This SAE Standard specifies procedures for measuring operator and exterior sound levels emitted by self-powered trenching machines regardless of engine size. This procedure does not cover operation of devices such as backup alarms, horns, or accessories such as paving breakers. The sound levels obtained using this procedure are repeatable and representative of the higher range of sound levels generated by machines under actual field operating conditions, but do not necessarily represent the average sound level over a field use cycle. measurement and calculation of the operator's sound exposure should follow SAE J1166.