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RR618 - Noise emissions and exposure from mobile woodchippers

Mobile wood chipping equipment used in forestry and arboriculture generates high levels of noise. Sustained excessive noise exposure leads to gradual hearing damage. This damage results in deafness and tinnitus. Under the Control of Noise at Work Regulations 2005 there is a requirement to control noise exposure by technical and managerial means with hearing protection only used as a last resort.

An important noise control measure is the selection of quieter machines. Noise emission data provided by the machine manufacturers and suppliers should enable this selection. Manufacturers are obliged to ensure low noise designs and to provide values for the noise emission under stated operating conditions. It is also recognised that the real world operating conditions will also influence the noise emission and the noise exposure of the operator.

The Health and Safety Laboratory performed measurements of the noise emission and operator noise exposure of a range of mobile, hand fed, wood chippers under simulated standard and real world operating conditions. These measurements were made on behalf of the Forestry Commission and Jason Liggins of the Health and Safety Executive’s Policy Group - Agriculture and Food Section.

The main aims of the work were:

  1. To provide information on the noise emission from a range of wood chipping equipment under a range of set, typical use conditions.
  2. To provide information on noise exposures from use of this equipment, and the operational factors which influence this including, but not limited to, materials being processed, methods of infeed and position of operator.
  3. To ascertain whether there are significant variations between manufacturer’s declared noise emissions and emissions under typical use.

This report describes the noise measurement procedure and details the results. Technical terms used in this report are explained in a glossary at the end of this report.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

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