English

Air change rates were measured in one two-storey detached house with five basic types of passive ventilation systems: an intake vent in the basement wall, an outdoor air supply ducted to the existing forced air heating system, an exhaust stack extending from the basement to the roof, and two combinations of the supply systems and the exhaust stack. An expression was developed for estimating house air change rate from house airtightness, neutral pressure level and indoor-outdoor air temperature difference.

The Swiss performance standard for energy conservation in buildings SIA 380/1 is explained. This standard leaves air infiltration and other detail decisions to planners if minimum performance levels are met. Calculation procedures for heat balances based on a standard occupancy are described. Tools to achieve optimum space heating and ventilation rates are explained. Instrumentation for checking the thermal performance of the house in operation is defined.

Reduction of fresh air ventilation is becoming the major means of energy conservation in office buildings. Simultaneously, health and comfort problems experienced by occupants are often suspected to be a direct result of reduced fresh air ventilation. However, there is little data available on health and comfort problems experienced by occupants of buildings operated under normal ventilation rates.

Ventilation standards in buildings are receiving increased attention because of energy conservation and indoor air quality. An important example of this is the current ASHRAE Standard 62-1981, "Ventilation for Acceptable Indoor Air Quality." This standard contains two distinct procedures that can be used to set ventilation rates. The first is a prescriptive specification that mandates ventilation rates for particular building types. The second is a performance specification that uses target concentrations of indoor contaminants as the basis for deciding the adequacy of ventilation rates.

Increased attention to the reduction of energy consumption in buildings and greater awareness of the need to maintain acceptable standards of indoor air quality have led to the development of new or revised standards of building airtightness and ventilation requirements. In this review of the existing standards of twelve countries, an attempt has been made to compare their main features and criteria. In many cases, direct comparison is not possible because of different ways of expressing the significant parameters.

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.

A microprocessor system is being developed for occupancy related ventilation control of mechanical ventilation in Brunel University Library. The objective is to reduce space heating costs by decreasing the input of (cold) fresh air to the building below existing (heating season) levels, when the number of occupants in the building is sufficiently small to allow this. The occupancy levels can be measured in terms of CO2 level in the exhaust duct. The microprocessor control system is operational when linked to a CO2 monitor.

Possible health effects and changes in sensation of comfort among tenants after replacement of single glass windows in leaky frames with double glass windows in airtight frames have been studied. The study design was observational, and included a study group and a corresponding control group. The results indicate essential improvements of the indoor climate and of the health status of the tenants after replacement of the windows (i.e.

ASHRAE is preparing a standard which addresses the maximum air leakage associated with good construction. This standard, 119P, links Standard 90, which addresses energy conservation in new residential construction, and Standard 62, which specifies the minimum acceptable ventilation to achieve adequate indoor air quality. Within Standard 119P there is currently a classification scheme that groups building tightness into categories depending on envelope leakage, floor area and building height.

The air tightness of 15 detached houses was measured firstly immediately after erection and secondly after a period of 1.5 to 4.5 years. All the houses were timber framed ones, equipped with mechanical ventilation systems. Only two houses out of the 15 tested showed clear changes in air tightness. Thus the air tightness behaviour of the houses seems to be fairly constant.