本标准的目的是规定一种确定土方机械在操作员位置处的排放声压级的方法，在机器静止且发动机在空载条件下以额定转速运行时，根据时间平均a加权排放声压级进行测量。

The objective of this Standard is to specify a method for determining the emission sound pressure level of earth-moving machinery at the operators position, measured in terms of the time-averaged A-weighted emission sound pressure level while the machine is stationary with the engine operating at the rated speed under no-load conditions.