EN 15794-2009 en Determination of explosion points of flammable liquids《易燃液体爆炸点的测定》.pdf

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1、BS EN 15794:2009ICS 75.160.20NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDDetermination ofexplosion points offlammable liquidsThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 30 April2010 BSI 2010ISBN 978 0

2、 580 61796 6Amendments/corrigenda issued since publicationDate CommentsBS EN 15794:2009National forewordThis British Standard is the UK implementation of EN 15794:2009.The UK participation in its preparation was entrusted to TechnicalCommittee FSH/23, Fire precautions in industrial and chemical plan

3、t.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom l

4、egal obligations.BS EN 15794:2009EUROPEAN 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 Bestimmung von Explosionspunkten brennbarer Flssi

5、gkeiten 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 bibliogra

6、phical 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

7、 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

8、, 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 NORMUNG Management Centre: Avenue Marnix 17,

9、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: EBS EN 15794:2009EN 15794:2009 (E) 2 Contents Page Foreword 4Introduction .51 Scope 62 Normative references 63 Terms and definitions .64 Principle of

10、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 .96.1 General 96.2 Details .96

11、.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 Pure substances . 13B.3 Mixt

12、ures 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 D

13、irective 94/9/EC . 18Bibliography . 19BS EN 15794:2009EN 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 ZA.1 Correspondence between this E

14、uropean Standard and Directive (Add the reference and title of the Directive) 18BS EN 15794:2009EN 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

15、 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 poss

16、ibility 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

17、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 bou

18、nd 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, S

19、witzerland and the United Kingdom. BS EN 15794:2009EN 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 mixtur

20、es 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 i

21、ncluding 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

22、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

23、) under which the explosion points are to be determined. BS EN 15794:2009EN 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 temper

24、atures 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 th

25、e 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

26、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 ha

27、ving 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,

28、 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, t

29、he 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

30、if possible according to the procedures given in EN ISO 3170, EN ISO 3171, EN ISO 15528 or an equivalent National Standard. BS EN 15794:2009EN 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 beginni

31、ng 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 t

32、emperature, 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

33、 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 K

34、ey 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 Tightly fitting lid allowing for pressure relief4 Elect

35、rodes 9 Inlet valve5 Stirrer 10 Outlet valveFigure 1 Explosion point apparatus; schematic BS EN 15794:2009EN 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 b

36、etween 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

37、 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

38、 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 / cooling chamber The test vessel is l

39、ocated 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 should have an air exchange rate of at least ten air changes

40、 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 has to be heated uniformly so that the temperature distribu

41、tion 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 source A series of induction sparks between two electrodes is

42、 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 mm 0,1 mm). The electrodes shall be mounted in a gas tight

43、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, with a root mean square of 13 kV to 16 kV (open circuit v

44、oltage) 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 spark discharge time shall be adjusted to 0,2 s. If a spark d

45、ischarge 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 conditions according to calorimetric and electric measurem

46、ents 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. BS EN 15794:2009EN 15794:2009 (E) 9 5.7 Barometer The barometer shall be accurate to 0,1 kPa. Barometers

47、 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 flashpoint of the sample or to estimate the explosion point (Annex B)

48、. 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-assessment is recommended if possible. If this is not possible the mixt

49、ure 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 LEP, the first test temperature should be either 5 K (for LEPs below 100