What determines the specification

Uniform and concentrated load requirements

Finished floor height, which sets the service void depth

Whether the void carries cooling air as well as services

Fire performance required by the building

Finish, including conductive finishes where static is a concern

What determines how it behaves in service

Flatness and the alignment of the pedestal grid

Stability under rolling and point loads

The quality of cut-outs and grommets, which affect both cables and airflow

Whether the perimeter and any ramps are properly detailed

Installation discipline

A raised floor is a structural system with tolerances. Floors that feel unstable under a rolling load, or that are not level, cause problems for every rack and every service run placed on them.