BS EN ISO 15012-2-2008 Health and safety in welding and allied processes - Requirements testing and marking of equipment for air filtration - Determination of the minimum air volum.pdf

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1、BRITISH STANDARDBS EN ISO 15012-2:2008Health and safety in welding and allied processes Requirements, testing and marking of equipment for air filtration Part 2: Determination of the minimum air volume flow rate of captor hoods and nozzlesICS 25.160.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g5

2、6g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 15012-2:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2008 BSI 200

3、8ISBN 978 0 580 53143 9National forewordThis British Standard is the UK implementation of EN ISO 15012-2:2008.The UK participation in its preparation was entrusted to Technical Committee WEE/40, Health and safety in welding.A list of organizations represented on this committee can be obtained on req

4、uest to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate Comment

5、sEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 15012-2April 2008ICS 25.160.30English VersionHealth and safety in welding and allied processes -Requirements, testing and marking of equipment for air filtration- Part 2: Determination of the minimum air volume flow rate ofcaptor hoods and nozzl

6、es (ISO 15012-2:2008)Hygine et scurit en soudage et techniques connexes -Exigences, essais et marquage des quipements defiltration dair - Partie 2: Dtermination du dbit volumiqueminimal dair des bouches de captage (ISO 15012-2:2008)Sicherheit und Gesundheitsschutz beim Schweien und beiverwandten Ver

7、fahren - Anforderungen, Prfung undKennzeichnung von Luftreinigungssystemen - Teil 2:Bestimmen des Mindestluftvolumenstroms vonAbsaughauben und Flanschplatten (ISO 15012-2:2008)This European Standard was approved by CEN on 21 March 2008.CEN members are bound to comply with the CEN/CENELEC Internal Re

8、gulations 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 application to the CEN Management Centre or to any CEN member.This

9、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 CEN Management Centre has the same status as theofficial versions.CEN members are the n

10、ational standards bodies of 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, Switzerland and

11、 United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 15012-2

12、:2008: EForeword This document (EN ISO 15012-2:2008) has been prepared by Technical Committee CEN/TC 121 “Welding“, the secretariat of which is held by DIN, in collaboration with Technical Committee ISO/TC 44 “Welding and allied processes“. This European Standard shall be given the status of a natio

13、nal standard, either by publication of an identical text or by endorsement, at the latest by October 2008, and conflicting national standards shall be withdrawn at the latest by October 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of paten

14、t rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. 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, Cypr

15、us, 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 the United Kingdom. BS EN ISO 15012-2:2008iiiForeword ISO

16、 (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical com

17、mittee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrot

18、echnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the mem

19、ber bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identify

20、ing any or all such patent rights. ISO 15012-2 was prepared by the European Committee for Standardization (CEN) Technical Committee CEN/TC 121, Welding, in collaboration with Technical Committee ISO/TC 44, Welding and allied processes, Subcommittee SC 9, Health and safety, in accordance with the Agr

21、eement on technical cooperation between ISO and CEN (Vienna Agreement). ISO 15012 consists of the following parts, under the general title Health and safety in welding and allied processes Requirements, testing and marking of equipment for air filtration: Part 1: Testing of the separation efficiency

22、 for welding fume Part 2: Determination of the minimum air volume flow rate of captor hoods and nozzles The following part is under preparation: Part 3: Determination of the capture efficiency of welding fume extraction devices using tracer gas Requests for official interpretations of any aspect of

23、this part of ISO 15012 should be directed to the Secretariat of ISO/TC 44/SC 9 via your national standards body. A complete listing of these bodies can be found at www.iso.org. BS EN ISO 15012-2:2008iv Introduction Welding and allied processes generate fume and gases, which, if inhaled, can be harmf

24、ul to human health. Control is often required to maintain exposure at acceptable levels and this can be achieved by capturing the fume and gases using local exhaust ventilation (LEV), which consists of a capture device, such as a captor hood or nozzle, connected, via ducting, to an exhaust system. T

25、he plume of welding fume rises at a velocity of about 0,3 m/s and the air draughts commonly encountered in workshops are of the same order and can be higher. Effective capture of welding fume and gases can only be achieved when the extracted air velocity at the emission point exceeds the resulting v

26、elocity of the draught and the plume, so a velocity of 0,4 m/s has been selected for testing. For a particular capture device, this capture velocity can only be achieved by applying a minimum air volume flow rate, which is dependent upon the aspect ratio, the cross-sectional area of the device and i

27、ts distance from the emission point. Consequently, capture devices need to be used with exhaust systems that provide, at least, the minimum air volume flow rate. The design of capture devices can be very different. Aspect ratios range from those applicable to circular hoods to those of slots, so the

28、 size and shape of the area (capture zone) where fume and gases are captured, while using the minimum air volume flow rate, also varies considerably. Therefore, this part of ISO 15012 requires manufacturers of capture devices to measure the minimum air volume flow rate at measurement points selected

29、 to give an estimate of the size and shape of the capture zone. BS EN ISO 15012-2:20081Health and safety in welding and allied processes Requirements, testing and marking of equipment for air filtration Part 2: Determination of the minimum air volume flow rate of captor hoods and nozzles 1 Scope Thi

30、s part of ISO 15012 specifies a method for establishing the minimum air volume flow rate required for captor hoods and nozzles to effectively capture fume and gases from welding and allied processes. The method can be used with capture devices of any aspect ratio and cross-sectional area, but it is

31、not applicable to on-gun extraction systems and down draught tables. This part of ISO 15012 also specifies the test data to be marked on the capture devices. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only t

32、he edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12100-1, Safety of machinery Basic concepts, general principles for design Part 1: Basic terminology, methodology ISO 12100-2, Safety of machinery Basic concepts, g

33、eneral principles for design Part 2: Technical principles BS EN ISO 15012-2:20082 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 12100-1 and ISO 12100-2 and the following apply. 3.1 capture device equipment for capturing welding fume at source See F

34、igure 1. Key 1 entry plane (cross-sectional area for capture devices without flange) 2 nozzle 3 duct 4 nozzle with flange 5 cross-sectional area of a flanged capture device ( W 30) 6 hood 7 hood with flange angle between entry plane and nozzle/hood angle between entry plane and flange Figure 1 Entry

35、 plane and cross-sectional area of different designs of capture device 3.2 capture zone three-dimensional space in front of the entry plane of a capture device in which the air velocity is greater than or equal to the minimum air velocity required for effective capture of welding fume 3.3 entry plan

36、 outermost area of a capture device 3.4 cross-sectional area area of the opening of a capture device in the entry plane (for a nozzle or hood without a flange), or, area of a capture device in the plane in which the flange is attached, excluding the area of any obstructions in the entry plane (for a

37、 nozzle or hood with a flange) See Figure 1. 3.5 aspect ratio ratio of the lengths, x and y, in the entry plane, with x1W y1See Figure 2. NOTE The aspect ratio is 1 for a circular device and greater than 1 for other shapes. BS EN ISO 15012-2:20083Key x0, y0, z0centre point of the entry plane and ori

38、gin for the measurement point co-ordinates x1length of the entry plane of the capture device in the x-direction (x1W y1) y1length of the entry plane of the capture device in the y-direction (x1W y1) Figure 2 Schematic layout for a capture device 3.6 measurement plane plane, parallel to the entry pla

39、ne, in which measurements of air velocity are made See Figure 1. 3.7 nozzle capture device with an angle, , smaller than 60 between the side of the device and the entry plane See Figure 1. 3.8 flange surface extending outwards from, and almost parallel to ( 30), the entry plane of a capture device,

40、providing a barrier to unwanted air flow from behind See Figure 1. 3.9 hood capture device with an angle, , greater than or equal to 60 between the side of the device and the entry plane See Figure 1. 3.10 minimum air volume flow rate air volume flow rate required for effective capture of welding fu

41、me NOTE The minimum air volume flow rate depends on the type and the geometric dimensions of the capture device and the test positions selected to demonstrate the extent of the capture zone (see 7.2). BS EN ISO 15012-2:20084 4 Principle Tests are performed to determine the air volume flow rate requi

42、red to achieve an air velocity of 0,4 m/s at a minimum of two measurements points in front of the capture device on a measurement plane parallel to the entry plane of the capture device. Three tests are performed at each measurement point with air volume flow rates that provide approximate velocitie

43、s of 0,3 m/s, 0,4 m/s and 0,5 m/s. The air volume flow rate that provides a velocity of exactly 0,4 m/s at each measurement point is calculated from linear regression of the results. The minimum air volume flow rate of the capture device is taken to be the highest of the values obtained at the diffe

44、rent measurement points. NOTE The minimum air volume flow rate is determined in this manner because it is difficult to set an air volume flow rate that gives an air velocity of exactly 0,4 m/s at a given measurement point. 5 Requirement The manufacturer of a hood or nozzle shall use the results of t

45、hese tests to specify and mark the device with the minimum air volume flow rate required to achieve an air velocity of 0,4 m/s in the measurement plane, the distance of the measurement plane from the entry plane and the position of the measurement points selected to demonstrate the extent of the cap

46、ture zone of the device. The measurement points shall be identified by their (x, y)-co-ordinates projected from the entry plane. NOTE A hood or nozzle is expected to achieve effective capture of welding fume if it is operated with an air volume flow rate greater than or equal to the determined minim

47、um air volume flow rate and, in addition, if it is positioned at a distance less than or equal to the distance between the measurement plane and the entry plane of the device. 6 Equipment 6.1 Anemometer, suitable for measuring air velocities in the range 0,3 m/s to 0,5 m/s with a maximum uncertainty

48、 of 0,02 m/s, with a response time less than or equal to 1 s and having a calibration that is traceable to national standards. 6.2 Flow meter, or other suitable device, capable of measuring air volume flow rate with a maximum uncertainty of 5 % and having a calibration that is traceable to national

49、standards. 6.3 Measure, suitable for measuring distances with an uncertainty of 1 mm. 7 Test method 7.1 Test conditions Position the hood or nozzle so that it is free standing and sited away from any obstructions. Take care to minimise the influence of any disturbing air draughts. 7.2 Position of the measurement plane 7.2.1 Hoods and nozzles with an aspect ratio of less than or equal to 4 Determine the required distance, zi, in centimetres, between the measurement plane and the entry plane of the hood or nozzle of the capture devi