BS 3473-1-1991 Chemical resistance of glass used in the production of laboratory glassware Method for determination of resistance of glass to attack by a boiling aqueous solution o.pdf

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1、BRITISH STANDARD BS 3473-1: 1991 ISO 695:1991 Chemical resistance of glass used in the production of laboratory glassware Part 1: Method for determination of resistance of glass to attack by a boiling aqueous solution of mixed alkaliBS3473-1:1991 This British Standard, having been prepared under the

2、 directionof the Laboratory Apparatus Standards Policy Committee, was published underthe authority of the Standards Board and comes into effect on 31July1991 BSI 10-1999 First published 1962 Second edition as Part 1, October1982 Third edition July 1985 Fourth edition July 1991 The following BSI refe

3、rences relate to the work on this standard: Committee reference LBC/8 Draft for comment 89/56195 DC ISBN 0 580 19894 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Laboratory Apparatus Standards Policy Committee (LBC/-) to Technical C

4、ommittee LBC/8, upon which the following bodies were represented: British Glass Manufacturers Confederation Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS3473-1:1991 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1

5、 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Preparation and number of samples 2 7 Procedure 2 8 Expression of results 3 9 Precision 3 10 Test report 3 Figure 1 Examples of suitable test vessels with a hemispherical and a flat base 4 Table 1 Limit values in the alkali

6、 resistance test 3 Publication(s) referred to Inside back coverBS3473-1:1991 ii BSI 10-1999 National foreword This Part of BS3473 has been prepared under the direction of the Laboratory Apparatus Standards Policy Committee. It supersedes BS3473-1:1985, which is withdrawn, and is identical with ISO69

7、5:1991 “Glass Resistance to attack by a boiling aqueous solution of mixed alkali Method of test and classification”, published by the International Organization for Standardization (ISO). It has been prepared by subcommittee5 of Technical Committee48, Laboratory glassware and related apparatus, with

8、 the active participation and approval of the UK. BS3473 was first published in1962 as a single publication which described procedures for determining the resistance of glass used in the production of laboratory glassware to attack by a boiling aqueous solution of mixed alkali, and to water at100 C

9、and121 C. To facilitate alignment with corresponding International Standards, the revision of BS3473 was begun in1981 with the publication of the first three Parts of what was then intended to be a six-Part standard. Part6, which was to deal with classification, will not now be issued as it has been

10、 agreed internationally to include classification in the individual test methods. BS3473 currently consists of the following Parts. Part 1: Method for determination of resistance of glass to attack by a boiling aqueous solution of mixed alkali; (Identical with ISO695:1991) Part 2: Method for determi

11、nation of hydrolytic resistance of glass grains at98 C; (Identical with ISO719:1985) Part 3: Method for determination of hydrolytic resistance of glass grains at121 C; (Identical with ISO720:1985) Part 4: Methods for determination of hydrolytic resistance of the interior surfaces of glass containers

12、; Section 4.1 Determination by titration method and classification; (Identical with ISO4802-1:1988) Section 4.2 Determination by flame photometry and classification; (Identical with ISO4802-2:1988) Part 5: Method for determination of resistance of glass to attack by6mol/L hydrochloric acid at100 C;

13、(Identical with ISO1776:1985) The procedures described in BS3473 are recommended as being capable of yielding consistent results in the hands of independent workers in different laboratories and offer a means of assessing the chemical resistance of glass used in the production of laboratory ware whe

14、n tested by the specified procedure. Because the term “laboratory glassware” covers a wide variety of articles to serve many different purposes and the glass types used include both borosilicate and soda-lime-silica glass, methods of test are required which are widely applicable. Tests of fractured

15、surfaces, such as the grain test described in Parts2 and3 give an assessment of the chemical behaviour of the body of the glass and can be applied to articles of laboratory glassware because they are usually used many times. Such tests have a more limited value for assessing the chemical resistance

16、of glass articles which are to be used once only because the resistance depends more on the condition of the surface than on the body of the glass; BS3473-4 relates to such applications.BS3473-1:1991 BSI 10-1999 iii It should be realized that whilst these procedures can be used to assess the behavio

17、ur of glass under the stated conditions, and thus to select glasses for general laboratory purposes, they can only reveal or measure limited aspects of chemical behaviour. Where articles are designed for a specific purpose, it is essential that the performance of the glass should be evaluated in ter

18、ms of precise service requirements by using simulative or functional tests. This revision introduces improvements to the test procedure and precision data derived from an inter-laboratory study. A related British Standard to ISO683-13:1986 is BS970 “Specification for wrought steels for mechanical an

19、d allied engineering purposes” Part1:1988 “General inspection and testing procedures and specific requirements for carbon, carbon manganese, alloy and stainless steels.” CAUTION. Attention is drawn to the Health and Safety at Work etc. Act,1974, and the need for ensuring that the method of test spec

20、ified in this standard is carried out with suitable precautions. The procedure described in this standard method is intended to be carried out by qualified chemists or other suitably trained and/or supervised personnel. Normal safety precautions should be observed throughout the use of the method. P

21、articular attention is drawn to the need to wear suitable eye-protectors during the preparation and handling of glass fragments; see BS2092 “Specification for eye-protectors for industrial and non-industrial uses” for details of suitable types. A British Standard does not purport to include all the

22、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. Cross-references International Standard Corresponding British Standard BS3473 Chemical resistanc

23、e of glass used in the production of laboratory glassware ISO 719:1985 Part 2:1987 Method for determination of hydrolytic resistance of glass grains at98 C (Identical) ISO 720:1985 Part 3:1987 Method for determination of hydrolytic resistance of glass grains at121 C (Identical) ISO 3693:1987 BS 3978

24、:1987 Specification for water for laboratory use (Identical) ISO 3819:1985 BS 6523:1984 Specification for glass beakers for laboratory use (Technically equivalent) ISO 4799:1978 BS 5922:1980 Specification for glass condensers for laboratory use (Identical) Summary of pages This document comprises a

25、front cover, an inside front cover, pages i to iv, pages1to4, 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.iv blankBS3473-1:1991 BSI 10-1999

26、 1 1 Scope This International Standard specifies a) a method for determining the resistance of glass to attack by a boiling aqueous solution of sodium carbonate and sodium hydroxide. The resistance is measured inversely by the loss in mass per unit surface area of the glass; b) a classification of g

27、lass according to the alkali resistance determined by the method of this International Standard. NOTE 1The method of test according to this International Standard is also applicable for determining the alkali resistance of glass ceramics. 2 Normative references The following standards contain provis

28、ions 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 based on this International Standard are encouraged to investigate the pos

29、sibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 683-13:1986, Heat-treatable steels, alloy steels and free-cutting steels Part 13: Wrought stainless steels. ISO 719:1985, Glass Hy

30、drolytic resistance of glass grains at98 C Method of test and classification. ISO 720:1985, Glass Hydrolytic resistance of glass grains at121 C Method of test and classification. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 3819:1985, Laboratory glassware Be

31、akers. ISO 4799:1978, Laboratory glassware Condensers. 3 Principle 3.1 Immersion of two sample pieces, each having a total surface area of10cm 2to15cm 2in a boiling aqueous solution of equal volumes of sodium carbonate, c(Na 2 CO 3 ) =0,5mol/l, and sodium hydroxide c(NaOH) =1mol/l, for3h. Calculatio

32、n of the loss in mass per unit surface area of the glass. 4 Reagents During the test, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity (grade3 water complying with the requirements of ISO3696). 4.1 Acetone, CH 3 COCH 3 .

33、 4.2 Hydrochloric acid, solution, c(HCl) 1mol/l. 4.3 Hydrochloric acid, solution, c(HCl) 2mol/l. 4.4 Hydrofluoric acid, c(HF) 22mol/l (i.e. 400g HF/l solution). 4.5 Sodium carbonate, solution, c(Na 2 CO 3 )=0,5mol/l 0,01mol/l, freshly prepared for each test. 4.6 Sodium hydroxide, solution, c(NaOH) =

34、1mol/l 0,02mol/l, freshly prepared for each test. 5 Apparatus 5.1 Test vessel, of pure silver, alkali-resistant silver alloy or stainless steel type15 1)complying with the requirements of ISO683-13. A recommended test vessel, as shown inFigure 1, is cylindrical with a hemispherical or flat base and

35、has a close-fitting lid. The lid has a wide neck and is equipped on the internal surface with four hooks from which to suspend the sample pieces. A gasket, made of a material which remains inert under the test conditions, shall be used to form a seal between the lid and the body of the test vessel.

36、5.2 Condenser, of the Allihn or Liebig-West type, complying with the requirements of ISO4799 and made of glass of hydrolytic resistance grain class HGA1 of ISO720 2)fitted to the neck of the lid through a bung of suitable inert material which has previously been boiled for60min in water. 5.3 Balance

37、, accurate to 0,1mg. 5.4 Desiccator, containing a suitable drying agent. 5.5 Measuring instruments, suitable for measuring lengths and diameters to an accuracy of 1%. 5.6 Drying oven, suitable for operation at a temperature of110 C. 5.7 Beaker, 1 litre capacity, complying with the requirements of IS

38、O3819. 5.8 Silver wire 5.9 Tongs, tipped, if necessary, with a suitable material, e.g.plastics, silver, platinum. 1) The relevant constituents of steel type15are18% Cr,10% Ni, maximum0,08% C and an addition of Ti. 2) Glass of hydrolytic resistance grain class ISO719-HGB1 adequately meets the require

39、ments of class HGA1 of ISO72O.BS3473-1:1991 2 BSI 10-1999 5.10 Heating bath, fitted with a thermostat and temperature controller capable of heating and maintaining the bath liquid, e.g.glycerol, at a temperature between110 C and112 C. The heating bath shall be supplied with a stirring device or a li

40、quid circulator and be fitted with a lid or a supply of plastics balls to completely cover the surface of the bath liquid. It shall be of sufficient capacity to allow each test vessel to be immersed in the bath liquid until the level of the liquid inside the test vessel is level with that in the hea

41、ting bath and with a distance of about60mm all round the test vessel. These conditions shall also be fulfilled if several test vessels are simultaneously placed in the heating bath. The heating bath shall be supplied with temperature measuring devices, e.g.digital thermometers, to allow the bath liq

42、uid temperature to be measured over the range110 C to112 C. 6 Preparation and number of samples 6.1 Glass “as delivered” Cut the sample piece or sample pieces (hereinafter referred to as “sample”) from the glass into easily measurable shapes such as squares, rectangles or, from tubing, open-ended cy

43、linders. Each sample shall have a total surface area, surfaces plus edges, of between10cm 2and15cm 2 . Remove any sharp angles, “hackles” or splinters by polishing the edges or bevelling the corners. Do not firepolish any part of the samples. This concerns only samples where the new cut surface area

44、 is not more than20% of the total surface area. Otherwise the sample shall be submitted to the etching procedure according to6.2 and regarded as glass “as a material”. 6.2 Glass “as a material” Immerse the sample(s) completely in a mixture of1 volume of hydrofluoric acid (4.4) and 9 volumes of hydro

45、chloric acid (4.3). Allow the samples to stand at ambient temperature for10min. Holding the samples in position, pour out the mixture very carefully. Rinse the sample(s) five times with distilled water (see first paragraph of clause4). 6.3 Number of samples For each test, both for glass “as delivere

46、d” or “as a material”, two samples shall be tested. 7 Procedure 7.1 Number of samples in a test vessel When “unknown” glasses are to be examined only two samples shall be tested at the same time. When glasses with a loss in mass per unit surface area not greater than200mg/dm 2are to be examined, up

47、to four samples of two different types of glasses may be tested simultaneously. 7.2 Method Measure and calculate the total surface area of each sample, surfaces plus edges, to an accuracy of2% and record the value obtained. Wash each sample, using the tongs (5.9) to hold the glass (as in subsequent

48、operations), three times with separate portions of water (see first paragraph of clause4), and then rinse with acetone (4.1). Dry the samples in the drying oven (5.6) at about110 C for60min, transfer to the desiccator (5.4) and allow to cool to room temperature. Then weigh each sample to an accuracy

49、 of0,1mg. Record the mass, m 1 , of each sample. Transfer800ml of a mixture of equal volumes of the sodium carbonate (4.5) and the sodium hydroxide(4.6) solutions to each test vessel (5.1). Immerse each test vessel in the heating bath (5.10) until the level of the liquid in the test vessel is the same as that of the liquid in the bath. Fit the condenser (5.2) to the lid of each test vessel and turn on the flow of water to the condenser jacket. Cover the open surfaces of the bath liquid and activate the stirrer or li