30 CFR § 56.19090
Dual signaling systems.
SIGNALING
There shall be at least two effective approved methods of signaling between each of the shaft stations and the hoist room, one of which shall be a telephone or speaking tube.
30 CFR § 56.19090
Dual signaling systems.
SIGNALING
There shall be at least two effective approved methods of signaling between each of the shaft stations and the hoist room, one of which shall be a telephone or speaking tube.