BS 684-1 17-1998 Methods of analysis of fats and fatty oils - Physical methods - Flashpoint limit test using Pensky-Martens closed-cup flash tester《脂肪和脂肪油分析方法 第1部分 物理方法 第17节 用Pensk.pdf

1、BRITISH STANDARD BS 684-1.17: 1998 ISO 15267: 1998 Methods of analysis of fats and fatty oils Part 1: Physical methods Section 1.17: Flashpoint limit test using Pensky-Martens closed-cup flash tester ICS 67.200.10BS684-1.17:1998 This British Standard, having been prepared under the directionof the C

2、onsumer Products and Services Sector Board, was published under theauthority of the Standards Board and comes into effect on 15September 1998 BSI 05-1999 ISBN 0 580 30210 5 National foreword This British Standard reproduces verbatim ISO15267:1998 and implements it as the UK national standard. The UK

3、 participation in its preparation was entrusted to Technical Committee AW/11, Animal and vegetable fats and oils, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for c

4、hange, 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. Cross-references The British Standards which implement international or

5、 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 Standard does not purport to include all the

6、 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, pages i and ii,

7、theISO title page, page ii, pages 1 and 2, 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 front cover. Amendments issued since publication Amd. No. Date C

8、ommentsBS684-1.17:1998 BSI 05-1999 i Contents Page National foreword Inside front cover Foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Apparatus 1 5 Reagents 1 6 Sampling 1 7 Preparation of test sample 1 8 Procedure 1 9 Precision 2 10 Test report 2 Annex A (informative) Results of in

9、terlaboratory test Inside back cover Table A.1 Results of international collaborative trial for flashpoint limit test at 121 C 3ii blankBS684-1.17:1998 ii BSI 05-1999 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member

10、bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental

11、and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member

12、bodies for voting. Publication as an International Standard requires approval by atleast75% of the member bodies casting a vote. International Standard ISO15267 was prepared by Technical Committee ISO/TC34, Agricultural food products, Subcommittee SC11, Animal and vegetable fats and oils. Annex A of

13、 this International Standard is for information only. Descriptors: Agricultural products, food products, animal fats, vegetable fats, animal oils, vegetable oils, tests, determination, flash point, Pensky-Martens apparatus.BS684-1.17:1998 BSI 05-1999 1 1 Scope This International Standard specifies a

14、 method to determine whether a sample of oil or fat at a given temperature will flash when a test flame is applied to the sample under specified conditions. It is applicable to animal, vegetable and marine fats and oils. The fats and oils may or may not contain small amounts of volatile inflammable

15、solvents. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements bas

16、ed on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 661:1989, Animal and vegetable fats and oils Preparation of

17、 test sample. ISO 2719:1988, Petroleum products and lubricantsDetermination of flash point Pensky-Martens closed cup method. 3 Principle The sample is heated at a slow constant rate with continual stirring. Once the temperature specified is stabilized, a small flame is directed into the cup. Thesamp

18、le is deemed to have flashed when a large flame appears and instantaneously propagates itself over the surface of the sample; a halo should be ignored. 4 Apparatus 4.1 Pensky-Martens closed cup flash tester For details, see ISO2719. 4.2 Thermometers, having a range from 10C to200C. Alternatively, an

19、 IP thermometer 101 C (having a range from 20 C to 150 C) can be used. 4.3 Laboratory centrifuge (swing type), of sufficient size to hold stoppered 120ml centrifuge tubes. 4.4 Centrifuge tubes, of 120ml capacity, with stoppers. 5 Reagents Use only reagents of recognized analytical grade, and distill

20、ed or demineralized water or water of equivalent purity. 5.1 Sodium sulfate, anhydrous. 6 Sampling Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO5555 1) . (See also 8.1.) It is important that the laboratory receive a sample

21、which is truly representative and has not been damaged or changed during transportation, sampling and storage. Samples shall be stored in bottles made of materials which do not allow diffusion of volatile compounds from the sample through the walls of the bottle. NOTEPET or glass bottles are preferr

22、ed. Some plastics (e.g.polyethylene or polypropylene) are not suitable for this purpose. 7 Preparation of test sample Prepare the test sample in accordance with ISO661. 8 Procedure Carry out the test in duplicate. 8.1 Preparation of test portion 8.1.1 During preparation of test portion and sampling

23、or sub-sampling for laboratory testing, and any other handling, care should be taken to minimize transfer between containers. It has been found that pouring samples from one container to another can cause evaporation of volatile solvents such as hexane, thus invalidating the result. For related reas

24、ons, it is advisable that containers be kept closed. 8.1.2 If the fat is a solid at room temperature, it should be liquefied by warming slowly, in the original container, to a temperature not higher than5C of its melting point. The flashpoint determination should then start at this elevated temperat

25、ure. 8.1.3 Carefully transfer approximately 90g of fat or oil from the original container directly into the tube(4.4) and add 5g of anhydrous sodium sulfate(5.1). Shake the mixture vigorously for1min with the stopper secured and allow it to stand for 30min, if necessary, at an elevated temperature(8

26、.1.2). 1) ISO5555:1991, Animal and vegetable fats and oils Sampling.BS684-1.17:1998 2 BSI 05-1999 8.1.4 Centrifuge the treated oil, as prepared in8.1.3, at 2 500 r/min for 3 min or until a sufficient amount of clear oil is available to make the flashpoint determination. The maximum time of centrifug

27、ing shall be 5min. 8.2 Determination 8.2.1 Fill the cup with the liquefied oil or fat sample(8.1.4) so that the top of the meniscus is exactly at the filling line marked in the cup. Place the lid on the cup and engage the locating devices. Insert the thermometer (4.2) and suspend it so that the bott

28、om of the bulb is a minimum of 43mm and a maximum of 46mm below the level of the rim of the cup, which corresponds to the level of the lower surface of the portion of the lid inside the rim. 8.2.2 Light the test flame and adjust it until it is approximately 4mm in diameter. 8.2.3 Heat the sample so

29、that the temperature increases not less than 5 C and not more than6Cper minute. During the heating, turn the stirring device at one or two revolutions per second. 8.2.4 At the specified temperature (usually 121 C), discontinue stirring and apply the test flame by operating the device which controls

30、the shutter and lowers the test flame into the shutter opening. Lower the test flame within 0,5 s and observe whether this causes a distinct flash in the interior of the cup. Do not confuse the true flash with the blue halo that sometimes surrounds the test flame. 8.2.5 Do not open the cup more than

31、 once during each determination because solvent vapour, although present in too low a concentration to cause a flash, might escape. This would lead to an incorrect result at the measuring temperature. 8.2.6 In order to conserve sample it is permissible to carry out successive flash tests on the same

32、 sub-sample to ascertain the temperature range in which the sample will flash. However, any such ranging tests shall not be used to establish or substantiate the reported test result which shall be determined on a fresh sample. 8.2.7 If information is needed about the precise level of the flashpoint

33、, the whole procedure should be repeated at temperatures other then 121C. Fresh portions of the test samples should be used for each temperature determination. 9 Precision Details of an interlaboratory test on the precision of the method are summarized in Annex A. The values derived from this interl

34、aboratory test may not be applicable to concentration ranges and matrices other than those given. 10 Test report Report “flash” or “no flash” at the specified temperature and state the method and apparatus used. If different results are obtained, disregard the “no flash” result.BS684-1.17:1998 BSI 0

35、5-1999 Annex A(informative) Results of interlaboratory test An interlaboratory test was carried out in 1995, organized by FOSFA International and NOFOTA. Twenty-one laboratories in eight countries participated. The results are summarized in Table A.1. Table A.1 Results of international collaborative

36、 trial for flashpoint limit test at 121C Sample No. of labs submitting flashpoint results No. of labs reporting “flash” No. of labs reporting “no flash” Labs reporting “flash” % Labs reporting “no flash” % 1 19 a 0 18 0,0 100,0 2 19 b 12 5 70,6 29,4 3 19 c 4 13 23,5 76,5 4 19 d 0 18 0,0 100,0 5 19 e

37、 15 3 83,3 16,7 6 19 2 17 10,5 89,5 a Laboratory 12 stated that oil had leaked from sample bottle and so it was excluded. b Laboratories 12 and 21 stated that oil had leaked from sample bottle and so they were excluded. c Laboratory 7 submitted “flash” and “no flash” as duplicates and so was not inc

38、luded in the summary. d Laboratory 10 submitted “flash” and “no flash” duplicates. e Laboratory 21 stated that oil had leaked from sample bottle and so it was excluded.BS 684-1.17: 1998 ISO 15267: 1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent nat

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