Treats importance of keeping uncontrolled ventilation to a minimum in buildings equipped with balanced ventilation. Provides theoretical and experimental description of leakage of air past windows. Includes comparison between standards of different countries. Discusses effect on building ventilation of variations of wind and outdoor temperature. Considers in conclusion measurement of air flows between rooms in a building. Describes development of tracer gas method based on computer-assisted evaluation.
Describes computer program developed by BSRIA to predict ventilation rates and directions of air flow in buildings for given sets of conditions. These conditions are wind speed and direction, temperature differences between inside and outside the building, air leakage characteristics of the components and the mechanically induced air flow rates. The report is in the form of anoperating manual for the program.
Outlines two techniques for estimating ventilation heat losses in houses. The first is a tracer gas technique using a constant concentration of gas and the second a theoretical prediction method. The theoretical technique treats the building as a multi-cell model with specified wind pressure, leakage openings and background leakage area. Reports use of the method for simulating the natural ventilation of a house in London and the effectiveness of sealing the windows and floor.
Gives regulations and performance guidelines for the ventilation of buildings. Includes guidelines for air quality and gives recommended supply and return air volumes for different rooms of a building.
Briefly discusses wind-pressure on buildings. Derives equations for air-flow in a building without internal walls caused by wind pressure from perpendicular and oblique wind. Gives simplified method for calculating air flows inside a building with internal walls. Gives tables showing results of calculation of air flows for a building with two and three rooms. Discusses more complicated building types and gives results of calculation. Outlines determination of ventilation heat loss, air leakage of windows and doors.
Reports tests made to examine moisture problems in a flat roof of cold deck construction. Tests simulated the effect of normal, wet and very wet conditions below the roof with no ventilation of the roof. Found that without ventilation there is a substantial risk of moisture degrade and condensation problems. Roof was then ventilated at five air changes per hour and this was found to be effective in solving moisture problems. Suggests this as a minimum ventilation rate and that where it is difficult to provide ventilation in a flat roof, a warm deck design should be considered.
Explains method for calculating time dependences and average values of gas and particle concentrations in ventilated rooms, which permits determination of air pollution propagation in a room by means of given target functions. Applies method forvarious ventilation rates. Provides calculated example of determination of gas concentration occurring in a room with a leaky gas container. Illustrates representative time functionfor different pollutants.
Reviews the requirement in building regulations for cavity barriers in roofs. States need for providing ventilation in the cavities of certain forms of roof construction,particularly those with a continuous waterproof vapour barrier to avoid moisture build-up. Examines how adequate air movement can be provided in both new and existing flat roof voids, designed with or having installed cavity barriers.
The fundamentals of natural ventilation are discussed with particular reference to the ventilation of houses. The laws of flow are presented and typical values are suggested for the acting pressures and the size of openings through which flow canoccur. As an example of the application of the laws, the effect of wind and temperature difference on the ventilation of an exposed house is discussed, and the theoretical treatment is illustrated by experimental results.
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