The main part of integral permeation apparatus is round stainless steel measuring cell. This cell is divided into two parts separated with porous stainless steel support made by Mikropur s.r.o. Measuring cell inner diameter is (50.00 ± 0.05) mm leading to active diameter of measured membrane less than (41.00 ± 0.05) mm depending on used seals or diameter reductions. Volume of permeate part is (50.0 ± 0.1) cm3. Apparatus is equipped with oil pump (Trivac D4B, Oerlikon Leybold.Temperature is measured with mercury thermometer.