Environmental Assessment of
Buildings and Building Developments
- a logical methodology for the world.
6 CASE STUDIES
This section is based loosely upon assessment work undertaken for Clients. Full details may be published later. Only a few key points of the assessments are discussed.
There may be several choices facing a commercial or industrial Client wishing to relocate. Another existing office or industrial building may be found to be suitable, or a new building can be designed and constructed. Two of the main design determinants of a new building are its location and its likely energy consumption. There are environmental implications to any choice and it is important both to keep these in perspective and not to attach importance to conclusions drawn from narrow analysis.
For the site of any new building, local environmental factors may include land use and public and wildlife amenity, and would need to focus upon starting conditions and changes imposed, rather than upon any end point. Other aspects of an assessment are logically independent of initial conditions and constraints, because there were no starting conditions.
One essential question is therefore:
would the development enhance the local environment, degrade it, or prevent a more environmentally sound project from proceeding?
This question should be considered widely, not confined to narrow perspectives. It has importance for reuse of derelict land.
Study of real problems is important. It demonstrates that BREEAM can give incorrect indications as to which of several options might be environmentally preferred. The implied criticism of BREEAM is sharpened by recognition that it is in the area of energy use where the method fails - the only area where BREEAM may be said to be well developed.
For a Company whose existing base is in an inner city it is likely that another city location would prove convenient for the majority of staff. Most will have developed travel arrangements making substantial use of public transport, and perhaps car sharing, simply because of the lack of or expense of parking near to work. A radical alternative for the Company would be relocation to an out-of-town or green field site with probably less well developed public transport and greater provision for car parking.
Thus in simplified terms, the energy implications of a move to new premises might be that either an air conditioned building in the inner city would be found to give the required standards of indoor air quality, or that a new and possibly naturally ventilated building could be found or built on a much less noisy site. Many staff would then live well away from their work-place and commuting by car would become an attractive option. It is known that most people prefer to travel door to door by car. It is primarily congestion and parking problems that deter them.
It is instructive therefore to calculate roughly the relative magnitudes of transport and office energy consumption for office workers. Industrial buildings may be analysed in a similar way.
Space heating and cooling energy for offices is usually expressed per square metre per year. A typical figure is 200 kWh/m2 of delivered energy. Each office worker may account for 8 to 15 m2 of total floor space. A figure of 10 m2 will be used. The office energy use of each worker would then be 2000 kWh per year with costs of around £40 to £140 depending upon fuel type. There are of course many variables including the ratio between primary and delivered energy. Actual energy use can easily range from half to double the illustrative figure. Exact numbers are not important here.
The energy content of petrol or diesel fuel is around 42 MJ/l (22). Thus an office worker may consume the equivalent of 38 gallons of fuel annually. If translated into transport energy, 38 gallons at 30 mpg would enable the worker to drive for 1140 miles, or about 5.4 miles per day (a journey of 2.7 miles each way) assuming 210 days at work per year.
The implications of locating low energy naturally ventilated offices in leafy green-field sites 10 miles out of town should now be obvious. It might be better in overall energy terms to construct a reasonably energy efficient air conditioned office block in the city centre and ensure that a majority of staff continue to use public transport. There would be further environmental benefits from reuse of a previously developed site, and possibly from helping to stem the exodus from city centres that has already been blamed for damaging the countryside.
Taken together with Section 4, further discussion of the inadequacy of BREEAM in helping Clients to come to an environmentally responsible decision in many real situations should be unnecessary. The overall arrogance that accompanied the development and promulgation of BREEAM merits further publication.