# Space Efficiency of Tall Buildings in Singapore
## 4 Results
### Relation of Space Efficiency and Key Design Considerations
Residential buildings exhibit a slightly lower space efficiency than their central counterparts, which could be due to less compact core designs or larger communal areas that reduce the percentage of usable space. Office buildings have a wider range of space efficiencies, from about 65% to 85%, reflecting a more varied approach to core design, possibly influenced by less stringent spatial constraints and varying tenant requirements. Hotel and mixed-use buildings in both core types demonstrate significant variability in space efficiency. This could be attributed to the diverse functional requirements of these buildings, which may necessitate larger or more complex service cores to support a variety of uses, such as guest rooms, conference facilities, dining areas, and retail spaces. Hotels, in particular, require a balance between private and public spaces, influencing core design and, subsequently, space efficiency. Overall, the data indicate that service core type and design are key factors in determining space efficiency in tall buildings, varying based on building function and location. Central-cored buildings typically achieve higher space efficiency due to optimized core designs that maximize usable space in dense urban areas. In contrast, peripheral-cored buildings show more variation, as their designs may cater to different functional needs or face less pressure to optimize space. This underscores the need to consider both function and location when designing service cores to maximize space efficiency in tall buildings. Figure 10 examines the relationship between form and space efficiency. Buildings with a prismatic form, which are characterized by regular, straightforward geometries like rectangles or squares, make up the majority of the dataset with 46 buildings. The figure  
Figure 9: Cases by core type. shows that residential buildings (22 in total) exhibit high space efficiency, primarily ranging between 75% and 90%. This high efficiency suggests that the regular geometric shapes of prismatic forms are conducive to maximizing usable space, making them suitable for residential purposes where the maximization of livable area is crucial. Office buildings (16 cases) also show relatively high space efficiencies, clustering between 70% and 85%, indicating that prismatic forms support efficient layouts for office spaces that require open-plan arrangements and flexible partitions. Hotel and mixed-use buildings with a prismatic form show more variability in space efficiency. Hotels (four cases) have a broader range of space efficiencies from about 60% to 90%, reflecting different design priorities such as larger lobbies, amenities, and common areas that may reduce the overall efficiency. Mixed-use buildings (four cases) also demonstrate variability, which is expected given the complexity of accommodating diverse functions within a single structure, often requiring more intricate core designs that can impact usable space. In contrast, cases with a free form consist of 17 buildings and display a wider range of space efficiencies across all building functions. Residential towers (nine in total) have space efficiencies ranging from 70% to 90%, indicating that, while some free-form designs can optimize space effectively, others may be less efficient due to their irregular shapes or more complex layouts that reduce usable area. Office buildings (six in total) also show a significant range in space efficiencies, highlighting that these forms might be tailored to specific architectural or aesthetic requirements that do not always prioritize maximizing space efficiency. Overall, the data show that prismatic forms typically offer higher space efficiency, especially for residential and office buildings, due to their simple, regular shapes that optimize space use. Free forms, while providing more design flexibility and aesthetic variety, tend to be less efficient, reflecting the trade-offs between visual appeal and space optimization.