2.19.3 Emergency Brake (See Nonmandatory Appendix F)
(a) function to decelerate the car by acting on one or more of the following (see also 2.19.4):
(2) the car.
(3) the suspension or compensation means system.
(4) the drive sheave of a traction machine.
(5) the brake drum or braking surface of the driving-machine brake, provided that one or more of the following are met:
(-c) the driving-machine brake acts directly on the driving-machine sheave or sheave shaft and is fully constrained mechanically in the direction of application of the braking torque so that the braking torque is transmitted to the driving sheave.
(b) be mechanically independent of the driving-machine brake [see also (a)(5)],
(e) be permitted to be applied to a stationary or moving braking surface when any electrical protective device (2.26.2) is actuated.
(f) be permitted to be applied to a stationary or moving braking surface when on continuous-pressure operation (e.g., continuous-pressure inspection operation, inspection operation with open door circuits, or hoistway access operation).
(g) not require the application of electrical power for its activation, nor be rendered inoperative by the failure of any power supply.
(h) not on its own cause the car average retardation to exceed 9.8 m/s2 (32.2 ft/s2) during the stopping or slowdown phase of ascending car overspeed.
(1) Where an emergency brake is applied when protecting against either an ascending car overspeed condition or unintended car movement with the car and hoistway doors open, the minimum factors of safety, when applied during the retardation phase of emergency braking, shall be not less than those specified in 22.214.171.124.
(2) Where an emergency brake is applied as permitted in (d) through (f), the minimum factors of safety, when applied during normal or continuous-pressure operation, shall be not less than those specified in 2.24.3 except 126.96.36.199. Degradation of the emergency brake due to wear shall be considered.
(j) be arranged to be tested in accordance with the requirements specified in 8.10.2.
(k) if the design of the emergency brake is such that field adjustment or servicing is required and the emergency brake acts on the brake drum or braking surface of the driving-machine brake, it shall be provided with a sign complying with 8.13.2 stating, "EMERGENCY BRAKE." The sign shall be located on the emergency brake at a location visible from the area likely to require service.