As noise disturbance is getting more attention because of changing regulations and increasing public concern, Dieseko Group invests in solutions that minimize noise pollution. Recently an external expert carried out an independent test to measure underwater sound levels during the dismantling of offshore wind farm Lely.
Four piles having a diameter between 3200 mm and 3700 mm and a length of 26 m long were removed from the seabed by our largest vibratory hammer, the PVE 500M. The hammer creates a centrifugal force of almost 1100 mt at 500 kgm eccentric moment and 1400 rpm. The PVE 500M was not equipped with soundproofing measures, in order to understand the effect of our basic design.
The results of the measurements are very promising. The German authorities, by means of the BMU 2013 “Konzept für den Schutz der Schweinswale vor Schallbelastungen bei der Errichtung von Offshore-Windparks in der deutschen Nordsee (Schallschutzkonzept)”, prescribes threshold values of 160 dB re 1μPa²s as a maximum Sound Exposure Level (SEL) and 190 dB re 1μPa as a maximum peak Sound Pressure Level (SPLpeak-peak) both at 750m from the source.
The equivalent values obtained during several tests with Dieseko Group vibrators are 112 – 135 dB re 1μPa²s and 132 – 161 dB re 1μPa, which are substantially lower than the maximum allowed levels at 750m from the source.
Therefore, it can be concluded that the application of Dieseko Group’s vibratory hammering techniques do significantly contribute to underwater noise reductions at offshore piling projects.