Prediction method of insertion loss of detached houses against road traffic noise based on a point sound source model-Prediction formula considering the heights of buildings and a prediction point

摘要

In the Environmental Quality Standards for Noise in Japan (EQS) revised in 1998, the problem of environmental noise at areas facing roads is evaluated by obtaining the numbers and the rates of buildings at which noise levels exceed the standard value. The Standards allow for the estimation of noise levels, instead of requiring actual measurements, in cases where taking the actual measurements would be difficult. In order to estimate noise levels, to grasp insertion loss of buildings in an evaluated area is needed. Based on the above background, the authors proposed F2012a which can predict insertion loss of detached houses against road traffic noise based on a point sound source model. However, F2012a confines the heights of buildings and a prediction point to 10m and 1.2m above the ground, respectively. To expand these heights, this paper proposes an extension formula of F2012 which can be applied to the condition when the height of buildings is less than 10m and a prediction point is lower than buildings. The validity of the proposed formula is verified through the experiments. This extended F2012 is adapted into ASJ RTN-Model 2013, a new version of ASJ RTN-Model, and applicable to the evaluation of EQS.