Analysis of pile driver exhaust and impact noise.

Abstract

In July 2008, NIOSH accomplished a preliminary noise survey focused on gathering impulsive noise data from pile drivers. The purpose of the noise survey was to better understand the noise characteristics of pile drivers. NIOSH gathered time record data of H‐beam piles being driven into hard rock. This data was used to characterize the frequency content of the major impulsive events (impact and exhaust cycles). Knowing the frequency content is necessary to apply existing or develop new noise controls, since many noise controls are frequency dependent. Gathering the frequency content of a pile driver’s impulsive noise signal is typically difficult using off‐the‐shelf measurement and analysis equipment and software. Reliable time record data is necessary to confidently extract the frequency content from the signal. NIOSH has developed an Impulsive Noise Meter laptop program to properly gather and analyze these impulsive signals. By analyzing the third octave band peak levels of each impact and exhaust cycle of the pile driver operation, the frequency dependence was determined. Results of this analysis showed the frequency content varied as the pile was driven further into the ground. This implies that broad spectrum noise controls are necessary to control those noise emissions.