ABSTRACT
The construction of buildings and the installation of ventilation systems are economic activities that often involve large budgets and major responsibilities. It is important that the client and the supplier (building contractor, ventilation firms, etc.) clearly agree on the expected performances of the building or system. In order to create a building environment that aims to meet the requirements of the client as well as of the society, it is preferable that for each project the needs are explicitly stated and that one counts not too much on so-called implied needs.
