BS EN 61144-1993 Test method for the determination of oxygen index of insulating liquids《测定绝缘液体氧气指数的试验方法》.pdf

1、BRITISH STANDARD BS EN 61144:1993 IEC 1144:1992 Incorporating Amendment No.1 Test method for the determination of oxygen index of insulating liquids The European Standard EN61144:1993 has the status of a British StandardBSEN61144:1993 This British Standard, having been prepared under the directionof

2、 the Cables and Insulation Standards Policy Committee, was published underthe authority of the Standards Board and comes into effect on 15May1993 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference CIL/10 Special announcement in BSINews, January1993 ISBN

3、 0 580 21786 8 Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was prepared, comprises the national committees of the following countries: Austria Italy Belgium Luxembourg Denmark Netherlands Finland Norw

4、ay France Portugal Germany Spain Greece Sweden Iceland Switzerland Ireland UnitedKingdom Amendments issued since publication Amd. No. Date Comments 8200 June 1994 Indicated by a sideline in the marginBSEN61144:1993 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover National for

5、eword ii Foreword 2 Text of EN 61144 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-reference Inside back coverBSEN61144:1993 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the Cables a

6、nd Insulation Standards Policy Committee and is the English language version ofEN61144:1993 Test method for the determination of oxygen index of insulating liquids, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical withIEC1144:1992 published by the I

7、nternational Electrotechnical Commission (IEC). WARNING. This British Standard calls for the use of substances that may be injurious to health if adequate precautions are not taken. It refers only to the technical suitability and does not absolve the user from legal obligations relating to health an

8、d safety at any stage. 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 T

9、his document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside fro

10、nt cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61144 February 1993 UDC 621.315:620.1:546.21 Descriptors: Electrical insulating materials, liquid electrical insulating materials, fire tests, flammability, combustion, measurements, oxygen index English version Test method for the determ

11、ination of oxygen index of insulating liquids (IEC 1144:1992) Mthode dessai pour la dtermination de lindice doxygne des isolants liquides (CEI1144:1992) Meverfahren zur Bestimmung des Sauerstoff-Kennwertes von Isolierflssigkeiten (IEC1144:1992) This European Standard was approved by CENELEC on1992-1

12、2-09. 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 obt

13、ained 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 Cen

14、tral Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom

15、. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1993 Copyright reserved to CENELEC members Ref. No. EN61144:1993EEN61144:1993 BS

16、I 11-1999 2 Foreword The text of document10(CO)264, as prepared by IEC Technical Committee No.10: Fluids for electrotechnical applications was submitted to the IEC-CENELEC parallel vote inMarch1992. The reference document was approved by CENELEC as EN61144 on9December1992. The following dates were f

17、ixed: Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative reference 3 3 Definition 3 4 Summary of method 3 5 Apparatus 3 6 Test specimens 4 7 Procedure 4 8 Calculations 4 9 Report 5 10 Precision 5 Figure 1 Schematic arrangement of apparatus for determination of oxygen index 6 Figure 2 Boro

18、silicate glass test cup for determination of oxygen index of liquids 7 Figure 3 Ignition system for determination of oxygen index of liquids 8 latest date of publication ofan identical national standard (dop) 1993-12-01 latest date of withdrawal ofconflicting national standards (dow) 1993-12-01EN611

19、44:1993 BSI 11-1999 3 Introduction IEC Technical Committee 89 has been issuing guidelines for the evaluation of the fire hazard associated with electrical equipment and solid electrical insulation. In IEC695-1-1 it is stated that the following properties are relevant to the full assessment of fire h

20、azard: ignitability; combustion; propagation; opacity, toxicity and corrosiveness of smoke and gaseous products of combustion. IECTC10 has planned to develop standard method of test covering each of the above properties for electrical insulating liquid. This publication contains a standard method fo

21、r the measurement of the oxygen index, a property which is considered to be related to the ease of ignition. 1 Scope 1.1 This International Standard describes a method for measuring the oxygen index of insulating liquids. 1.2 The general principles of this test method as applied to solids are descri

22、bed in ISO4589. 1.3 This method is generally considered as a method describing one of the combustion characteristics of products. 1.4 This test method is applicable to all liquids, the viscosity of which is lower than or equal to50mm 2 /s at40 C 1 C. WARNING: When burning a liquid, hazardous gases a

23、nd/or vapours may be evolved. Adequate precaution shall be taken to protect the operator. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this InternationalStandard. At the time of publication, the edition ind

24、icated was valid. All normative documents are subject to revision, and parties to agreements based on this InternationalStandard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. Members of IEC and ISO maintain registers of c

25、urrently valid InternationalStandards. ISO 4589:1984, Plastics Determination of flammability by oxygen index. 3 Definition Oxygen index is defined in ISO4589 as the minimum concentration of oxygen, by percentage volume in a mixture of oxygen and nitrogen, introduced at23 C 2 C, that will just suppor

26、t combustion of a material under specified test conditions. 4 Summary of method A small quantity of a liquid sample in a borosilicate glass cup is placed in a test chimney containing an upwardly flowing mixture of oxygen and nitrogen, then ignited. The minimum concentration of oxygen that will just

27、support combustion of the liquid for60s or more is taken as the oxygen index. 5 Apparatus The following apparatus shall be arranged as indicated by the diagram inFigure 1. 5.1 Test chimney The chimney shall be a heat-resistant glass tube of75 mm minimum inside diameter and450mm minimum height. The b

28、ottom of the chimney or the base to which the tube is attached shall contain non-combustible material to mix and distribute evenly the gas mixture entering at this base. Glass beads3mm to5mm in diameter in a bed80mm to100mm deep have been found suitable. Chimneys of other dimensions may be used, if

29、shown to give equivalent results. 5.2 Test cup A test cup made of borosilicate glass. The inside dimensions of the cup shall be22mm diameter and4mm high. The wall thickness shall be1,5mm. The cup shall be so designed as to permit exterior handling(Figure 2). 5.3 Cup holder A cup holder made of stain

30、less steel suitable for supporting the borosilicate cup in the centre of the chimney, approximately20cm below the top. 5.4 Gas supply Commercial grade oxygen and nitrogen shall be used. 5.5 Ignition source The igniter shall be a copper tube having an inside diameter of1,5mm. The flame source shall b

31、e propane, without premixed air. The shape of the tube is represented inFigure 3. A gas flow rate of3cm 3 /s is suitable to produce a flame40mm high when the igniter is upright.EN61144:1993 4 BSI 11-1999 Experience shows that minor changes in the flame height are not significant in their effect on t

32、est results. 5.6 Flow measurement and control devices Suitable flow measurement and control devices shall be available in each line that will allow monitoring the volumetric flow of each gas into the chimney within1% in the range being used. After the flow is measured in each line, the lines shall b

33、e joined to allow the gases to mix before being fed into the chimney. 5.7 Paramagnetic oxygen analyzer For accurate measurement of the oxygen concentration in the flowing mixture. 5.8 Timer A suitable timer capable of indicating at least10min and accurate to1s shall be used. 5.9 Soot, fumes and heat

34、 removal To ensure the removal of noxious fumes, soot, heat and other possible products, the chimney shall be installed in a hood or other facilities providing adequate exhaust. NOTEIf soot-generating specimens are being tested, the glass chimney becomes coated on the inside with soot and should be

35、cleaned as often as necessary to maintain good visibility. 6 Test specimens The liquid samples shall be stored in a clean container and conditioned at23 C 2 C for at least24h. 7 Procedure 7.1 Calibration 7.1.1 Calibrate the flow-measuring system using a soap bubble flowmeter or by equivalent calibra

36、tion devices. It is recommended that this calibration will be repeated at least every six months. NOTEOne step in the calibration should be to check all joints carefully for leaks. 7.1.2 Calibrate the paramagnetic oxygen analyzer according to the instruments operating manual. 7.1.3 Adjust the flame

37、size of the igniter as illustrated inFigure 3. 7.2 The test shall be conducted at room temperature,23 C 2 C. 7.3 Remove the glass chimney and secure the cup holder in the centre of the chimney as shown inFigure 1. Place a clean cup on top of the cup holder. 7.4 Use a pipette to fill the cup with liq

38、uid sample such that the upper meniscus of the liquid is1mm below the top of the cup. 7.5 Select the desired initial concentration of oxygen based on experience with similar liquids. If there is no experience with similar liquids, ignite the sample in air and note the burning behaviour. If the sampl

39、e burns, start at an oxygen concentration of about18%; but if the sample does not burn, start at about25%. 7.6 Adjust the oxygen and nitrogen regulators to give the desired oxygen concentration. The gas velocity in the chimney shall be4cm/s 1cm/s as calculated from the total flow of gas incm 3 /s di

40、vided by the area of the chimney incm 2 . Purge the system for at least30s. 7.7 Apply the igniter so that the flame covers the entire surface area of the liquid sample until the liquid ignites(seeFigure 3). Then remove the igniter. 7.8 Preliminary adjusting 7.8.1 If the flame extinguishes before60s,

41、 the oxygen concentration is too low and shall be increased. Repeat test at a higher oxygen concentration using a fresh liquid sample. NOTEIf there is no ignition, the same sample may be used again. 7.8.2 If steady state burning is obtained and it continues beyond60s, the oxygen concentration is too

42、 high and shall be reduced. Repeat test at a lower oxygen concentration using a clean cup and a fresh liquid sample. 7.9 Perform steps7.6 to7.8 until the minimum oxygen concentration that will just support combustion of the liquid for60s or more is obtained. At the next lower oxygen concentration (t

43、hat will give a difference in oxygen index of about0,5%), the sample shall not burn for more than60s. NOTESilicon liquids exhibit sporadic burning accompanied by silicon dioxide ash formation and glowing ash with occasional flame renewal. 7.10 Test five specimens at the critical oxygen concentration

44、 obtained from7.9. When three or more specimens burn more than60s, this is taken as the oxygen index. 8 Calculations In case a paramagnetic oxygen analyzer is not available, the oxygen concentration as defined in7.6 shall be calculated as follows: where V O is the volumetric flow rate of oxygen (inc

45、m 3 /s) V N is the volumetric flow rate of nitrogen (incm 3 /s)EN61144:1993 BSI 11-1999 5 9 Report The report shall include the following: 9.1 Identification of the liquid tested including the type, viscosity, density, source, manufacturers code number, previous history, and conditioning (if any). 9

46、.2 Individual oxygen index value for each of the tests, and average oxygen index value. 9.3 Description of any unusual behaviour such as ash formation, ash glowing, renewed flaming, etc. 10 Precision Under consideration.EN61144:1993 6 BSI 11-1999 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Test cup Cup h

47、older Igniter Disk-shaped screen of wire mesh Ring stand Glass beads Base plate Gas premixing joint Cut-off valve Orifice Pressure gauge Precision pressure Filter Gas flow regulator Gas flow meter Temperature sensor Figure 1 Schematic arrangement of apparatus for determination of oxygen indexEN61144

48、:1993 BSI 11-1999 7 Figure 2 Borosilicate glass test cup for determination of oxygen index of liquidsEN61144:1993 8 BSI 11-1999 1 Flame size when igniter is upright 2 Flame shape when igniter is inverted 3 Apply flame so that the centre coincides with the centre of the cup and that the flame touches

49、 the entire surface area of the liquid NOTEPropane gas flame Flame height: 40mm Gas flow rate: 3ml/s Figure 3 Ignition system for determination of oxygen index of liquidsBSEN61144:1993 BSI 11-1999 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Cables and Insulation Standards Policy Committee (CIL/-) to Technical Committee CIL/10 upon which the following bodies were represented: Association of Consulting