Green bim – a lean methodology to support sustainability assessment protocols

Abstract

This research aims at exploiting COBie to develop a lean methodology to rate existing assets using sustainability assessment protocols like LEED, BREEAM, DGNB and CESBA. The methodology includes an efficient information management process in a BIM-oriented framework. BIM processes are frequently considered too much expensive and effort consuming for being applied in the retrofit or in the management of existing buildings because they demand a lot of data. The proposed methodology is founded on the idea that a COBie collection of spreadsheets is a BIM model even if it does not have any 3D geometrical information, which are often very expensive to collect for existing buildings. The COBie model may be populated of data coming from different sources, like the analysis of existing documents, inexpensive visual survey, interviews with peoples living the asset, etc.. The COBie model is used to store both information to be used in sustainability rating and the (partial) results coming from calculations. The methodology is presented here with the help of a case study: the rating of an existing building in the north of Italy, currently used as a private gym, using the CESBA protocol. The existing documents, managed in a Document Management System, have been analyzed and then all the information needed for the CESBA protocol have been transferred to the COBie spreadsheet, being able to satisfy (in terms of data requirements) the 85% of the CESBA criteria. The innovation in this research does not lie in the computation of the sustainability score itself, but in the way in which data both used for and obtained from calculation are organized, stored and shared among the stakeholders. The COBie spreadsheets, as well as the mapping of the sustainability data contained in them, allows for the creation of an Asset Information Model (AIM), even if not geometrical, well integrated in a BIM process. This methodology for sustainability assessment is well fitted in the BIM Bronze approach by UK Ministry of Justice (MoJ) to create and manage existing assets data in a BIM environment. Moreover, thanks to its simple but robust data structure, COBie data can be easily imported in current Computer-Aided Facility Management software.