FIG. 1 is a perspective view of a portion of an equipment rack indicated generally at 100. An assembly 110 is supported by multiple rails 115 comprising the equipment rack 100. Only one assembly 110 is shown, but the rails 115 may support multiple assemblies in various embodiments. Assembly 110 in one embodiment forms an enclosure that contains equipment, such as computers, storage devices, network cards, power supplies/power bricks, power boards, and other devices, one or more of which generate heat during operation. In one embodiment, the computers, such as Mac Pro? computers, are designed for vertical orientation during operation, drawing cooling air in through a bottom of the computer chassis, through the chassis, and out through a top of the chassis.

Assembly 110 in one embodiment includes multiple subassemblies. A first sub-assembly 120, referred to as an upper sub-assembly, comprises a plenum, basically an open space permitting airflow through it. One or more fans, referred to as a fan, to exhaust air to ambient may be provided to facilitate airflow through the first sub-assembly 120 but are not visible in this perspective view. The first sub-assembly 120 has a handle 122 for facilitating lifting of the first sub-assembly 120 to provide access to equipment, such as computers for installation and service. The first sub-assembly has sides, a front, a back, and a top, all formed of sheet metal that may be fairly light weight, such as ?^th inch steel sheet metal or other material providing sufficient structural support and heat conductivity.