This Standard is a differ revision of Determination of the gas transmission rate of films and thin sheets under atmospheric pressure (ISO 2556:1974).
Compared with the previous version Determination of gas-transmission rate of plastics film (GB/T 1038-1970), the changes as follows:
The Standard applicable scope is extended to plastics film and sheeting.
This standard stipulates the working principle and key elements of the instrument and doesn't have specific requirements on instrument models. It also confirms that the instruments are allowed to be equipped with computer arithmetic unit.
The use of pressure unit “atmospheric pressure (atm)” was prohibited in China. “Pa” as a permitted pressure unit shall be used in this Standard. Time units are consistent with ISO 2556, “day (d)” as the unit of measurement.