What happens if the fingerprint scanner doesn't hold enough fingerprint for the building?

The scanner we are using has the ability to hold hundreds of fingerprints therefor should not be a problem. In a case where there are too many people, more than one scanner could be used or you have the option to install multiple products into your building.

How long does it take for the system to let somebody into the building?

As shown in the video in the homepage, it is fairly quick and will take. around 1 second per scan.