Abstract: An air injection tube for injecting ventilating, cooling and/or heating air for installation in a room where the tube has a plurality of small, mutually spaced air injecting openings defined in its peripheral wall along longitudinally extending wall zones of the tube. The air injection openings are arranged in a plurality of groups or patterns each comprising two or more peripherally spaced rows of openings which are mutually spaced along the length of the zone and the longitudinal spacing of adjacent groups or patterns substantially exceeds the mutual longitudinal spacing of the openings in each group or pattern of openings.