Whole Body Vibration (WBV) can increase the risk of musculoskeletal injuries, particularly the lower back. If workers are sitting down for an extended period of time and are subjected to vibration, then lower back injuries may arise. The Whole Body Vibration assessment of a Melbourne manufacturing plant was of a twofold approach. One, being the ergonomic posture of the employee at the workstation and secondly the vibration of the worker while seated.
Ergonomic Posture for Control Rooms
A workplace which has a control room and where workers will be sitting for extended periods of time has the same risk of musculoskeletal injuries as those in a normal office job. Attention needs to be paid to the ergonomic posture of the worker. These include correct chair set-up, keyboard location, position of the visual display unit (VDU or screen) and ensuring that there is sufficient breaks.
The chair set up in control rooms should be that you sit right into the bucket of the seat. The height of the seat should be so that your feet are flat on the control room floor and the seat should be at an angle of 100 to 11o degrees in a slightly reclined position. Arm rests generally are not a good idea in a workplace control room as it may place stress on the shoulders and upper limbs. The height of the desk should also be adjusted so that your arms are approximately 100 degrees that is slightly lower than horizontal.
The above is just a few suggestions for ergonomics postures in a control room environment that can help to assist in reducing musculoskeletal injuries. A good rule of thumb to assist with ergonomic assessments is to ensure that workers use the 20/20/20 rule. This where is recommended that every 20 minutes, workers get up, pause, and look 20 meters away for at least 20 seconds.
At this Melbourne control room, the employees were concerned about the vibration that was occurring as a result of machines within the manufacturing plant. Safe Environments attended the Melbourne site to inspect the operations and the control room. A number of operational modes from the manufacturing plant was induced and then measured.
Whole Body Vibration Testing
The Whole Body Vibration testing was undertaken in line with Australian Standard AS 2670 .1 Evaluation of human exposure to whole-body vibration. The vibration measurements were taken using a seat pad with an accelerometer and a Type 4447 analyser. A number of sequences were set in which the control room operated to measure the overall Whole Body Vibration.
In this instance for a control room, there was no significant jerking, therefore the VDV vibration dose measurements tend not to be significant. The average Root Mean Square (RMS) vibration values are the most significant factor.
Control Room Vibration Results
In this case study, the RMS vibration within the Melbourne manufacturing control room was found to be 10 % of the action level for whole body vibration exposure. The health risk was therefore found to be negligible and the results communicated to all staff. What was perceived to be a significant health risk was confirmed that this was not actually the case and was more perceived risk.
All in all this instance, the Whole Body Vibration was not significant, however workers are still at risk of musculoskeletal injury due to ergonomic postures at the control room workstation. Continual training and vigilance is required to ensure that workplace injury is reduced to as low as practical.
If you are concerned with the potential risk resulting from Whole Body Vibration, please contact Safe Environments, based in Melbourne and Sydney.