BS EN 14522-2005 Determination of the auto ignition temperature of gases and vapours《测定气体和蒸气的自动点火温度》.pdf

1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58and vapoursThe European Standard EN 14522:2005 has the status of a British StandardICS 13.230Determ

2、ination of the auto ignition temperature of gases BRITISH STANDARDBS EN 14522:2005BS EN 14522:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 November 2005 BSI 28 November 2005ISBN 0 580 47321 XCross-referencesThe British Standards whi

3、ch implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publicat

4、ion does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, th

5、e EN title page, pages 2 to 22, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsA list of organizations represented on this committee can be obtained on requ

6、est to its secretary. present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard

7、 is the official English language version of EN 14522:2005.The UK participation in its preparation was entrusted to Technical Committee FSH/23, Fire precautions in industrial and chemical plant, which has the responsibility to: aid enquirers to understand the text;EUROPEAN STANDARDNORME EUROPENNEEUR

8、OPISCHE NORMEN 14522September 2005ICS 13.230English VersionDetermination of the auto ignition temperature of gases andvapoursDtermination de la temprature dauto-allumage des gazet des vapeursBestimmung der Zndtemperatur von Gasen und DmpfenThis European Standard was approved by CEN on 1 August 2005.

9、CEN members are bound to 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 nationalstandards may be obtained on app

10、lication to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has t

11、he same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia

12、,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN

13、 national Members.Ref. No. EN 14522:2005: EEN 14522:2005 (E) 2 Contents Page Foreword 3 Introduction4 1 Scope .5 2 Normative references .5 3 Terms and definitions.5 4 Test method.5 4.1 Principle.5 4.2 Apparatus 5 4.3 Ignition criterion7 4.4 Sampling, preparation and preservation of test samples8 4.5

14、 Procedure 8 4.6 Expression of results11 Annex A (normative) Verification 14 Annex B (informative) Example of test apparatus assembly 15 Annex C (informative) Illustration of parabolic fit procedure in method P 17 Annex D (normative) Safety aspects.18 Annex E (informative) Volume dependence of auto

15、ignition temperature .19 Annex F (informative) Example for a form expressing the results .20 Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC 21 Bibliography.22 Figures Figure B.1 Test apparatus assembly 15 Figure B.2 Example o

16、f the support for the Erlenmeyer flask. 16 Figure C.1 Parabolic fit procedure 17 Figure E.1 Volume dependence of auto ignition temperature. 19 Tables Table A1 Valuesafor Verification of the apparatus. 14 Table ZA.1 Correspondence between this European Standard and Directive 94/9/EC 21 EN 14522:2005

17、(E) 3 Foreword This European Standard (EN 14522:2005) 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

18、by publication of an identical text or by endorsement, at the latest by March 2006, and conflicting national standards shall be withdrawn at the latest by March 2006. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and

19、supports essential requirements of EU Directive. For relationship with EU Directive, 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 Eu

20、ropean Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14522:20

21、05 (E) 4 Introduction To avoid the hazard of explosion, an appropriate measure is to prevent effective ignition sources. Hot surfaces (heated active or passive) are one of the widespread potential ignition sources. The ignition potential of hot surfaces can be characterized with respect to the flamm

22、able substance under use by the auto ignition temperature of the flammable substance. The auto ignition temperature depends mainly on: the properties of the flammable substance; oxidiser; pressure; volume of the test vessel; material of the test vessel (hot surface); shape of the hot surface (this i

23、ncludes the fact whether the hot surface is surrounded by the cool flammable mixture or the flammable mixture is surrounded by the hot surface); flow and turbulence of the mixture; inert gas. Therefore it is necessary to standardize the conditions at which the auto ignition temperature is to be dete

24、rmined. Auto ignition temperatures as determined according to this European Standard are used first of all for classifying substances and explosion-proof electrical as well as non-electrical equipment into temperature classes. They may be used for designing explosion protection measures when the inf

25、luence of process conditions is known and taken into account. They may also be element of fire risk assessment. Because of the influences mentioned above, care shall be taken when applying such results measured under laboratory conditions to industrial applications. The apparatus and procedure descr

26、ibed below is also used for carrying out the Surface ignition test in IEC 60601-2-13 Medical electrical equipment Part 2-13: Particular requirements for the safety of anaesthetic systems. EN 14522:2005 (E) 5 1 Scope This European Standard test method is designed to determine the auto ignition temper

27、ature of a flammable gas or vapour in mixture with air, or air/inert gas, at ambient pressure up to 650 C. It is not suitable to describe the interactions of hot surfaces with explosives. 2 Normative references The following referenced documents are indispensable for the application of this document

28、. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including amendments) applies. ISO 1773, Laboratory glassware Narrow-necked boiling flasks 3 Terms and definitions For the purposes of this European Standard, the following

29、terms and definitions apply. 3.1 auto ignition temperature Tilowest temperature (of a hot surface) at which under specified test conditions an ignition of a flammable gas or flammable vapour in mixture with air or air/inert gas occurs 3.2 ignition delay time time between the completed injection of t

30、he flammable substance and the ignition NOTE 1 The ignition delay time may vary between fractions of a second and some minutes. NOTE 2 In literature auto ignition temperature is also referred to as self ignition temperature. In the case of dusts the respective safety characteristic is referred to as

31、 minimum ignition temperature. 4 Test method 4.1 Principle The amount of substance and the temperature of the test vessel, which is filled with air or air/inert gas, are varied to find the lowest temperature (of the hot surface) that causes an ignition. 4.2 Apparatus 4.2.1 General The test apparatus

32、 consists of: a test vessel; support for the test vessel; calibrated measuring thermocouple; EN 14522:2005 (E) 6 an electrical hot-air oven; metering devices for metering the flammable substance; a mirror for observing the ignition; timer; equipment for cleaning the test vessel. 4.2.2 Test vessel an

33、d support The test vessel shall be a 200 ml narrow-necked Erlenmeyer flask made of borosilicat glass according ISO 1773, or equivalent national standards. It shall be ensured that the inner surface of the bottom is not domed anyway. It shall be equipped with at least one calibrated measuring thermoc

34、ouple of 1,5 mm maximum diameter, having an accuracy of 0,5 K. The thermocouple(s) shall be mounted with intimate contact to the external surface of the flask at a distance of (25 2) mm to the bottom of the flask (see Annex B). The support for the Erlenmeyer flask shall ensure, that the heat dissipa

35、tion via the support is as low as possible. If the support is mounted at the neck it shall be ensured that it does not use more than (5 2) mm of the height of the neck of the Erlenmeyer flask (for example see Annex B). NOTE If there is special need to know exactly the influence of volume on the auto

36、 ignition temperature additional experiments in larger (respectively smaller) volumes of the same shape and material may be carried out. Data from literature show a decrease of the auto ignition temperature with increasing volume where at the same time the ignition delay time increases. See Annex E.

37、 4.2.3 Hot air oven and mounting of the vessel The hot air oven shall be of sufficient dimensions to heat up the test vessel in a uniform manner. It shall be designed in such a way that 1) when the oven is covered with a well fitting lid and after having reached the respective temperature equilibriu

38、m the temperature at the position of the measuring thermocouple and the temperature at the position of the centre of the bottom of the Erlenmeyer flask differ not more than 3 K over the whole temperature range and the temperature measured at the position of the measuring thermocouple and the tempera

39、ture measured at the position half of the height of the Erlenmeyer flask differ not more than 15 K over the whole temperature range; 2) when the oven is equipped with the Erlenmeyer flask filled with air the temperature measured with the measuring thermocouple varies not more than 2 K over a period

40、of 6 min over the whole temperature range. Care shall be taken that there is no direct contact between the test vessel and the inner walls of the oven. The distance between the inner walls and the Erlenmeyer flask shall be at least 4 mm. The test vessel shall be mounted in such a way that it is tota

41、lly immersed in the oven, whereas the oven should not overlap the Erlenmeyer flask more than 30 mm; it is uniformly heated; the mixture of air and flammable substance which is generated inside the Erlenmeyer flask by introducing the sample is not affected by the convection inside the oven; there is

42、no possibility that the (explosive) mixture of air and flammable substance which is generated inside the Erlenmeyer flask by introducing the sample enters into the oven and EN 14522:2005 (E) 7 that it is possible to meter the flammable substances and to observe the ignition (see Annex B for schemati

43、c representation). NOTE Ovens according to IEC 60079-4 or DIN 51794 are suitable ones. 4.2.4 Metering devices Gases The metering device (e.g. flow meter, pump, syringe) shall be designed in such a way that it is possible to meter the gas with an accuracy of 10 % at a rate of (25 5) ml/s. A filling t

44、ube that can be introduced into the test vessel shall be connected (movably) to the metering device. Liquids The metering device (e.g. pump, pipette, syringe) shall be designed in such a way that it is possible to meter droplets having a volume of (25 10) l. 4.2.5 Mirror A mirror of sufficient dimen

45、sions shall be positioned in such a way that it allows to observe the ignition of the flammable gas/air mixture (e.g. a distance of about 25 cm above the opening of the test vessel). 4.2.6 Timer A timer calibrated in one-second intervals shall be used to determine the ignition delay time. 4.2.7 Equi

46、pment for cleaning the test vessel with air The equipment (e.g. pump, air gun) shall allow the quick and complete cleaning of the test vessel by flushing it with clean air. After the cleaning only pure air shall fill the flask. 4.2.8 Automated apparatus If automated apparatus are used they shall ful

47、fil all the requirements stated in 4.2.2 to 4.2.7. If the monitoring of the ignition is automated as well, it shall be ensured that all kinds of flames (even the very pale ones and the very small ones) are monitored e.g. by thermocouple and photodiode. For safety reasons additional visual observatio

48、n should be possible. 4.3 Ignition criterion Any visible flame observed via the mirror (apparatus in a darkened room) shall be taken as ignition. NOTE Normally hot flames are observed. Even if they are very pale ones (e.g. hydrogen, methane), these are hot flames. Some substances or mixtures of subs

49、tances are able to form cool flames. Cool flames are characterized by a very weak luminosity and a small temperature difference (increase) to the unburned mixture. They are the first steps in the case of multi step ignition. They are more likely to appear in rich mixtures than in lean ones and with larger molecules than with smaller ones, as well as in larger volumes than in smaller ones. The apparatus and procedures described here cover to some extent