The relation between air infiltration rate and indoor concentrations of radon gas, radon daughters, and formaldehyde has been investigated for both summer and winter conditions in a number of Toronto houses with low rates of natural ventilation.
In Finland there are not yet any regulations or standards concerning the airtightness of buildings. Drafts have caused discussion about whether controlled airtightness would increase the building costs too much, and improved airtightness worsen the indoor air quality. In modern Finnish buildings a good or satisfactory airtightness can be achieved with normal careful workmanship. To secure good indoor air quality, a functioning ventilation system is also necessary. There seems to be no return to traditional 'breathing' structures and natural ventilation.
This paper compares the conventional exhaust system with a supply-exhaust system with regard to the possible degree of control of the air exchange in the individual rooms. Ventilation efficiency and air exchange efficiency are defined and some examples show the local concentration, mean ventilation efficiency and mean air exchange efficiency for some simple ventilation schemes. Exhaust systems require a very tight building with small make up air openings. The ability of the different systems to avoid leakage out from the building of indoor air is also compared.
An investigation of the minimum fresh air supply per person required to prevent the occurrence of unacceptably offensive odour due to stale air in offices and similar buildings. The study was made under everyday conditions as far as possible, in different buildings, various size rooms, different densities of occupancy, with men or men and women, and with mechanical or natural ventilation.
In discussion of air infiltration, we must consider air leakage flow, air change, air changes per hour at 50Pa, the surface permeability coefficient, the component permeability coefficient and equivalent leakage area. Air change and air leakage data are given for multiple family houses, single family houses, offices, industrial buildings and single cell elements.
The minimum fresh air requirements needed for perfect indoor air quality are being studied and these will form the basis of the Swiss Guidelines for Ventilation. An optimization between the need to reduce heat loss and fresh air requirements for health is the aim. Pollutants in indoor air, such as formaldehydes, radon, carbon dioxide, tobacco smoke, carbon monoxide, nitrogen dioxide and particulates, have to be considered.
This paper deals with the concept of energy efficient houses as integrated systems. Quantitative analysis is used to show that evenly distributed insulation is more effective than excessive insulation applied to only one element of a house and that ventilation rates are a critical factor in determining the magnitude of energy loss. For a new approach to be adopted on a large scale, it is suggested that a means to implement Planned Change is required. Various models to bring about this change are discussed with an indication of the final recipe used for a demonstration project.
Sedentary subjects occupied an environmental chamber (20-22 deg C, 35-50% RH) with low ventilation for 90 min. Judges (visitors) evaluated the odour of the chamber before and during, and after the 90-min period of occupancy. Odour intensity increased throughout occupancy and decayed afterwards. However, therate of decay exceeded that anticipated from ventilation rate alone. The results implied that body odour is unstable with a half-life of 55 min. This instability will influence quantitative requirements for ventilation during nonsmoking occupancy.
Demonstrates that complaints by office staff about their physical environment are not necessarily caused by physical deficiencies. Trying to reduce the level of complaints by adjusting heating ventilating and air conditioning (HVAC) systems can therefore be an unrewarding task. Greater attention needs to be placed on - communications between management, those responsible for running HVAC systems and staff. Staff need the feeling that they can influence, if not control, their environment. Staff should also have more realistic expectations about their thermal comfort.
An account is given of what the kindergarten staff wrongly believed caused the problems and what measures they carried out in an attempt to solve them. On the spot measurements showed however what the real main cause of the problems was. Results from the comprehensive measurements of CO2 concentrations andother ventilation performance criteria in a room occupied by 12 children and 3adults are then presented.
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