How to reduce the risks of hand-arm vibration syndrome when using handheld tools
Chicago pneumatic offers a wide range of ergonomic tools that helps in improving the health of operators by lowering the vibration exposure when working with handheld tools, thereby, helping our customers to reduce the risks of hand-arm vibration syndrome and provide a safe working environment.
What is hand-arm vibration syndrome and what is the potential risk?
Exposure to vibration for longer duration while working with a handheld tool can cause significant health risks to an operator, such as painful and disabling disorders of blood vessels, nerves and joints. The damage includes the inability to fine work and cold weather can trigger painful finger blanching attacks which are permanent.
Reducing or preventing the risk of hand-arm vibration syndrome (HAVS) is one of the primary focus areas in the construction and mining industries.
What is the source of the vibration?
Hand-arm vibration is the result of forces from two sources: the tool itself, and the interaction between the tool and the material worked on. The vibration from the machine is caused by the forces required to operate it, for example, to accelerate the piston in a breaker. This can be minimized by using a tool that is designed to dampen vibrations.
However, the vibration caused by the interaction between the tool and the material, for example, when a drill enters a concrete block, is harder to eliminate. Instead, it is passed through the machine and onto the operator’s hands. The total amount of vibration depends on the material, the operator's skill, and the type of tool and inserts used. Additional factors, including how the tool is used, whether it is blunt, sharp, or poorly maintained, also contribute to the total vibrations experienced.
Vibration reduction technology
The most efficient way to reduce the risk is by controlling the exposure of vibration and this can be achieved by using an ergonomically designed handheld tool with a lower vibration emission.
European regulation states that manufacturers must present the single-axis vibration emission value of the tool when it is above 2.5 m/s². Comparing these values from different manufacturers can help highlight tools that have exceptionally high vibration emission values. Chicago Pneumatic's ergonomic tools, also called as vibration-dampening tools, are easily identified by a VR-mark in the model name. When this information is not readily available, it is useful to pay attention to the vibration emission value to determine the exposure of vibration.
Estimation of daily vibration exposure using the point system
Operators commonly use several different handheld machines during a single working day. A method frequently used by employers to simplify the estimation of daily vibration exposure is the point system. Under this system, exposure levels for different combinations of vibration magnitude and exposure time are normally given in exposure points instead of values in m/s². You may find the exposure points easier to work with than the values:
› Exposure points change simply with time: twice the exposure time, twice the number of points.
› Exposure points can be added together, for example, when a worker is exposed to two or more different sources of vibration in a day.
› The Exposure Action Value (2.5 m/s²) is equal to 100 points.
› The Exposure Action Value (5 m/s²) is equal to 400 points.
The graph below illustrates how vibration magnitude affects the exposure time, regulated by the European Vibration Directive, that can be allowed. The colors represent the Exposure Action Value and the Exposure Limit Value, defined in the European Vibration Directive.
Vibration exposure graphic
The number in each square is the points accumulated by working with a certain machine, with a certain declared vibration emission value, during a certain time (effective trigger time).
An employer might determine that this is an effective way to keep track of the total daily exposure if operators are working with several handheld machines during a typical working day, in connection with the employer’s responsibilities, to ensure that vibration exposure remains within the limits specified by the European Vibration Directive 2002/44/EC. When using several machines on the same working day, the total vibration exposure points, PE total, can be estimated by the employer by adding up the vibration exposure points of the individual machines.
Let us take an example, the vibration-dampening tools offer significant advantages compared to traditional handheld tools, especially when handled over longer periods.
If we compare handheld tool (A) with a vibration emission value of 14.5m/s² with a tool featuring our vibration-dampening technology (B), with a vibration emission value of 5m/s², the benefits are evident. With tool A, operators will be above exposure action value after using it for 12 minutes. However, they will only reach that point after working with tool B for 2 hours.
Using a VR tool is thus always recommended. You can get the job done faster, whilst reducing the risk of hand-arm vibration syndrome.
Tips to help reduce the impact of vibration
In addition to leveraging vibration-dampening technology, operators can take some additional steps to reduce the impact further.
First, it is essential to ensure that the tool is the best possible match for the job. If it is not right for the application, it can pose a risk to the operator's health and safety, and damage the material and the tool.
Secondly, try to avoid gripping the machine any harder than necessary: the machine will be able to do the job with the feed force specified by the manufacturer and applying additional pressure will not deliver better results.
If any unusual vibrations are experienced, it is crucial to stop work and diagnose the fault before continuing. Regular preventive maintenance will help optimize the tool's working life and address potential issues before they pose any risk to the operator.
- Use vibration-dampening tools
- Operate at the correct pressure (6 bar for pneumatic tools)
- Don’t press the trigger while retrieving the tool after breaking to avoid blank firing
- Make sure the inserted working tools are well-maintained
- Stop working if you notice unusual vibrations and diagnose the cause
- Take regular breaks
- Keep hands warm and dry to encourage blood circulation
- Relax and exercise your fingers during breaks
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