As the true environmental costs of buildings come under increasing scrutiny, designers need all the help they can get in assessing the various options. The BRE’s Envest program aims to do just that.
The effect that buildings have on the environment is shifting from the assessment of the immediate impact to life cycle costs. Designers are increasingly being asked by clients, developers and, perhaps more importantly, driven by government and EC policy, to assess the environmental implications of a project from its inception to decommissioning.

Although data on life cycle costs are gradually being collated and synthesised for use, there are very few design tools available. That is, until now.

The Building Research Establishment’s Centre for Sustainable Construction has devised Envest, a computer program that aims to enable a comparative assessment to be made of various design options, from building shape down to the selection of materials.

So how does it work? For a start the program is aimed at the non-domestic building sector – offices and other commercial buildings.

Initially the program requires basic concept design information, such as the shape and choice of construction material. This is used to identify the building parts that will cause the greatest overall environmental impact.

The process takes five steps:

  • selection of building shape from eight generic choices

  • input proposed building dimensions

  • input details of main building elements

  • input details of servicing

  • examine and compare building score

    These processes are completed on a series of simple data screens that clearly identify the data that is required, such as building shape and choice of servicing.

    The nature of the program allows the designer to change the shape and construction of the building to reduce the environmental penalties.

    For example, if the chosen roof would cause 4% of the overall impact and the floor 40%, the designers know that the biggest environmental saving can be achieved by concentrating on the type of construction and the materials used for the floor.

    The program provides a value for each set of options. The final values can then be compared with benchmark buildings whose details are contained in Envest, and shown as a pie-chart breakdown of element impacts.

    The scoring system uses ‘Ecopoints’, a single-score assessment method – devised by the BRE – which enables direct comparisons between designs and specifications.

    One hundred Ecopoints are equivalent to the environmental impact of a single UK citizen over one year. Therefore the higher the Eco-points value, the higher the environmental impact.

    The Ecopoints system relies on many environmental factors, with the weighting of each issue being generated from industry input. These include ozone depletion factors, water consumption data and the effect of consuming natural resources, such as minerals extraction. The program also includes the effects of maintenance and operational variables over a building’s lifetime.

    In addition to helping designers stay within current and future regulations, the package can be used to demonstrate to clients and developers the environmental benefits of the proposed scheme. Vice versa, it allows clients to give guidelines to designers based on an environmental brief derived from Envest calculations.

    Envest was launched on 10 May, having already been tried and tested on outline and scheme design stages of current construction projects, such as Wessex Water’s new operations centre in Bath1.

    • Source

    Building Sustainable Design

    Postscript

    1Bunn R, ‘Learning to skip’, BSJ, May 2000.