Hand-Arm Vibration Syndrome: Causes, Symptoms and Safety Measures
A Common Yet Preventable Hazard: What is Hand-Arm Vibration Syndrome and Who’s at Risk?
Vibration is one of the most common occupational hazards encountered by workers in a wide range of professions. It has been estimated that 3.8% of Australia’s workforce exceeds safe hand-arm vibration thresholds.1
Hand-Arm Vibration Syndrome (HAVS) is a medical condition that is caused by prolonged exposure to vibrations being transmitted through the hand and arm when hand-held power tools such as electric screw drivers and power saws or hand-guided machinery like lawn mowers and jackhammers are used.
A large proportion of the Australian workforce uses vibration-transmitting tools and machinery every day in industries such as construction, mining, manufacturing and more. Hand-arm vibration is distinguished from whole-body vibration which affects the whole body due to vibrations in the supporting surface such as the seat of a vehicle or machinery.
It is essential that these workers and businesses are aware of the risks of excessive vibration exposure so that appropriate mitigation and prevention measures can be implemented to reduce the risk of hazardous levels of exposure. Once the condition has developed, it is often irreversible, making early detection and prevention measures crucial.
Symptoms of HAVS and the Impact on Work and Life
Symptoms of HAVS can be subtle and people who believe they are at risk should consult a doctor or appropriate medical professional. Everyone should have a basic understanding of whether they may be at risk and what symptoms they should be aware of.
When power tools or hand-guided machinery are operated, vibrations are transmitted through the body, particularly the arms and hands. Prolonged exposure, even to low levels of vibration, can damage the nervous system, bones, joints and muscles by inhibiting ordinary circulation. HAVS can manifest as a range of conditions such as carpel tunnel syndrome or vibration white finger (which is sometimes used interchangeably with HAVS).
Some general early symptoms of HAVS-related conditions may include tingling, numbness, stiffness, weakness, or change in skin-colour in the fingers, hand or arm. Damage can become permanent or more severe over-time which means advice from a doctor, or another appropriate medical professional should be sought by anyone who believes they may be at risk of HAVS. People who suffer from HAVS may face challenges performing tasks both in everyday life and in the workplace due to these symptoms. As a result, HAVS is a condition that is the subject of a significant number of worker’s compensation claims each year.
The relationship between vibration and noise and their combined impact on health is an ongoing area of research. Exposure to noise and vibration are closely associated as they are both generally emitted from the same sources, with higher levels of tool or machinery vibration potentially creating louder noise. It has been suggested that combined exposure to noise and vibration makes workers more prone to hearing loss compared to those less affected by vibration but the mechanism behind this relationship is unclear.2
Safety Measures and Prevention of HAVS
Fortunately, it is well understood how HAVS can be prevented, or how the risks can be mitigated. In many occupations, removing the hazardous vibration entirely is impractical due to the necessity for power tools and hand-guided machinery to be used to complete the work. However, there are range of measures that should be implemented to mitigate the risk.
Regulation for HAVs in Australia
Australia does not regulate vibration by providing a specific threshold where exposure becomes a breach of a person conducting a business or undertaking’s (PCBU’s) duties under the Workplace Health and Safety Laws. Safe Work Australia provides a range of guides for managing vibration related risks for PCBU’s but it is largely the responsibility of those with duties under relevant work health and safety legislation to ensure that the risk is adequately controlled.
SafeWork Australia’s ‘guide to measuring and assessing workplace exposure to hand-arm vibration’ informs PCBUs of steps that may be taken to meet their obligations. The guide also refers to AS ISO 5348.1-2013: Mechanical vibration – Measurement and evaluation of human exposure to hand-transmitted vibration – Part 1: General requirements and Part 2: Practical guidance for measurement at the workplace for further guidance for PCBUs.
Safe Work Australia provides several examples of how control measures may be implemented in their ‘Guide to managing risks of exposure to hand arm vibration’:
Substituting tools – Vibration reduced tools may be available or newer tools may vibrate less.
Isolating the hazard – Change the path of vibration such as by adding shock absorbing components to tool handles to absorb some of the vibration before it reaches the worker’s hand.
Engineering controls – Modify existing tools to minimise vibration or other exacerbating factors such as ensuring cold air from the exhaust is not directed onto the hand operating the instrument.
Administrative controls – Changing how work is conducted by implementing measures such as by limiting the time a worker can use a tool or machine.
Personal protective equipment (PPE) – gloves can be used to protect hands from cold temperatures but should not be used as a method of reducing vibration as they may cause vibration exposure to increase by making the user grip tighter to the tool or machine than necessary.
The Role of Vibration Monitoring in Preventing HAVS
Vibration monitoring can be used to assess initial vibration exposure before controls are implemented and to determine the effectiveness of the controls after their implementation. There are various types of vibration meters that are designed to monitor different types of vibration including hand-arm vibration.
Personal Vibration Monitors and How They Are Used
Personal Vibration Monitors are worn by a worker as they perform their usual tasks to measure the vibration they are exposed to in their job. Instruments such as the SV 103 Personal Human Vibration Exposure Meter are compact which allows them to be secured to the arm of a worker without inhibiting how the task is performed and provide more accurate measurements of the vibration that travels through the wearer’s hands and arms. They measure both the amount of vibration (in m s-2) over time and provide data that can be used to determine what tasks place the worker at risk of HAVS.
The data collected can be used to assess whether vibration levels are exposing the worker to the risk of HAVS. Measuring HAV is quite complicated as exposure is highly dependent on both the duration of exposure and the magnitude of vibration. Daily vibration exposure (A(8)) is the most common parameter used to measure worker exposure to vibration. Used globally, this is a normalised value to an 8-hour reference period and takes into account both duration and level of exposure. EU 2002/44/EC Physical Agents Directive is widely referred to as an authority that an A(8) exposure of 2.5 m s-2 requires controls to be put in place and workers must not be exposed to an A(8) exposure above 5.0 m s-2 under any circumstances. Whilst not specified in Australian regulations, these values provide an indication of what may be required.
Personal vibration meters can operate in a range of modes, including A(8) measurement, which makes them simple to use but capable of providing in-depth data for further analysis.
Is Hand-Vibration Syndrome a risk in your workplace? A range of vibration meters are available for sale and/or rental at Air-Met Scientific. Contact your local Air-Met Scientific to discuss your vibration monitoring options.
