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Handheld Hazards

Published: 07th May 2015

The phrase ‘a safe pair of hands’ is thought to have originated from the United Kingdom when politicians or diplomatics were entrusted with knowledge of sensitive information that required careful handling of application.

This turn of phrase was then captured in the sporting tutorials of several public schools, having been referenced in the sports of both cricket and rugby. A quote from James Pycroft’s 1851 The Cricket Field suggests the colloquial term of endearment to a fielder who never dropped a catch from any batsman as “ the safest pair of hands in England .” Similarly, the phrase was also used in the 1933 book How to Play Rugby Football by William John Abbott Davies: “ A safe pair of hands is of paramount importance .”

There are several industries in which hand injuries are prevalent, directly occurring from the manufacturing industry, wholesale and retail trade industries, as well as the construction industry, where workers most commonly sustain hand and wrist injuries during working days. This is possibly due to the direct manual handling of tasks being undertaken and the equipment being used, which has the potential to exert large forces directly or indirectly to the hand and wrist.

Using a sharp edged tool, particularly a knife, is the one task that results in the highest number of work-related hand and wrist injuries. Other common activities and agencies were power tools that locked suddenly, mobile machinery and fixed machinery such as cutting plant, presses and conveyors. Preparing food and welding are the most common activities associated with burn injuries to the hand and wrist. Similar results have been reported for Australia (Hockey and Miles, 1999; Muscatello and Mitchell, 2001; Routley and Valuri 1993, 1994; Stathakis and Cassell, 2004) and elsewhere (Barr et al , 2004; Muggleton et al , 1999; Thomsen et al , 2007). The extent to which repetitive strain injuries are classified as injuries or diseases, however, affects the extent to which direct comparisons can be made between different studies.

Information on the agency of injury for hospital data came from the External Cause codes, described as the ‘mechanism of injury’ for the detailed hospital analysis. In reality, however, the analysis combines information on agency and mechanism. For hospital data, the main agencies identified by the External Cause analysis were powered hand tools, household machinery, knives, woodworking and forming machinery, non-powered hand tools, and metalworking machinery. The most common work-related injury type in the Australian workforce is predominantly work-related hand and wrist injuries, resulting in around 8,400 admissions to hospital every year. The injuries range from being relatively minor such as open wounds to the fingers, to very severe, such as amputation.

Open wound was the most common type of injury. It accounted for 28% of hospitalisations, 55% of emergency department presentations and 35% of workers’ compensation claims for work-related hand and wrist injuries. Fractures were the next most common injury type in hospitalised cases and the third most common injury type in workers’ compensation cases, but were much less frequent in the emergency department.

Work-related hand and wrist injuries in Australia accounted for 17 cases, for which superficial injuries were the second most common injury type. Sprains and strains were prominent only in workers’ compensation cases. The pattern of injury types was broadly similar across industries. Prominent exceptions were a much higher proportion of burns in the catering industry, while emergency department crush injuries were more prominent in the agriculture, forestry and fishing, manufacturing, construction and transport industries.

Hand and wrist injuries have previously been shown to be an important reason for presentation at emergency departments. In 2007 Driscoll and Harrison used information from emergency departments, hospital separations and workers’ compensation to examine the characteristics of these injuries, and the circumstances surrounding their occurrence, in more depth. This analysis confirmed that hand and wrist injuries comprise a considerable proportion (about 30% to 40%) of all work-related injuries seen in emergency departments and all work-related injuries resulting in hospital admission, but that very few (less than 2%) such hand and wrist injuries result in hospital admission. Nevertheless, it is worth repeating the earlier statement that nearly 8,400 persons each year sustain a work-related hand and wrist injury that is severe enough to require hospitalisation.

One area that has very little information is the injuries sustained from hand and arm vibration. Hand-arm vibration (HAV) is vibration transmitted to the hand and arm during the operation of hand-held power tools and hand-guided equipment, or when holding materials being processed by machines (Safe Work Australia, 2012). HAV is commonly experienced by workers who regularly use tools such as jackhammers, chainsaws, grinders, drills, riveters and impact wrenches.

Workers using hand-held power tools in workplaces can be exposed to harmful levels of HAV. Reducing vibration exposure and/or duration of use reduces the risk of musculoskeletal disorders.

Health effects

Exposure to HAV can disrupt circulation to the hand and forearm and/or damage, nerves, tendons, muscles, bones and joints of the hand and arm. It can cause a range of conditions collectively known as hand–arm vibration syndrome (HAVS) and specific disorders such as carpal tunnel syndrome, ‘tennis elbow’ and ‘vibration white finger’.

Workers with exposure to vibration while performing other hazardous manual tasks may also experience:

• Pain in the hands and arms

• Diminished muscle strength

Longer periods of exposure, i.e. years, may result in episodes of whitening of the fingers, usually triggered by cold exposure. This is from temporary closing down of blood circulation to the fingers.

Workers who use equipment that subjects the worker to both HAV and to noise may also be more likely to suffer from hearing loss.

Effects of exposure to HAV

The longer a worker using tools is exposed to HAV, the greater the risk becomes of developing HAVS.

As detailed in the following sections, exposure to HAV can be increased by factors including tool characteristics, the work organisation, and the individual’s characteristics.

Tool characteristics:

• Higher magnitude of acceleration of vibration

• Poor tool maintenance

• Minimal handle insulation

• Increased weight of tool

• Increased surface area of hand in contact with tool

• Harder material being contacted

Work organisation:

• Long exposure during each work shift and years of exposure

• Lower duration and frequency of rest periods

• Lower temperature of work environment

Individual’s characteristics:

• Gripping the tool’s handle more tightly than needed

• Awkward postures and working overhead

• Low operator skill or poor technique

• Lifestyle factors, e.g. smoking

• Medical history, e.g. disease or prior injury to fingers, hands or wrists

Reducing harmful exposure

Eliminating or minimising exposure to HAV usually involves isolating or cushioning methods. Workers should be consulted and involved in setting priorities and identifying solutions, including the selection and trialling of new powered hand-tools.

Successful HAV exposure reduction usually requires a combination of control measures. Such measures, listed in order of priority (high-low), include:

• Substituting alternative methods or processes to eliminate the need to use vibrating hand-held tools

• Selecting tools with low vibration emission levels to eliminate or minimise exposure to vibration

•Modifying existing tools to either minimise the vibration or prevent the vibration from moving into the handle of the tool

• Directing cold air away from the worker’s hand

• Maintaining equipment regularly to minimise vibration

• Modifying work methods to reduce exposure to vibration

• Altering work practices and the way work is organised to reduce exposure to vibration

These measures need to be accompanied by training, education and supervision, including advice on good work practices and tool maintenance, the effects of individual factors (smoking and some medications may impact on circulation and vibration white finger), as well as recognising and reporting symptoms of HAVS.

Gloves should not be relied upon to provide protection from vibration. They only provide protection from cold temperatures, water, and cuts and abrasions. The use of thick gloves may worsen exposure as workers may then apply increased grip forces to the tool, thereby increasing transmitted vibration.

Making the right choice

There is considerable variation in emitted vibration between tools of the same type.

Tools that incorporate vibration-reduction innovations in their design or are manufactured to higher specifications may vibrate less than other tools. To make an informed choice, obtain as much information about the vibration emissions of the tool as possible.

Consider the suitability of hand-held power tools for the work being undertaken – an underpowered or blunt tool may take longer to do the job, increasing the time of exposure. On the other hand, an overpowered or oversized tool may emit more vibration than necessary.

Information on the vibration emitted by a specific tool can be provided by the tool manufacturer or supplier.

When considering the vibration emitted by a tool during a specific task, try to find data that is measured while undertaking the same task as your intended use. This will provide a better guide to the levels likely to be found in practice when the task is performed in the workplace.

Data from suppliers and some workplace data are available at: www.vibration.db.umu.se

Mandatory exposure levels

In Europe there are mandatory exposure level requirements, but these do not exist in all countries. If you are without mandatory levels, you should select tools that can be used with the daily vibration exposure of a user remaining below 2.5 m/s 2 averaged over an eight-hour working day. If this is not possible, consider changing or rearranging the task. You should never allow a worker to be exposed to more than 5m/s 2 in an eight-hour day.

A ready reckoner for calculating daily vibration exposure is available through the UK’s Health and Safety Executive: www.hse.gov.uk/vibration/hav/readyreckoner.htm

To make use of this, you need to know the vibration magnitude (in m/s 2 ) from the manufacturer and exposure time, which is the time the tool is operational. This can easily be measured by an observer with a stopwatch in normal working conditions.

The ready reckoner can give workers an indication of how long they can work before the recommended action level and exposure limit levels are exceeded.

Measuring vibration levels

Ordinarily it is not necessary to measure vibration levels. Expert measurement of vibration exposure should only be necessary in situations where there is no information available on the emission of the tool, the vibration levels are likely to be high, and the tool is used for long periods of time. You can put controls in place to minimise exposure without measuring.

Conclusion

Thinking back to the start of this article, and in the context of workplace safety the idea of a safe pair of hands takes two meanings. Sure, you want to keep your hands injury free, but equally you want to feel that when going to work you are safe in the care of your employer.

It's an ideal world where health, wealth and happiness are held simultaneously, and many people have to sacrifice one or more, choosing which they think is most important.

Weighing the importance of income against health is a not an enviable task. Do you stay in a dangerous job to provide for your family, even if there's a risk of losing limbs? How sustainable will that job be with an injury?

Workers need to take a certain level of responsibility for their own safety – deciding what risks they will tolerate and speaking out against unsafe situations.

At the same time, however, the onus really is on employers to do everything possible to keep their workers safe, including conducting risk assessments and eliminating hazards where possible, providing suitable and sufficient training and PPE, as well as fostering a culture of safety.

Published: 07th May 2015 in Health and Safety Middle East

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Mark Da Silva
Mark Da Silva is Director of Work, Health and Safety Programmes at WorkSafe Victoria. As the Director of Programmes his remit includes leading and facilitating the delivery of the strategic health and safety improvement programmes; aimed at reducing injury, illness and fatalities in Victoria workplaces.