Residential mechanical ventilation systems: performance criteria and evaluations.

The performance of mechanical ventilation systems has been checked in several innovative residential houses in the frame of Swiss research as well as pilot and demonstration projects. This paper gives a list of performance criteria for the ongoing comparison and evaluation of these mechanical ventilation systems. For some criteria, target values are proposed. In the second part, this paper shortly describes four residential buildings with mechanical ventilation systems where such evaluations were performed and highlights interesting design features and results from the measurements.

Comparison of indoor levels of radon between workplaces and homes located nearby in different parts of Finland.

The aim of this study was to compare the radon levels at workplaces and in homes located nearby. Homes (number of 57) and partly or fully underground workrooms (number of 55) have been studied at the four workplaces in southern Finland and one workplace in northern Finland. Radon concentrations both at workplaces and in homes seemed to be at the same level in the same district. The mean radon concentration in workrooms was 406 Bq.m³, and in homes concentration was 398 Bq.m³.

Ventilation Effectiveness Parameters Resulting from Mechanical Ventilation with Recirculation

The effectiveness of a ventilation system in terms of the age of air and its ability to remove contaminants will be significantly affected if part of the exhaust air is recirculated. In this paper the consequences of recirculation of air in mechanical ventilation systems on ventilation effectiveness parameters is examined. Two alternative methods of establishing ventilation effectiveness parameters relating to air change efficiency and contaminant removal effectiveness when recirculation of air is present are presented.