1、BRITISH STANDARD Common test methods for cables under fire conditions - Tests on gases evolved during combustion of materials from cables - Part 2-3: Procedures - Determination of degree of acidity of gases for cables by determination of the weighted average of pH and conductivity The European Stand
2、ard EN 50267-2-3 1998 has the status of a British Standard ICs 13.220.40: 29.060.20 BS EN 50267-2-3:1999 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo
3、 reproduction or networking permitted without license from IHS-,-STi).BSI BS EN 502b7-2-3-ENGL 1777 M lb2qbb9 08004b5 703 direction of the Electrotechnicai hd. No. D - present to the responsible European committee any enquiries on the - monitor related intemationai and European developments and prom
4、ulgate interpretation, or proposals for change, and keep the UK interests informed them in the UK. A list of organizations represented on this subcommittee can be obtajned on request to its secretaqy. Cross-references The British Standards which implement international or European publications refer
5、red to in this document may be found in the BSI Standards Catalogue under the section entitled “Intemational Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include a3l the necessary provisions of a co
6、ntract. 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 cover, an inside front cover, the EN title page, pages 2 to 6, an inside ba
7、ck cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. O BSI 09-1999 I I ISBN O 580 32735 3 Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction o
8、r networking permitted without license from IHS-,-EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 50267-2-3 June 1998 ICs 13.220.40; 29.060.20 Partly supersedes HD 602 S 1 : 1992 Descriptors: electrical installation, electric cables, fire tests, combustion tests, combustion products, burning ga
9、ses, corrosive gases, determination, acidity, measurements, pH, conductivity, testing conditions, procedure English version Common test methods for cables under fire conditions - Tests on gases evolved during combustion of materials from cables - Part 2-3: Procedures - Determination of degree of aci
10、dity of gases for cables by determination of the weighted average of pH and conductivity Mthodes dessai communes aux cbles soumis au feu - Essais sur les gaz mis lors de ia combustion dun matriau prlev sw un cble - Partie 2-3: Procdures -Determination de lacidit des gaz des cibles par une mesure de
11、la moyenne pondere du pH et de la conductivit Allgemeine Prfierfahren fiir das Verhalten von Kabeln und isolierten Leitungen im Brandfall - Prfung der bei der Verbrennung der Werkstoffe von Kabeln und isolierten Leitungen entstehenden Gase - Teil 2-3: Prfverfahren - Bestimmung des Grades der Aziditt
12、 der wesentlichen Werkstoffe von Kabeln durch die Bestimmung eines gewichteten Mittelwertes von pH-Wert und Leitfahgkeit This European Standard was approved by CENELEC on 1998-04-0 1. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions. for giv
13、ing this European Standard 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 Central Secretariat or to any CENELEC member. This European Standard exists in three official
14、versions (English, French, Geman). A version in any other language made by translation under the responsibiliy of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees
15、of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotec
16、hnique Europisches Komitee I, Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels (6 1998 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC national members. Ref. No. EN 50267-2-3: 1998 E Copyright European Committee for Ele
17、ctrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-STD.BS1 BS EN 502b7-2-3-ENGL 1777 Lb24bb7 08004b7 7 b) requirements are given in an informative annex, as recommendations only. The text of the dra
18、ft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as EN 50267-2-3 on 1998-04-0 1. The following dates were fixed: - latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dp) 1999-03-0 1 -
19、latest date by which national standards conflicting with the EN have to be withdrawn (dw) 2000-03-0 1 Annexes designated “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard annex A is informative. There is no normative a
20、nnex. Contents Page 1 Scope 2 Normative references 3 Defmitions 4 Test apparatus 5 Test method and procedure 5.1 General principle 5.2 Samples and conditioning 5.3 Test pieces 5.4 Procedure 5.5 Determination of the pH value and conductivity 6 Expression of the results 6.1 Mean value 6.2 Weighted val
21、ues Annex A (informative) Performance requirements 3 3 3 3 3 3 4 4 4 4 4 4 5 6 6 BSI 09-1 999 Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-Page 3 EN 50267-2
22、-3 : 1998 1 Scope EN 50267-2-3 specifies the test method and procedure for the determination of the degree of acidity of gases evolved during the combustion of electric or optical cables by determination of the weighted average of pH and conductivity of the constituent materials. NOTE The relevant c
23、able standard should indicate which materials from the cable should be tested. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These nonnative references are cited at the appropriate places in the text and the publications
24、 are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Sandard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 50267-1, Common t
25、est methods for cables underfire conditions - Tests on gases evolved during the combustion of materialsfiom cables -Part I: Test apparatus. EN 60695-4, Fire hazard testing -Part 4: Terminology concerningfire tests. NOTE IEC 60695 is in the course of re-numbering its parts and sections. This will als
26、o affect the equivalent ENS. 3 Definitions For the purposes of EN 50267-2-3 the following definition applies. The definition is taken from EN 60695-4. 3.1 combustion exothermic reaction of a substance with an oxidizer with emission of effluent, generally accompanied by flames and/or glowing dor emis
27、sion of smoke 4 Test apparatus The apparatus used shall be that specified in EN 50267-1 together with the following measuring instruments: - analytical balance of an accuracy of M,1 mg; - pH meter to an accuracy of i0,02, equipped with a suitable pH electrode; - conductivity measuring device with a
28、range lo- pS/mm to 102 pismm and a suitable electrode; - timer. 5 Test method and procedure 5.1 General principle A pre-determined quantity of the test material is burned in a tube furnace. The evolved gases are trapped by bubbling through wash bottles filled with distilled or demineralized water. E
29、ach wash bottle shall contain approximately 450 ml of distilled or demineralized water with the following properties: pH 6,5 f 1,O; conductivity I 0,5 pS/mm. The acidity is measured by determination of pH value. The conductivity of the solution is also measured. 0 BSI 09-1 999 Copyright European Com
30、mittee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-STD-BSI BS EN 50267-2-3-ENGL 1777 Lb24bb7 08004b7 557 Page 4 EN50267-2-3:1998 5.2 Samples and conditioning Representative samples of
31、the materials of the cable to be tested shall be taken. The samples shall be stored for at least 16 h at a temperature of (23 f 2) OC and a relative humidity of (50 f 5) %. 53 Test pieces A test piece shall consist of (1 O00 f 5) mg of each material to be tested taken from the representative sample.
32、 The test piece shall be cut into a number of smaller pieces. 5.4 Procedure The test pieces, which shall be weighed to an accuracy of 1 mg, shall be put into a combustion boat. They shall be evenly distributed on the bottom of the boat. The air flow shall be adjusted by means of a needle valve at (0
33、,015 702) th- I10 % and kept constant during the test. NOTE I It is recommended that the air flow is not started until immediately prior to the commencement of the test. The temperature value shall be measured by a thermocouple suitably protected against corrosion and placed inside the tube. The boa
34、t containing the test pieces shall be quickly inserted into the effective zone of the tube and the timer shall be started. The combustion boat shall be placed in such a way that the distance between the boat and the exit end of the effective heating zone is 2 300 mm; the temperature measured at the
35、position of the boat shall be not less than 935 OC. The temperature measured at a position 300 mm from the boat in the direction of the air flow shall be not less than 900 OC. The combustion procedure under the air flow condition shall be continued for 30 min in the fumace. NOTE 2 Th? operator shoul
36、d take precautions, .e. the wearing of eye protection and suitable protective clothing, because certain materials ignite quickly, and can cause blow-back” of hot gascs. Care should also be taken to avoid over-pressurization of the system, and to allow for venting of exhaust gases. After the test, an
37、d before determination of the pH and conductivity, the contents of both bottles shall be aggregated in a volumetric flask and made up to 1 O00 mi using water with the properties given in 5.1. NOTE 3 After removing the combustion boat, the tube has to be cleaned throughout its length by calcination a
38、t 950 OC, 5.5 Determination of the pH value and conductivity 55.1 Calibration of hepH meter The pH meter shall be calibrated as proposed by the instrument supplier. 55.2 Determination of thepH value and conductiviv of the solution The pH value of the solution shall be determined at room temperature.
39、 The pH value shall be read by using the automatic temperature compensation, usually integral with the instrument. Conductivity measurements shall be performed in accordance with the test procedures as prescribed by the supplier. 6 Expression of the results 6.1 Mean value For each material, three te
40、st determinations shall be undertaken. Calculate the mean value, standard deviation and coefkient of variation. Q BSI 09-1 999 Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without lic
41、ense from IHS-,-STD-BSI BS EN 502b7-2-3-ENGL 1977 II Lb24bb9 080070 270 W Page 5 EN 50267-2-3 : 1998 If the coefficient of variation expressed in per cent is higher than 5, a further three tests on this material are required and the mean value, standard deviation and coefficient of variation should
42、be recalculated using the six values. 6.2 Weighted values Using the mean values for each material determined from 6.1, the assessment of the pH and conductivity of fire gases expected to be evolved by a combination of materials found in a specified cable under similar test conditions may be estimate
43、d as follows. 6.2.1pH Measure the weight wi ,of each non-metallic material, i, per unit length of cable. The weighted value of pH, pH, is calculated as follows: where x is the pH of each non-metallic material, i. 6.2.2 Conductivity Measure the weight, w, of each non-metallic material, i, per unit le
44、ngth of cable. The weighted value of conductivity, c, is calculated as follows: where c is the conductivity of each non-metallic material, i. Q BS109-1999 Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or netw
45、orking permitted without license from IHS-,-Page 6 EN 50267-2-31998 Annex A (informative) Performance requirements No requirements for conformity are included in this standard. The method specified in this standard is intended for type testing of specific cables. Where no requirements are specified
46、in the particular cable specification, and where the cable is described as “zero halogen” or “halogen-free” it is recommended that the following requirements should be met. a) The weighted pH value, as determined in 6.2.1, should not be less than 4.3, when related to 1 1 of b) The weighted value of
47、conductivity, as determined in 6.2.2, should not exceed 10 pS/mm when water. related to 1 1 of water. In case of dispute over the conductivity value, such as may occur if the recommended value is exceeded even though the test shows compliance with the recommended pH value, alternative methods of inv
48、estigation should be agreed between interested parties. 8 BSI 09- I999 Copyright European Committee for Electrotechnical Standardization Provided by IHS under license with CENELECNot for ResaleNo reproduction or networking permitted without license from IHS-,-BS EN 50267-2-3:1999 BSI 389 Chiswick Hi
49、&. Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the intemational level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they pos
