FOERFARANDE OCH ANORDNING FOER ATT AOSTADKOMMA EN LUFTVAEXLING FOER ETT BEHANDLINGSRUM

A method of providing ventilation for a processing space (1) with an access opening (3) from the surroundings, the space being separated from the surroundings by blowing treated supply air (A) into it to form an air curtain (5) at the opening in order to prevent the entrance of surrounding air. To enable an efficient separation of the space even with a great temperature difference between the supply air and the surrounding air, the supply air is blown to form a free circulation flow (A') in the space. The direction of the circulation flow at the opening is opposite to the direction of convection flows (B) of surrounding air created by the temperature difference, and the flow rate at the opening is greater than that of the convection flows. In an equipment for realizing the method, devices (6, 7) for introducing supply air are mounted to create a free circulation flow (A') in the processing space (1), forming an air curtain at the opening.