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Washington Administrative Code (Last Updated: November 23, 2016) |
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Title 296. Labor and Industries, Department of |
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Chapter 296-96. Safety regulations and fees for all elevators, dumbwaiters, escalators and other conveyances. |
Section 296-96-23227. What requirements apply to car safeties?
Latest version.
- Every elevator car suspended by wire ropes must be equipped with safeties. The safety device must be capable of stopping and sustaining the entire car with its rated load in the event of cable severance or overspeed. There must be a switch on the car activated by the setting of the safeties that will stop electric power from the driving machine motor and brake. Car safeties are identified and classified on the basis of performance characteristics after the safety begins to apply pressure on the guide rails.(1) Type A safeties:(a) Develop a rapidly increasing pressure on the guide rails during the stopping interval, the stopping distance being very short due to the inherent design of the safety.(b) Operating force is derived entirely from the mass and the motion of the car or the counterweight being stopped.(c) Apply pressure on the guide rails through eccentrics, rollers, or similar devices without any flexible medium purposely introduced to limit the retarding force and increase the stopping distance.(2) Type B safeties:(a) Apply limited pressure on the guide rails during the stopping interval and provide stopping distances that are related to the mass being stopped and the speed at which application of the safety is initiated.(b) Retarding forces are reasonably uniform after the safety is fully applied.(c) Continuous tension in the governor rope may or may not be required to operate the safety during the entire stopping interval.(d) Minimum and maximum distances are specified on the basis of governor tripping speed.(3) Type C safeties (Type A with oil buffers):(a) Develop retarding forces during the compression stroke of one or more oil buffers interposed between the lower members of the car frame and a governor-operated Type A auxiliary safety plank applied on the guide rails.(b) The stopping distance is equal to the effective stroke of the buffers.(4) Type G safeties:(a) Are similar to Type B except for having a gradually increasing retarding force.(b) May be either of the wedge clamp type or the flexible guide clamp type applied by a cable which unwinds a drum below the car floor.(5) Slack rope safeties:(a) Are actuated by the slackening or breaking of the hoisting ropes.(b) Are not actuated by an overspeed governor.