A requisite decision model for the selection of mechanical and electrical services in buildings

The role of mechanical and electrical services engineers in building design is increasingly one of 'decision maker' rather than conventional 'designer’. Much of the design effort occurs at the manufacturing stage, as witnessed by the proliferation of package units and modular fittings. The engineer is therefore engaged in major investment decisions. These concern innumerable technologies available from competing manufacturers and suppliers. An attempt is made in this thesis to define a formal decision model which will help decision makers make more judicious choices from these technologies. Any such decision model must consider three complicating features which enter into the equation; 1) the intangible outcomes, which cannot be expressed in monetary terms, that occur as a result of design decisions; 2) the strategic and uncertain implications of many design decisions, committing the user organisation to technologies which may or may not impair the long-term performance of that organisation; 3) the numerous user and operating groups affected by the decision. The methods used in the model try to reflect these issues. The model interrelates life cycle costing; multi-attribute utility theory; risk analysis and technological forecasting to this end. It is hoped that such a model will provide a vehicle for discussion and justification. In this way a design is arrived at which is not only compatible with the client's short-term needs, but also his/her long-term requirements.