(a) Mechanically operated.
- (1) Cargo door counterweights shall be guarded.
- (2) Lift trucks and cranes shall not be used to move mechanically operated doors except when necessary during repair on the doors, in which case ropes or other guarding shall be provided to prevent entry into the area where the door may fall or slide.
- (3) Vertically operated doors partially opened for work or ventilation shall be secured to prevent accidental closing.