Abstract: A method and a means for supplying clean or sterile air to an area intended to be kept clean or sterile in an operating room or similar. The means comprises a central supply member (10) for a central carry beam directed towards said area and at two secondary air supply members (12, 13) adapted adjacent said central supply member (10), said secondary air supply members (12, 13l) being adapted for supplying secondary air beams in an area surrounding the carry beam. The air velocity of the carry beam is greater than the air velocity of the secondary air beams. The central supply member (10) for the central carry beam comprises one or several slits (11) for directing and supplying the carry beam. Preferably, the supply member (10) is surrounded by secondary air supply members (12, 13) on either sides thereof and the air beams from the secondary air members (12, 13) are directed towards the carry beam. The central supply member (10) may be positioned in a corner about 45.degree.