Energy and Buildings 76 (2014) 228–237 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me pa g e: www.elsevier.com/locate/enbuild Impact of the lifespan of different external walls of buildings on greenhouse gas emissions under tropical climate conditions Eduardo Breviglieri Pereira de Castro a,∗ , Marc Mequignon b , Luc Adolphe c , Pedro Koptschitz d a Universidade Federal de Juiz de Fora, Departamento de Engenharia de Produc ¸ ão e Mecânica, Rua José Lourenc ¸ o Kelmer, s/n – Campus Universitário Bairro São Pedro, CEP 36036-900, Juiz de Fora, MG, Brazil b Université de Toulouse, UPS, LERASS-ERPURS (Laboratoire d‘Etudes ET Recherches Appliquées en Sciences Sociales), IUT A, 115B route de Narbonne, F-31 077 Toulouse, France c Université Toulouse, INSA LMDC, Laboratoire Matériaux et Durabilité des Constructions de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse Cedex 4, France d Universidade Federal de Juiz de Fora, Departamento de Construc ¸ ão Civil, Rua José Lourenc ¸ o Kelmer, s/n – Campus Universitário Bairro São Pedro, CEP 36036-900, Juiz de Fora, MG, Brazil a r t i c l e i n f o Article history: Received 21 November 2013 Received in revised form 18 February 2014 Accepted 22 February 2014 Available online 12 March 2014 Keywords: Building lifespan Materials lifespans Greenhouse gas Life cycle assessment a b s t r a c t This paper presents a comparative study of greenhouse gas emissions due to different wall compositions in accordance with their lifespans. The assessments carried out take into consideration the construction, maintenance and end of life of the walls, for a specific tropical climate site. The energy spent for heat- ing and cooling during the utilization phase of the building was made equivalent for all calculations, in order to isolate the study on the evaluation of the performance of each technical solution. Initially, the methodology is described by choosing technical solutions to the building envelope, determining the cor- responding service life for each solution and finding the corresponding GHG index from an appropriate database. Then, the evolution of this indicator is calculated within a given time for the four different tech- nical solutions: Concrete Block; Solid Clay Brick; Cellular Concrete Block; Multicell Clay Brick. Brazilian national standard materials lifespans were adopted. A building lifespan of 150 years was considered. The results of this analysis suggest and quantify the important impact of the lifespans of both the materials and the building itself on greenhouse gas emission indicators. The numerical results presented point out the need to revisit the current life cycle analysis practices. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The total greenhouse gas (GHG) emissions over the life cycle of a building is an emerging research field thanks to the ever- growing concern on sustainability in the construction sector, which accounts for more than 40% of the overall global consumption of natural resources and energy. It is also responsible for almost 33% of the total emissions of carbon dioxide (CO 2 ) [1]. One main con- clusion that can be drawn from the current studies is that the assessment of this type of emission in buildings can vary substan- tially due to a quite high variability in the materials used as well as regional characteristics related to the technical solutions proposed by the industry. ∗ Corresponding author. Tel.: +55 32 2102 3498/32 3211 2764. E-mail addresses: eduardo.castro@ufjf.edu.br, eduardo.brevi@terra.com.br (E.B.P. de Castro). Technology and material choices for building envelopes have different environmental impacts. First, there is the problem of the amount of resources which are used for building the envelope itself – materials and processes – and what the impacts due to this activ- ity are. Second, there is the issue of the resources used within the lifespan of the envelope, considering its necessary maintenance and periodical renovation. So, environmental accounting methods should be used to provide information that is important for evaluat- ing building materials and technologies under different scenarios, in order to aid decision making concerning material choices and building procedures. Generally, the determination of the “greenness” of a material is established by a comparison of different solutions in terms of one of three categories: (1) resource management; (2) toxicity; and (3) performance. If performance is to be taken for comparison between different technical practices, one must consider a specific func- tion that is to be performed by the product. Performance issues include durability, energy efficiency, amount of waste generated http://dx.doi.org/10.1016/j.enbuild.2014.02.071 0378-7788/© 2014 Elsevier B.V. All rights reserved.