The impact of unintentional air flows on the performance of ventilation units with heat recovery is discussed on the basis of single room ventilation units. Assuming an external short circuit (outdoor) and internal (inside the ventilation unit) air leakages, which lead to internal short circuits, a model is developed and characteristic numbers for ventilation efficiency, efficiency of heating load reduction and effectiveness of electrical energy use are derived.

Control of indoor pollution sources and ventilation are both means of improving indoor air quality. Three independent experiments have recently documented that removing a pollution source or increasing the ventilation rate will improve perceived air quality, reduce the intensity of several Sick Building Syndrome (SBS) symptoms and improve the productivity of office workers.

Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity were studied in a normally furnished office space (108 m3) ventilated with an outdoor airflow of 3, 10 or 30 L/s per person, corresponding to an air change rate of 0.6, 2 or 6 h-1. The temperature of 22°C, the relative humidity of 40% and all other environmental parameters remained unchanged. Five groups of six female subjects were each exposed to the three ventilation rates, one group and one ventilation rate at a time. Each exposure lasted 4.6 h and took place in the afternoon.

We analyzed 1994 sick leave for 3,720 hourly employees of a large Massachusetts manufacturer, in 40 buildings with 115 independently ventilated work areas. Corporate records identified building characteristics and IEQ complaints.

Efficient control of ventilation systems needs information on indoor air pollutant concentration. But most of the time, the pollutant concentration is not measured. However, outdoor air pollution forecast models are becoming operational and a relation between outdoor and indoor pollutant concentration may be used to predict pollutant concentration peaks and to infer recommendations to reduce its value . A prediction model of the outdoor/indoor air pollutant transfer, based on experimental data, was obtained using multiple linear regression.

The opportunities offered by National Lottery Funding has focused attention in recent years upon the poor conditions in which much of our written history has to be stored. The documentary record of each county is held in a record office and pressures on local authority spending have meant that often only basic and sometimes inadequate provision for the safe keeping of the documents has been made.

The aim of this Chapter is to break down barriers to concepts of natural ventilation. The study is part of a Pan European project titled NatVent that involves seven countries in the north of Europe. The project leaders are the UK Building Research establishment. Urban pollution is a major barrier to the adoption of natural ventilation, so successful ways of avoiding these problems need to be found.