The following report documents the design and development of an automatic vent closure system for residential exhaust systems. The report discusses the rationale behind the perceived need for such a system and defines the objectives of the design and development work with respect to these needs. A detailed account of the development of the design and construction of successive prototypes will be given along with a thorough description of the testing procedures employed to evaluate the operational characteristics of each prototype as their design was further refined and developed.

The Air Lock Floor and the Pressure Ring are two effective measures for control of air flow directions between rooms or zones in buildings. They create a pressure hierarchy that controls spread of pollutants. Here an example has been given for radon from a crawl space, odours from a bakery into a dwelling above and an isolation chamber with a leaky facade. The Air Lock floor can operate with a 7 W fan and at the same time extractthe normal dwelling ventilation flowrate. Used in the ground floor, the Air Lock Floor results in a warmer floor and contributes to energy savings.

The purpose of this study was to test an Indoor Air Quality model on a variety of Canadian homes, and use this model to determine the optimal ventilation levels necessary to provide appropriate comfort levels. The Indoor Air Quality model tested (the AQ1 program), was a single zone hour-by-hour model of air leakage, mechanical ventilation and pollutant concentration. Measured weekly air change rates were compared to the model's predicted rates, and sensitivity analysis' performed on a number of inputs.

This paper investigates possible natural ventilation strategies to reduce exposure to environmental tobacco smoke (ETS) in dwellings. Particular attention is paid to the migration of tobacco smoke from the living room (usually the smoking room) to the bedrooms which may be occupied by children. This addresses an area of current concern regarding the possible association between passive smoking and adverse health conditions; in particular the link between parental smoking and respiratory illness in children.

Occupant response in a good indicator of the effectiveness of a ventilation system. In a one-year study in the province of Quebec region, 20 public buildings were studied. Occupants were asked to answer questions on their perception of their environment and the ventilation at their workstation. Annual energy consumption for each building was recorded. The ventilation systems were studied as well as their rates; minimum outdoor air rates and average total air rates, at each workstation and at the ventilation system. Ventilation rates were plotted against energy consumption.

Measurements of interzone airflow and movement of aerosol particles were carried out in an environmental chamber. SF tracer gas and oil-smoke particles were used for this work. A series of measurements were conducted to investigate the effect of parameters such as interzone temperature difference and size of opening on the flow of aerosol particles. The particle deposition rate on thesurfaces of the chamber together with algorithms for interzonal particle flow through the openings were determined. Results were compared with those obtained using the tracer-gas.

The work was concerned with measuring natural convection through a large horizontal opening of different sizes and shapes located between two rooms in a building. Airflow rates between the two rooms were measured using a tracer-gas decay technique. Room 1 was heated to various temperatures in the range 18°C to 33°C using thermostatically controlled heaters; room 2 was unheated. A multi-point sampling unit was used to collect tracer-gas samples from each room. The concentration of SF6 tracer was measured using an infra-red gas analyser.

Simulation is proving more and more important in building physics. Programs of different levels of complexity are today available for researchers and designers to model and plan buildings. But the accuracy of the output is not usually provided as a common result. This paper is a short summary of a dissertation [1] focused on the accuracy of the simulation outputs as a function of the accuracy of the input parameters.

A series of laboratory experiments are described which investigated the effect of surface roughness on the air flow characteristics of simple, straight-through, no-bend cracks with smooth and rough internal surfaces. Thecrack lengths, in the direction of flow, were 50.8mm and 76.2mm. For the rough cracks the roughness was simulated with two different grades of commercially available emery-cloth (grade 60 and 100). The effect of roughness on the reduction of air flowing through a crack is also discussed.