It also, IIRC has a special exemption in which unlike almost all buildings its elevators are for use in fires. In a typical building the notices tell you emphat

It also, IIRC has a special exemption in which unlike almost all buildings its elevators are for use in fires. In a typical building the notices tell you emphatically you should not use elevators if there's a fire, you should all use the stairs which are rated to handle the entire population of the building leaving in a timely fashion. But (if I'm thinking of the right tower) the BT Tower was specified so that the only effective way to evacuate the building during a fire is with elevators, for which purpose those elevators are rated differently.