Crane, Derrick, and Hoist Hazards
The primary functions of the hoisting apparatus are to:
- raise and lower the drill string components during tripping and drill stem lengthening operations,and
- support the drill string at the desired bit weight during drilling.
Rig Hoisting System
Drawworks
The drawworks is a hoisting mechanism on a drilling rig. It is essentially a large winch that spools off or takes in the drilling line and thus lowers or raises the drill stem and bit.
The wire rope drill line runs from the drawworks to the crown block at the top of the derrick, and then to the traveling block and hook, which is attached to the drill string during drilling operations.
To protect workers, a barrier guard or screens must be installed in front of the drawworks drum or mounted on top of the existing drum casing to effectively isolate the ingoing nip point hazard. (See image) The barrier must be designed to eliminate any penetration by the worker's body parts such as hands and fingers, as well as materials such as chains or slings or any other object that could become entangled. The shield should extend at least 7 feet above the working level and effectively isolate all exposed sides. The guard should have features to allow for easy removal to provide access during servicing or inspection operations. The guard must be in place at all other times.
In addition to installing the barrier guard, all employers should inform workers of the potential hazard described and implement work practices to avoid the hazard of contacting moving parts such as hoist cables and rotating drums.
Knowledge Check Choose the best answer for the question.
3-2. What is an effective control method to reduce the likelihood of an accident involving drawworks?
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