Pennsylvania Code › Title 34 - LABOR AND INDUSTRY › Part I - Department of Labor and Industry › Chapter 7 - ELEVATORS, LIFTS, ESCALATORS, DUMBWAITERS, HOISTS ANDTRAMWAYS › Subchapter I - FREIGHT ELEVATORS › GENERAL REQUIREMENTS › Section 7.283 - Safety requirements

Current through Register Vol. 54, No. 28, July 13, 2024
(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.