Environmental Assessment of Building Products and Components in a Service Life Perspective

Abstract: This thesis presents a survey of different tools, used byenvironmental consultants in Sweden, for their recommendationsof building products and components in different constructionprojects. The goal was to identify possible improvements of thetools so that life cycle methodology could be used to a largerextent than today. This thesis also presents a general methodfor multi-criteria assessment. The purpose of this generalmethod was to show how assessment of environmental impacts,cost and prediction of service life have to be combined for acomprehensive view over all the criteria that influencedecision-making in different construction projects.The evaluation of the present role of environmentalconsultants in the building process in Sweden and their toolsis based on a literature study together with interviews.Advantages and disadvantages of the different tools fordecision-making have been identified. It was found that thereare many improvements to be made, for example, concerningbuilding product declarations. The declarations have to containmore quantitative data and the guidelines have to be furtherdeveloped to secure equivalence in product comparisons. Thestudy showed that an environmental consultant seldom makes anelaborate assessment of aspects other than environmentalimpacts. Others, for example, the client or contractor,consider aspects of economy and technical functionality.However, there is a need of a more comprehensive view wherecosts and technical functionality are included in theassessment together with environmental concerns. If differentaspects are treated separately there is a risk ofsuboptimisations. This need has been identified by for exampleconsultants and the commission of the Swedish government and isoften emphasised by the building material industry.In Life Cycle Assessment (LCA) the functionality, as well asthe time of use should be reflected in the definition thefunctional unit of the study. Calculations of Life Cycle Cost(LCC) also include the time aspect and compared systems shouldfulfil the same requirements of functionality. Therefore, it isof obvious interest to find a method that brings together LCA,LCC and service life planning (with estimations of servicelives). The presented method of multi-criteria assessment is toa large extent considered to be of practical use for practisingconsultants in their recommendations of the preferable choice,as soon as a pedagogical interface has been developed. Inaddition, a simplified LCA technique has to be used, where somesystemlimits and assumptions are pre-defined. A multi-criteriaassessment approach is one step ahead to fulfil therequirements of the authorities and the society. Themulti-criteria approach also helps the building sector to worktowards the goal of increased environmental concern in thesector and the overarching goal of an environmental sustainablesociety.Key words:life cycle assessment, LCA, environmentaldeclarations, building product declarations, environmentalconsultants, tool for decision-making, service life planning,estimation of service life, the factor method, multi-criteriaassessment