Design for excellence (DfX) for high-rise modular buildings: from DfX considerations to module design guidelines using the case of Hong Kong

Design for excellence (DfX) presents a significant opportunity for early design to ensure the efficiency and buildability of high-rise modular buildings and realize their multidimensional benefits. Previous DfX contributions have primarily concentrated on its conception, offering various considerations from downstream construction stakeholders. Little research has integrated and transformed them into more practical, ready-to-use guidelines for upstream design professionals. This research, therefore, aims to incorporate prevailing piecemeal DfX considerations and establish module design guidelines. The guidelines were initially developed based on prior literature and case study, and their alignment with existing practices was subsequently tested. They recommend 1) a simplified rectangular module shape, 2) suggested module size, 3) standardized space across projects, and 4) dimensional coordination among modules and spaces. By utilizing them to analyze 39 high-rise module designs in Hong Kong, the results reveal some similarities between the proposed guidelines and real-world practices, affirming their concurrent validity and creating warrant assertions. This research bridges the knowledge gap between upstream and downstream practitioners, offers transformed DfX knowledge to systematically guide future implementations, and finally explains changes in architectural design. Future studies are advised to fine-tune the guidelines and incorporate findings with computational technologies to enhance generative DfX.