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What is the minimum safety factor when a rope is used for hoisting materials?
Apply the design factor of 5 (10 for ropes used to support or hoist personnel).
What are minimum number of ropes a traction elevator can be built with?
three
(d) Minimum Number and Diameter of Ropes. The minimum number of hoisting ropes used shall be three for traction hoists and two for drum type hoists.
What are OSHA requirements for inspecting wire rope?
Annual/comprehensive. At least every 12 months, wire ropes in use on equipment must be inspected by a qualified person in accordance with paragraph (a) of this section (shift inspection). The inspection must be for deficiencies of the types listed in paragraph (a)(2) of this section.
How do you calculate the safe working rope?
Once you know the diameter of the rope, you can apply it to the formula, which is SWL = D2 x 8. D represents the diameter of the rope in inches. If you’re working with a 1.5-inch diameter cable, for example, then the formula would be SWL = 1.52 x 8 or SWL = 2.25 x 8.
How is wire rope size?
Wire rope, often called cable, is sized by diameter (not circumference, as large sizes of fiber rope are). The diameter is measured across the rope, not from flat to flat. The rope’s construction is described by a designation like “6 × 17”. the first number is the number of strands.
How do you calculate minimum breaking load?
This load represents a force that is much less than that required to make the lifting equipment fail or yield, also known as the Minimum Breaking Load (MBL). SWL or WLL are calculated by dividing MBL by a safety factor (SF).
What is elevator roping?
Hoist ropes are connected to an elevator car (cab) at one end and to a counterweight at the other end. Ropes are laid over grooves on the drive sheave, which is driven by a motor via a brake with or without a gearbox. The frictional force between the grooves and ropes drives the ropes up and down.
What rope is used for elevators?
The world’s most frequently used strand construction for elevator ropes is the 19-wire Seale strand (1-9-9). Because of the thick outer wires, the Seale strand offers a higher degree of resistance against external wear in use when running over the traction sheave and the deflection points. What is a Warrington strand?
How do you measure the diameter of a wire rope?
A rope must always be measured at its widest point, i.e. from strand crown to strand crown. A complete measurement consists of two measurements in the X-direction and two measurements in the Y-direction, each approximately 1 m apart. The resulting average of the values describes the current rope diameter.