SIST EN ISO 2556:2001

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Polimerni materiali - Filmi in folije - Ugotavljanje prepustnosti plinov pri atmosferskem tlaku - Manometrijska metoda (ISO 2556:1974)Kunststoffe - Bestimmung der Gasdurchlässigkeit von Folien und dünnen Tafeln unter atmosphärischem Druck -Druckmessgerät- Verfahren (ISO 2556:1974)Matieres plastiques - Détermination du coefficient de transmission d'un gaz par les feuilles et plaques minces, sous pression atmosphérique - Méthode manométrique (ISO 2556:1974)Plastics - Determination of the gas transmission rate of films and thin sheets under atmospheric pressure - Manometric method (ISO 2556:1974)83.140.10Filmi in folijeFilms and sheetsICS:Ta slovenski standard je istoveten z:EN ISO 2556:2000SIST EN ISO 2556:2001en01-junij-2001SIST EN ISO 2556:2001SLOVENSKI
STANDARD
INTERNATIONAL STANDARD. INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXAYHAPOAHAII OPTAHM3ALWI l-IO CTAHAAPTI13AL@iW-ORGANISATION INTERNATIONALE DE NORMALISATION Plastics - Determination of the gas transmission rate of films and thin sheets under atmospheric pressure - Manometric method Ma tieres plastiques - Determination du coefficient de transmission d’un gaz par fes feuilles et plaques minces, sous Pression a tmospherique - Mthode manometrique First edition - 1974-06-01 UDC 678.5/.8-416 : 620.165.29 Descriptors : plastics, sheets, thin films, diffusion, gas, determination, pressure test. Rd. No. ISO 2556-1974 (E) Price based on 6 pages SIST EN ISO 2556:2001

FOREWORD ISO (the international Organization for Standardization) is a worldwide federation of national Standards institutes (ISO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 2556 was drawn up by Technical Committee ISO/TC 61, Plastics, and circulated to the Member Bodies in February 1972. lt has been approved by the Member Bodies of the following countries : Australia Austria Belgium Brazil Canada Czechoslovakia Egypt, Arab Rep. of France Germany The Member Body o on technical grounds f the following country expr India I reland Israel Japan New Zealand Poland Portugal Romania South Africa, Rep. of Netherlands Spain Sweden Switzerland Thailand Turkey United Kingdom U.S.A. U.S.S.R. disapproval of the document 0 International Organkation for Standardkation, 1974 l Printed in Switzerland SIST EN ISO 2556:2001

INTERNATIONAL STANDARD ISO 2556-1974 (E) Plastics - Determination of the gas transmission rate of films and thin sheets under atmospheric pressure - Manometric method 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a method for the determination of the gas transmission rate of plastics films and thin sheets. The limits of the values which tan be measured are from 1 to 20 000 cm3/m2.d.atm. The method tan be used for measurements made either with air or with other test gases. 2 REFERENCE ISO/ R 29 1, Plastics - Standard a tmospheres for conditioning and testing. 3 DEFINITION gas transmission rate : The volume of gas which, under steady conditions, crosses unit area of the Sample in unit time under unit pressure differente and at constant temperature. This volume is expressed at Standard temperature and pressure. The rate depends on the thickness of the test specimen, and the reliability of the results depends on the evenness of the specimen thickness. The rate is usually expressed in cubic centimetres (at 0 “C under Standard atmospheric pressure per Square metre per 24 h under a pressure differente of 1 atm (cm3/m2.d.atm). NOTES 1 The SI unit of gas transmission rate is fm/Pa.s [ 1 fm (femtometre) = 10 -=15 m] 1 cm3/m2.d.atm = 0,114 3 fm/Pa.s and 1 fm/Pa.s = 8,752 cm3/m2.d.atm. 2 The Standard atmospheric pressure corresponds to the pressure of a mercury column 760 mm high : either 1 013 mbar or 101,3 kPa. 4 PRINCIPLE The plastic test specimen separates two chambers num- bered 1 and 2. Chamber 1 contains the test gas at atmos- pheric pressure. Chamber 2, of know initial volume, has the air pumped out until the pressure is practically Zero, then is hermetically sealed. The quantity of gas which Passes through the specimen from chamber 1 to chamber 2 is determined as a function of time by measuring the increases of pressure occurring in chamber 2 by means of a manometer. The transmission rate is calculated from the values obtained, excluding the initial period during which the rate of passage of gas increases with time. 5 APPARATUS AND MATERIALS The apparatus which comprises the Parts described in 5.1 to 5.4, and of which suitable examples are shown in figures 1 and 2, must be placed in an enclosure with the temperature constant to within + 2 “C during the test. 5.1 Metal cell consisting of two detachable Parts, as follows : 1) an upper part forming the cylindrical chamber 1 to contain the test gas, provided with tubes for the entry and exit of the gas employed; 2) a lower part forming a plane and polished “test plate” of diameter 100 to 120 mm and having at its centre either a) a cavity of about 20 mm diameter containing a perforated disc and below this a small empty space so that the total depth of the cavity is 12 to 15 mm (see figure 1). In this type of apparatus a filter Paper must be interposed between the specimen and the test plate. The diameter of this filter Paper must be near, but not greater than, the internal diameter of the gasket; OL b) a cavity about 60 mm diameter and a few millimetres deep, filled with a sintered disc of glass or of bronze (see figure 2). The filter Paper indicated in a) or the sintered disc indicated in b) are to support the test specimen while at the same time allowing the passage of gas. In case b) the upper part of the sintered disc must be level with the test plate so that the specimen rests flat over its whole surface. The closed space below the test specimen forms chamber 2, and is attached to a capillary tube (5.2) forming the manometer and to a vacuum pump (5.5). 1 SIST EN ISO 2556:2001

ISO 2556-1974 (E) The two Parts of the cell are clamped together by means of an effective clamping device, a circular gasket of rubber being l.lsed to isolate the cell completely from the external atmosphere and to prevent the passage of gas from chamber 1 to chamber 2 other than through the test specimen. 5.5 Vacuum pump giving a pressure at the most equal to 13 Pa (0,13 mbar or 0,l mmHg) in the Iower chamber, and a gauge to measure this pressure with an accuracy of 6 Pa (0,06 bar or 0,05 mmHg) or better. 5.6 Mercury barometer. NOTE - lt is recommended that a check of the airtightness of the apparatus should be made by carrying out a blank test in accordance with the procedure of clause 7 but with the test specimen replaced by metal foil. 5.7 Thermometer which tan be read to 0,5 “C. 5.8 Mercury. The level of the mercury in the capillary must remain practically unchanged during a period of the same Order as that needed for the proposed measurements. 5.9 Test gases and drying column if required. 5.2 Calibrated capillary tube about 1,5 to 2 mm internal diameter and 200 to 400 mm in length, connected to the base of the metal cell. A scale graduated to 0,5 mm indicates the mercury level in the capillary tube. 6 TEST SPECIMENS The specimens shall be representative of the batch of sheet or film for test and free from marks or visible defects (creases, thin spots, porosity, holes, etc.). 5.3 U-tube about 5 mm diameter, connected to bottom of the capillary tube as shown i n figures 1 a nd 2 the One arm of the tube is closed. The other arm is joined to a vacuum stopcock (which tan be connected to a vacuum pump) and to a mercury reservoir (5.4) into which the mercury tan be poured by overflowing. 5.4 Mercury reservoir fixed to the arm of the U-tube connected to the vacuum stopcock. This fixing tan be done by method 1) or 2) described below. 1) Fixing directly to the U-tube arm (see figure 1). This type of apparatus tan be arranged to function either with or without overflowing of mercury during the test. a) In the case of apparatus with overflowing, the U-tube is filled with mercury up to the overflowing level which also corresponds to the scale zero (as shown in figure 1). During the test the mercury level is maintained constant by overflowing. Nevertheless the regulation sf the level is not altogether perfett since the overflowing occurs jerkily. It may ther efore be prefera the manner described in b). ble to use the apparatus in b) In the case of apparatus without overflowing, the U-tube is only filled to a Point appreciably below the overflowing level, so that the whole test is carried out without overflowing. In this case the scale zero is below the overflowing level and in the calculation a correction is essential (see 8.2). 2) The reservoir may be fixed to a greatly enlarged Portion of this arm of the tube (about 20 mm diameter) and there is no overflowing during the test (see figure 2). They shall be in the form of discs with a diameter, depending on the apparatus used, large enough to overlap the joint between the two portions of the metal cell. This diameter is usually about 80 mm. At least three specimens must be tested. Spetimens of
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