Why a server room is excluded even though it collects dust
A comms room contains equipment that is sensitive to dust, static and moisture, and it usually sits behind an access control that logs every entry. Introducing a vacuum, a damp mop or a cloth near active hardware carries a genuine risk, and the room's owner is normally responsible for its condition under an entirely separate arrangement. A cleaning provider entering it also breaks the access log's usefulness.
Where these rooms do need attention, it is arranged as a scheduled task with the owner present, using equipment suited to the environment and avoiding anything that generates static or airborne dust. That is a described item rather than part of a routine round. It happens rarely, and it works far better when it is planned than when a cleaner is handed a key one evening.
