One more interesting find at the IFSEC 2015 was Avertic Armour. They provide a high strength woven mesh which helps protect against power drill attacks and cutting disk attacks. You embed the mesh in the walls of the object to wish to protect. The strands of the mesh rapidly clog any cutting tool which is used to attempt to break through the wall.
This armour technology has its origins in the protective clothing worn by forestry workers to protect their bodies from chain saw injuries. If the moving saw chain comes in contact with the protective clothing the strong threads are not cut but entangle the saw mechanism causing the motor to stall.
If you wished to protect the doors and/or walls of a data centre you'd probably use this material in conjunction with other security strengthening measures such as expanded steel mesh, perhaps a ballistic layer, and a vibration sensor for an alarm system. The lightweight Avertic Armour in one or more layers would greatly delay intruders wishing to break through by denying the use of powered cutting disks to cut through other reinforcements such as steel.