Urban Legends in the Lift Industry

Everyone knows about urban myths, those stories of unnatural creatures, incredible cures, conspiracy theories and easy ways to get rich. These are the folk tales that range from Microsoft cash giveaways to chain letters, cures for warts, and the recent 'news' that Mars will be closer to the Earth this year than at any other time within the next 25,000 years. A number of TV producers have made quite a killing bringing these yarns to the airwaves and this list is heralded by the infamous, Ripley's 'Believe it or Not'.

What most of these tales have in common is that they are not only far fetched, but for the most part have no real grounding in reality. For instance, how many “real” documented pictures are there of the Loch Ness monster or Bigfoot?

We have the very same sort of thing, believe it or not (no pun intended), happening within the lift industry. I would like this column to be a collection point for the aerial lift 'urban myths', and encourage readers to contribute any they have heard to the staff at Lift and Access. I'd love to discuss these legends and how they stack up against actual ANSI standards and OSHA regulations, as well as typical custom, practice and just plain common sense.

What I'm talking about here are “rules” that have been circulating around for as long as there have been aerial lifts on the planet and simply don't stop circulating no matter how far they stray from ANSI/OSHA mandates. Some of these are not only practiced by operators as a matter of course, some are actually taught by professionals in safety management and training, further perpetuating the myths.

One particular legend that never seems to die is called the “Six Foot Rule” and is actually perpetuated in some sectors of the aerial lift industry. This conjuring of the lift user's imagination states that, “it is perfectly acceptable to use any aerial lift without benefit of fall protection provided the personnel carrying portion of the lift is elevated six feet or less”.

Like many myths and legends, this one is based on facts, but remains far from the actual truth. This “Six Foot Rule” spawns from actual regulations for stationary scaffolding that state that fall protection and tie-off is not required unless you are more than six feet off the ground. Since aerial lift standards organizations are an offshoot of the Scaffold Industry Association, it follows that some might think that the standards for stationary lifts would carry over onto aerial lifts, often thought of as “mobile scaffolding”.

Some types of aerial lift equipment pose no more threat of injury in the event of a fall from six feet or less than does that of stationary scaffolding. Other pieces of aerial lift machinery, such as the boom lift, pose a serious hazard to occupants without fall protection, even if the basket is at ground level.

The boom lift is unique in that it has the potential of catapulting its occupants out of the operator's platform with the platform raised or lowered. Normally these machines are driven with the boom and platform to the rear, often with the platform elevated just enough so that the operator can see over the structure of the machine. If either axle encounters a drop off, bump or other obstacle, the shifting of the axle creates an even greater jarring of the boom. When an axle hits a bump, its motion can stop abruptly. When it does, the boom movement also stops suddenly, and there can be a slingshot or catapult effect. This action is quite a bit like the medieval catapult or trebuchet, only in the case of the lift, it is not slinging rocks, but occupants.

This hazard is not readily apparent to inexperienced operators. Seeing the basket at a very low elevation, they tend to think of only the fall hazard, which, from a diminished height, is perceived as minimal. It is when the machine is in motion that this hazard really rears its head. With the boom at its lowest position and retracted, the boom lift can reach its maximum travel speed. At higher speeds the dynamics of hitting depressions and other obstacles increases the catapult effect of the boom and basket. A machine with the boom lowered and retracted can actually be the most hazardous position in terms of catapulting action, even though it can pose little comparative fall hazard.

Because of this catapulting action, the ANSI A92.5 standard requires fall protection on boom lifts when operated from any height. Fall protection devices such as lanyards and harnesses not only protect operators from the 'open and obvious' hazards such as falls from platforms during tipovers, but also from the not-so-obvious hazard as the trebuchet effect. Be careful, “If one don't getcha, the other one could!”

You might think of this slingshot-like effect as happening only in rough terrain construction situations, but this is certainly not the case. A number of accidents I have investigated involved boom lifts operated indoors in warehousing situations. One in particular involved the lift striking heavy items that were stored in the warehouse, and another involved an axle dropping off a dock ledge. Still another involved a drive-off from a loading platform onto a flatbed truck.

Lift maintenance personnel often do not use fall protection while driving lifts throughout a maintenance or rental facility. They regard the heights as minimal and the travel distances as short. Remember, the catapult effect can occur at any height, and an obstacle causing the catapulting can be encountered in short or long travel distances. This is no different that the fact that most auto accidents occur less than 15 miles from home.

One of the objections maintenance personnel have to using fall protection is the harness itself. Putting it on and taking it off can be a hassle. In a way this is no different than the lifting belts that warehouse personnel use when hefting materials. These workers wear their belts throughout their shifts because they never know when they will have to do lifting. Maybe equipment maintenance personnel could adopt the same habit, especially if their primary duty is moving boom lifts from place to place. Hey, it's a boom lift maintenance facility, not a GQ fashion show.

It's easy to see how the urban myth of the “Six Foot Rule” got started, and why many people would think it makes sense, but if you “toss out” the possibility of the catapult effect, it could “throw you for a loop”.

If you know of any other “urban myths”, please email them to the Lift and Access 360 staff.

Category: 
About the Author: 

Les Knoll

Les Knoll is a project manager for Rimkus Consulting Group, Inc., Chicago Ill. He has experience in accident investigation and reconstruction, failure analysis, product liability studies, product design and testing, structural analysis and litigation support. His work includes experience with aerial work platforms, mining equipment, and maintenance equipment. In previous positions, he served as a product engineer for Snorkel Economy and Economy Engineering where his responsibilities included the structural, mechanical and electrical testing of elevating platforms. He has also worked for Bucyrus-Erie Company, a manufacturer of construction and mining machinery. Contact Les at lrknoll@rimkus.com.