Excessive vibrations can affect the long-term health of workers

Construction workers are particularly prone to the condition known as HAV (Hand Arm Vibration), which can occur as a result of extensive use of power tools. While several countries have regulations in place to help both employers and employees take preventative action against HAV, no such legislation exists in the UAE.

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By  Colin Foreman Published  July 16, 2005

Excessive vibrations can affect the long-term health of workers |~|300765200.jpg|~|By using well-designed and well-maintained tools in a safe and controlled manner, contractors can help prevent injuries amongst the workforce.|~|Exposure to hand arm vibration (HAV) occurs in all industries that use power tools extensively. Construction is one of the main culprits around the world, and is the largest user of power tools in the UAE. In the UK, HAV has become a major concern with an estimated five million workers exposed to HAV in the workplace. Two million of these are exposed to levels of vibration where there are clear risks of developing disease, and every year there are approximately 3000 new claims for Industrial Injury Disability Benefit. In the UAE no statisitics are available, but with so many large scale developments that rely heavily on the use of power tools, it would be safe to say that the problem here is a considerable one. The excessive hand arm vibrations generated by the regular use of power tools may cause a number of diseases, which are painful as well as disabling. The first is Vibration White Fingers (VWF), which disrupts the blood supply to the fingers leaving them blanched and painful to use. The second disease is carpal tunnel syndrome, which results from the compression of the nerves in the wrist and reduces grip strength. Other disorders of bones, muscles, joints and the nervous system may also occur causing finger blanching, numbness, and the inability to grip. New regulations that will help both employers and employees to take preventive action from vibration risks in the workplace came into force this month in the UK. The legislation deals with the control of diseases caused by vibration at work from equipment, vehicles and machines. The new legislation provides employers with simple guidance to help them to decide whether their employees are likely to exceed the new exposure action or limit values. Employers are therefore required to assess exposure levels, keep exposure to a minimum, provide information and training, and implement a programme of health checks for all at risk employees. The new law also provides advice on practical actions employers can take to control the risk, stressing the importance of simple, common sense measures to reduce exposure. Unlike the UK, no such legislation exists in the UAE. “Legally in the UAE, there is a requirement under the UAE Federal and Dubai Local Orders to ensure tools and equipment are in good condition and to provide PPE (Personal Protective Equipment) as necessary to protect the operative,” says Bill Tunney, a safety officer on one of Dubai’s largest sites. “Dubai Municipality in its Code of Construction Safety Practice make reference and guidance for noise, but not for vibration. “However it reinforces the fact that tools must be in good condition, and that PPE be provided for the hazards identified,” adds Tunney. Although legislation is somewhat lacking, it does not absolve contractors from providing a safe environment for their staff to work in, and this includes limiting the exposure to HAV. There are a number of key actions that an employer can carry out. Maintenance of equipment can have a significant effect on tool vibration magnitudes. Maintenance of tool bit and blade can also reduce vibration levels and exposure time. With low-vibration tools, the regular maintenance of specific anti-vibration features is also important to retain low tool vibration levels. Reducing the exposure of individuals by introducing formal job rotation is an effective control measure, providing employees have the relevant experience and training, and there is a pool of non-exposed employees who can share exposure with exposed employees. Issuing and reinforcing the wearing of PPE will also help to reduce the vibration effect of power tools, especially if it is possible to issue anti-vibration gloves. “All these things require good management, but guidance is available. For example, they could contact a reputable tool manufacturer and ask what they are doing to control the risks of HAV,” says Tunney. DeWalt is one manufacturer that has carried out research and has studied the New Measurement Standard BS EN ISO 5349-1:2001 (for example the section for hammer drills — EN 60745-2-6 clause 6.2) which now requires measurements to be taken in three axes at two points on the tool, as opposed to the old standard (EN50144) that required measurement at one point and one axis only. The new vibrations requirement is known as ‘tri axial’ vibration measurement, compared to the old requirement of ‘single axis’ measurement. The new standard restricts the usage time of power tools based on vibration levels. DeWalt’s Active Vibration Control (AVC) Systems help make the tools safer for the user by minimising the harmful vibration effects of the long-term use of power tools on the operator. The system’s innovative technology also helps to increase the usage time. Other manufacturers such as Hilti have similar systems in place. The company has developed its patented active vibration reduction (AVR) system. “A lot of tools in the market pretend to reduce vibration, and have, for example, a soft grip, but the machine still vibrates,” says Charles Daher, market segment manager, Hilti. “With the AVR system, a counterweight is used to cancel out the vibration caused by the hammering action of the tool,” he adds. Other features include active torque control (ATC) that is used on bigger machines to help prevent them from jamming and spinning out of control when the drill bit hits rebar. ACT operates as a clutch and as soon as the machine jerks slightly, it stops drilling.Hilti also provides easy-to-interpret data with its tools that inform the user how many holes can be drilled, or how long a certain tool can be used for a given application before the vibration levels become dangerous. By using well-designed and well-maintained power tools in a safe and controlled manner, contractors can prevent many of the debilitating injuries caused by excessive vibrations from developing in the first place.||**||

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