Optimal floor height to estimate building height from the number of storeys considering building use in the Tokyo metropolitan region

Abstract

Precise building height is indispensable for evaluating variability in building heights. Conventionally, building height is approximated as the product of the number of storeys and the floor height and is called the approximated building height. However, there is no consensus on how the floor height, a key determinant of the approximated building height, should be set. In Japan, increasingly precise building height data are becoming available as an open 3D urban model. This provides the motivation for answering the following research question in the context of the Tokyo metropolitan region: How should we set the floor height to minimise the difference between the approximated and the precise building height considering the building use? The results show that: (1) the optimal floor height ranges from 3.28 (condominium complexes) to 3.59 (detached housing), 4.14 (office buildings), 4.39 (commercial buildings) and 5.37 metres (supply and disposal service facilities); and (2) the optimal floor height of living space ranges from 1.92 (detached housing) to 3.03 (condominium complexes), 3.96 (commercial buildings) and 4.10 metres (office buildings). The findings of this paper can help urban planners to find the optimal floor height for each building use and understand spatial variations in building and floor heights.