DIN EN 14034-4-2011 Determination of explosion characteristics of dust clouds - Part 4 Determination of the limiting oxygen concentration LOC of dust clouds German version EN 14034.pdf

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1、April 2011 Translation by DIN-Sprachendienst.English price group 14No part of this translation 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

2、13.230!$n|j“1758971www.din.deDDIN EN 14034-4Determination of explosion characteristics of dust clouds Part 4: Determination of the limiting oxygen concentration LOC of dustclouds (includes Amendment A1:2011)English translation of DIN EN 14034-4:2011-04Bestimmung der Explosionskenngren von Staub/Luft

3、-Gemischen Teil 4: Bestimmung der Sauerstoffgrenzkonzentration SGK von Staub/Luft-Gemischen(enthlt nderung A1:2011)Englische bersetzung von DIN EN 14034-4:2011-04Dtermination des caractristiques dexplosion des nuages de poussire Partie 4: Dtermination de la concentration limite en oxygne CLO des nua

4、ges depoussire (Amendement A1:2011 inclus)Traduction anglaise de DIN EN 14034-4:2011-04SupersedesDIN EN 14034-4:2004-12See start of applicationwww.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.3203.11 DIN EN 14034-4:2011-04 A comma i

5、s used as the decimal marker. Start of application The start of application of this standard is 1 April 2011. National foreword This standard includes safety requirements. This standard has been prepared by Technical Committee CEN/TC 305 “Potentially explosive atmospheres Explosion prevention and pr

6、otection” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Sicherheitstechnische Grundstze (Safety Design Principles Standards Committee), Working Committee NA 095-02-09 AA Kenngren fr Stube, Gase und Dmpfe. The DIN Standard corresponding t

7、o the International Standard referred to in this document is as follows: ISO 4225 DIN ISO 4225 Amendments This standard differs from DIN EN 14034-4:2004-12 as follows: a) specifications relating to the use of barium nitrate have been deleted. Previous editions DIN EN 14034-4: 2004-12 National Annex

8、NA (informative) Bibliography DIN ISO 4225, Air quality General aspects Vocabulary 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14034-4:2004+A1 January 2011 ICS 13.230 Supersedes EN 14034-4:2004English Version Determination of explosion characteristics of dust clouds Part 4: Determination

9、of the limiting oxygen concentration LOC of dust clouds Dtermination des caractristiques dexplosion des nuages de poussire Partie 4: Dtermination de la concentration limite en oxygne CLO des nuages de poussire Bestimmung der Explosionskenngren von Staub/Luft-Gemischen Teil 4: Bestimmung der Sauersto

10、ffgrenzkonzentration SGK von Staub/Luft-Gemischen This European Standard was approved by CEN on 9 July 2004 and includes Amendment 1 approved by CEN on 13 November 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanS

11、tandard 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 (Eng

12、lish, 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,

13、 Bulgaria, Croatia, 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

14、FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14034-4:2004+A1:2011: EEN 14034-4:2004+A1:2

15、011 (E) 2 Contents Page Foreword 31 Scope 52 Normative references 53 Terms and definitions .54 Test apparatus .64.1 General 64.2 Explosion vessel 84.3 Dust dispersion system (dust container, fast acting valve, connecting tube, dust disperser) 84.4 Ignition source 124.5 Control unit 124.6 Pressure me

16、asuring system 124.7 Oxygen measuring system 124.8 System to create the inert gas/air-mixture . 125 Dust sample . 126 Test procedure 127 Calibration and verification . 157.1 Calibration . 157.2 Verification 158 Safety precautions / instructions for use . 159 Alternative test equipment / procedures 1

17、610 Test report . 16Annex A (normative) Electro pneumatic valve . 17Annex B (normative) Dust disperser with 5 mm holes 20Annex C (normative) 20 l sphere 24C.1 General . 24C.2 Test apparatus 24C.3 Test conditions . 25C.4 System to create the inert gas/air-mixture . 26C.5 Test procedure 26Annex D (inf

18、ormative) Examples of procedures to determine the LOC . 27Annex ZA (informative) ! Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC“ 29Bibliography . 30DIN EN 14034-4:2011-04 Introduction .4EN 14034-4:2004+A1:2011 (E) 3 Foreword This document (EN 140

19、34-4:2004+A1:2011) 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 te

20、xt or by endorsement, at the latest by July 2011, and conflicting national standards shall be withdrawn at the latest by July 2011. 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 f

21、or identifying any or all such patent rights. This document includes Amendment 1, approved by CEN on 2010-11-13. This document supersedes EN 14034-4:2004. The start and finish of text introduced or altered by amendment is indicated in the text by tags !“. This document has been prepared under a mand

22、ate 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. This document includes a Bibliography. This docume

23、nt is one of a series of standards as listed below: EN 14034-1,Determination of explosion characteristics of dust clouds Part 1: Determination of the maximum explosion pressure pmaxof dust clouds; !EN 14034-2“, Determination of explosion characteristics of dust clouds Part 2: Determination of the ma

24、ximum rate of explosion pressure rise (dp/dt)maxof dust clouds; !EN 14034-3“, Determination of explosion characteristics of dust clouds Part 3: Determination of the lower explosion limit LEL of dust clouds; EN 14034-4, Determination of explosion characteristics of dust clouds Part 4: Determination o

25、f the limiting oxygen concentration LOC of dust clouds. 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, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Fin

26、land, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DIN EN 14034-4:2011-04 EN 14034-4:2004+A1:2011 (E) 4 Introduction This document sp

27、ecifies a method for experimental determination of the limiting oxygen concentration of dust/air/inert gas mixtures. The limiting oxygen concentration is the maximum concentration of oxygen of a dust/air/inert gas mixture at which dust explosions cannot occur. The measurement of the limiting oxygen

28、concentration forms the basis for explosion protection by ”Inerting“. This limiting oxygen concentration is a safety characteristic used for hazard identification and designing safety measures. This is done by avoidance or reduction of the amount of explosive atmosphere. !deleted text“ DIN EN 14034-

29、4:2011-04 EN 14034-4:2004+A1:2011 (E) 5 1 Scope This document describes a test method for the determination of the limiting oxygen concentration of dust clouds in a closed vessel under defined initial conditions of pressure and temperature. This method is not suitable for use with recognised explosi

30、ves, like gunpowder and dynamite, substances which do not require oxygen for combustion, pyrophoric substances, or substances or mixtures of substances which may under some circumstances behave in a similar manner. Where any doubt exists about the existence of hazard due to explosive properties, exp

31、ert advice should be sought. 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) applie

32、s. !EN 14034-1:2004+A1:2011“; Determination of explosion characteristics of dust clouds Part 1: Determination of the maximum explosion pressure pmaxof dust clouds !EN 14034-2:2006+A1:2011; Determination of explosion characteristics of dust clouds Part 2: Determination of the maximum rate of explosio

33、n pressure rise (dp/dt)maxof dust clouds“ !EN 14460“, Explosion resistant equipment 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 dust small solid particles in the atmosphere which settle out under their own weight, but which may remain sus

34、pended in air for some time (includes dust and grit, as defined in ISO 4225). NOTE Generally maximum particle size will not exceed 500 m. 3.2 combustible dust dust able to undergo an exothermic reaction with air when ignited NOTE The terms “flammable” and “combustible” are used synonymously. 3.3 ign

35、ition delay tv time between the initiation of the dust dispersion and the activation of the ignition source 3.4 inert gas non-flammable gas which will not support combustion and does not react to produce a flammable gas DIN EN 14034-4:2011-04 EN 14034-4:2004+A1:2011 (E) 6 3.5 initial pressure pi the

36、 pressure in the explosion vessel at the moment of ignition 3.6 initial temperature Ti the temperature in the explosion vessel at the moment of ignition 3.7 limiting oxygen concentration of dust clouds (LOC) maximum oxygen concentration in mixture of a combustible dust and air and an inert gas, in w

37、hich an explosion will not occur, determined under test conditions specified by this document 3.8 maximum explosion pressure pmax maximum overpressure occurring in a closed vessel during the explosion of an explosive atmosphere determined under specified test conditions and standard atmospheric cond

38、itions 3.9 maximum rate of explosion pressure rise (dp/dt)max maximum value of the pressure rise per unit time during explosions of all explosive atmospheres in the explosion range of a combustible substance in a closed vessel under specified test conditions and standard atmospheric conditions NOTE

39、This parameter when determined in the 1 m3vessel is numerically identical with the parameters Kmax(ISO 6184-1) and KSt(VDI 2263-1) but the units of the latter are bar m s-1whereas the unit of the (dp/dt)maxis bar s-1. 4 Test apparatus 4.1 General The standard test apparatus to determine limiting oxy

40、gen concentrations is an explosion pressure resistant vessel of 1 m, as used for the determination of the maximum explosion pressure, the maximum rate of explosion pressure rise (KSt-value) and the lower explosion limit of dust clouds. The main components of the test apparatus are the explosion vess

41、el; the dust dispersion system; the ignition source; the control unit; the pressure measuring system; the oxygen measuring system; the system to create the inert gas/air-mixture. NOTE The 20 l sphere apparatus is an alternative explosion vessel for these determinations (see annex C). DIN EN 14034-4:

42、2011-04 EN 14034-4:2004+A1:2011 (E) 7 Key 1 Pressure sensor 2 Chemical igniters 3 Inlet for purge air / inert gas 4 Dust disperser 5 Dust container 6 Fast acting valve 7 Connecting tube 8 Outlet for exhaust gas 9 Oxygen analyser Figure 1 1 m vessel (schematic) DIN EN 14034-4:2011-04 EN 14034-4:2004+

43、A1:2011 (E) 8 4.2 Explosion vessel The standard explosion vessel is an explosion pressure resistant, spherical or cylindrical vessel having a volume of 1 m in accordance with !EN 14460“. The aspect ratio of the cylindrical vessel shall be 1:1 10 % (see Figure 1). NOTE It is recommended that the expl

44、osion vessel be designed to withstand an overpressure of at least 20 bar. The apparatus shall be fitted with electrical and/or mechanical cut-offs as far as possible to ensure that any openings in the vessel (e.g. main door, instrument ports, inlet or outlet) are properly closed before a test proced

45、ure can start. The apparatus shall also be equipped as far as possible to ensure that any residual pressure inside the vessel is vented before the vessel can be opened. 4.3 Dust dispersion system (dust container, fast acting valve, connecting tube, dust disperser) The dust to be dispersed is charged

46、 into a dust container having a volume of 5,4 dm. Its aspect ratio is 3:1. It is designed to withstand an overpressure of at least 20 bar (see Figure 2). The dust container has an outlet at the base, through which the dust leaves the container. This outlet is closed by a fast acting valve activated

47、by a blasting cap. The valve has a mushroom-shaped seal. The seal is held in position against the pressure in the dust container by a small ring. The ring is destroyed by firing a blasting cap and the valve opens due to the pressure inside the dust container (see Figure 2). The valve shall be design

48、ed so that it opens in less than 10 ms. For alternative valves see annex A. The fast acting valve is connected to the side of the explosion vessel. The connecting tube between the fast acting valve and the dust disperser shall be not longer than 350 mm (see Figure 1). DIN EN 14034-4:2011-04 EN 14034-4:2004+A1:2011 (E) 9 Key 1 Dust container 5 Protective hood