bre has completed the first phase of a system of environmental profiles for building materials and components that will help specifiers make green choices. While the report* on the profiling methodology will be of most interest to the specialist, its general significance is the consensus it represents. Having established the methodology, bre is working with 24 trade associations to arrive at sectoral views (profiles) of life-cycle energy and environmental impacts for 33 common materials and components.
Profiles are environmental data sets for each material in standardised categories. At the launch of the report, Digby Harper of bmp (the association of Building Materials Producers) praised the availability of such base data from which designers are free to make their own choices, in contrast to ecolabels, which he saw as a 'nanny state pass/fail system'.
Despite the commercial sensitivity of setting out environmental impacts - there will be losers as well as winners among suppliers - the database is growing. Software (Envest) due for release in the autumn will provide designers with tools for using the profiles data to compare construction alternatives.
These profiles cover energy inputs, constituent materials and process water use, solid wastes and emissions to air and water. Database profiles are held for three periods:
per tonne, ie cradle to factory gate, such as manufacture of one tonne of Portland cement
element installed, ie cradle to installation
element 60 year life, ie cradle to grave, spanning a 60 year life, including any cycles of maintenance (except cleaning) and replacement. In the latter two cases the measure is the 'functional unit' rather than the tonne. Thus the quantity of steel in a frame could be compared with the amount of concrete for a frame of the same functionality.
This first edition of the methodology does not include the impacts of construction and dismantling, which are poorly understood, though it does include ultimate disposal or recycling. While the database presents data for comparison purposes over a 60 year life, the Envest software will allow specifiers to pick their own, project-specific life cycles.
The data covers traditional construction. This is not surprising, given that aggregates, cement, masonry walling and roofing, and timber account for more than 99 per cent of the mass of UK construction, adding up to 6 tonnes per person per year. Other materials and components in the database are forms of aluminium, copper, fibre insulation, lime, some boards, pvc and steel.
The report itself details the method of data collection and its processing into standard forms. Appendices give examples of the data. Though not particularly meaningful to the average designer, they are indicative of the thoroughness of the scientific work. Having sound data does not remove subjective judgement about the relative importance of different factors, both between impacts and with other performance criteria such as strength, fire resistance or buildability.
The potential this profiling system provides to make environmental impact assessments of individual buildings is not the limit. It is seen as a basic building block in the longer term development of a system to assess groups of buildings and ultimately areas of development.
* bre Methodology for Environmental Profiles of Construction Materials, Components and Buildings. By Nigel Howard, Suzy Edwards and Jane Anderson. bre. From crc, tel 0171 505 6622. £75 plus £5 p&p.
Database membership costs £200/year for academe and organisations with a turnover below £2M. Above that, the cost is £500/year.