Hammering In Ergonomics

"Ergonomics" has become a common buzzword when it comes to equipment design, and demolition hammers are certainly no exception. In fact, regulations in Europe have mandated a focus on ergonomics for various types of hand-held tools.

"The European market has laws regulating both the amount and duration of vibration that an operator can be exposed to during a working shift," explains John Vogel, vice president of sales - hand-held tools, Atlas Copco Construction Tools LLC. "Because of this legislation, private companies have been forced to conform to the standards."

Although no such standards yet exist in the U.S., the growing concern over the risks of prolonged exposure to vibration is causing many manufacturers to look to the future.

"Some forward-looking companies have sought ergonomic solutions to protect workers from noise and vibration, with the added benefit of increasing productivity from the workforce," says Vogel. "A tool that is less fatiguing helps a worker accomplish more in a single work shift."

The reason for regulation
The primary risk associated with long-term use of hand-held equipment is hand-arm vibration syndrome, an industrial injury triggered by continuous exposure to high levels of vibration. The most common variant is vibration white finger, sometimes called "dead man's hand" due to the white, dead-looking condition of the fingers.

"White finger is what happens when your blood vessels become very narrow," says Rebekah Gallert, product manager - demolition, Wacker Corp. "In a very minor case, you may feel tingling in your fingertips, maybe a loss of feeling at the ends. Worst-case scenario - which I don't think is very common, but could happen - is you will have to lose a finger altogether."

Due to their higher vibration levels, demolition hammers have historically been viewed as a common culprit. "In some severe cases, the vibrations from running these breakers over extended periods of time could actually cause nerve damage and the loss of feeling in the operator's fingers," says Jonathan Cook, key account manager, Chicago Pneumatic Construction Tools.

And the affects are cumulative. "So though you may only work a couple of hours a day or once a week [with the tool], all those affects start to add up," says Gallert.

In 2005, Europe took regulatory steps to mitigate the risks of vibration exposure. The regulations set a limit on the vibration level a worker may be subjected to over an eight-hour period. If a tool's vibration exceeds 5 meters per second squared (m/s2), the employer must limit and document its use.

"For the contractor, it has huge implications because it affects their productivity," says Gallert. "If they're using a tool that is, say, measured at 10 m/s2, they may only be able to work an hour in a day. Then they have to rotate operators, and they have to keep track of all this and document it for the regulations."

The closer the tool is rated to the regulated limit, the better. "If a manufacturer can get a tool down below 5 m/s2, then [contractors] can operate it for eight hours in a day," Gallert states. "If the tool is below 2.5 m/s2, then [contractors] can operate it all day and they don't have to document it."

Getting a handle on vibration
It seems only a matter of time before the U.S. follows Europe's lead. Fortunately, many demolition hammer suppliers are well ahead of the game. Most either market the same hammers here as in Europe, or offer a choice between standard and ergonomic models.

The emphasis has been primarily on handle designs. "For hand-held breakers, the key ergonomic improvement is the introduction of spring-loaded handles that reduce tool vibration for the operator," says Cook.

Nearly all manufacturers offer some form of shock mounting in the handles. However, some companies have taken this a step further. For example, Atlas Copco's LH Series hydraulic hand-held breakers are available in ergonomic versions with a patented four-spring E-handle said to reduce vibration by up to 71%.