I used to work at a supercomputing center. The building where the machines where housed had offices above it (they were housed in a nuclear research facility,

I used to work at a supercomputing center. The building where the machines where housed had offices above it (they were housed in a nuclear research facility, so security was already high) and the building management had to turn the heaters on twice: once to test them and once when we had all the machines down for a while for major across-the-board upgrades.