The strength of the magnetizable layer on the tape is about 6.5 microns. During read and write the material is passed with a speed of 2 to 3.74 m/s (4.95 in older drives) along to the heads of the drives.
These values ilustrate the important role of the purity of environment.
With the air conditioning of the data store room (Lampertz strong room) the air is led through a separate circular flow. A mixture of that air with the air of the data center or any other air-conditioned room is does not take place.
Of cause he data store room is not a cleanroom. However the air is filtered according to the european norm EN779 filter grade F7.
The particle size handled by this norm starts at particles with a size of 0.1 microns. This is a dimension which is far under the observable size for human eyes. This is the dimension of bacteria and even some great viruses.