Avoid Hand-Arm Vibration Syndrome – Tips for Safe Power Tool Use
When workers use vibrating power tools like jackhammers or chainsaws, they may experience tingling in their hands immediately after use. While this tingling isn’t necessarily the sign of a serious problem, over time tool vibration can cause lasting damage to the hands and arms. After repeated exposure, workers may experience numbness, pain and white fingers in addition to tingling, and these symptoms can eventually become quite debilitating.
To prevent this kind of workplace illness—called hand-arm vibration syndrome (HAVS)—safety managers need to put safety measures in place for the use of vibrating power tools. Some of these measures include personal protective equipment (PPE) and administrative controls, while others involve opting for safer tools in the first place.
In this post we will examine HAVS, its symptoms, its causes and means of prevention in the workplace.
HAVS, sometimes referred to as “white fingers” or work-related Raynaud’s Syndrome, develops over time in workers who use vibrating power tools regularly. Symptoms can begin to occur within months, but in some cases can take many years to manifest. A study of forestry workers found that symptoms began to appear after 2000 hours of work with vibrating tools, and by the time workers had used vibrating tools for 8000 hours, more than half of them were experiencing HAVS.
The disorder’s nickname comes from the fact that many sufferers’ fingers turn white because of reduced blood flow. Over time, the vibration causes blood vessels in the fingers to collapse, OSHA explains. The “white fingers” symptom occurs most often when a worker’s hands are exposed to the cold.
Vibration can also damage sensory nerve fibers and muscles in the hands. Additional symptoms of HAVS include tingling, loss of sensation in the fingers, pain, feelings of coldness, bone cysts and a weakened grip, according to the Canadian Centre for Occupational Safety and Health. Symptoms generally become more severe over time, and if exposure to vibration isn’t lessened or stopped, they can become permanent. This eventually leads to further disruptions to daily life such as sleep disturbance and distress. In some cases, workers with HAVS must leave their professions to avoid more hand and arm damage.
Tools that Vibrate
Tool vibration is a problem in many industries including construction, forestry, engineering, vehicle repair and manufacturing, outdoor maintenance work and utility work.
Common tools that vibrate include chainsaws, impact drills, grinders, scaling hammers, powered saws, sanders and polishers. Less obvious vibrating machinery like lawnmowers and floor polishers can also cause HAVS, as can any piece of equipment in a workplace that vibrates while operating.
(A recent study even found that vibrating video game controllers can lead to HAVS, so workers should be aware of all kinds of exposure to vibration that they face!)
Measuring Hand-Arm Vibration
While specific OSHA regulations for hand-arm vibration do not exist in the United States, European standards offer helpful information about exposure limits. The American National Standards Institute (ANSI) has also adopted these limits.
The European exposure limit value (ELV) is based on a combination of factors including the amount of vibration at the location where a worker grips a vibrating tool and the amount of time spent gripping the tool. According to the Health and Safety Executive (HSE) (the United Kingdom’s version of OSHA), the daily ELV is 5 m/s2 (meters per second per second). To stay beneath the daily exposure limits for vibration, workers would need to work for a shorter period of time with a tool that has a higher vibration amount (such as 10 m/s2).
Power tool manufacturers often provide information about a tool’s vibration level, and if you know this value you can calculate the amount of time a worker can safely use a tool. This safe amount of time is called trigger time. HSE offers an online exposure calculator for determining trigger times.
Safety managers and employers can take a number of steps to reduce workers’ exposure to unsafe levels of vibration. Let’s take a look at them.
Tips for Reducing Vibration Exposure
The Centers for Disease Control and Prevention (CDC) advises employers to purchase reduced vibration power tools for their worksites. Many manufacturers now make these tools because other countries regulate vibration. The CDC also recommends providing anti-vibration gloves that meet the standards of the International Organization for Standardization for use with these tools.
In addition to providing safer work materials like tools and gloves, the following safety measures can also help prevent HAVS:
- Regular Breaks – For every hour spent working with vibrating tools, OSHA recommends employees take a 10 to 15 minute break. An administrative control like this can help allow time for hands and arms to recover throughout the workday. Managers can also schedule projects so that employees aren’t performing tasks requiring vibrating tools for extended periods of time.
- Keep Hands Warm and Dry – Cold temperatures can exacerbate HAVS symptoms and make employees more susceptible to problems. It’s best to avoid using vibrating tools in cold weather if possible.
- Use a Lighter Grip – While employees shouldn’t grip tools so loosely that they drop them, using as light a grip as possible will limit the amount of vibration transmitted from the tool to the hand.
- Maintain Tools – Older tools may vibrate more because rotating parts become unbalanced or cutting parts become dull. Regularly servicing tools can help limit the amount of vibration a tool produces.
The symptoms of HAVS in the workplace have been recognized for many decades, yet these health problems often go underreported. Employees may not realize they have a problem at first or they may feel their symptoms don’t warrant a trip to the doctor. Employers should educate workers who use vibrating tools about the symptoms and risks associated with HAVS and encourage them to seek medical treatment. Doing so could ultimately result in less time away from work in the future.
Did you know non-powered hand tools like hammers can also cause a significant amount of vibration? Learn more about selecting safe hand tools in this blog post about ergonomics.
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