Vibration white finger

Vibration white finger (VWF), also known as hand-arm vibration syndrome (HAVS) or dead finger, is a secondary form of Raynaud's syndrome, an industrial injury triggered by continuous use of vibrating hand-held machinery. Use of the term 'vibration white finger' has generally been superseded in professional usage by broader concept of HAVS, although it is still used by the general public. The symptoms of vibrating white finger are the vascular component of HAVS. Vibration white finger (VWF), also known as hand-arm vibration syndrome (HAVS) or dead finger, is a secondary form of Raynaud's syndrome, an industrial injury triggered by continuous use of vibrating hand-held machinery. Use of the term 'vibration white finger' has generally been superseded in professional usage by broader concept of HAVS, although it is still used by the general public. The symptoms of vibrating white finger are the vascular component of HAVS. HAVS is a widespread recognized industrial disease affecting tens of thousands of workers. It is a disorder that affects the blood vessels, nerves, muscles, and joints, of the hand, wrist, and arm. Its best known effect is vibration-induced white finger (VWF), a term introduced by the Industrial Injury Advisory Council in 1970. Injury can occur at frequencies between 5 and 2000 Hz but the greatest risk for fingers is between 50 and 300 Hz. The total risk exposure for hand and arm is calculated by the use of ISO 5349-1, which stipulates maximum damage between 8 and 16 Hz and a rapidly declining risk at higher frequencies. The ISO 5349-1 frequency risk assessment does not match the estimated risks for vibration-induced white finger well. Excessive exposure to hand arm vibrations can result in various patterns of diseases casually known as HAVS or VWF. This can affect nerves, joints, muscles, blood vessels or connective tissues of the hand and forearm: In extreme cases, the sufferer may lose fingers. The effects are cumulative. When symptoms first appear, they may disappear after a short time. If exposure to vibration continues over months or years, the symptoms can worsen and become permanent. The Control of Vibration at Work Regulations 2005, created under the Health and Safety at Work etc. Act 1974. is the legislation in the UK that governs exposure to vibration and assists with preventing HAVS occurring. Good practice in industrial health and safety management requires that worker vibration exposure is assessed in terms of acceleration, amplitude, and duration. Using a tool that vibrates slightly for a long time can be as damaging as using a heavily vibrating tool for a short time. The duration of use of the 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 typically quoted in hours per day. Vibration amplitude is quoted in metres per second squared, and is measured by an accelerometer on the tool or given by the manufacturer. Amplitudes can vary significantly with tool design, condition and style of use, even for the same type of tool. In the UK, Health and Safety Executive gives the example of a hammer drill which can vary from 6m/s² to 25m/s². HSE publishes a list of typically observed vibration levels for various tools, and graphs of how long each day a worker can be exposed to particular vibration levels. This makes managing the risk relatively straightforward. Tools are given an Exposure Action Value (EAV, the time which a tool can be used before action needs to be taken to reduce vibration exposure) and an Exposure Limit Value (ELV, the time after which a tool may not be used). In the United States, the National Institute for Occupational Safety and Health published a similar database where values for sound power and vibrations for commonly found tools from large commercial vendors in the United States were surveyed. Further testing is underway for more and newer tools. The effect of legislation in various countries on worker vibration limits has been to oblige equipment providers to develop better-designed, better-maintained tools, and for employers to train workers appropriately. It also drives tool designers to innovate to reduce vibration. Some examples are the easily manipulated mechanical arm (EMMA) and the suspension mechanism designed into chainsaws.