Finnish

Gives air leakage measurements which show that improvement of the tightness of the outer core of a building gives an energy saving of 5000 Kw/a in comparison to a conventionally constructed building.< Finds that the most leakage occurs at the joints of walls and ceiling, followed by the breakthrough for electrical wiring, the corners of the buildings, the windows, the joints of wall and floor and the joints of ducts and ceiling.< Older houses in Sweden have approximately the same rate of leakage as in Finland, ie 5-10 changes per hour at 50 pa.

Shows that the leakage test in most buildings with mechanical ventilation may be performed with the ventilation system itself with only a slight reduction in the accuracy of the measurements. Using fans in the ventilation system, the pressure difference inside/outside may often reach a measurable value of 5-10 pa. If such a pressure difference is not obtained, the leakage exceeds allowable values and the building should be tightened. Before measuring, all of the supply air openings in outer core of the building should be closed and taped. All doors inside the apartment should be open.

Sponsored by the Ministry of Trade and Industry, a consulting firm performed an investigation of the possible energy savings in industrial halls outside working hours. The ventilation should be closed during shut-down periods, and air change through natural draught cut down to a minimum. The ventilation by leakage of an industrial building may be estimated at 0.1-0.5 air changes per hour, therefore the tightness of the constructions is imperative. The decrease of the temperature in industrial halls during non-working hours is imperative.

The first part of the study describes thermography generally as a method for non-destructive testing of a building envelope for thermal and air tightness properties. The study has resulted in a two stage testing method of which pressurizing is an essential part. The field study has shown that thetwo-stage method is suitable in detection of air leakages, showing that the major part of thermal defects in the building envelope are due to air leakages.

Reports pressure tests of the air leakage of an apartment building. The building is three storeys with a cellar above ground. There is a mechanical exhaust system and in addition every apartment has a kitchen fan.Pressure tests were made in each apartment. Leakage points were located with smoke tests. The leakage of windows and doors was determined with the "plenum" method. Each window was surrounded by a "plenum" and leakage at the boundary between plenum and wall was eliminated by an auxiliary fan which maintains the same pressure in the room as in the "plenum".

At the HPAC laboratory of the State Research Centre, supply air tests were conducted partly with a supply air window, partly with a porous, 0. 1m thick insulation above the window. The best results were obtained with low supply air velocities allowing the air to flow down close to the outside wall. Thetests with a supply air window of about 1m*1m showed that an upward air-flow between the panes gave better results then down- flow. The air distribution was improved with a guiding vane in front of the air-flow holes in the window frame.

A fair comparison of ventilation systems is almost an impossible achievement. Even an economic comparison causes difficulties; the different systems render different room air qualities which cannot be counted in money. 

Notes that if the exhaust air flows in an apartment building are adjusted to the same value in similar apartments, the pressure conditions may not be the same in these apartments. 

In order to investigate the possibilities of installing heat recovery equipment in old apartment houses, a large project has been started. There are 30,000 to 35,000 apartment houses in Finland with an average volume of6000-7000 cu.m. Possible savings from heat recovery in houses with mechanical exhaust are the transfer of heat to supply air using standard equipment and heat recovery from exhaust air using heat pumps.

Radon, an inert radioactive gas, and its products of decomposition, will attack the lungs when present in high enough concentrations. Notes high concentrations of radon in mines and other underground spaces and even in well water. Radioactivity of building materials is a problem in Sweden. States concentration of radon in air is highly dependent on ventilation. Radioactivity in a dwelling is highest in the morning and drops in the daytime when doors and windows are open. Normally an air change rate of 0.5 per hour keeps radon content of indoor air at an acceptable level.