1979 a project was launched at Technological Institute, Copenhagen with the purpose of developing a method for continuous measurement of air change rates in occupied dwellings. Today - 10 years later - we can introduce the first generation of mass-produced measuring equipment performing measurements of air change rates employing the method of constant concentration of tracer gas. The principles used in the first model, which was introduced 1981, are largely identical to those used in the latest model.

The AIVC nowadays is an established Centre on infiltration and ventilation research. It is well known throughout the world. This position has not been reached easily. But years of hard working and critical managing of the Centre were a necessity. Goes on to discuss the future development of the Centre.

This paper examines some designs which lead to indoor air pollution and exhorts mandatory maintenance of all building services which determine the health and safety of the building occupants as anintegral part of our city bylaws. Effect of poor maintenance of some of these systems on the indoor air quality is examined together with the effect of the interruption of the ventilation fans for energy conservation pwrposes, not always done legally.

Whole-building pressurisation tests can quantify the air-leakiness of a building's external envelope. The resulting information can be used in assessing the quality of the building fabric. At present there is little information regarding the leakage characteristics of large, non-domestic UK buldings. As a step towards providing more information, the Building Research Establishment (BRE) has developed and constructed a multifan pressurisation system known as BREFAN to pressurise large buildings like offices and hangars.

A test room with a Displacement Ventilation System has been built. Air velocity and temperature profiles were measured at different places in the room under summer and winter conditions. Additional numerical simulations for the same conditions as in the experiment were performed. The measured and calculated values showed good correspondence. An office room is normally not occupied permanently therefore its transient ---behaviour was also investigated.

Displacement flow systems are becoming popular, especially in Scandinavia, for comfort ventilation. In these systems air is supplied near the floor at low velocity; the temperature of the supply air is a few degrees below that of the air in the room. The supply air is heated by persons and/or machinery in the room. Turbulent plumes are formed above these heat sources.

A new visual method is yielded by a particular application of Mollier's h,x-diagram. Point fields (temperature and humidity) lead to a significant improvement upon previous graphic methods. Flats with mechanical balanced ventilation are drier and more influenced by the exterior climate than are with shaft ventilation system ventilated flats ("Berlin ventilation"). The evaluation of the graphic representation of the experimental results in the form of curves permits rapid assessment of the experimental results.

Canadian research into residential ventilation and combustion venting revealed that the installed performance of exhaust equipment, ducting passages, and site-built chimneys was largely unknown. It became necessary to establish actual characteristics in order to be better able to predict the safety and effectiveness of various ventilation measures. For this reason, Canada Mortgage and Housing Corporation (CMHC), the federal agency responsible for housing policy, had a research device designed and fabricated.

The indoor climate and ventilation were measured in 50 dwellings with various ventilation systems. The health and comfort of people living in the dwellings were studied with a simultaneous questionnaire. The ventilation rates measured with a tracer gas using the decay method varied from 0.1 to 1.2 m³/hm³, with an average of 0.5 m³/hm³. The ventilation rate in the bedroom was usually lower than the mean ventilation rate of the dwelling. The ventilation rates measured in a two-week period with the passive perfluorocarbon method varied from 0.2 to 1.9 m³/hm³, with an average of 0.8 m³/hm³.

The air exfiltration part of ventilation is often difficult to determine and its part of the energy balance is therefore usually determined as a remainder or given a constant value. This paper examines ventilation systems in six different modern houses. The constant concentration tracer gas technique tended to underestimate the total ventilation. A simplified theoretical one-zone model made accurate estimations of the air exfiltration. For detailed information on air flows a multi-zone network model was useful.