Protecting Retractable Lifelines from Arcing Damage

Red line indicates how the retractable lifeline was left extended and unattended during a break from work, putting it at exposure to damage from welding arc.

Summary
A construction crew installing bleacher seating and treads was using retractable vertical lifelines for fall protection. When taking a lunch break, the crew left the unattended equipment extended and attached to a permanent guardrail on an adjacent structure. During that time, the steel erector’s employees continued to weld plate washers on column anchor bolts, as they had been doing during the previous hours, prior to the construction crew taking a break. The lifeline acted as a ground conductor and the lifelines were damaged.

When both crews were working, the steel erection contractor was not welding above or near the bleacher installers, remaining a full bay distance away from the other workers, as protocol dictates. But when the bleacher installers left for lunch, the lifelines were wrapped onto an adjacent structure that was closer to the welding work than the actual ground cable that was established for welding operation. This essentially created a new grounding line as the path of least resistance for the welding current to travel through. Upon return, the bleacher crew noticed broken wires due to arcing, and immediately removed the lifelines from service.

Best Practices

• Always inspect fall protection equipment prior to use. Remove from service any equipment that does not meet manufacturer’s requirements.
• Educate crews on what arcing damage looks like.
• Use ropes on hooks of retractable lifeline units to allow for full retraction when not in use, and to easily retract the cable when released.
• Never store lifelines in the extended position to prolong the life of the retracting mechanism inside the housing.
• Verify that the type of retractable lifeline used is permitted for horizontal use, as most are intended for vertical use only.