《BS-EN-50268-1-2000.pdf》由会员分享，可在线阅读，更多相关《BS-EN-50268-1-2000.pdf（10页珍藏版）》请在三一文库上搜索。
1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 50268-1:2000 The Eu
2、ropean Standard EN 50268-1:1999 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 Common test methods for cables under fire conditions Measurement of smoke density of cables burning under defined conditions Part 1: Ap
3、paratus 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 April 2000 BSI 04-2000 ISBN 0 580 34494 0 BS EN 50268-1:2000 Amendments issued since publication
4、Amd. No.DateComments National foreword This British Standard is the official English language version of EN 50268-1:1999. It supersedes BS 7622-1:1993, which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee GEL/20, Electric cables, to Subcommittee GEL/20/3,
5、Insulation and sheath, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and pr
6、omulgate 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
7、the section entitled International Standards Correspondence Index, or by using the Find 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 applicat
8、ion. 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 7 and a back cover. The BSI copyright notice displayed in this document indicates when the d
9、ocument was last issued. CENELEC European Committee for Electrotechnical Standardization Comite Europe en de Normalisation Electrotechnique Europa isches Komitee fu r Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1999 CENELEC All rights of exploitation in any for
10、m and by any means reserved worldwide for CENELEC members. Ref. No. EN 50268-1:1999 E EUROPEAN STANDARDEN 50268-1 NORME EUROPE ENNE EUROPA ISCHE NORM September 1999 ICS 13.220.40; 29.060.20Supersedes HD 606.1 S1:1992 English version Common test methods for cables under fire conditions Measurement of
11、 smoke density of cables burning under defined conditions Part 1: Apparatus Me thodes dessai communes aux ca bles soumis au feu Mesure de la densite de fume es de gage es par des ca bles bru lant dans des conditions de finies Partie 1: Appareillage Allgemeine Pru fverfahren fu r das Verhalten von Ka
12、beln und isolierten Leitungen im Brandfall Messung der Rauchdichte von Kabeln und isolierten Leitungen beim Brennen unter definierten Bedingungen Teil 1: Pru feinrichtung This European Standard was approved by CENELEC on 1997-04-01. CENELEC members are bound to comply with the CEN/CENELEC Internal R
13、egulations 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.
14、 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 me
15、mbers 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. Page 2 EN 50268-1:1999 BSI 04-2000 Foreword This European Sta
16、ndard was prepared by the Technical Committee CENELEC TC20, Electric cables, and agreed at its Dublin meeting (April 1997). The text of the draft was submitted to the Unique Acceptance Procedure and approved by CENELEC as EN 50268-1 on 1999-04-01. This European Standard supersedes HD 606.1 Sl:1992 T
17、he 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) 2000-04-01 latest date by which national standards conflicting with the EN have to be withdrawn (dow) 2001-04-01 Annexes designa
18、ted informative are given for information only. In this standard annexes A and B are informative. Contents Page Foreword2 1Scope3 2Normative references3 3Definitions3 4Details of test enclosure3 5Photometric system3 6Standard fire source4 7Smoke mixing4 8Blank test4 8.1Purpose4 8.2Procedure4 9Qualif
19、ication of test apparatus4 10Qualification burning test4 10.1 Purpose4 10.2 Preparation of cube4 10.3 Qualification smoke sources4 10.4 Test procedure4 10.5 Calculation4 10.6 Requirements5 Annex A (informative) Guidance notes7 Annex B (informative) Bibliography7 Page 3 EN 50268-1:1999 BSI 04-2000 1
20、Scope EN 50268 specifies a method of test for measurement of smoke density of cables burning under defined conditions. It is suitable for electric insulated conductor or cable, or optical cables. This part 1 details the apparatus. The procedure, together with an informative annex of recommended requ
21、irements for compliance, is given in part 2. NOTE Experience has shown that the test protocol is not suitable for some cables that exceed 70 mm overall diameter. In such cases the manufacturer should be consulted. 2 Normative references This European Standard incorporates by dated or undated referen
22、ce, 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 incorporate
23、d in it by amendment or revision. For undated references the latest edition of the publication referred to applies. 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
24、ENs. 3 Definitions For the purposes of this part 1 of EN 50268 the definitions in EN 60695-4 apply. 4 Details of test enclosure The equipment shall comprise a cubic enclosure with inside dimensions of 3 000 mm30 mm and constructed of a suitable material fixed on to a steel angle frame. One side shal
25、l have a door, with a glass inspection window. Transparent sealed windows (minimum size 100 mm 3 100 mm) shall be provided on two opposite sides to permit the transmission of a beam of light from the horizontal photometric system. The distance from the floor to the centre of these windows shall be 2
26、 150 mm100 mm (see Figure 1 for plan view). The walls of the enclosure shall include orifices at ground level, i.e. not greater than 100 mm above the level of the chamber floor, for the passage of cables etc., and to permit the enclosure to be at atmospheric pressure. No orifice shall be directly be
27、hind the fire source or on the same wall. A minimum of two orifices shall be provided and the total area of the orifices open during the test shall be 50 cm210 cm2. The ambient temperature outside the enclosure shall be 20 8C10 8C and the enclosure shall not be directly exposed to sunlight or extrem
28、e climatic changes. NOTE It should normally be possible to extract fumes from the enclosure after each test through a duct complete with valve which should be closed during the test. The duct may include a fan to increase the rate of extraction. It is recommended that the door of the enclosure be op
29、ened to assist the extraction process. A draught screen, 1 500 mm long and 1 000 mm high, shall be placed in the enclosure, at the position shown in Figure 1. It shall abut the back wall at a point 750 mm from the side wall, and shall be curved to intersect the centre line of the enclosure at a poin
30、t 1 400 mm from the back wall. 5 Photometric system 5.1 The photometric system is illustrated in Figure 2. The light source and the receiver shall be placed externally in the centre of both windows in the two opposite walls of the cube without making physical contact. The light beam shall traverse t
31、he cube through the glass windows in the side walls. 5.2 The light source shall be a halogen lamp with a tungsten filament with a clear quartz bulb having the following characteristics: nominal power:100 W nominal voltage:12 V d.c. nominal luminous flux:2 000 lm to 3 000 lm nominal colour temperatur
32、e:2 800 K to 3 200 K The bulb shall be supplied with a voltage of 12,0 V0,1 V (mean value). During the test the voltage shall be stabilized to a range of0,01 V (see A.2c) for additional guidance). The lamp shall be mounted in a housing and the beam adjusted by a lens system to give an evenly illumin
33、ated circular area of 1,5 m0,1 m diameter on the interior of the opposite wall. 5.3 The receptor photocell shall be of the selenium or silicon type with a spectral response matching the International Commission on Illumination (CIE) photopic observer (equivalent to the human eye). The photocell shal
34、l be mounted at the end of 150 mm10 mm tube with a dust protection window at the other end. The inside of the tube shall be matt black to prevent reflections. The photocell shall be connected to a potentiometric recorder to produce a linear proportional output. The cell shall be resistance-loaded to
35、 operate in its linear range and the input impedance of the recorder shall be at least 104 times greater than the load resistance of the cell which shall not exceed 100 V. 5.4 The photometric system shall be energized before the blank test. When stability has been attained, the zero and full scale r
36、eading of the recorder shall be adjusted for light on the detector corresponding to 0 % (absence of light) and 100 % luminous transmission. NOTE Periodically, for example at the beginning of a test series, the performance of the photocell should be verified by placing standard neutral density filter
37、s in the light beam, It is essential that these filters cover the entire optical entry port of the photocell and the values of absorbance (or optical density) measured by the photocell fall within5 % of the calibrated value of the filter. The filters should also permit the verification of the linear
38、ity of response of the detector which should be proportional to the absorbance of light in the range used. Page 4 EN 50268-1:1999 BSI 04-2000 6 Standard fire source The standard fire source shall be 1,00 litre0,01 litre of alcohol having the following composition by volume: ethanol:90 %1 % methanol:
39、4 %1 % water:6 %1 % When a denaturing agent is added to the alcohol, it shall have no effect on the smoke emission of any cable under test. The alcohol shall be contained in a tray made from galvanised or stainless steel with jointed sealed edges, a trapezoidal trunk section and the following interi
40、or dimensions (see Figure 3): bottom base:210 mm 3 110 mm top base:240 mm 3 140 mm height:80 mm All dimensions2 mm Thickness of tray: 1,0 mm0,1 mm The tray shall be supported at a height of 100 mm10 mm from the floor to permit air circulation around and beneath the tray. 7 Smoke mixing In order to e
41、nsure uniform distribution of the smoke, a table-type fan shall be placed on the floor of the cube as shown in Figure 1, the fan axis being between 200 mm and 300 mm from the floor and the distance from the wall being 500 mm50 mm. The fan shall have a blade sweep of 300 mm60 mm and a flow rate of 7
42、m3/min to 15 m3/min. Air shall then be blown horizontally by the fan during the tests but the ignition source shall be protected by the screen as shown. NOTE Suitable fans may be found by reference to IEC 60879, Performance and construction of electric circulating fans and regulators. 8 Blank test 8
43、.1 Purpose The purpose of the blank test is to condition the interior of the cube to the specified temperature range, when necessary, prior to carrying out tests. 8.2 Procedure 8.2.1 Burn approximately 1 litre of alcohol as detailed in clause 6, in order to preheat the test enclosure. 8.2.2 Purge th
44、e inside of the cube of all combustion products by operating the extraction system. 9 Qualification of test apparatus In order to ensure that the combination of the test cube and the optical system produce results consistent with other test cubes when identical cables are burned under the same condi
45、tions, the test apparatus shall be subject to qualification. Qualification shall be achieved by carrying out the Qualification Burning Test (clause 10). The test apparatus shall meet the stated requirements. 10 Qualification burning test 10.1 Purpose The purpose of the qualification burning test is
46、to verify that the smoke produced in the cube gives standard absorbance values within the limits quoted in 10.6 for both of the alcohol/toluene smoke sources described in 10.3. 10.2 Preparation of cube Clean the windows of the photometric system to regain 100 % transmission after stabilization of th
47、e voltage. Immediately before commencing the test, the temperature inside the cube shall be within the range 25 8C5 8C when measured at the internal door surface at a height of 1,5 m to 2,0 m and a minimum of 0,2 m from the walls. If necessary, carry out a blank test in order to condition the interi
48、or of the cube to the specific temperature range. 10.3 Qualification smoke sources Mixtures of PA (pro analysis) toluene and alcohol (as defined in clause 6) shall be made up in the following proportions by volume: (i) 4 parts of toluene to 96 parts alcohol; (ii) 10 parts of toluene to 90 parts alco
49、hol; using a pipette and volumetric flask for accuracy of measurement. NOTE PA toluene has a purity of greater than 99,5 %. The mixtures shall be contained in a tray as described in clause 6. 10.4 Test procedure Burn 1,00 litre0,01 litre of the test solutions specified in 10.3. Record the minimum measured transmittance level lt, during the test. 10.5 Calculation Calculate the measured absorbance (Am) as follows: Am= lg lo lt where 1ois the initial transmittance. Calculate the standard absorbance (Ao): Ao=3 Am