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.

BRE have experimental data for the flows found in Passive Stack Ventilation (PSV) ducts from a test house in Garston. These data cover different duct diameters, number of bends and roof terminals, all measured over a variety of weather conditions. In the first part of this paper the data are analyzed to separate temperature and wind effects, and to see how well they fit well to the expected model of duct flow. The second part gives a comparison of the same data with predictions from the single zone ventilation model BREVENT.

The adequate ventilation of houses is essential for both the occupants and the building fabric. As air-tightness standards increase, background infiltration levels decrease and extra ventilation has to be designed into the building. Passive stack ventilation has many advantages - particularly when employed in low cost housing schemes - but it is essential that it performs satisfactorily. This paper give the results from monitoring two passive stack ventilation schemes.

The UK factory stock is predominantly naturally ventilated. Measurements performed in this class of building have indicated that air infiltration rates in factories are usually excessive in relation to occupants' requirements for health and safety, resulting in an energy penalty. As part of a project to investigate construction options for energy efficient industrial buildings, three factories of different cladding construction types were designed and then built at Aberarnan, South Wales.

Ventilation of the void below suspended timber floors is necessary to prevent dampness, which leads to wet and dry rot. The air flow beneath such a floor has been investigated for a range of ventilator hole positions, using a full-sized test room. The variations in heatlosses with ventilation rate have been measured, for floors with and without insulation. The use of radiation barriers in place of conventional thermal insulation was found to cut down the heat losses significantly at low ventilation rates, but was not so effective at higher rates.