Exposure to excess vibration through the hand and arm (HARM) has been known to cause debilitating conditions for nearly a century. The most common permanent condition brought on by excess vibration exposure is hand arm vibration syndrome (HAVS), commonly manifested in vibration white finger. The condition affects workers across a range of industries with the Health and Safety Executive calculating that nearly two million people are at risk.
What are the Causes of HAVS?
HAVS is a form of secondary Raynaud’s phenomenon, which is caused by over-sensitive blood vessels in the body’s extremities. These blood vessels contract too much in cold conditions which results in loss of feeling and numbness in the fingers. In the case of HAVS, the phenomenon is brought on by excess vibration through the hand and arm across a certain frequency range.
High-frequency vibration can be absorbed by the skin whilst low frequencies are more likely to be absorbed by the skeleton, leaving a certain range where vibration is hazardous. Acceleration and exposure time are other factors that may increase the likelihood of HAVS. According to the HSE, a hammer-action tool used for more than fifteen minutes per day or rotary tool used for more than an hour may put the user at risk which must therefore be managed.
What are the Symptoms of HAVS?
Vibration white finger, the most well-known symptom of HAVS, is characterised by intermittent loss of feeling in the fingers, usually triggered by cold and wet conditions, and a blanching effect that turns the finger almost completely white. In many cases, the finger will then adopt a blueish complexion as it is starved of oxygen before turning red as circulation returns and eventually reverting to a normal colour. The ‘red’ phase is often very painful with swelling, tingling, and ‘pins and needles’.
Non-visible effects of HAVS include consistent or permanent numbness in the hands and fingers leading to difficulties picking up small objects like screws and bolts. This loss of manual dexterity makes it more difficult to handle small components or even perform simple tasks like doing up a button. Damage caused by HAVS is permanent so correct safeguarding is vital to employees’ wellbeing.
What is required under the Vibration at Work Regulations 2005?
Since 2005, a legal duty has been placed on employers by the Vibration at Work Regulations to ensure that risks from vibration are controlled; that information, instructions and training are provided on risk and how to control said risk; and to provide suitable health surveillance. In addition, the regulations define two important limits at which to take action. Vibration above the exposure action value (EAV) of 2.5m/s2 constitutes a risk in need of management whilst the 5m/s2 exposure limit value (ELV) is the level to which employees should not be exposed.
How can Vibration at Work be Managed?
In order to properly measure HARM, a tool timer should be used to measure the ‘trigger time’ - i.e. the amount of time an employee’s hand is contact with a vibrating tool - alongside a HARM vibration meter which measures the vibration. Some solutions such as the HAVi Vibration Monitor simply attach to the tool handle, thereby providing time and vibration measurement in a single package. The HAVi also stands out thanks to its ability to measure HSE exposure points and warn the operator if either EAV or ELV is exceeded. Accurate measurement of vibration exposure allows employers to take practical steps such as limiting operation time for individual employees and replacing tools that vibrate excessively.
Aside from measuring vibration exposure, there are several ways to minimise the effects. Firstly, vibrating power tools should be kept warm to prevent the handles being cold or frosty when they are first turned on. This will help maintain blood flow in the fingers. Secondly, anti-vibration gloves help absorb vibration and keep the hands warm. Thirdly, equipment should be properly maintained. This might include sharpening cutting blades and making sure that bearings are secure. By taking these steps and monitoring exposure to vibration, employers will safeguard their workers’ health and comply with their statutory duties.