DIN EN 14034-2-2011 Determination of explosion characteristics of dust clouds - Part 2 Determination of the maximum rate of explosion pressure rise (dp dt) of dust clouds German ve.pdf

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|h“1758969www.din.deDDIN EN 14034-2Determination of explosion characteristics of dust clouds Part 2: Determination of the maximum rate of explosion pressurerise of dust clouds (includes Amendment A1:2011)English translation of DIN EN 14034-2:2011-04Bestimmung der Explosionskenngren von Stau

3、b/Luft-Gemischen Teil 2: Bestimmung des maximalen zeitlichen Druckanstiegs vonStaub/Luft-Gemischen (enthlt nderung A1:2011)Englische bersetzung von DIN EN 14034-2:2011-04Dtermination des caractristiques dexplosion des nuages de poussire Partie 2: Dtermination de la vitesse maximale de monte en press

4、iondexplosion des nuages de poussire (Amendement A1:2011 inclus)Traduction anglaise de DIN EN 14034-2:2011-04SupersedesDIN EN 14034-2:2006-08See start of applicationwww.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.(dp/dt)max(dp/dt)m

5、ax(dp/dt)max3103.11 DIN EN 14034-2:2011-04 A comma is 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 “Potential

6、ly 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 Standards Committee), Working Committee NA 095-02-09 AA Kenngren fr Stu

7、be, Gase und Dmpfe. The DIN Standards corresponding to the International Standards referred to in this document is as follows: ISO 4225 DIN ISO 4225 Amendments This standard differs from DIN EN 14034-2:2006-08 as follows: a) specifications relating to the use of barium nitrate have been deleted. Pre

8、vious editions DIN EN 14034-2: 2006-08 National Annex NA (informative) Bibliography DIN ISO 4225, Air quality General aspects Vocabulary 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14034-2:2006+A1 January 2011 ICS 13.230 Supersedes EN 14034-2:2006English Version Determination of explosion

9、 characteristics of dust clouds Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)maxof dust clouds Dtermination des caractristiques dexplosion des nuages de poussire Partie 2: Dtermination de la vitesse maximale de monte en pression dexplosion (dp/dt)maxdes nuages de pouss

10、ireBestimmung der Explosionskenngren von Staub/Luft-Gemischen Teil 2: Bestimmung des maximalen zeitlichen Druckanstiegs (dp/dt)maxvon Staub/Luft-Gemischen This European Standard was approved by CEN on 20 April 2006 and includes Amendment 1 approved by CEN on 13 November 2010. CEN members are bound t

11、o comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard 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-CE

12、NELEC 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-CENELEC Management Centre has t

13、he same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pola

14、nd,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, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by an

15、y means reserved worldwide for CEN national Members. Ref. No. EN 14034-2:2006+A1:2011: EEN 14034-2:2006+A1:2011 (E) 2 Contents Page Foreword 4Introduction .51 Scope 62 Normative references 63 Terms and definitions .64 Test apparatus .74.1 General 74.2 Explosion vessel 84.3 Dust dispersion system (du

16、st container, fast acting valve, connecting tube, dust disperser) . 104.4 Ignition source 134.5 Control unit 134.6 Pressure measuring system 135 Dust sample . 136 Test procedure 137 Calibration and verification . 167.1 Calibration . 167.2 Verification 168 Safety precautions / instructions 179 Altern

17、ative test equipment / procedures 1710 Test report . 18Annex A (normative) Electro Pneumatic Valve . 19Annex B (normative) Dust dispenser with 5 mm holes 22Annex C (normative) 20 l sphere 25C.1 General . 25C.2 Test apparatus 25C.3 Test conditions . 26C.4 Test procedure 26C.5 Calculation of (dp/dt)ma

18、x, 20 l, Kmaxand KSt. 27Annex ZA (informative) !Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC“ 28Bibliography . 29Figures Figure 1 1 m vessel (schematic) . 9Figure 2 Dust container with blasting cap activated valve as commonly used for explosion s

19、uppression (schematic; it is commercially available) 10Figure 3 Location of the 6 mm holes in the dust disperser 12Figure 4 Dust dispersion and pressure-time curve . 15Figure 5 Determination of the maximum rate of explosion pressure rise (dp/dt)max16Figure A.1 Electro Pneumatic Valve (schematic) . 2

20、0DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 3 Figure A.2 Discharge characteristic of dust dispersers (without dust) . 21Figure B.1 Location of the 5 mm holes in the dust disperser . 23Figure B.2 Rebound nozzle . 24Figure B.3 Dispersion cup 24Figure C.1 Test equipment 20 l sphere (schematic)

21、. 26Tables Table 1 Maximum permissible deviations SEQ 17DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 4 Foreword This document (EN 14034-2:2006+A1:2011) has been prepared by Technical Committee CEN/TC 305 “Potentially explosive atmospheres - Explosion prevention and protection”, the secretariat

22、 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 July 2011, and conflicting national standards shall be withdrawn at the latest by July 2011. Attention is drawn to the pos

23、sibility 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 includes Amendment 1, approved by CEN on 2010-11-13. This document supersedes EN 14034-2:2006. The st

24、art and finish of text introduced or altered by amendment is indicated in the text by tags !“. 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 Directives. For relationship with

25、the EU Directive 94/9/EC, see informative Annex ZA, which is an integral part of this document. This European Standard is one of a series of standards as listed below: EN 14034 “Determination of explosion characteristics of dust clouds“ Part 1: Determination of the maximum explosion pressure pmaxof

26、dust clouds; Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)maxof dust clouds; Part 3: Determination of the lower explosion limit LEL of dust clouds; Part 4: Determination of the limiting oxygen concentration LOC of dust clouds. According to the CEN/CENELEC Internal Regu

27、lations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Ma

28、lta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 5 Introduction This European Standard specifies a method for experimental determination of the maximum rate of explosion pressure

29、 rise of dust clouds. The maximum rate of explosion pressure rise is the maximum value of the pressure rise per unit time during explosions of explosive atmospheres in the explosion range of a combustible dust in a closed vessel. The measurement of the maximum rate of explosion pressure rise forms t

30、he basis for explosion protection by design and construction of equipment, protective systems and components to reduce the explosion effects. !deleted text“ DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 6 1 Scope This standard describes a test method for the determination of the maximum rate of

31、 explosion pressure rise of dust clouds in a closed vessel under defined initial conditions of pressure and temperature. This method is not suitable for use with recognised explosives, like gunpowder and dynamite, explosives which do not require oxygen for combustion, pyrophoric substances, or subst

32、ances 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, expert advice should be sought. 2 Normative references The following referenced documents are indispensable for the applica

33、tion 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 14460, Explosion resistant equipment 3 Terms and definitions For the purposes of this document, the following term

34、s and definitions apply. 3.1 dust small solid particles in the atmosphere which settle out under their own weight, but which may remain suspended 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 dus

35、t able to undergo an exothermic reaction with air when ignited NOTE The terms “flammable” and “combustible” are used synonymously. 3.3 explosion pressure pexhighest overpressure occurring during an explosion of a dust cloud in a closed vessel 3.4 explosive atmosphere mixture with air, under atmosphe

36、ric conditions, of flammable (combustible) substances in the form of gases, vapours, mists or dusts, in which, after ignition has occurred, combustion spreads to the entire unburned mixture 3.5 ignition delay tvtime between the initiation of the dust dispersion and the activation of the ignition sou

37、rce DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 7 3.6 initial pressure pi pressure in the explosion vessel at the moment of ignition 3.7 initial temperature Ti temperature in the explosion vessel at the moment of ignition 3.8 Kmax, KSt dust specific, volume independent characteristic which is

38、 calculated using the cubic law equation ()maxSt3/1maxconst.d/d KKVtp = 3.9 rate of explosion pressure rise (dp/dt)ex the maximum slope of the pressure/time curve during an explosion of a dust cloud in a closed vessel 3.10 maximum rate of explosion pressure rise (dp/dt)max maximum value of the press

39、ure 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 This parameter when determined in the 1 m3vessel is numerically identical with the param

40、eters Kmax(EN 26184-1) 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 the maximum rate of explosion pressure rise (dp/dt)maxof dust clouds is an explosion pressure resist

41、ant vessel of 1 m, as used for the determination of the maximum explosion pressure and the lower explosion limit of dust clouds as well as the limiting oxygen concentration of dust/air/inert gas mixtures. The main components of the test apparatus are explosion vessel; dust dispersion system; ignitio

42、n source; control unit; pressure measuring system. NOTE The 20 l sphere apparatus is an alternative explosion vessel for these determinations (see Annex C). DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 8 4.2 Explosion vessel The standard explosion vessel is an explosion pressure resistant, sph

43、erical 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 explosion vessel be designed to withstand an overpressure of at least 20 bar. The apparatus shall be fitted wi

44、th 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 procedure can start. The apparatus shall also be equipped as far as possible to ensure that any residual pressur

45、e inside the vessel is vented before the vessel can be opened. DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 9 Key 1 pressure sensor 5 dust container 2 chemical igniters 6 fast acting valve 3 inlet for purge air 7 connecting tube 4 dust disperser 8 outlet for exhaust gas Figure 1 1 m vessel (sc

46、hematic) DIN EN 14034-2:2011-04 EN 14034-2:2006+A1:2011 (E) 10 4.3 Dust dispersion system (dust container, fast acting valve, connecting tube, dust disperser) The dust to be dispersed is charged into a dust container having a volume of 5,4 dm. Its aspect ratio is 3:1. It is designed to withstand an

47、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 by a blasting cap. The valve has a mushroom-shaped seal. The seal is held in position against the pressure

48、 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 designed 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 t