18.104.22.168.2 Equipment Specifications
(a) Earthquake protective devices shall be of the failsafe type.
(b) Seismic switch shall activate upon excitation in a vertical direction of not more than 0.15 times gravity acceleration, 9.81 m/s2 (32.2 ft/s2). The frequency response of the switch shall be 1 Hz to 10 Hz.
Where the seismic switch is used exclusively to control the elevators, it shall be located in the elevator machine room and, where possible, shall be mounted adjacent to a vertical load-bearing building structural member.
(c) A displacement switch shall be activated by the derailment of the counterweight at any point in the hoistway to provide information to the control system that the counterweight has left its guides.
(d) Earthquake protective devices with exposed live electrical parts in the hoistway shall operate at not more than 24 V root mean square alternating current or 24 V direct current above or below ground potential and shall not be capable of supplying more than 0.5 A when short-circuited.