Vibration white finger

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Vibrating white finger ( VWF ), also known as hand-arm vibration syndrome ( HAVS ) or dead fingers , is a secondary form of Raynaud's syndrome, an industrial injury that is triggered by the continuous use of the vibrating hand machine. The use of the term "white finger vibrations" has generally been superseded in professional use by the broader concept of HAVS, although it is still used by the general public. The symptoms of a vibrating white finger are the HAVS vascular component.

HAVS is a widely known industrial disease affecting tens of thousands of workers. It is a disorder that affects the blood vessels, nerves, muscles, and joints, hands, wrists, and arms. The best known effect is the vibration-induced white finger (VWF), a term introduced by the Industrial Injury Advisory Council in 1970. Injuries can occur at frequencies between 5 and 2000Hz but the greatest risk for fingers is between 50 and 300Hz. Total risk exposure for hands and arms was calculated using ISO 5349-1, which specified maximum damage between 8-16 Hz and risk decreased rapidly at higher frequencies. The risk-frequency assessment of ISO 5349-1 does not match the estimated risk for well-induced vibration white fingers.

Video Vibration white finger

Effects

Excessive exposure to hand-arm vibration can lead to various patterns of disease known as HAVS or VWF. It can affect the nerves, joints, muscles, blood vessels or connective tissue of the hands and forearm:

• Tingling "whiteness" or numbness in the fingers (blood vessels and nerves affected) : This may not be noticeable at the end of the working day, and in mild cases may affect only the fingertips -finger. When the condition becomes more severe, the entire finger up to the knuckles can become white. Feelings can also be lost.
• The finger changes color (affected blood vessels) : With continued exposure, the person may experience periodic attacks in which the fingers change color when exposed to cold. Initially the fingers quickly become pale and feeling lost. This phase is followed by an intense red hue (sometimes preceded by a blackish-blue phase) that signifies the return of blood circulation to the fingers and is usually accompanied by an uncomfortable pulse.
• Hand loss of dexterity (affected nerves and muscles) : In more severe form, attacks can often occur in cold weather, not only at work, but during recreational activities, such as gardening, washing cars or even outdoor sports and can take up to an hour to cause pain and loss of manual dexterity and reduce grip strength.

In extreme cases, the sufferer may lose a finger. The effect is cumulative. When symptoms first appear, they may disappear after a short time. If vibration exposure persists for months or years, the symptoms may worsen and become permanent.

Maps Vibration white finger

History

The phenomenon was first described by Professor Giovanni Loriga in Italy in 1911, although the relationship did not occur between symptoms and a hand tool that vibrated up to research conducted by Alice Hamilton MD in 1918. He formed his theory by following symptoms reported by a mine digger and sculptor in Bedford, Indiana. He also found a link between increased HAV symptoms and cold weather like 1918 is a very harsh winter.

The first scale to assess the condition, the Taylor-Pelmear scale, was published in 1975, but was not listed as a prescribed illness in Britain until 1985, and the Stockholm scale was introduced in 1987. In 1997, the British High Court gave Ã, £ 127,000 as compensation to seven coal miners for a vibrant white finger. The British government fund set up to cover subsequent claims by former coal miners has exceeded Ã, Â £ 100 million in payments in 2004.

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Prevention

Vibration Control on the 2005 Working Rules, created under Occupational Health and Safety etc. Act 1974. is a law in the United Kingdom that regulates exposure to vibrations and helps prevent HAVs from occurring.

Good practice in industrial health and safety management requires that workers' vibration exposure be assessed in terms of amplitude of acceleration and duration. Using a slightly vibrating tool for a long time can be just as damaging as using a very vibrating tool for a short time. The length of use of this tool is measured as trigger time , the period when the worker actually has their finger on the trigger to make the tool run, and is usually quoted in hours per day. The vibration amplitude is quoted in meters per second squared, and measured by the accelerometer on the tool or provided by the manufacturer. Amplitude can vary significantly with tool design, conditions and usage styles, even for the same type of tool.

In the UK, the Health and Safety Executive provides an example of a hammer drill that can vary from 6m/sÃ,² to 25m/sÃ,². HSE publishes a list of vibration levels normally observed for various tools, and a graph of how long each day a worker can be exposed to a certain level of vibration. This makes risk management relatively easy. The tool is given Exposure Action Value (EAV, the time before which the tool can be used to reduce vibration exposure) and Lighting Limit Values ​​(ELV, time after tool can not be used).

In the United States, the National Institute for Occupational Safety and Health published the same database in which the values ​​for sound power and vibration for the tools commonly found from major commercial vendors in the United States were surveyed. Further testing is underway for more and more new tools.

The effect of legislation in different countries on the limits of worker vibration is to require equipment providers to develop better designed tools, better maintained, and for employers to train workers appropriately. It also encourages tool designers to innovate to reduce vibration. Some examples are easily manipulated mechanical arm (EMMA) and suspension mechanisms designed into chainsaws.

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Anti-vibration gloves

Anti-vibration gloves are traditionally made with a thick and soft palm material to protect from vibration. Protection is highly dependent on the frequency range, most gloves do not provide protection on the palms and wrists below ~ 50Hz and fingers below ~ 400Hz. Factors such as high grip strength, cold hand or vibrational force in the shear direction can have the effect of reducing and or increasing damage to the hands and arms. The gloves help keep the hands warm but to get the desired effect, the frequency output of the tool must match the nature of the selected vibration sheath. Anti-Vibration Gloves in many cases amplify vibrations at lower frequencies than those mentioned in the text above

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Reactive monitoring

A simpler system, known as reactive monitoring, can be used by, for example, monitoring the usage level of consumables. Such a system was introduced by Carl West at a fabrication workshop in Rotherham, England. In this system, the degree of vibration of the angle grinding device used is measured, such as the average life of the milling disc. So by noting the number of grinding disks used, the vibration exposure can be calculated.

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See also

• List of skin conditions
• Hypothenar hammer syndrome

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References

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External links

• BBC News article on coal miners' claims
• Trades Union Congress - basic facts
• UK Health and Safety Executive
• NIOSH Power Tools Sound and Vibration Database
• HAV case study HAV web page

Source of the article : Wikipedia