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BRITISH STANDARD Common test methods for cables under fire conditions Ð Tests on gases evolved during combustion of materials from cables Ð Part 2-2: Procedures Ð Determination of degree of acidity of gases for materials by measuring pH and conductivity The European Standard EN 50267-2-2:1998 has the status of a British Standard ICS 13.220.40; 29.060.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BS EN 50267-2-2:1999 BS EN 50267-2-2:1999 National foreword This British Standard is the English language version of EN 50267-2-2:1999 The UK participation in its preparation was entrusted by Technical Committee GEL/20, Electric cables, to Subcommittee GEL/20/3, Insulation and sheath, which has the responsibility to: Ð aid enquirers to understand the text; Ð present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; Ð monitor related international and European developments and promulgate them in the UK A list of organizations represented on this subcommittee can be obtained on request to its secretary Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled ªInternational Standards Correspondence Indexº, or by using the ªFindº facility of the BSI Standards Electronic Catalogue A British Standard 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 cover, an inside front cover, the EN title page, pages to and a back cover The BSI copyright notice displayed in this document indicates when the document was last issued This British Standard, having been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 1999 BSI 09-1999 ISBN 580 32734 Amendments issued since publication Amd No Date Comments EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 50267-2-2 June 1998 ICS 13.220.40; 29.060.20 Descriptors: electrical installation, electrical cables, fire tests, combustion tests, combustion products, burning gases, corrosive gases, determination, acidity, measurements, pH conductivity, testing, conditions, procedures English version Common test methods for cables under fire conditions — Tests on gases evolved during combustion of materials from cables — Part 2-2: Procedures — Determination of degree of acidity of gases for materials by materials by measuring pH and conductivity Méthodes d’essai communes aux câbles soumis au feu — Essais sur les gaz émis lors de la combustion d’un matériau prélevé sur un câble — Partie 2-2: Procédures — Détermination de l’acidité des gaz des matériaux par une mesure du pH et de la conductivité Allgemeine Prüfverfahren für das Verhalten von Kabeln und isolierten Leitungen im Brandfall — Prüfung der bei der Verbrennung der Werkstoffe von Kabeln und isolierten Leitungen entstehenden Gase — Teil 2-2: Prüfverfahren — Bestimmung des Grades der Azidität von Gasen bei Werkstoffen durch pH-Wert und Leitfähigkeit This European Standard was approved by CENELEC on 1998 04.01 CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving 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 versions (English, French, German) A version in any other language made by translation under the responsibility 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 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 Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels © 1998 CENELEC — All rights of exploitation in any form and by any means reserved worldwide for CENELEC national members Ref No EN 50267-2-2:1998 E Page EN 50267-2-2:1998 Foreword This European Standard was prepared by the Technical Committee CENELEC TC20, Electric Cables The text of the draft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as EN 50267-2-2 on 1998-04-01 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 (dop) 1999-03-01 latest date by which national standards conflicting with the EN have to be withdrawn (dow) 2000-03-01 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 annex Contents Page Foreword Scope Normative references Definition Test apparatus Test method and procedure 5.1 General principle 5.2 Samples and conditioning 5.3 Test pieces 5.4 Procedure 5.5 Determination of pH and conductivity Expression of the results Annex A (informative) Performance requirements 3 3 3 4 4 © BSI 09-1999 Page EN 50267-2-2:1998 Scope EN 50267-2-2 specifies the test method and procedure for the determination of the degree of acidity of gases evolved during the combustion of materials taken from electric or optical cables by measuring pH and conductivity NOTE The relevant cable standard should indicate which materials from the cable should be tested 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 the 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 EN 50267-1, Common test methods for cables under fire conditions — Tests on gases evolved during the combustion of materials from cables Part 1: Test apparatus EN 60695-4, Fire Hazard testing — Part 4: Terminology concerning fire tests NOTE IEC 60695 is in the course of re-numbering its parts and sections This will also affect the equivalent ENs Definition For the purposes of EN 50267-2-2 the following definition applies The definition is taken from EN 60695-4 ｗｗｗ．ｂｚｆｘｗ．ｃｏｍ 3.1 combustion exothermic reaction of a substance with an oxidizer with emission of effluent, generally accompanied by flames and/or glowing and/or emission of smoke 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 ±0,1 mg; — pH meter to an accuracy of ±0,02, equipped with a suitable pH electrode; — conductivity measuring device with a range 10 µS/mm to 10² µS/mm and a suitable electrode; — timer -2 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 Each wash bottle shall contain approximately 450 ml of distilled or demineralized water with the following properties: pH 6,5 ± 1,0; conductivity ≤ 0,5µS/mm The acidity is measured by determination of pH value The conductivity of the solution is also measured © BSI 09-1999 Page EN 50267-2-2:1998 5.2 Samples and conditioning Representative samples of the material to be tested shall be taken The samples shall be stored for at least 16 h at a temperature of (23 ± 2) °C and a relative humidity of (50 ± 5) % 5.3 Test pieces A test piece shall consist of (1 000 ± 5) mg of the material to be tested taken from the representative sample The test piece shall be cut into a number of smaller pieces 1.4 Procedure The test pieces, which shall be weighed to an accuracy of 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 (0,015 7D2) l·h − ±10 % and kept constant during the test NOTE 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 boat 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 ≥ 300 mm; the temperature measured at the position of the boat shall be not less than 935 °C The temperature measured at a position 300 mm from the boat in the direction of the air flow shall be not less than 900 °C ｗｗｗ．ｂｚｆｘｗ．ｃｏｍ The combustion procedure under the air flow condition shall be continued for 30 in the furnace NOTE The operator should take precautions, i.e the wearing of eye protection and suitable protective clothing, because certain materials ignite quickly, and can cause “blow-back” of hot gases Care should also be taken to avoid over-pressurisation of the system, and to allow for venting of exhaust gases After the test, and before determination of the pH and conductivity, the contents of both bottles shall be aggregated in a volumetric flask and made up to 000 ml using water with the properties given in 5.1 NOTE After removing the combustion boat, the tube has to be cleaned throughout its length by calcination at 950 °C 5.5 Determination of the pH value and conductivity 5.5.1 Calibration of the pH meter The pH meter shall be calibrated as proposed by the instrument supplier 5.5.2 Determination of the pH value and conductivity of the solution The pH value of the solution shall be determined at room temperature 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 Expression of the results Two test determinations shall be undertaken on each non-metallic individual material to be tested The test is considered to be passed if both the pH value of each sample of the material is not less than the specified value and the conductivity does not exceed the specified value If one sample fails, the test determination shall be repeated on two further samples of the relevant material Both repeat samples shall comply with specified limit values © BSI 09-1999 Page EN 50267-2-2:1998 Annex A (informative) Performance requirements No requirements for conformity are included in this standard The method specified in this standard is intended for testing of individual materials used in cable construction The use of this method will enable the requirements for individual materials of a cable construction to be stated in the appropriate cable specification Where no requirements are specified in the particular cable specification, and where the cable is described as “zero halogen” or “halogen-free” it is recommended that at least both the following requirements should be met for each of the individual materials of a cable construction a) The pH value as determined in 6, should not be less than 4,3, when related to one litre of water b) The conductivity value as determined in 6, should not exceed 10 µS/mm, when related to one litre 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 investigation should be agreed between interested parties ｗｗｗ．ｂｚｆｘｗ．ｃｏｍ © BSI 09-1999 BS EN 50267-2-2:1999 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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