Traffic Noise

The following Swedish quality goals and deviation cases have been produced by the Stockholm County Council together with the Stockholm City Planning Committee and the Stockholm Environment and Health Administration.

Quality Goals

• 30 dB(A) equivalent sound level indoors and 45 dB(A) maximum sound level indoors
• 55 dB(A) equivalent sound level outdoors at façades, balconies, patios and recreational areas in densely populated areas (free-field value)
• 40 dB(A) equivalent sound level on the residential building’s quiet side (free-field value)
• 70 dB(A) maximum sound level outdoors at façades, balconies and patios (free-field value)

The purpose of the following deviation cases is to facilitate matters in planning situations where it is difficult to meet guide values, for example for residential buildings in central locations or in other locations with adequate public transport.

Deviation Case A

From the guide values according to the quality goals, deviations are made outdoors from 70 dB(A) maximum sound level and 55 dB(A) equivalent sound level. All flats shall, however, have access to a quiet side for at least half of the habitable rooms with considerably lower levels than 55 dB(A), i.e. approx. 40-45 dB(A). A quiet patio may be arranged adjacent to the residence.

Deviation Case B

From the guide values as per above, deviations are done outdoors from the guide values on the quiet side. All flats shall, however, have access to a quiet side with no more than 55 dB(A) for at least half of the habitable rooms.

Method

The identification of traffic noise problems is carried out using sound level measurements of existing traffic corrected against measured normal traffic quantities or prognoses. Another common method is to calculate traffic noise levels at façades and over an area using the Cadna/A calculation program. In order to perform a noise calculation, a situation plan is normally needed, including height curves, information on traffic quantities and information on the location and floor plan of the building.

Early in the project, we conduct a dialogue and update our calculations as the pre-conditions for the building change. We calculate sound propagation and sound pressure at façades in complex environments with many sources of disturbance. Based on our results and your needs, we help you, among other things, to calculate composite sound reduction, dimension windows, design screens and create well-functioning patios.

We deliver easy-to-understand reports with educational illustrations and discuss any problems that might arise and require action with you.