Human vibration

Industry workers are continuously exposed to mechanical vibration for performing their job daily, such as operating power tools, machinery or heavy vehicles. The effect of this vibrational phenomenon on the human body can be harmful depending on its intensity and the duration of exposure. This is a severe problem that has to be addressed in the industry. There is a high likelihood of damage to parts of the human body that are continually exposed.

Mechanical vibrations transmitted from the vibrating tools may negatively affect the tissues and internal organs from the shock excitation. Prolonged exposure of the human body to mechanical vibration will cause pathological changes in the nervous, vascular and osteoarticular systems. As workers from the industry sectors experience these days, the changes resulting from contact with mechanical vibration are called occupational disease. Occupational diseases are prominent for workers that operate heavy equipment in the forestry, mining, metals and construction industry.

Exposure to vibration does not directly translate to damage as injury may develop over a long period and repetitive activities. Therefore, employers need to prevent workers from excessive exposure by controlling the risk and limiting their daily exposure. The daily exposure limit is 5g and 1.15g for hand-arm and whole-body vibrations, respectively. The workplace must assess the risk and ensure that this value is not exceeded by implementing a maintenance program.

Performing vibration measurements to judge the risk of damages and injuries have become essential in the workplace. Measurement standards were developed based on ISO5349 and ISO2631 to evaluate human exposure to hand-arm and whole-body vibration, respectively. The triaxial accelerometers can be used with their special adapter to perform the specific measurement and must be capable of measuring the highest magnitude of peak accelerations.

The VM31 vibration meter is designed with the module suitable to perform triaxial measurement of hand-arm and whole-body vibration conforming to ISO2631, ISO5349 and ISO8041. It can display the running and interval RMS, maximum RMS, and maximum peak value with data logging function and capability for PC interface via USB or RS-232 interface.

As a starting point, vibration data is recorded when the workers are operating on a particular tool or machinery. Although the equipment manufacturers may have provided such data, the actual measurement may be more significant due to external circumstances commonly encountered in daily operations. This emission data is used to validate that the machine is safe to operate within the specification provided by the equipment manufacturers.

When determining the duration of exposure, the user should make the correct assessment based on observing the working process. For example, driving a truck may continuously last several hours, while operating a forklift or using power tools are intermittent.

The whole-body vibration measurement should be conducted over the entire exposure time as it mimics the actual working environment. It can be evaluated through the buttocks and feet of a seated person or the feet of a standing person. For accurate representation, it can be expressed as equivalent frequency-weighted acceleration within the test duration and the highest value of RMS or VDV in the three axis.

Hand-arm vibration can be performed by installing the sensors on special adapters and holding them on a handle or between fingers. The measurement is performed over a few short measurements rather than continuous measurements to mimic the typical operations when the workers are in contact with the tool.

A vibration meter is a reliable evaluation tool to implement a whole-plant action for monitoring and reducing human exposure to vibration. This system provides data in a clear format and comes with accessories kits to suit hand-arm vibration or whole-body vibration applications. Bestech Australia provides the VM31 vibration meter and accelerometers to support you in providing a safer workplace for your workers.