This part of ISO 2782 specifes two methods for the determination of the permeability to gases of vulcanized or thermoplastic rubber under a differential partial pressure.The two methods specifed are as follows:- a pressure sensor method: for determining the gas transmission rate, gas permeability coeffcient, gas diffusion coeffcient and gas solubility coeffcient;- a gas-chromatographic method: for determining the gas transmission rate and gas permeability coeffcient.These methods apply to vulcanized and thermoplastic rubbers of hardness not less than 35 IRHD (international rubber hardness degrees) and to both single gases and mixtures of gases.