Proceedings of the XVIII IAHS World Congress April 16‐19, 2012, Istanbul, Turkey Flexibility in typology, technology, construction and performances: an innovative approach for an open construction kit Angelo Lucchini, Gabriele Masera, Enrico Sergio Mazzucchelli, Tiziana Poli BEST (Building Environment Science and Technology) Department, Politecnico di Milano, Milan, Italy angelo.lucchini@polimi.it Keywords: flexibility in construction, flexibility of performances, low environmental impact building. Abstract In recent years, the topic of flexibility has been widely investigated, but the prediction of performances for flexible construction systems was hardly addressed. Research works mainly focused on the issues related to typology, technology and construction, with the aims of rational use of resources and cost optimisation. The concept of flexible performances was limited to the possible variations of the energy transmission and reflection characteristics of the building envelope. In particular, the possibility of controlling and predicting the environmental and energy performances of a modular construction system has not yet been considered. The aim of this paper is to show how, using simplified assessment tools, it is possible to estimate the energy performance of a modular construction system in the preliminary design phase. First, the paper shortly describes the proposed construction system, which is modular, but with a large degree of adaptability as concerns: structural grid, envelope, internal partitions and building services. Then the paper presents the methodology for the estimation of the energy and environmental performances according to the basic design parameters (orientation, floor plan, window to wall ratio, U‐values and shading system) and to the boundary conditions around the building (obstructions). Finally, the simplified tools developed at Politecnico di Milano – BEST Department for the preliminary design, the integration and the optimisation of the performances of both building fabric and services are presented. These tools have been developed in a research programme with TIS Innovation Park – Cluster Edilizia, Bolzano, Italy. 1 Introduction Industrialisation of the building process has long been considered a way to increase productivity and cut production costs while guaranteeing high performance standards [1]. Although post‐war prefabrication techniques, mainly based on concrete, led to architectural uniformity and monotony and poor performances [2], the strategy of pre‐assembly is still identified as one of the tenets of improving construction in the 21st century [3] through the transfer of activities from the construction site to the