The monitoring of the performance of domestic ventilation systems is quite a complex exercise. A wide variety of parameters must be taken into account in order that a suitable assessment of performance may be made - in many cases, insufficient data is collected. Even when the data has been collected, it is often the case that comparison of results from different studies is made very difficult due to variations in the treatment and presentation of the data.

This paper discusses four concepts that have been found useful in improving estimates of ventilation rates in residential buildings. These concepts are improved methods for describing leakage distribution and wind pressures: 1. Separation of large, well defined "local" leakage sites from the background building leakage. 2. Changing surface pressure coefficients to account for the effect of upwind obstacles. 3. Making wind pressures (in terms of pressure coefficient and wind shelter) continuous functions of wind direction. 4.

Proper dimensioning of natural ventilation system for multi-storey buildings is a critical matter, because the air flow rate depends on many parameters as outdoor temperature, wind, distribution of air inlets and envelope air leakage, characteristics of outlets and cowls. The computer code GAILNE BIZONE predicts the ventilation rates in multi-storey dwellings equipped with passive stack ventilation system. Each level is treated as a two-zones configuration, but each zone is linked to the collective ventilation shaft of the building.

A new multizone airflow and contaminant dispersal model CONTAM93 is described, along with a demonstration of its application in a study of ventilation and contaminant control in single-family residential buildings. While CONTAM93 is based on existing theory of network airflow analysis and contaminant dispersal, the model employs a unique graphic interface for data input and display. The interface uses a sketchpad to describe the connections between zones and icons to represent zones, openings, ventilation system components, and contaminant sources and sinks.

A measurement system is described to record the movement in a room of neutral density balloons or bubbles, and thus the movement of air in that room. It is based on photogrammetric analysis of coincident video recordings made from several view points. Under laboratory conditions, the system was found capable of measuring position to an accuracy of +/-3cm over a range of 8m, andof measuring 3-D velocities to better than +/-0.05 m/s. The system was usable under field conditions, and could be operated in an occupied building. The largest space tested was approximately 30x15x10m.

The paper describes the application of a new tracer gas technique for studying ventilation. The technique is called the homogeneous injection technique, since it relies on the continuous injection of tracer gas in all parts of a zone-divided ventilated system, with tracer injection rates, which are strictly proportional to the zone volumes. The steady state concentrations of tracer gas in the different zones are proportional to the local mean ages of air.

This paper briefly reviews the weather data available for natural ventilation and briefly reviews hourly data for simulation. It starts by reviewing the need for basic data for initial manual calculations. It then discusses the hourly weather data available for example the UK CIBSE Example Weather Years, and the European Community Test Reference Years. These are mostly selected for energy analyses rather than design, but there is still aneed for establishing general criteria for weather data for design of HVAC services and natural ventilation.

The Building Research Establishment has set up various passive stack ventilation systems (PSV) in a test house in order to assess their performance. The test house used was a two storey, end terrace dwelling on the BRE site at Garston. A PSV was installed in the kitchen of the test dwelling. The duct material, diameter and configuration were varied to determine any differences that they would make to the air flow rates obtained in the duct. In addition, three different ridge terminals were tested and three ceiling inlets.

The use of PSV (Passive Stack Ventilation) systems in two and three storey dwellings is now widely accepted as a method of achieving adequate ventilation levels for indoor air quality control. However, the application of PSV systems to multiple-storey dwellings is, in the United Kingdom, in its infancy. This paper provides detailed performance data relating to extensive monitoring of PSV systems in multi-storey dwellings in three EC countries (France, Belgium and Holland).

In the UK the increased use of natural ventilation in buildings is being encouraged, particularly during hot weather as an alternative to air conditioning or mechanical ventilation. In order to take advantage of this option building designers need to be able to estimate potential air flows. Conventional calculation methods assume windows to be simple openings, however in practice the situation is more complex since during hot weather the opening is likely to be shielded by some form of solar shading device.