This European Standard describes the test method for the determination of gas leakage rate and specifies the requirements for limit values for gas leakage rate and gas concentration for gas filled insulating glass units made a) in accordance with EN 1279 1:2018 and manufactured to EN 1279 6:2018, or b) for the purpose to demonstrate that components (e.g. edge seals or spacers) will allow the insulating glass unit to conform to the requirements given in EN 1279 1:2018, Clause 6.