Long-term monitoring of radon, aerosol and carbon dioxide concentrations was carried out in two Finnish public buildings. In each case, a distinct periodic behaviour of pollutant concentrations was observed. CO2 and aerosol showed maxima during the working hours, but the fluctuations of the aerosol concentration were faster and more irregular. The radon concentration peaked at night and on weekends, dropping off rapidly in the working day mornings when ventilation was turned on.
A major pathway for loss of conditioned air in East Tennessee homes with externally located heating, ventilation, and air-conditioning (HVAC) systems is leakage in the ductwork. The average infiltration rate, as measured by Freon-12 trace
As part of an investigation into the influence of a residential weatherization program on indoor air quality and energy efficiency, a multi-pollutant survey of the air inside 50 Wisconsin homes was conducted three times during the heating season
The physical reason for draughts is in the first place the convective surface-heat-transfer coefficient. To find out about the influence of turbulence on draughts, it is necessary to carry out measurements of the surface-heat-transfer coefficient in relation to air turbulence. The results of first measurements of this kind are the subject of this paper.
In this paper a hypothesis is set up for explaining the discrepancies between the relatively high acceptable air velocities found during many earlier climate chamber tests, and the much lower acceptable velocities found under many practical circ
One hundred subjects were exposed to air velocities fluctuating in the same manner as in typically ventilated spaces in practice. Each subject participated in three experiments at 20, 23 and 26 degrees C, dressed toobtain a neutral thermal sensation. In each experiment the subject was exposed to six mean velocities from 0.05 to 0.40 m/s. He was asked whether and wherehe could feel air movement and whether it felt uncomfortable. A relation was established between the percentage of people feeling draught and the mean velocity. The subjects were most sensitive to draught on the head region.
In the weatherization of building structures to minimize convective heat loss, the air exchange rate is reduced. Pollutants of indoor origin are retained near the occupants. Further, outdoor pollutants may be concentrated indoors under partic
Decreased ventilation, achieved by weather stripping and other tightening measures, is the most cost effective way to energy conservation. A very low investment can result in a considerable decrease in ventilation rate. For a typical detached
The simple steady state model which is frequently used to relate radon concentration (C), source strength (S) and ventilation rate (l/tau) is expressed in the equation C=S tau. The assumptions of this model are given and their validity explor
To propose guidelines for minimum ventilation rates which are sufficiently large to meet the demand for fresh air without unnecessarily wasting energy, in IX "Minimum ventilation rates" within the IEA Programme "Energy conservation in buildings and community systems" nine countries are co-operating. The participants have in a first step summarised existing knowledge, national standards and current and required research. The work that was required covers a wide range of disciplines, from hygiene and medicine on one hand to engineering and building science on the other.
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