Jack Hammer Gloves – Yes or No?
Anti-Vibration Gloves: Should They Be a Part of an Overall Hand Vibration Protection Strategies?
The primary purpose behind the concept of anti-vibration gloves is to reduce the risk of workers developing a condition or symptoms collectively known as Hand-Arm Vibration Syndrome (HAVS). These conditions, produced by repetitive and frequent vibration on the hands from using vibrating machinery and power tools, damages nerves and blood vessels that innervate and supply the muscles of the hand, wrists, and arms. If left unchecked overtime or if causative behavior/activity remains unchanged, the condition can progress form tingling in the fingers to numbness, severe pain and can greatly diminished manual dexterity that can make fine hand motor tasks difficult. Simple tasks like buttoning up a shirt, tying shoes, etc. can become problematic. In a worst-case scenario, these symptoms may even become permeant.
What Does Research Show and What Does Anecdotal Evidence Suggest?
Research and testing has lead to the development of ergonomically engineered gloves that are reported to reduce the transmission of vibration through the gloves and to the palm, fingers, and thumb. In addition, they are also purported to provide for increased comfort, a more snug fit, and added protection from other types of workforce trauma that can damage hands and fingers.
However, other data suggest that anti-vibration (AV) gloves may not be that effective in reducing the effects of vibration. These seemingly conflicting positions suggest that it remains unclear as to the real benefits of anti-vibration gloves in reducing the transmission of vibration exposure and the development of HAVS in the workplace. While there is a standard for measuring a glove’s ability to attenuate some vibration at the palm of the hand (International Organization for Standardization ISO 10819) there is error inherent in these measures as the inter-subject variability can be extremely large.
There is data showing that research on one glove for a tool with a dominant frequency of vibration at around 160 Hz could produce a range of results from a 36% reduction in vibration transmission to the palm for one person to a 79% amplification of vibration transmission for another person. Without assessment on an individual basis, inter-subject variations would make it impossible to identify which operator, glove, and tool combinations might produce a reduction in vibration exposure, yield no results, or which might result in potentially harmful exposures. Add to this other hard to control variables such as varying glove thickness and what role this might play on grip force and muscle fatigue, for good or bad, and the picture of effectiveness becomes more unclear.
Also, consider that evaluations that have been conducted show that the vibration isolation effectiveness of a glove is not only impacted by the glove itself, but many other factors such as the:
- Conditions in which the tool is being used
- Specific material that the vibrating machinery or tool is being applied to
- Specific assessment location on the hand or arm,
- Individual vibration directions
- Differences between operators including size, build, strength, leverage arm, hand size, grip force, posture when working, etc.
- Frequency spectrum for a given power tool is not always constant
While it is virtually impossible to take all these variables into account in evaluating an individual glove’s effectiveness, it has generally been shown that gloves, in general, are not very effective in reducing vibration transmission when working with machinery that produces low-frequency vibrations. However, most powered hand tools and machinery do not fit this description and as such AV gloves have shown to marginally reduce the frequency-weighted vibration transmitted to the palm of the hand, with a lesser reduction impact to the fingers.
The Bigger Picture
A comprehensive worksite safety anti-vibration program must address all aspects of vibration control and consider other impacting factors to be effective. These include:
- Lowering the total vibration value – incorporating new low-vibration tools and selecting effective anti-vibration gloves (sometimes called jackhammer gloves) and developing alternative production techniques with lower vibration values.
- Decreasing a worker’s exposure time – worksite limits on exposure time in using vibrating machinery and tools including mandatory break times.
- Physiological intervention strategies – reducing caffeine intake and incorporating post equipment usage interventions such as icing and limb compression to reduce the impact of microscopic tissue damage.
- Ergonomic assessments – to evaluate if a worker’s stance base, use of or lack of use of body and arm leverage, hand-tool interaction, posture, etc. is consistent with healthy ergonomic standards.
- The use of gloves in general – gloves are recommended for operation of powered hand tools for many good reasons including:
- To protect hands against blister formation
- To protect hands from mechanical cuts, contusions, and abrasions
- To keep hands warm, clean, and dry which has also been shown to reduce the potential for developing HAVS
- To protect hands from burns and biological and chemical exposures
Which Anti-Vibration Hand Protection Gloves Are Right for You and Your Worksite?
Research into worksite and anti-vibration glove design has enhanced the overall protective properties of these gloves but has also created a vast assortment of unique features that may or may not be useful for a specific work environment. Consider these glove features when evaluating which glove might be best suited for your particular work requirements.
- Gloves have been tested and meet EN ISO/ANSI standards for reduction of vibration
- Insulation layer for protection from cold exposure, which can increase the stress to the hand tissues and make symptoms worse
- Built to provide for ventilation and a cooling effect when working in warm conditions
- Job task requirements that call for a thicker and more durable webbing between the thumb and index finger for greater shock absorption vs a more pliable webbing to allow for greater coordination and dexterity for enhanced grip capability
- The likelihood of a glove’s design to reduce hand strain and muscle fatigue which can increase the risk for industrial accidents
- A terry cloth pad on the dorsal thumb area to allow for wiping away sweat when working in hot environments
- Knuckle and back of hand padded or hard plastic rubber protection for blunt force possibilities
- Anti-odor technology
- Full 360-degree wrist wrap for maximal securement to hand, designed to reduce the risk for being caught in machinery
When you consider a comprehensive anti-vibration and hand protection program the Personal Protective Equipment (PPE) of an anti-vibration or jack hammer glove and its associated hand trauma protection characteristics should be an important component in your overall strategy. A good assessment of the particular glove characteristics that are needed for your work environment will help you select the best glove for your tasks.
Reference: Anti-Vibration Gloves? The Annals of Occupational Hygiene, Volume 59, Issue 2, 1 March 2015, Pages 127 – 141, https://doi.org/10.1093/annhyg/meu089
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