English

A short treatment of the concepts and aspects that play a role in ventilation is followed by a brief description of the investigation methods employed. Gives a concise survey of the equipment and mathematical models used. Reviews the ventilation research carried out by the IMG-TNO. Covers factories, laboratories, hospitals, auction halls and similar buildings.

Measures the airtightness of various types of 25 residential units (9 detached houses and 16 apartments) using the fan pressurization technique. Shows the relationship between the pressure difference across the building envelope and the volumetric flow rate of air as well as the ratio of the effective leakage area of one building element to the total leakage area. Compares the airtightness of various types of houses in different countries using the valueof the effective leakage area per floor a at a pressure difference of 10 Pa.

Describes pressurization tests conducted by the National Testing Institute on 3 large industrial buildings. Sets out equipment and methods used including atracer gas method to calculate air flow through the fan rather than the usual measuring duct. Gives construction and volume details of buildings measured.

Reviews air infiltration studies in New Zealand. Tighter houses have evolved over the years through changes in building methods and materials. Some of the tighter houses can have condensation problems. Investigates the airtightness of 40 houses together with the leakage resistances of a range of building components and bulk sheathing materials. A comparison with houses in other countries shows that comparatively tight houses can arise from simple construction methods not employing vapour barriers. Gives air infiltration rates as a function of windspeed for 4 of the 40 houses.

Describes the testing of 8 federal office buildings (size from 3000 sq.m. - 45000 sq.m.) for their air infiltration characteristics, as part of the NBS program to develop diagnostic test methods for evaluating the thermal integrity of federal office buildings. Performs tracer gas tests in the autumn, winter and spring to evaluate both the ventilation of these buildings during occupied periods and the natural air leakage under various weather conditions.

Reports the results of measurement of ventilation efficiency in a full scale model of a small office with a diffuse air supply, which can be used to improve ventilation efficiency and therefore reduce air supply rates. Steady state and transient definitions of ventilation efficiency are given. Finds that ventilation efficiency depends on air flow rate and heat gain in the office. Higher air flow rates give lower pollutant concentration in the ocupied zone but also more mixing between the occupied and under-ceiling zones.

Despite having balanced mechanical ventilation, a large number of modern buildings in Sweden have unsatisfactory indoor climate. Problems include mould, irritation of the eyes, nose and throat, skin rashes, feelings of dryness, hoarseness andheadaches. To control ventilation according to requirements the right indicator variable must be selected and the system must permit the proper control in the occupied zones. Measurements of air pollutants were carried out outside and inside a mechanically ventilated office building.

Discusses the problems associated with poor air quality in tight buildings. Considers how problem conditions can be identified and evaluated, and gives some possible solutions to improving air quality. These include turning the thermostat down slightly, increasing ventilation levels, and ensuring that themechanical ventilation system is working properly, or calling in a specialist to identify the problem.

States that in localities which must be ventilated by law such as cinemas, restaurants and assembly rooms of various kinds the fresh air supply is often greatly in excess of what is strictly needed. This excess air has to be transported, and possibly heated, cooled, humidified and dehumidified. Describes how controlling the air quality makes it possible to restrict the quantity of fresh air to the basic requirements, thereby keeping ventilation heat losses to a minimum. The control variable is the room air quality as monitored by a sensor.

Describes the results of air tightness tests of various service penetrations through a polythene vapour barrier and associated insulation. The service penetrations studied were insulated and uninsulated ventilation ducts, plastics, pipes, electrical boxes and electrical conduits. Various methods of sealing the penetration were tested for each case. Recommendations are made for choice of sealing method based on performance and case of installation. Examples are given of the effect of leakage through service penetrations on total building leakage.