By Grainger Editorial Staff 1/3/24
Power tools can help make manual tasks easier, but they come with their own problems.
One of the most common downsides is the vibration that many tools transmit to workers' hands and arms. When workers must control these tools for lengthy work shifts and absorb the vibration, it can lead to fatigue and injuries such as carpal tunnel and tendinitis.
Even more serious is hand arm vibration syndrome (HAVS). This disorder represents a collection of many different symptoms often resulting from repetitive or prolonged use of vibrating tools. According to Safety+Health magazine, researchers identified these symptoms more than a century ago in limestone cutters.
Initial symptoms can include persistent numbness and tingling in the hands. As the condition progresses, workers may experience a discoloring condition known as vibrating white finger, which results from reduced blood flow to the hand. Another common symptom is a weakened grip. HAVS can be more pronounced in cold weather, and over time it could become permanent. Safety+Health notes that the most severe cases could even result in gangrene, a condition in which blood stops flowing to muscle tissues and those tissues die.
Any tool that vibrates and transmits that vibration through a worker's hands could result in some of the conditions cited, up to HAVS.
The National Institute for Occupational Safety and Health (NIOSH) publishes a database of hand-arm vibration exposure levels for many power tools, broken down by manufacturer and model. Another approach is to use information outlining typical exposures by type of tool, such as the chart published by the UK's Health and Safety Executive (HSE).
The standard way of measuring vibration exposure is acceleration, which is expressed in meters per second squared (m/s2). For example, orbital sanders have a typical vibration acceleration of 9 m/s2, while pneumatic hammers have a typical vibration acceleration of 25 m/s2.
These measurements are usually determined in a lab, in accordance with ISO 28927. Real-world conditions – such as work conditions, how the worker uses the tool and especially the amount of time the tool is being used – will contribute to the effect it has on a worker.
But even with all this information, understanding the limits for your own usage of power tools is an inexact science. OSHA does not regulate vibration exposures for power tools or recommend standards, and according to a study published by the National Institute of Health, research has not been able to quantify now much vibration exposure leads to HAVS symptoms. Still, experts agree that exposure can be harmful, and workers at risk should be aware of the early onset of symptoms.
Using NIOSH's hierarchy of controls may help provide protection from power tool vibration.
The first step in the hierarchy, elimination, might not be practical. In most cases, the work done by a power tool has to be completed somehow. But there still may be ways to reduce the amount of that work, such as improving upstream quality control processes.
Substitution is the second step in the hierarchy. In this case a power tool could be swapped for a manual one, but that change could slow the work and lead to different types of musculoskeletal disorders. However, choosing a different model with specific ergonomic features or a lower measured vibration acceleration might provide some relief.
Tool manufacturers are keenly aware of the issue and have developed many features to limit transfer of vibration to the user. These advancements include:
Moving down the hierarchy, administrative controls such as job rotation could limit the amount of time any single worker is using a high-vibration tool. Hourly breaks of 10 to 15 minutes from vibrating tools are also recommended in Safety+Health. And it's always good idea to maintain vibrating tools according to manufacturers' recommendations.
Finally, PPE such as antivibration gloves may use an air bladder, gel, padding or rubber on the fingers and palms to help absorb the vibrations. The voluntary consensus standards for antivibration gloves are ANSI/ASA S2.73-2014/ISO 10819:2013, and Safety+Health recommends using gloves tested to meet those standards.
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The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.