Effects of weld damage on the dynamics of energy-absorbing lanyards

Abstract

Manufacturers recommend removing fall protection system components from service for any indication of weld spatter or tool damage; however, little is known about the specific effects of lanyard damage on fall arrest dynamics. Thirty-two energy-absorbing lanyards were drop tested after being damaged with weld spatter, plasma torches and cutting tools and compared with new, undamaged lanyards. Two lanyards damaged with a plasma torch failed completely without deploying the energy absorber while weld spatter damage and tool cuts, up to two-thirds through the width of the webbing, had no effect on fall arrest dynamics. The results highlight the catastrophic implications of high-temperature damage to lanyard webbing resulting from plasma torches – which require immediate removal from service. In addition, the integrated energy absorber design in bungee-style lanyards makes them more susceptible to damage anywhere along the length. We therefore recommended against bungee lanyards for ironworkers and welders.

Keywords:

• fall protection
• compliance
• equipment
• replacement
• weld damage

Acknowledgements

The authors gratefully acknowledge the assistance of Ehsan Daneshi Kohan in setting up the data-acquisition system for these drop tests and the team of ironworker instructors, students and technicians at the British Columbia Institute of Technology (BCIT) for fabricating the drop tower and test mass.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was funded by the Natural Sciences and Engineering Council of Canada [grant number EGP #445780-12]; WorkSafeBC [grant number RS2013-IG25].