Common practice in acoustic design does not consider air gaps. Thereare different opinions about air gaps and their affect on noise reduction.The report analyzes the credibility of the requirements used in a theoretical calculation model that addresses noise reduction in acoustic screens. Several measurement results from empirical attempts in a realistic environment for different screen models are compared.The result shows that a horizontal 50-millimeter gap has no noticeable impact on noise reduction. The result for horizontal air gaps against ground is of particular interest as it allows a simplified foundation to be used.Vertical air gaps have a greater negative influence on noise reduction but the results presented in the report can be used when lower demands are set on screens.An economic analysis shows that the result from the experiment when using a simplified foundation results in a cost reduction ofapproximately 300 SEK per meter acoustic screen.

This doctoral thesis focuses on noise generated during construction. It defines the legislative and physical aspects of this topic. It determines heavy machinery as noise source and categorizes them by their usage in construction technologies. It collects source data of the machinery noises which can be further used in prognostic models. It analyses the level of construction noise which can impact the nearby residential areas and offers methodology for modelling and designing the possible arrangements for the noise reduction. It defines partial effects of the construction site which are significant for the noise spreading. It establishes their role in the value of acoustic pressure level of the noise affecting the façade of the considered building. With the data collection and with case study verification it offers a prepared work tool which can be easily used to predict noise levels on construction sites and can be applied in the early constructions preparations. The structure of this thesis is planned for possible usage as university textbook or study support.