In Scandinavia draught, cold and temperature changes are very general problems. About 50-70 % of responders in the questionnaires have reported about these adverse effects and this trend has increased during last decades. These problems are related to discomfort, accident risks and also indoor air quality. Reason behind problems in industrial buildings is mostly related to climate, draught at outer door openings and problems with ventilation.

The present state of ventilation design for industrial premises follows rules of thumb or other rules based on sometimes questionable experience. During the last years increasing effort has been successfully invested into research work to enlarge the theoretical and practical knowledge of industrial ventilation. One of the practical results of that research work has been national guidelines (in Germany e.g. VDI 3802) which give more or less detailed recommendations for the design process.

Large premises, such as airport tenninals or international conference centers, have high ceilings and large floor area. Most of passengers who use these facilities do not stay for a long time as they do in office blocks or residential housings, but occupy the buildings en masse for short periods of times.

The penetration of cold outdoor air into industrial buildings is a severe problem in countries having a cold, arctic or subarctic climate. The cold air, penetrating into the building mainly through the open doorways, causes discomfort to the workers, disturbs the functioning of the ventilation system and increases the energy and maintenance costs of the building. What even worse, the industrial process could be disturbed and even stopped, which could lead to high production and financial losses.

Ventilation filters are classified according to the results from standard laboratory tests. These tests, however, produce information which may be insufficient for estimating the true filter performance. The properties of a ventilation filter in the ambient air conditions may be quite different compared to filter behavior in the standard test. The disagreement may be especially strong in the case of electrostatically charged filters. The loss of electrostatic removal mechanism can lead to a significant decrease in the efficiency.

There has been lack of fact based knowledge for design and operation of supply air jilter for general ventilation. An Invent multi-component project was started in 1994 to tackle this problem area. The paper describes the basic performances of air filters and requirements to be included in the Design Guide Handbook, managed by Invent, Finland.