Integrated Ecological Footprint Assessment: A Sustainable Comparative Study of Office Buildings

The Architecture-Engineering-Construction-Operation industry has been widely known as a major contributor to global gas emissions (GHG) and resources consumption. Buildings, and especially office buildings, consume 40% of the total materials consumed in the economy and emit 50% of the total GHG. To solve this problem the European Commission has established several legislative frameworks with the goal to build nearly zero-energy buildings and reduce the environmental pressure of the industry. These policies have principally focused on design and construction stages. However, the definition of sustainable development encompasses several areas, which include the operational stage of building life cycle. In addition, studies demonstrate that users are a key element in the maximization of buildings’ sustainable performance. To overcome the gap, this study develops a multi-method approach, based on the Ecological Footprint. This sustainable index allows to model the users’ influence in office building environmental impact. The aim of the method is to identify the environmental impact of office buildings during their in-use stage. The method is based on nine addenda (Built-up, Energy Consumption, Water Consumption, Material Consumption, Food & Drink, Mobility, Waste Generation, Recycle Potential, and Occupant) that reveal the building impact of consumptions, and waste generation. So, the Occupant addendum aims to understand the relevance of users’ behaviours in the estimation of sustainability performance. To test the model, the present research interviews four facility managers of Italian companies on data of the year 2020. The comparison demonstrates the importance of monitoring users’ behaviours to minimize office buildings footprints. Indeed, in all case studies the Food & Drink addendum represents a high percentage of the total footprint. The main limit of the research is the collection of data, which cannot be standardized among companies. Facility managers found hard the collections of data about consumptions and maintenance activities, as they had general expenditures reports. Moreover, other information, such as the amount of hour each employee spend in the building, are collected in different ways among companies. Therefore, the paper comments on the results and give back some possible overcomes of the limits.