1、BRITISH STANDARD BS EN 993-4:1995 BS 1902-3.9: 1995 Methods of test for Dense shaped refractory products Part 4: Determination of permeability to gases The European Standard EN993-4:1995 has the status of a British StandardBS EN993-4:1995 This British Standard, having been prepared under the directi
2、onof the Refractory Products Standard Policy Committee, was published underthe authority of the Standards Board and comes into effect on 15May1995 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference RPM/1 Draft for comment 93/303889 DC ISBN 0 580 23605 6
3、 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denm
4、ark Dansk Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente
5、Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i S
6、verige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBS EN993-4:1995 BSI 10-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 993-4 3 Na
7、tional annex NA (informative) Committees responsible Inside back coverBS EN993-4:1995 ii BSI 10-1999 National foreword This British Standard has been prepared under the direction of the Refractory Products Standards Policy Committee and is the English language version of EN993-4:1995 Methods of test
8、 for dense shaped refractory products Part4: Determination of permeability to gases, published by the European Committee for Standardization (CEN). It supersedes BS1902-3.9:1981 which is withdrawn. EN 993-4 was produced as a result of international discussions in which the UK took an active part. A
9、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
10、front cover, an inside front cover, pagesi andii, the EN title page, pages2 to8, 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.EUROPEAN STAND
11、ARD NORME EUROPENNE EUROPISCHE NORM EN 993-4 February 1995 ICS 81.080 Descriptors: Refractory materials, shaped refractories, dense shaped refractory products, tests, measurements, gas permeability English version Methods of test for dense shaped refractory products Part 4: Determination of permeabi
12、lity to gases Mthodes dessai pour produits rfractaires faonns denses Partie 4: Dtermination de la permabilit aux gaz Prfverfahren fr dichte geformte feuerfeste Erzeugnisse Teil 4: Bestimmung der Gasdurchlssigkeit This European Standard was approved by CEN on1995-02-15. CEN members are bound to compl
13、y 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 Secr
14、etariat or to any CEN 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 CEN member into its own language and notified to the Central Secretariat has the same status as the offi
15、cial versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de
16、Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995Copyright reserved to CEN members Ref. No. EN 993-4:1995 EEN993-4:1995 BSI 10-1999 2 Foreword This European Standard has been prepared by the Technical Committee CEN/TC187, Refractory products a
17、nd materials, the secretariat of which is held by BSI. It is closely based on the corresponding International Standard ISO8841:1991 Dense, shaped refractory products Determination of permeability to gases, published by the International Organization for Standardization (ISO). Reproducibility and rep
18、eatability are not available, but may be given in a subsequent edition. EN 993 Methods of test for dense shaped refractory products consists of18 Parts: Part 1: Determination of bulk density, apparent porosity and true porosity; Part 2: Determination of true density; Part 3: Test methods for carbon-
19、containing refractories; Part 4: Determination of permeability to gases; Part 5: Determination of cold crushing strength; Part 6: Determination of modulus of rupture at ambient temperature; Part 7: Determination of modulus of rupture at elevated temperatures; Part 8: Determination of refractoriness-
20、under-load; Part 9: Determination of creep in compression; Part 10: Determination of permanent change in dimensions on heating; Part 11: Determination of resistance to thermal shock; Part 12: Determination of pyrometric cone equivalent; Part 13: Specification for pyrometric cones; Part 14: Determina
21、tion of thermal conductivity (hot wire, cross-array); Part 15: Determination of thermal conductivity (hot wire, parallel); Part 16: Determination of resistance to acids; Part 17: Determination of bulk density of granular material (mercury method); Part 18: Determination of bulk density of granular m
22、aterial (water method). This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August1995, and conflicting national standards shall be withdrawn at the latest by August1995. According to the CEN/CENELEC
23、Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. Contents Page Foreword 2 1 Scope 3
24、 2 Normative reference 3 3 Definition 3 4 Principle 3 5 Apparatus 3 6 Test pieces 4 7 Procedure 6 8 Expression of results 6 9 Test report 7 Figure 1 Arrangement of instruments for measuring gas permeability (measured under a pressure head) 5 Figure 2 Arrangement of instruments for measuring gas perm
25、eability (measured under suction) 5 Figure 3 Test piece holder 6 Table 1 Dynamic viscosity of air 7 Table 2 Dynamic viscosity of nitrogen 7EN993-4:1995 BSI 10-1999 3 1 Scope This European Standard specifies a method for the measurement of the permeability to gases of dense, shaped refractory product
26、s. NOTE 1The method specified takes account of the dynamic viscosity of the gas, and therefore the results obtained may not be directly comparable with those obtained by earlier methods which took no account of viscosity. The determination is generally made by the passage of air. Other gases may be
27、used when required, and the viscosities of air and nitrogen are given. 2 Normative reference This European Standard incorporates by dated or undated reference, provisions from another publication. This normative reference is cited at the appropriate places in the text and the publication is listed h
28、ereafter. For a dated reference, subsequent amendments to or revisions of this publication apply to this European Standard only when incorporated in it by amendment or revision. For an undated reference the latest edition of the publication referred to applies. ISO 6906:1984, Vernier callipers readi
29、ng to0,02mm. 3 Definition For the purposes of this European Standard, the following definition applies. 3.1 permeability of a material the property by which the material allows a gas to pass through it when under a difference of pressure the permeability () is calculated using the following equation
30、, given for the volume of gas passing through a test piece in a given time: where NOTE 1Equation (1) corresponds to Darcys Law, and is deduced from the Hagen Poiseuille Law. NOTE 2Since p is the pressure under which the volume of gas is measured, p = p 1when operating under positive pressure, and p
31、= p 2when operating under negative pressure. NOTE 3The factor (p 1+ p 2 )/2p is usually very close to unity and may be neglected when operating with small pressure differences, e.g. when (p 1 p 2 ) is less than1000 Pa. equation (1) may be rearranged as writing equation (2) in the units involved, the
32、 unit for permeability is square metres, derived from if, in equation (1), is expressed in centimetres, A in square centimetres and V in cubic centimetres (the units for the other quantities being unchanged), an alternative unit for permeability may be derived, namely square centimetres. However, si
33、nce compound prefixes are not permissible, the conventional prefixes may be used only with the unit square metres, thus10 8 cm 2 =10 12 m 2 =1 4m 2 4 Principle A stream of dry gas is passed through the test piece, and the pressure drop across the test piece is recorded for at least three different r
34、ates of flow. From these values, and from the size and shape of the test piece, the permeability of the material is determined by calculation. 5 Apparatus 5.1 General The general layout of the apparatus is shown diagrammatically inFigure 1 andFigure 2. Figure 1 shows the arrangement for the passage
35、of gas under pressure andFigure 2 for the passage of gas under suction. The connecting piping shall be made of glass in preference to rubber, and shall be as short as possible, so that the pressure loss in the apparatus is very small when compared with the pressure loss produced by the test piece. 5
36、.1.1 Supply of gas (under pressure or suction), consisting of a reservoir of gas at constant pressure. . . .(1) V is the volume of gas passing through the material, in cubic metres; t is the time, in seconds, in which that volume of gas passes through the material; is the permeability of the materia
37、l, in square metres; is the dynamic viscosity, in pascal seconds, of the gas at the temperature of the test; A is the cross-sectional area, in square metres, of the material traversed; is the thickness, in metres, of the material traversed; p is the absolute pressure, in pascals, of the gas; p 1 is
38、the absolute pressure, in pascals, where the gas enters the material; p 2 is the absolute pressure, in pascals, where the gas leaves the material. . . .(2)EN993-4:1995 4 BSI 10-1999 5.1.2 Test piece holder, with gas-tight seals at the sides of the test piece. Gas tightness shall be ensured by a rubb
39、er membrane that is inflated to a pressure of0,2N/mm 2to0,4N/mm 2 . SeeFigure 3. NOTEModifications will be required if the alternative test piece size (seenote to6.1) is used. 5.1.3 Liquid manometer, of the U-tube type, for measuring the difference in pressure between the two faces of the test piece
40、. The usual experimental precautions for this type of measurement shall be taken, so that the error in the pressure determination does not exceed1% (including error in reading column height, meniscus error, error in the verticality of the manometer, and measurement of the density of the manometer li
41、quid). The pressure shall be determined close to one face of the test piece in the vessel containing the test piece holder (5.1.2). NOTEA lower pressure reading may result when the pressure away from the test piece is determined in the connecting tubes. 5.1.4 Gas flow measuring equipment, consisting
42、 of a sensitive floating flowmeter calibrated for a given temperature and pressure of entry. The flowmeter shall be accurate to within2%. The flowmeter shall be calibrated periodically for the gas to be used, and only the middle section of its measuring scale shall be used. For the measurement of pe
43、rmeability to air only, the rate of air flow is measured by the displacement of air by water, using a graduated cylinder device and a chronometer. Water sensitive materials, such as doloma, shall not be measured by the method in which air flow is obtained by the displacement of water. 5.1.5 Vernier
44、callipers, in accordance with ISO6906. 5.1.6 Drying oven, capable of being controlled at110 C 5 C. 5.1.7 Impermeable dummy test piece, for example an aluminium cylinder. 6 Test pieces 6.1 Dimensions The test pieces shall be cylindrical, with diameter50mm 0,5mm and height50mm 0,5mm. The perpendicular
45、ity of the axis of the test piece to the faces, and the parallelism between the top and bottom faces of the test piece shall both be within0,5mm. NOTEA50mm cube test piece may also be used where necessary. In this case the test piece holder (seenote to5.1.2) will need to be modified and the calculat
46、ion of the results (see8.3) will be slightly different. 6.2 Preparation The test pieces shall be cut in such a way that no material is included that was within4mm of a face of the brick or item. The direction in which the test pieces are cut, relative to the direction of pressing, shall be stated in
47、 the test report. The faces shall be freed from dust formed during the cutting, by brushing under a jet of water following wet cutting, or by a jet of compressed air following dry cutting. 6.3 Drying The test pieces shall be dried to constant mass in the drying oven (5.1.6) at110 C 5 C. Before measu
48、rement, the test pieces shall be allowed to cool to room temperature in a desiccator; the time of cooling shall be at least2h.EN993-4:1995 BSI 10-1999 5 Figure 1 Arrangement of instruments for measuring gas permeability (measured under a pressure head) Figure 2 Arrangement of instruments for measuri
49、ng gas permeability (measured under suction)EN993-4:1995 6 BSI 10-1999 7 Procedure 7.1 Carry out a blank determination to establish that the test rig is gas-tight using an impermeable dummy test piece (5.1.7) in the place of the normal test piece. 7.2 Measure the diameter and the height of the test piece to0,1mm, using the Vernier callipers (5.1.5). 7.3 Place the test piece in the holder (5.1.2), ensuring that the pressure on the rubber membrane is sufficient to rend
