An example air barrier system for a data center within a building is disclosed. The example air barrier system includes a pliable barrier material to partition an area above a top of row of computer cabinets in the data center and below an overhead surface of the building. The pliable barrier material is to reduce mixing of air between first and second aisles on opposites sides of the row of computer cabinets. The example air barrier system also includes a frame to support the pliable barrier material in position when in the area above the top of the row of computer cabinets. The frame is to be supported by the row of computer cabinets without support from the overhead surface.