Upcycling shipping containers as building components: an environmental impact assessment

Purpose. The introduction of shipping containers in the trading system has increased world economic growth exponentially. The main drawback of this linear economy is the accumulation of empty containers in import-based countries. Designers throughout the world are working with intermodal containers for environmental purposes, often employing them as building components. This research aims to evaluate the environmental impact of a container dwelling in comparison with similar steel and X-Lam structures. Methods. In order to estimate the effective sustainability of container structures, a comparative LCA has been undertaken. A mid-point approach was adopted focusing on Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Acidification Potential (AP) and Eutrophication Potential (EP). To ensure reliable comparisons a functional unit with combined spatial and thermal requirements has been defined. The proposed unit includes a total floor surface of 206,6 m2 and transmittance requirements in accordance with IECC and ASHRAE standards. Three representative scenarios have been identified to address cold, temperate and hot climates within import-oriented places: Vancouver, Durban and Chennai. For hot climates the functional unit has been implemented with a minimum Periodic Thermal Transmittance to ensure interior thermal comfort. Results and discussion. It can be generally stated that the use of shipping containers as building components leads to overall environmental benefits compared to steel and X-Lam structures within the boundaries of this analysis. The main advantages of container structures are related to avoided extraction of structural materials, shorter construction schedules and high recycling potential at their end of life. Instead, the use of a combined functional unit leads to equal results on transport and operational stages which can be excluded from a whole life cycle comparison. The use of high thermal mass materials is particularly relevant for container homes in hot climates, and superficial mass is very incisive in whole life cycle assessment. Conclusions. Empty containers are accumulated worldwide as a result of the linear nature of the trading system. A container building presents 2,33 times the amount of structural material of a functionally comparable steel frame. With an upcycling process, the “stored” steel contained within freight containers is introduced into the circular economy of the building sector. After the End of Life stage, this leads to the “release” of 13,6 tons of structural steel for a 200 m2 house. Recommendations. Results and conclusions of this article are strictly connected to the availability of empty and used containers in the study location. Shipping containers are outputs of a linear system, the trading economy, and intended to be used as input of a different system, the building sector, which aims to be circular. Therefore, the use of newly manufactured containers has not been considered, and emissions for their production, related to the trading sector, are not allocated to the building footprint