Bjarne W. Olesen
Bibliographic info:
32nd AIVC Conference " Towards Optimal Airtightness Performance", Brussels, Belgium, 12-13 October 2011

Today an acceptable indoor air quality is mainly defined by specifying the required level of ventilation in air changes per hour or the outside air supply rate. This would be equivalent to defining the requirements for thermal comfort by specifying the level of heating or cooling in Watts. The increasing societal need for energy efficiency will often result in very tight buildings. This means that the amount of outside air supplied by infiltration is not enough to provide the required ventilation. In some standards the required ventilation is based on adapted people (occupants) while other standards refer to un-adapted persons, who have just entered a room. Which approach is correct? Or should it depend on the type of space or occupancy? Furthermore, the level of ventilation will depend on the criteria for acceptability, like health, comfort (perceived air quality) or occupant performance. The required outside air supply rate will be the same or higher than the required ventilation rate depending on the ventilation effectiveness. Existing standards do not or only in a limited way acknowledge the use of air cleaning as substitute for outside air. Furthermore the concept of demand controlled ventilation is in many cases not taken into account.
The present paper provides an overview and discusses the criteria used for specifying required ventilation rates, and suggest ways of meeting the criteria in a more energy efficient way by means of improved ventilation effectiveness, use of air cleaning and by means of demand controlled ventilation