 |
Michigan Administrative Code (Last Updated: November 16, 2016) |
 |
Department LR. Licensing and Regulatory Affairs |
|
MIOSHA |
|
Chapter Part 15 Excavators, Hoists, Elevators, Helicopters, and Conveyors |
|
Part 15. EXCAVATORS, HOISTS, ELEVATORS, HELICOPTERS, AND CONVEYORS |
Section 408.41542. Wire rope.
All data is extracted from pdf, click here to view the pdf.
-
(1) Wire rope used for material hoists, personnel hoists, and elevators shall be removed from service when any of the following conditions exists:
(a) In hoisting ropes and running ropes, 6 randomly distributed broken wires in 1 rope lay or 3 broken wires in 1 strand in 1 rope lay.
(b) Abrasion, scrubbing, flattening, peening, kinking, crushing, bird caging, or any other damage resulting in distortion of the rope structure and causing loss of more than 1/3 of the original diameter of the outside wires.
(c) Evidence of any heat damage from any cause, including damage resulting from a torch or any damage caused by contact with electrical wires.
(d) Reduction from nominal diameter of more than 3/64 inch for diameters up to and including 3/4 inch; 1/16 inch for diameters 7/8 to 1-1/8 inches; and 3/32 inch for diameters 1-1/4 to 1- 1/2 inches.
(e) In standing ropes, more than 2 broken wires in 1 lay in sections beyond end connections or more than 1 broken wire at an end connection.
(2) Hoisting ropes shall be installed in accordance with the wire rope manufacturers' recommendations.
(3) A wire rope shall be in compliance with all of the following requirements:
(a) The minimum number of hoisting ropes used shall be 3 for traction hoists and 2 for drum- type hoists.
(b) The minimum diameter of hoisting and counterweight wire ropes shall be 1/2-inch.
(c) Not less than 2 ropes shall be used for the counterweights on the rack and pinion.
(d) Safety factors shall be as in Table C “Minimum Factors of Safety for Suspension Wire Ropes”.
(e) The following formula shall be used to calculate the allowable gross load:
L = SN
F
L = Allowable gross load
S =
Manufacturer’s rated
breaking
strength
N F
=
=
Number of parts of rope Safety factor
TABLE C
MINIMUM FACTORS OF SAFETY FOR SUSPENSION WIRE ROPES
Rope speed in feet per minute
Minimum Factor of safety
50
7.60
75
7.75
100
7.95
125
8.10
150
8.25
175
8.40
200
8.60
225
8.75
250
8.90
300
9.20
350
9.50
400
9.75
450
10.00
500
10.25
550
10.45
600
10.70
History: 2016 MR 6, Eff. March 22, 2016.