OPTIMUM VENTILATION AND AIR-FLOW CONTROL IN BUILDINGS

The LTEE laboratory of Hydro-Quebec, in collaboration with Canada Mort gage and Housing conducted an indoor air quality study involving 30 si ngle family-detached houses heated with electric baseboard heaters in the vicinity of Trois-Rivieres during the 1993-94 heating season. The houses were selected according to the measured air leakage at 50 Pa so as to have a sample distribution similar to the distribution of air l eakage of houses in the province of Quebec. The 'source strength' of s everal air pollutants were calculated from measurements of ambient pol lutant levels and total ventilation during a 2 week test. In addition: the indoor CO2 and humidity levels were recorded in eight of the hous es continuously during the heating season. Model studies using the mea sured pollutant source strengths and measured equivalent leakage areas of the buildings indicated that the recommended health guidelines for airborne respirable solid particles (RSP's), CO2 and formaldehyde are exceeded during periods of low total ventilation, coinciding with mil d outdoor temperatures and low wind conditions. With the room occupied and the door closed, CO2 levels in the bedroom increased steadily dur ing the night until morning, when the door was opened, to levels in ex cess of 3500 ppm with one person and in excess of 4500 ppm with two pe rsons. Various different methods of ventilating some of the houses wer e tested, including quiet replacement exhaust fans, mixing fans for in door air and a fresh air intake and mixing system. The effects of oper ating various air handling systems were monitored by keeping track of indoor CO2 and relative humidity in the master bedroom and occupancy i n person-hours per day. (C) 1998 Elsevier Science S.A. ALI rights rese rved.