ISO 22868:2005 specifies a noise test code for determining, efficiently and under standardized conditions, the noise emission characteristics of portable, hand-held, combustion-engine-powered forest machines such as chain-saws, brush cutters and grass trimmers. Noise emission characteristics include the A-weighted emission sound pressure level at the operator position and the A-weighted sound power level. The code is applicable for manufacturers' product controls as well as type tests. It is intended that the results obtained will be able to be used to compare different machines or different models of the same type of machine. Although the noise emission values determined are obtained in an artificial operation, they are representative of noise emission in a real work situation.