Air conditioning systems and heat pumps are often associated with noise pollution. In the Netherlands, legislation has been drawn up to regulate the noise of airco systems and heat pumps. A lot depends on various conditions and parameters. Conditions often cannot be influenced but measurement parameters can.
The 2012 Building Decree, Article 3.8(2) for adjacent properties and Article 3.9(3) for on properties on the same property, sets out values that must be met. These values taking into account the ‘Manual for Measuring and Calculating Industrial Noise’ provide a clear guideline that must be complied with and how to measure. Yet there is always a grey area as to whether the measured value of e.g. <40dB(A) covers everything making good measurements and correct assessment of the noise spectrum very important. An air conditioner and a heat pump have rotating parts, namely the pump itself and the fan. Both these parts produces noise and have a tonal character. A fan can run relatively low in rpm but a blade passing frequency can throw quite a spanner in the works on the tonal character of a source. Brüel & Kjær’s sound level meter type 2245 and 2255, in combination with the Enviro Noise Partner app, can assess tonality in accordance with the latest ISO 1996 and PAS 20065 standards. This can be done according to 2 methods, Annex J Engineering method and Annex K Survey method. Annex K Survey method is based on 1/3 octave and Annex J Enginering method is based on FFT. The FFT method requires a long measurement time to have enough temporal information to do a proper assessment on tonalities in the FFT spectrum. In the Enviro Noise Partner app, both can be analysed. With one click, it is possible to assess whether the measured data has a tonal character or not.
Before a final assessment can be made, other conditions must of course be met. As this assessment differs from country to country, it is up to the final manager to assess this correctly.