 1 Explosion point apparatus; schematic . 7Figure C.1 Flame detachment . 15Figure C.2 Halo (UNDETACHED FLAME) 15Tables Table D.1 Data for verification of the apparatus . 16Table Z
14、A.1 Correspondence between this European Standard and Directive (Add the reference and title of the Directive) 18DIN EN 15794:2010-02 EN 15794:2009 (E) 4 Foreword This document (EN 15794:2009) has been prepared by Technical Committee CEN/TC 305 “Potentially explosive atmospheres - Explosion preventi
15、on 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 Apri
16、l 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 C
17、ommission 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 organizati
18、ons 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
19、, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DIN EN 15794:2010-02 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 expl
20、osion 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 limi
21、ts, 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.
22、 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 standard
23、ize the conditions (apparatus and procedure) under which the explosion points are to be determined. DIN EN 15794:2010-02 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 flammab
24、le 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 followi
25、ng 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 d
26、efinitions 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 an
27、d 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 t
28、he 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 liqui
29、d 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 Samp
30、ling 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. DIN EN 15794:2010-02 EN 15794:2009 (E) 7 Sufficient sample volume for testing shall be placed in a tightly sealed container appr
31、opriate 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
32、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
33、, 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 Apparat
34、us Apparatus see Figure 1 Dimensions in millimetres Key 1 Heating chamber with air circulation andtemperature regulator6 Thermocouple determining the explosion point and checking the equilibrium2 Test vessel 7 Thermocouple for ignition detection and checking equilibrium3 Ignition source (spark) 8 Ti
35、ghtly fitting lid allowing for pressure relief4 Electrodes 9 Inlet valve5 Stirrer 10 Outlet valveFigure 1 Explosion point apparatus; schematic DIN EN 15794:2010-02 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 i
36、nner 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 p
37、ositioned 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 det
38、ection, 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 t
39、he lid. 5.4 Heating / cooling chamber The test vessel is located in a heating/cooling chamber with air circulation, isolated from the ground by a spacer of low thermal conductivity. The chamber should have at least a volume of ten times the test volume and should be greater than 15 l. The chamber sh
40、ould have an air exchange rate of at least ten air changes per h to avoid accumulation of flammable vapours in the chamber. The temperature differences inside the chamber should not exceed 1 K. The temperature regulating device shall fulfil the following requirements: test vessel including the lid h
41、as to be heated uniformly so that the temperature distribution inside the empty test vessel does not vary by more than 1,0 K in all directions, temperature of the test vessel can be incremented in steps of 1,0 0,2 K. NOTE Fitting the chamber with an explosion proof fan is advisable. 5.5 Ignition sou
42、rce A series of induction sparks between two electrodes is used as the ignition source. Stainless steel is a suitable material for the electrodes. The electrodes shall be pointed rods with a maximum diameter of 4 mm. The angle of the tips shall be (60 3) . The distance between the tips shall be (5 m
43、m 0,1 mm). The electrodes shall be mounted in a gas tight seal, so that it is possible to vary the distance to the liquid. The mounting shall be resistant to heat and the test mixture, and provide adequate electrical resistance to prevent shorting to the test vessel body. A high voltage transformer,
44、 with a root mean square of 13 kV to 16 kV (open circuit voltage) and a short circuit current of 20 mA to 30 mA, shall be used for producing the ignition spark. The primary winding of the high voltage transformer shall be connected to the mains via a timer set to the required discharge time. The spa
45、rk discharge time shall be adjusted to 0,2 s. If a spark discharge time of 0,2 s does not result in ignition of the test mixture, the test may be repeated with a spark discharge time of up to 0,5 s. The power of the induction sparks depends on the gas mixture and its pressure. In air at atmospheric
46、conditions according to calorimetric and electric measurements such a source gives a spark with a power of approximately 10 W. 5.6 Stirrer The stirrer shall be magnetically driven from the bottom of the vessel, so as not to disturb the flame detachment. DIN EN 15794:2010-02 EN 15794:2009 (E) 9 5.7 B
47、arometer The barometer shall be accurate to 0,1 kPa. Barometers pre-corrected to give sea-level readings shall not be used. 5.8 Safety advice The safety advice given in Annex A should be followed. 6 Test procedure 6.1 General When determining the LEP or UEP it is useful to know the closed cup flashp
48、oint of the sample or to estimate the explosion point (Annex B). In the case of an unknown sample composition, it is recommended that the flashpoint is determined first. In the case of samples consisting of or containing compounds having no flashpoint but an explosion range mathematical pre-assessme
49、nt is recommended if possible. If this is not possible the mixture composition should be analysed to identify the component having the lowest flashpoint. This flashpoint should be used as the starting temperature. 6.2 Details 6.2.1 Step 1 6.2.1.1 Record the ambient pressure in the vicinity of the test equipment. 6.2.1.2 Choose an appropriate starting temperature. When determining the
