ISO 9932-2021 pdf free download – Paper and board — Determination of water vapour transmission rate of sheet materials — Dynamic sweep and static gas methods.
This document describes general test methods for determining the water vapour transmission rate ofsheet materials by means of a dynamic gas method or a static gas method. Depending on the methodand specific apparatus employed, materials up to 38 mm thick and with water vapour transmissionrates in the range from 0,05 g/[(m2-d) to 65 g/([m2-d) can be tested.The basis of the function of theinstrumental techniques is briefly described.Advice on calibration is given in Annex B.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.ISO 186:2002, Paper and board — Sampling to determine average quality
ISO 2528;2017,Sheet materials – Determination of water vapour transmission rate (WVTR) 一Gravimetric (dish) method
3Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:- ISO online browsing platform: available at https://www.iso.org/obp
一IEC Electropedia: available at http://www.electropedia.org/
3.1
water vapour transmission rate
mass of water vapour transmitted through unit area in unit time under specified conditions oftemperature and humidity. It is expressed in grams per square metre per 24 h [g/[m2-d)J
3.2
dry side
side of the test cell which is exposed to low humidity
3.3
wet side
side of the test cell which is exposed to high humidity
4 Method A: Dynamic sweep gas method
4.1 Principle
The test piece is mounted between two chambers.One at a known relative humidity and the otherswept by a dry gas. The amount of water vapour picked up by the dry gas stream is detected by an electrical sensor and converted to a reading which directly, or after calculation,is a measure of the rateof water vapour transmission through the test piece.
4.2Apparatus
4.2.1 Test cell, designed to clamp a test piece having a defined area, between two chambers, one sweptby a dry gas (the dry side) and the other containing an atmosphere of high relative humidity (the wetside) (see Figure 1).
4.2.2 Clamping arrangements, to allow rapid insertion and removal of the test piece, equipped with suitable gaskets against which the test piece is sealed by the clamping force.
4.2.3 Provision for maintaining humidity on the wet side at the desired level. The required level of relative humidity may be obtained with saturated saline solutions containing a solid phase as described in Annex A or by distilled water if 100 % relative humidity is required.
4.2.4 Inert dry gas (as required by the specific apparatus to be used), for purging on the dry side.NOTE The gas is normally desiccated air or dry nitrogen.
4.2.5 Sensor,with rapid response and high sensitivity capable of detecting levels in the moisturecontent of the sweep gas equivaient to 0,05 % relative humidity or less. The sensor may take a number offorms: an electrical resistance element, an electrolytic cell, or an infrared detector.
4.2.6 Means to convert the output from the sensor into a signal that can be used to calculate theamount of moisture passing through the test piece being tested in unit time.
4.2.7 Means of maintaining the test chamber and the sweep gas and the sensor at the requiredtemperature.
NOTE The normal test temperature is either 23 °C± 1C or 38 °C± 1 °C, but other temperatures can be used.
4.2.8 Specimen of stated water vapour transmission rate supplied by the instrument manufacturerfor standardization of the test cell.ISO 9932 pdf download.