Safe Environments were engaged to undertake Whole Body Vibration assessments of bulldozer due to concerns of the potential health risk of workers. The bulldozer being inspected was considered to be relatively old and part of the Whole Body Vibration assessment was to assess whether a new bulldozer may assist in reducing the vibration levels.

Safe Environments Pty Ltd was commissioned to provide a preliminary report for occupational noise assessments and whole body vibration exposure to workers who are responsible for road upkeep and maintenance. The Whole Body Vibration assessment was undertaken to determine compliance with the NSW Work Health and Safety Regulation 2011.

The NSW Work Health and Safety Regulation 2011 at Clause 60 requires that a person conducting a business or undertaking (PCBU) must manage risks to health and safety relating to a musculoskeletal disorder associated with a hazardous manual task. As part of all relevant matters must be assessed including postures, movements, forces and vibration relating to the hazardous manual task, and the duration and frequency of the hazardous manual task.

The WHS Regulation does not provide exposure limits similar to noise or chemicals; however the two most commonly referred standards in regards to vibration are:

• ISO 2631-1:1997, Mechanical vibration and shock- Evaluation of human exposure to whole-body vibration and AS 2670 .1 Evaluation of human exposure to whole-body vibration. AS 2670.1 is essentially adopted from ISO 2631-1.
• The European Union Vibration Directive 2002/44/EC.

Both guidance documents quantify the vibrations measurements through the average root mean square acceleration values and the Vibration Dose Value (VDV) however there are slight differences in the recommended Caution Zone or Action Values and the Likely Health Exposure Zone or Limit Values.

The basis of the assessment was to also assess the particular tasks that may exacerbate the Whole Body Vibrations to the workers. This was assess by measure the Whole Body Vibration of Ripping and Pushing tasks that the bulldozer were replicating.

The vibration measurements were undertaken using a Brüel & Kjær Human Vibration Analyser Type 4447 according to ISO 2631-1 Mechanical vibration and shock, Evaluation of human exposure to whole body vibration Part 1: General requirements. Representative measurements were taken for between 10 – 40 minutes using a Type 4515-B-002 Seat Pad including Type 4524-B Accelerometer.

The Whole Body Vibrations were measured to exceed the exposure limits and control measures were recommended. Some of the resulting recommendations include:

• Increased road maintenance with a preference to develop sealed roads;
• Operator driving speed and awareness;
• Isolation of cabin and chassis;
• Seat performance in dampening vibration been cab and operator use including posture;
• Increased mobile plant maintenance to reduce engine vibration; and
• Job rotation to limit total daily exposure

Please contact Safe Environments if you would like further information on Whole Body Vibration testing and assessments