With correct application of vapour barriers the ventilation of building structures is in general not necessary, unless such barriers prevent the escape of trapped moisture from moisture-sensitive - especially organic - materials. Indoor and outd
Measurements were made in the PIKO low-rise pilot building project to study air tightness, interior air quality, and air heating in 15-30 residences in various seasons. Exterior wall air tightness was measured in 70 units and repeated in 10.
Notes the contaminants which may be contained in room air - radon, solvents, tobacco smoke, formaldehyde, dust mites etc. Points out that no definitive threshold values have been established for contaminants representing health hazards. Points out that the reactions of various individuals to them differ widely, determined by a number of factors.
Reviews current knowledge about the sources of a number of indoor pollutants and their concentrations: tobacco smoke, NO2, CO, radon, formaldehyde, SO2, CO2, O3, asbestos, mineral fibres, organics and allergens. Lists the adverse health effects from exposure to each of the pollutants. Finds instrumentation for measuring exposure acceptable, but monitoring and knowledge of distribution of sources and concentrations inadequate or marginal. Knowledge of exposure-effects relationship is inadequate, especially with regard to delayed effects of chronic exposures.
Aerodynamic phenomena affecting the ventilation process, such as aerodynamic mixing, generation of secondary and slightly turbulent flows, roof contours, infiltration and convection and their connection with geometric parameters of the object and energy expenditure for ventilation are analysed.
Reports a case study dealing with the relation between ventilating and airing behaviour and the outside climate. Also the significance of other variables such as preferences with respect to the indoor climate are considered. Wind speed is found to correlate, but outside temperature (varying from -3 to +9 degrees C) does not correlate with the length of time the windows in the bedrooms and bathrooms are opened. Rainfall and sunshine also seem to have some influence. The main reasons for airing are that the bedrooms are too warm and not fresh.
Ventilation requirements for the reduction of humidity. Required air change rates for hygiene and moisture removal for various rooms are given. Air flow rates are calculated for natural ventilation with closed windows, hopper windows and controlled ventilation. Ventilation by window opening is discussed. Gives examples of the transfer of moisture within a building, and the main reasons for ventilation, with particular emphasis on moisture removal. Lists danger of condensation on various building elements, causes and remedies. Advises on ventilation measures.
Discusses how air flow in a building is affected by the position of the ventilation openings in the outside wall. Treats factors determining selection of controlled ventilation system and provides examples of systems available: small air vents, mechanical ventilation with acoustic and thermal insulation, ventilation with heat recovery, etc. Discusses an optimal solution with air quality control.
It is necessary to design the ventilation system to avoid excess humidity in the apartments. Discusses the sources of moisture release in rooms, properties of air temperatures in relation to moisture absorption, condensation in bedrooms in particular, and moisture damage to building fabric. Advises on ventilation measures to control humidity.
Ventilation efficiency was measured with freon gas in 3 large industrial buildings under normal working conditions. Size of building varied from 3000 to 10000 m2 and room height from 5-19 m. The ventilation systems were of 3 types: 1. Overhead fresh air supply network with conventional air inlets, 2. Fresh air supply direct to occupied zones by a low impulse system, and 3. Overhead fresh air supply distributed by the Dirivent system. Describes techniques of tracer gas measurements. Illustrates some results in graphs.
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