In a computer or control room where the plenum is used for heating, ventilating, and air- conditioning, the finished floor height should be a minimum of how many inches?

Eight inches is insufficient to support both HVAC airflow volume requirements and cable pathway routing beneath a raised floor plenum.

A minimum raised floor height of 12 inches is required in computer and control rooms where the plenum is used for HVAC to ensure sufficient airflow volume beneath the floor for cooling equipment. This height also provides adequate space for power and data cable routing under the floor panels. Standards such as BICSI TDMM and ASHRAE guidelines for data centers support this minimum dimension.

Two inches provides no meaningful plenum space and cannot support any air distribution or cable management function.

Six inches is below the 12-inch minimum and would restrict airflow, potentially causing hot spots and inadequate cooling for equipment.