1、BRITISH STANDARD Non-de structive testing Leak test Guide to the selection of instrumentation for the measurement of gas leakage U The European Standard EN 13625:2001 has the status ofa British Standard ICs 19.100 BS EN 13625:2002 Wk present to the responsible European committee any enquiries on the
2、 interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. - A list of organizations represented on this committee can be obtained on request to its secretary. Cr oss-r e fer enc e s The British
3、 Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British S
4、tandard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cov
5、er, an inside front cover, the EN title page, pages 2 to 19 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. O BSI 05 March 2002 ISBN O 580 39203 I EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13625 December 2001 ICs 19.100 Engl
6、ish version Non-destructive testing - Leak test - Guide to the selection of instrumentation for the measurement of gas leakage Essais non destructifs - Contrle dtanchit - Guide pour la slection des instruments utiliss pour le mesurage des fuites gazeuses Zerstrungsfreie Prfung - Dichtheitsprfung - A
7、nleitung zur Auswahl von Gerten zur Messung von Gasleckagen This European Standard was approved by CEN on 5 October 2001 CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without
8、 any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the 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 b
9、y translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Irel
10、and, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION EUROPISCHES KOMITEE FR NORMUNG COMIT EUROPEN DE NORMALISATION Management Centre: rue de Stassart, 36 B-1050 Brussels O 2001 CEN All rights of exploitation in a
11、ny form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13625:2001 E EN 13625:2001 (E) Contents page Foreword 3 1 2 3 4 4.1 4.2 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 6 6.1 6.2 6.3 7 7.1 7.2 7.3 7.4 7.5 Scope 4 Normative references 4 Terms and definitions 4 Tracer gas method . Group
12、 A techniques (gas flowing into object) 4 Equipment and Material required for all group A techniques . 4 Vacuum technique . 5 Tracer gas method . Group B techniques (gas flowing out of the object) 6 Equipment and materials required for all group B techniques . 6 Ammonia technique (B.l) 7 Vacuum box
13、technique, for large enclosures or open walls (B.2.1, B.2.2) 7 Direct sample probing technique (B.4) 8 Pressurizing-Evacuation technique (B.5) 8 Sealed object by vacuum technique (B.6) . 9 Bubble test method . Group C techniques 9 Immersion technique (C.l) 9 Liquid application technique (C.2) . 10 L
14、iquid technique with vacuum box 10 Equipment and Material required for all group D techniques . 11 Enclosure techniques (B.3, B.6) . 8 Total pressure change method . Group D techniques . II Pressure decay technique (D.l) . II Pressure rise technique (D.2) . 12 Pressure change test (bell pressure cha
15、nge - D.3) . 12 Flow measurement technique (D.4) . 13 Bibliography 19 2 EN 13625:2001 (E) Foreword This European Standard has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing“, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a na
16、tional standard, either by publication of an identical text or by endorsement, at the latest by June 2002, and conflicting national standards shall be withdrawn at the latest by June 2002. According to the CENKENELEC Internal Regulations, the national standards organizations of the following countri
17、es are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 3 EN 13625:2001 (E) 1 Scope This European Standard spe
18、cifies criteria for the selection of equipment for the leak detection methods described in EN 1779. The minimum requirements for the performance of the instruments used are also given as a guideline for personnel involved in testing. The definite selection of an instrument for a given test is within
19、 the responsibility of a qualified operator (at minimum level 2 qualification -see EN 473). 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and th
20、e publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (inclu
21、ding amendments). EN 1330-8, Non-destructive testing - Terminology - Part 8: Terms used in leak tightness testing. EN 1779: 1999, Non-destructive testing - Leak testing - Criteria for method and technique selection. 3 Terms and definitions For the purposes of this European Standard, the terms and de
22、finitions given in EN 1330-8 apply. In this document the methods and techniques are referred to the annex A of the EN 1779:1999. 4 Tracer gas method - Group A techniques (gas flowing into object) 4.1 Equipment and Material required for all group A techniques 4.1 .I Leak detector In this type of test
23、, a leak detector (LD) of the mass spectrometer type (MSLD) according to the minimum requirements of Table 1 is used. 4.1.2 Calibration leaks At least one calibration leak for discharge to vacuum or against atmospheric pressure shall be used. These are used for the direct calibration of the MLSD (if
24、 a built-in calibration leak does not exist) or for system calibration (response time, sensitivity). If required, standard leaks shall be used. See Table 2. 4.1.3 Auxiliary pumping system An auxiliary pumping system should be used if: - the object volume or desorption gas load are too large for the
25、built-in pumps of the MSLD; - the leakage rate to be measured is too large for the measurement range of the MSLD. The auxiliary vacuum pumping system shall comply with the minimum requirements of Table 4. 4 EN 13625:2001 (E) 4.1.4 Connections Pipes and valves of suitable conductance with a port for
26、vacuum pressure measurement, previously tested for tightness so that they can not influence the test results, are required for: - connection of the object to the MSLD; - connection of the calibration leak to the system; - connection of the object to the auxiliary pumping system (if necessary). There
27、 should be a device for discharging the tracer gas outside the test area. 4.1.5 Tracer gas Pure tracer gas or a known and homogeneous mixture containing tracer gas shall be supplied to ensure repeatability. 4.1.6 Test condition measurements Calibrated pressure gauges and thermometers are required to
28、 monitor the object conditions. If required, ambient condition (pressure, temperature and humidity) shall also be measured. Response time shall be measured. 4.1.7 Cleaning and drying material and equipment Solvents or degreasing agents shall be available to clean the surfaces to be tested. Drying is
29、 important to eliminate vapours that can increase the evacuation time or can interfere with tracer gas detection. 4.2 Vacuum technique 4.2.1 Vacuum technique total (A.l) 4.2.1.1 Hood or rigid chamber The hood can be fabricated from a plastic film that is able to enclose entirely the object. It shoul
30、d be leak-tight enough to keep the tracer gas concentration constant. The rigid chamber shall be leaktight and enclose the object entirely. It should allow easy handling of the test object. It shall be evacuable to purge the internal volume. Suitable crossing in the walls shall allow the connections
31、. The chamber pressure shall be measured. NOTE The enclosure should present a leakage rate 10 times less than the maximum allowed rate specified. 4.2.1.2 Time measurement If the test is performed using an accumulation technique, the time from the initial tracer gas application shall be measured. 4.2
32、.2 Vacuum technique partial (A.2) 4.2.2.1 Cups or partial hoods Parts of the outer surface of the object are covered to admit selectively the tracer gas to the areas under test. Cups shall have soft edges or gaskets to adhere as much as possible to the surface. The plastic hoods shall be sealed, for
33、 example with adhesive tape. It should be leak-tight enough to keep the tracer gas concentration constant. 5 EN 13625:2001 (E) 4.2.3 Vacuum technique (local) (A.3) 4.2.3.1 Spray gun A spray gun with regulating valve is needed. If a tracer gas mixture is required for the test, the mixture can be obta
34、ined using a proportioning spray gun. 4.2.3.2 Calibration leak A conductance leak, calibrated for discharge to vacuum shall be used to verify the response time and the signal amplitude at the scanning speed. This calibration leak should be in the same range as the expected maximum leakage rate. 5 Tr
35、acer gas method - Group B techniques (gas flowing out of the object) 5.1 Equipment and materials required for all group B techniques 5.1 .I Leak detector Except for the Ammonia Technique (B.l) a leak detector with recorder is required. The leak detector (except for bombing test) shall be able to sam
36、ple at a relatively high pressure (20 kPa to 100 kPa). The MSLD shall have a regulating inlet valve or a sampling probe to adjust the inlet pressure to the maximum working pressure. 5.1.2 Calibration leaks Calibration leaks for discharge to atmosphere shall be used. These leaks should have a leakage
37、 rate close to the maximum allowable in the case of acceptance test or close to the minimum rate in leak location. 5.1.3 Test condition measurements Calibrated pressure gauges are required to monitor the object pressure. If necessary, overpressure protection devices shall be used to avoid damage to
38、the object and danger to personnel. If required, the object temperature and ambient conditions (pressure, temperature and humidity) have also to be measured. Response and impregnation time shall be measured. 5.1.4 Connections Piping system, with port for pressure - and, if necessary, temperature-mea
39、surement, previously tested for leak tightness, is required for: - filling the object with tracer gas; - connecting (if necessary) any enclosure to the LD and to the pumping system. Piping system is also required to discharge the tracer gas outside the area where the test is being conducted. 5.1.5 G
40、ases Pure tracer gas or a constant mixture containing tracer gas shall be supplied at the pressure required for the test. Other dry (or dried) gases are necessary for purging the object or the enclosures. 6 EN 13625:2001 (E) 5.2 Ammonia technique (B.l) 5.2.1 Chemical material The reagents are genera
41、lly colour-changing compounds, either in liquid form or supported on paper band. Their reactivity shall be verified before the test. For preparation after cleaning, passivation using dilute nitric acid (a volume fraction of 5 %) is required. The application of the reagent is made using a spray gun o
42、r a brush. Warm, dry air or inert gas, is needed to dry the applied reagent. The paper band is fixed with adhesive tape. The tracer gas shall be dry ammonia or a certified mixture of ammonia in inert gas, having a pressure and concentration sufficient to meet the test specifications. 5.2.2 Drying, p
43、ressurization, ammonia discharge A suitable pumping system is necessary for drying after the cleaning-passivation, for pressurization with ammonia mixture and for the removal of tracer gas from the system. 5.2.3 Pressure and concentration control An absolute gauge with a full scale range of 0,4 Mpa
44、to 0,5 MPa is needed for evacuation/pressurization monitoring. Ammonia concentration shall be checked using reactive tubes in the following ranges: - concentration for test : range 1 % to 10 % . 10 % to 100 %; - concentration after purging: range 5 x to 500 x . 0,05 x to 5 x pH Indicating equipment
45、is required to check the wastes before the discharge. 5.2.4 Ammonia disposal equipment Equipment to discharge and treat used ammonia, in accordance with local regulations, shall be used. 5.2.5 Illumination and visual equipment The reagent-covered surface shall be examined with white light, either di
46、rectly or with instruments able to show spots larger than 1 mm. A minimum illumination of 350 Ix shall be attained and measured. 5.3 Vacuum box technique, for large enclosures or open walls (B.2.1, B.2.2) 5.3.1 Vacuum box The rigid vacuum box shall have a soft seal to adhere as effectively as possib
47、le to the object wall. The leak- tightness of this seal is very important to increase the test sensitivity and to minimize the inlet of contaminated air from the ambient. 5.3.2 Pumping system The pumping system shall be able to achieve and maintain the vacuum box pressure at a specified level. 7 EN
48、13625:2001 (E) 5.3.3 Cups or spray gun For open objects the tracer gas is applied on the opposite side of the wall using cups, bags or a spray gun. 5.4 Enclosure techniques (B.3, B.6) 5.4.1 Tight enclosure The enclosure can be a rigid chamber or a plastic bag, it shall entirely contain the object, a
49、nd, allow for easy handling. For leakage rate measurement, the internal free volume shall be known and this is best achieved using a rigid chamber. The tightness of the enclosure shall be previously verified. The maximum allowed leakage rate shall be related to the test sensitivity. Suitable flange in the walls shall allow the connections of the chamber to the LD, to a known leak, to the pumping system and a suitable feed through may be needed to connect the object to the tracer gas supply. The chamber pressure shall be monitored. NOTE object. The enclosure should have a le
