ISO-187-1990.pdf
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1、INTERNATIONAL STANDARD Second edition 1990-l 2-01 Paper, board and pulps - Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples Papier, carton et pstes - Atmosphere normale de conditionnement et d essai et mgfhode de surveillance de
2、 I atmosph 23 “C/50 % r.h. and 27 “C/65 Y!./o r.h. At the time of publication of this revision of IS0 187: 1977 the atmos- phere 23 V50 % r-h. is used almost exclusively in most countries and after 1 January 1993 is to be considered the IS0 standard test atmos- phere for testing of pulp, paper and b
3、oard. However, the 23 “C/50 % r.h. atmosphere is difficult to attain in some of the countries located in tropical zones, and in such countries the 27 “C/65 O/o rh. atmosphere is permitted. Until 1 January 1993 the 20 “C/65 O/o r.h. atmosphere is ac- ceptable as a standard test atmosphere. . . . III
4、-,-,- This page intentionally left blank -,-,- INTERNATIONAL STANDARD IS0 187:1990(E) Paper, board and pulps - Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples 1 Scope This International Standard specifies the standard atmospher
5、e for conditioning, and for testing pulp, paper and board, and also the procedures for measuring the temperature and relative humidity. For the conditioning of laboratory prepared handsheets in accordance with IS0 5269-1, the standard atmosphere is that defined in this Inter- national Standard but t
6、he procedure is different? 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All stan- dards are subject to revision, and part
7、ies to agreements based on this International Standard are encouraged io investigate the possibility of ap- plying the most !*ecent editions of the standards in- dicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 554:1976, Standard atmospheres fo
8、r conditioning and/or testing - Specifications. IS0 4677-l :I 985, Atmospberes for conditioning and testing - Determination of relative humidity - Part I: Aspirated psychrometer method. IS0 526%1:1979, Pulps - Preparation of laboratory sheets for physical testing - Part 1: Conventional sheet-former
9、method. IS0 526%211980, Pulps - Preparation of laboratory sheets for physical testing - Par? 2: Rapid-k oethen method. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 relative humidity (r.h.): The ratio, expressed as a percentage, of the actual wat
10、er vapour content of the air to the water vapour content of air saturated with water vapour at the same temperature and pressure. 3.2 conditioning: A process of establishing a re- producible moisture content equilibrium between the sample and an atmosphere of specified temper- ature and relative hum
11、idity. This equilibrium is con- sidered to be attained when the results of two consecutive weighings of the sample, carried out at an interval of time of not less than I h, do not differ by more than a specified amount. NOTE 1 The interval between weighings is dependent on the grammage of the sample
12、 and the degree of agreement expected between successive weighings should take account of the known cycling characteristics of the particular test room. The establishment of moisture content equilibrium is accepted as ensuring that the paper is in a stable physical state, but in special circumstance
13、s, conditioning may have to be prolonged until the desired physical equilibrium is attained. Such circumstances are not within the scope of this International Standard. 4 Principle Exposure of the sample to a specific conditioning atmosphere in such a manner that a reproducible state of moisture con
14、tent equilibrium is reached be- tween the sample and this atmosphere. 1) IS0 5269-l requires Pul p handsheets to be c followed by conditioning bY sorption of moisture. .ondi ti oned by desorption of moisture, whilst IS0 5269-2 requires drying -,-,- IS0 187:1990(E) 5 Standard atmosphere 6 Conditionin
15、g procedure The standard atmosphere for testing pulp, paper and paperboard shall be 23 “C + 1 “C and (50 + 2) % r.h. In tropical countries an atmosphere of 27 OC + .- 1 T and (65 + 2) % r-h. may be used. - NOTE 2 The temperature and relative humidity condi- tions are those specified in IS0 554. The
16、tolerances quoted are the reduced or close tolerances specified in IS0 554. A test atmosphere shall be deemed to be within the requirements of this International Standard if all the test results determined as described in annex A (see, in particular, A-4.2) are within the prescribed limits. Even sho
17、rt-term excursions of temperature or humidity beyond these limits, to the extent that the equilibrium moisture content of the sample will be affected, are not permitted. Whenever the test atmosphere is known to have been outside the limits and if there is any chance that the moisture content of samp
18、les has been changed by such excursions, all samples must be reconditioned (repeating clause 6) before any further testing is done. NOTES 3 If it is known or suspected that the relative humidity has exceeded the upper limit to the extent that the moisture content may have increased, all samples exce
19、pt those prepared in accordance with IS0 5269-1, must be subjected to the preliminary low humidity treatment dc- scribed in 6.1 before reconditioning. If it is known or suspected that the relative humidity has fallen below the limit to the extent that the moisture con- tent may have decreased, sampl
20、es prepared in accord- ance with IS0 5269-l should be discarded and new samples prepared. If this is not possible and the samples are tested, the circumstance must be reported. 4 A recording hygrometer, either independent of or part of the control system, should be in continuous operation in the roo
21、m, but such hygrometer must not be used to assess whether the atmosphere meets the requirements of this International Standard unless it also meets the re- quirements of annex A of this standard. The hygrometer should respond rapidly to changes in relative humidity, for example, less than 1 min +or
22、a change in relative humidity of 10 O/o. 6.1 Pre-conditioning of the sample For tests in which the hysteresis of the equilibrium moisture content may lead to important errors, the sample shall be pre-conditioned before conditioning, for 24 h in air of relative humidity between IO % and 35 % and a te
23、mperature not above 40 “C. If it is known that conditioning (6.2) will result in an equi- librium moisture content equivalent to that achieved by sorption (see Introduction) this preliminary treat- ment may be omitted. NOTE 5 Since the effect of hysteresis may not be known until after the event, it
24、is recommended that precondi- tioning be always carried out. 6.2 Conditioning The specimens of the sample shall be held such that the conditioning air has free access to all their sur- faces so that their moisture contents attain a state of equilibrium with the water vapour in the atmos- phere. This
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