Tackling hand-arm vibration risks

Hilti Breaker

It has been well-known for years that too much use of many common power tools can be hazardous. The vibrations of the tool can damage the operators’ hands and arms if used for too long.

Hand-arm vibration syndrome (HAVS) and carpal tunnel syndrome (CTS) can result from the long-term exposure of mechanical vibrations transmitted by power tools through the limbs.  Nerves, muscles and blood vessels are affected. Fingers turn numb, white or red and are susceptible to extreme stiffness in cold or damp weather. (The condition is also unofficially known as vibration white finger.) Everyday tasks like buttoning up a coat can become extremely challenging, if not impossible. It is not generally life threatening but it can bring a working life to a premature conclusion. There is no cure for the damage done.

European regulations to combat HAVS and CTS are now approaching their 10th anniversary. The European Physical Agents (Vibration) Directive 2002/44/EC has been in force in all European Union countries since July 2005. These require employers to assess and, where necessary, measure the exposure of employees to mechanical vibration and to take appropriate measures.

Over the past 10 years, equipment manufacturers have continually improved tools to increase the length of time for which they can be safely used. So if you are using power tools that fall short of current state of the art, you might want to look again at what is on the market.

Hilti, for example, has a useful tool selector chart that sets out how much each tool such as it various drills and hammers can be used and for what application without breaching EU regulations. Hilti`s Active Vibration Reduction (AVR) technology reduces vibration by up to two-thirds compared with conventional tools, the company claims.

It is an issue that all the leading tool brands have had top address. Atlas Copco, for example, equips its breakers with its proprietary Hand-Arm Protection System, or HAPS. The PE series pneumatic breakers allow up to seven times the trigger time of conventional fixed-handled tools at a given level of operator vibration exposure, Atlas Copco says, while its LT series of rammers have special vibration-absorbing handles to minimise hand-arm vibration (pictured below).

Atlas-Copco-LT-rammer

Some equipment producers have shown ingenuity to further reduce exposure to vibrations. Canadian company RNP Industries makes something called the Positioner-Actuator-Manipulator, or PAM, which as the photo below shows is an articulating arm that takes the weight of a pneumatic power tool.

PAM hand arm vibration

There are measuring devices available to monitor exposure to vibrations but there accuracy is not always great. Polish company Svantek, a specialist in sound and vibration measurement solutions, produces a personal hand-arm vibration exposure meter.

The SV 103 (pictured below) is attached to the user’s arm and takes daily vibration exposure measurements using a microelectromechanical accelerometer without getting in the way of with normal working activities. It also has an additional contact force transducer that measures whether the tool is being gripped correctly.

Svantek SV103

Svantek says that many vibration measuring systems can vary in their accuracy by up to plus or minus 40% but because this device is strapped to the user’s arm it is more accurate. The SV103 has an 8GB memory and comes with software for data assessment.

Despite 10 years of legislation and the improvements in product design and technology, however, workers all over the world, particularly in the construction industry, are still falling victim to vibration white finger. The message, it seems, is still not getting across properly.

 

Steve Rhine

About Steve Rhine

Community Manager at MachineryZone USA - All latest construction news on MachineryZone Mag!