Unsafe Use of Fall Arrest System Hazard Alert No. 1

HA-005



Summary

Even the state-of-the-art Fall Arrest System (FAS), when anchored improperly, may lead to its users swing fall (aka pendulum effect) during fall arrest and result in the victim striking a side object and subsequently suffering injury of high severity.


The Hazard

What is it? When the Fall Arrest System (FAS) anchorage is not directly above the worker at the onset of the fall, the worker will initially travel straight down until tensioning of the Fall Arrest System (FAS) occurs. At this moment, the fall victim will begin a swing fall which will subsequently bring him/her under the anchorage and beyond. If there are any objects in the path of such swing fall, the fall victim will strike them with his/her body. A high severity injury may occur particularly when the victim loses his/her hard hat during the fall, thus exposing himself/herself to head injury.

Why does it exist? This hazard exists primarily because in the majority of “real world” industrial situations, there is simply no adequate anchorage available directly above the work location. Where such anchorage does exist, and it was not selected by the Fall Arrest System (FAS) user (or the Fall Arrest System [FAS] designer) - inadequate training in fall protection is usually to blame.

Where can you experience it? This hazard exists in all temporary Fall Arrest Systems (FASs) because it depends on the external factors of how the Fall Arrest System (FAS) is used and not on the Fall Arrest System (FAS) itself. In case of a permanent Fall Arrest System (FAS), the system designer might have been forced to use the only available anchorage which happened to be located not directly above the work area. When a Fall Arrest System (FAS) is attached to a flexible Horizontal Lifeline, the fall will always come to a stop when the fall victim is at the maximum sag of the line. The path of such fall is a quasi-pendulum. Nonetheless, its consequences can be as severe as in a Fall Arrest System (FAS) with pendulum effect and no Horizontal Lifeline (HLL).

Who is affected by it and when? Users with inadequate training and those who use their Fall Arrest System (FAS) either in a constantly changing environment (the construction industry) or in a very large variety of work areas (maintenance personnel) are the most likely to experience swing falls. Workers using Fall Arrest Systems (FASs) which are attached to Horizontal Lifelines (HLLs) are at risk of a swing fall every time the fall happens away from the middle of the Horizontal Lifeline's (HLL’s) span.


How to Eliminate It Or Minimize Its Consequences?

  1. Train all Fall Arrest System (FAS) users in proper selection of anchorages for their systems.
  2. Consider using portable anchorages.
  3. Evaluate pros and cons of employing a Horizontal Lifeline.
  4. When employing a flexible Horizontal Lifeline, minimize the risk by selecting properly the Horizontal Lifeline's (HLL’s) anchors, and attempt to minimize the lengths of uninterrupted spans by introducing intermediate supports/stanchions//posts every 30 ft [9 m] or less.
  5. When designing a permanent Horizontal Lifeline (HLL) - consider a rigid rail instead of a flexible line.
  6. Employ a shock absorber or a shock absorbing lanyard in the Fall Arrest System (FAS).
  7. When selecting and/or designing permanent anchorages - adopt measures to minimize the swing fall, or design the anchor in such a way that the swing fall would take the fall victim away from, and not in the direction of, the side objects.
  8. Provide proper training in fall protection to all users of Fall Arrest Systems (FASs).
  9. Follow User’s Instructions supplied by manufacturers of fall protection equipment.



Additional Information and Comments

It is almost impossible to completely eliminate the risk of injury due to a swing fall. The realities of industrial work environments are different than those recommended by the authors of the Fall Arrest System (FAS) User Instructions. We have to accept the fact that this risk will exist BUT we must minimize its consequences.

Training in fall protection seems to be one of the best ways to deal with the swing fall hazard.


References

  1. “Fundamentals of Fall Protection” Sulowski et al, ISFP, Toronto, 1991.
  2. Accident report. Steel erection - nuclear power plant construction. Classified document.
  3. Accident report. Steel erection - building construction. Out-of court settlement. Classified document.
  4. “Fall Arrest Systems - Practical Essentials”, Sulowski, A.C., CSA International, Toronto, ON, 2000.
  5. “Introduction to Fall Protection”, Second Edition, Ellis, J.N., ASSE, Des Plaines, IL, 1993.
  6. “The Fundamentals of Fall Protection” Seminar, CSA International, Toronto, ON, 1999.
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