Lifelines
A lifeline is a cable or rope that connects to a body harness, lanyard, or deceleration device, and at least one anchorage. There are two types of lifelines. (Vertical and Horizontal)
Vertical Lifeline
A vertical lifeline is attached to an overhead anchorage and must be connected directly to a worker's full-body harness, lanyard, retractable device, or rope grab; it must have a minimum breaking strength of 5,000 pounds.
However, when a worker needs to move horizontally, a vertical lifeline can be hazardous because of the potential for a swing fall – the pendulum motion that results when the worker swings back under the anchor point. A swing fall increases a worker's risk of striking an object or a lower level during the pendulum motion.
Horizontal Lifeline
Unlike a vertical lifeline, the horizontal lifeline stretches between two anchorages.
When you connect a lanyard or rope grab to the horizontal lifeline, you can move about freely, thus reducing the risk of a swing fall. However, horizontal lifelines are subject to much greater loads than vertical lifelines.
If they are not installed correctly, horizontal lifelines can fail at the anchorage points. For this reason, horizontal lifelines must be designed, installed, and used under the supervision of a qualified person.
Horizontal Lifeline Load Forces
When the sag angle is 15 degrees, the force on the lifeline and anchorages subjected to a load is about 2:1. However, if you decrease the sag angle to 5 degrees, the load force increases to about 6:1.
To reduce loads on a horizontal lifeline, increase the sag angle or connect to the lifeline with a shock-absorbing lanyard.
Knowledge Check Choose the best answer for the question.
3-9. When using a horizontal lifeline, to reduce load forces, _____ the sag angle.
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