The main objective of the PRESCO-network is to define a European Code of Practice for Sustainable Building. The Code contains widely accepted and scientifically supported guidance for the construction of sustainable buildings. It enables all construction industry’s stakeholders to incorporate their sustainability ideas in their projects. The LCA Unit of the EMPA’s Technology and Society Laboratory contributed with its expertise in co-development, testing and using of the Swiss assessment tool OGIP and the assessment of sustainability in construction in general.

The project covers all phases of the life cycle of a building, going from inception and feasibility study through design and construction to use and refurbishment and finally to decommissioning, dismantling and disposal. Within the task of PRESCO two work-packages (WP) were defined:

WP 1: Definition of a European guideline on sustainable construction
WP 2: Characterization and comparison of computer-based LCA software for integrated building planning

Following building assessment tools were analysed in WP2 :

• ECO-QUANTUM (W/E Sustainable Building, The Netherlands)
• LEGEP (ASCONA, Germany)
• OGIP (EMPA, Switzerland)
• EQUER (ARMINES, France)
• ENVEST (BRE, United Kingdom)
• Eco-Soft (IBO, Austria)
• BeCost (VTT, Finland)
• SIMA-PRO (BDA Milieu, The Netherlands)
• ESCALE (CSTB, France)

The comparison of the tools was structured in three case studies:
The first case study consisted in an analysis of a simple geometrical volume (Cube), with two main materials concrete and steel (reinforced concrete). The aim of this was to see on the level of some limited number of parameters how different the results from each are.
The second was the assessment of a complete building (FUTURA house) in three different construction types (wooden, concrete or brick walls).
The third consisted in applying some general recommendations for sustainable constructions from WP1 on the concrete type of the FUTURA house. The impact of each of these recommendations subsequently was investigated. The aim was a comparison of the sensitivity of the tools to some recommendations.

All tools show in good accordance that the application of a single recommendation has but a limited influence on the greenhouse gas emissions. The impact of each recommendation on the total impact of the building is marginal, except those which affect the heating demand. To improve the ecological quality of a project in a significant way, eco-design should include several aspects simultaneously. The analysis of the results of all three case studies has resulted in a list of recommendations to be used for improving existing assess-ment tools or for designing new tools. Some of the considered most important ones:

• Try to have consistent LCI data with high transparency: same system boundary, clear allocation methods, no mixing of data from differ-ent sources, etc. If possible use up-to-date specific product LCI data with a clear user area.
• Include all transports (also from upstream processes). If no exact data are available, country specific default values should be proposed.
• Proposed cut of rules: All In- and Output materials which have more than 2%mass of the end product must be included regardless of the environmental relevance. If relevant also materials with less than 2%mass must be taken into account.
• Account for both the use of recycled material in construction and the recycling at the end of life in a consistent and transparent way.
• If possible include the land-use in the whole process from cradle to gate.
• Include water consumption in the analysis although it is no indicator for the environmental impact.
• The choice of the impact assessment indicators is arbitrary but needs explanation. Be careful using cumulated indicators as different environmental impacts are calculated into one value.
• Substitutions of certain materials/constructions must be taken into account after their service life. Be aware that a certain time before demolition no substitution will be made.
• In an outlook this study recommends, that further work is needed in harmonisation and facilitation of the building assessment tools. For the interpretation of the results the practitioner (architects, civil engineers, etc.) must be trained. Many of the tools must be much more transparent and easier to use.

The study was presented at the 12th case study symposium of SETAC Europe in Bologna, 11. - 12. Jan 2005. (>Slideshow, >Summary)

Project term: 2000 - 2004

   
Contact: Daniel Kellenberger

    
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