34 Pa. Code § 7.374 – Ropes.

(a) The minimum number of hoisting ropes used shall be three for traction hoists and two for drum-type hoists.
(b) The minimum diameter of hoisting and counterweight wire ropes shall be 1/2-inch.
(c) Minimum factors of safety for suspension shall conform with the following
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