Compaq AlphaServer GS60 Operation Manual page 67

The cooling system is designed to keep system components at an optimal operating
temperature. It is important to keep the front and rear doors free of obstructions,
leaving a minimum clearance space of 1.5 meters (59 inches) in the front and 1 meter
(39 inches) in the rear between cabinets (see Figure 3-9) to maximize airflow.
The blower, located in the center of the cabinet, draws air downward through the
power regulators and TLSB card cage. It draws air upward through the PIUs. Filler
modules, located in the TLSB card cage, help to direct airflow. Air is exhausted at the
middle of the cabinet front and rear. The blower speed varies based on the system's
ambient temperature.
CAUTION: Anything placed on top of the cabinet could restrict airflow. This will
cause the system to power down.
AlphaServer 8400 System 3-19