Second Consortium of Local Authorities
Year:
1987
Bibliographic info:
Scola/DES Workshop, October 1987

 It was generally recognised that because of occupants' behaviour, natural ventilation rates were usually much lower than the accepted criteria for calculation. A great deal of anecdotal data existed which showed that frequency of opening windows bore a direct relation to external temperature and that the greater the volume the less the frequency of opening. The recent BRE survey also shows that very low ventilation rates, below 4 cubic metres/ person/hr have been found to be acceptable. Recent work by Portsmouth Polytechnic on schools in England and New Zealand also confirms this.* Appendix 2 summarises calculations and measurements in a range of new school buildings, mostly large volumes.

Both discussion groups considered that satisfactory design for natural ventilation was only achieved if the design team accepted this as a priority from the beginning. As windows are the usual vehicle for natural ventilation, daylighting also becomes a consideration balanced against heating and comfort requirements. Without doubt the BRE Design Aids would be an invaluable help at this stage. Graphical aids and computer programmes would both be useful.

Users of buildings need to be fully informed of how their building is meant to work. Many users' complaints could be reduced if they 'understood' their buildings better, but designers had to bear in mind that the occupants are in the building to do a particular job, and running the building is not necessarily their concern. Their involvement can only be for simple and common sense operations. Clear instructions are essential, even if the mechanisms are obvious, such as windows, but more so if ventilation grilles, fans or ducts are incorporated.

Feedback from building users is seen as an important part of the design process, not only to find out what can be improved, but also what is successful; this information can be applied to future designs.