§ 7.283. Safety requirements.
(a) Slack cable device. A slack cable device shall be used in connection with all power-driven freight elevator machinery of the winding drum type which will automatically shut off the power, apply the brake, and stop the machinery if the car is obstructed in its descent. The device shall be so designed and installed that, after functioning, the mere resetting of the device is not sufficient to move the elevator car unless the operator is in the car and starts it in the normal manner.
(b) Shaftway limit switches. Direct connected drum-type elevators shall be equipped with upper and lower final limit switches regardless of car travel or speed. All other electric freight elevators having magnetic brakes shall be provided with upper and lower final limit switches, except traction type with a speed of less than 125 feet per minute. Final limit switches shall automatically cut off the current, apply the brake and stop the machinery, and may be located in the shaftway with a cam on the car or on the car with cams in the shaftway. When necessary because of flood conditions, lower shaftway limit switches may be actuated by the counterweight at the top of the shaftway. All cams actuating limit switches shall be of metal. A stopping switch may also be mounted on the elevator car in addition to limit switches in the shaftway, and so arranged as to be actuated by stationary inclines placed in the shaftway at the upper and lower limits of travel. A sequence relay shall be installed in connection with final limit and direction switches of all electric rope control freight elevators, so connected as to require the centering of the controlling mechanism before the elevator car may be placed in operation. Friction-type governors without cable clamp dogs are not permitted.
(c) Automatic terminal stops. Automatic terminal stops shall be provided on the machines of all power-driven freight elevators of the winding drum type. Such devices shall operate independently of the car controlling mechanism.
(d) Brakes. Power-driven freight elevators, except hydraulic elevators, shall be equipped with an effective brake which automatically engages when the controlling mechanism of the elevator car is in a ‘‘stop’’ position. Electric brakes are required in all existing elevators where electric interlocks are installed. In such instances the requirements of subsection (b), and § § 7.285(b) and 7.292(d) (relating to control apparatus; and electric freight elevators) shall be met. When a direct current elevator motor or motors derive current from an alternating current power source through a nonrotating rectifying unit, means shall be provided to absorb a sufficient amount of energy regenerated by the motor or motors under overhauling load conditions to prevent any elevator from attaining at any time, or under any conditions of load, more than 120 % of the contract speed of the elevator. When a single rectifier is installed to supply power for a number of elevators, or elevators in conjunction with other electrical equipment in the building, separate means for absorbing the generated power shall be installed for each elevator and other equipment in the building shall not be depended upon for the absorption of this power.
(e) Car safeties. Car safeties are required in conformance with the following:
(1) New installations. New power-driven freight elevator cars suspended from cables shall be provided with car safeties located under the car floors. Such safeties shall be capable of stopping or holding the elevator car at any point of its travel. Freight elevators having a speed of 100 feet per minute or less shall be provided with car safeties actuated by a centrifugal speed governor, except when the car travel does not exceed 20 feet, in which case car safeties of the spring grip or broken rope type may be used. When the speed exceeds 100 feet per minute, regardless of car travel, the car shall be provided with car safeties of the friction clamp or other approved type, actuated by a centrifugal speed governor in such a manner as to bring the elevator car to a gradual stop within a distance of approximately 8 feet. A rack and pawl are not acceptable as a car safety device. Tiller rope construction shall not be used for governor cables except when used for the portion of the cable wound on the safety drum. Governor cables shall be of iron or steel, monel metal, phosphor bronze or equivalent, and shall not be less than 3/8 inch in diameter. The size, material and construction of the governor rope, and the proper tripping speed of the governor, shall be stamped on the governor stand or on a brass plate attached to it in letters not less than 1/4 inch in height.
(2) Existing installations. When no car safeties are provided, they shall be installed in accordance with the requirements for new installations. Existing car safeties may remain in their present position if they are, upon being tested, found to be reliable. Otherwise, they shall be replaced by new car safeties in accordance with the requirements for new installations. A rack and pawl is not acceptable as a car safety device. Whenever necessary to renew governor ropes or cables, such renewals shall conform to the requirements for new construction.
(f) Signs—riders. Power-driven freight elevators shall have signs posted at every landing and in the elevator car prohibiting all persons, except the operator and not more than three designated assistants from riding on such car. See also § 7.12(d) (relating to rules of operation).
(g) Illumination. The landings of all freight elevators shall be adequately illuminated at all times when the building is in use so that the entrance to the elevator car can be readily observed.
Cross References This section cited in 34 Pa. Code § 7.285 (relating to control apparatus); 34 Pa. Code § 7.291 (relating to general); 34 Pa. Code § 7.295 (relating to hydraulic freight elevators); and 34 Pa. Code § 7.296 (relating to belted and silent chain drive elevators).
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