Author(s): Campmans Theo
In Noordwijk, a Dutch village near the coast, former industrial terrains are transformed into residential areas. Houses will be built as close as 14 m to an existing 50 kV electric transformer station. Since this area has to become a quiet residential area, Dutch regulations prescribe a maximum noise level of 30 dB(A) during nighttime. This limit contains a 5 dB(A) penalty for tonal noise. \n\nTo achieve this low noise level, additional noise reduction measures are necessary, with a required reduction of 9 dB(A) for the most nearby houses. In this case, the tonal contribution at 200 Hz proved to be critical. The total package of measures to achieve this reduction will be described. \n\nSpecial attention will be given to noise reduction of the ventilation outlet. In the original situation this outlet has noise reducing grids. The transformer owner’s consultant proposed to replace these grids by relatively long silencers. We alternatively proposed to apply an absorbing baffle at the inside of the outlet stack, which gives a unusual configuration. The noise reduction effect of this special measure was calculated with a Finite Element Method (Comsol). This alternative measure reduces costs enormously. The calculated noise reduction was verified by laboratory measurements. The calculated and measured results will be presented.
Name: Mr Theo Campmans