air leakage

According to TGL standard 112-0319, the demand of heat required for ventilating a building essentially depends on the passage of air through its window and door joints. This varies to a great extent. The losses of thermal energy can be reduced substantially by tolerance specifications for joint dimensions. Such tolerances will result in permissible resistance coefficients for different types of windows. Depending on thehygienic requirements suitable selection is then possible within a narrow margin of error.

Gives general data about windows in the experimental dwellings and the transport of air through small openings. Describes method for calculating the rate of air infiltration through windows as a function of the pressure difference between both sides of the construction. Presents results for each type of window graphically in several ways. Gives figures for cracks between movable construction parts.

Reviews means of rain water penetration and how to apply one-stage weather proofing listing the disadvantages. Reviews research results obtained with two-stage weather proofing by adding an additional seal and summarises the pressure variations resulting from wind plus the design of horizontal and vertical joints between individual facade segments. Discusses the practical design of joint and sealant illustrating this for a few window types and adds that this design is also applicable for a complete curtain wall.

Describes retrofitting a wood-frame residence, having only limited insulation in the attic, to reduce its energy requirements for heating and cooling. The three retrofit stages comprised : reducing air leaks ; adding storm windows : andinstalling insulation in the floor, ceiling and walls. The housewas extensively insulated to evaluate energy savings and other performance factors. an economic model was used to evaluate the cost effectiveness of the retrofit options.

Describes the results of an investigation carried out to determine the rate of fresh air infiltration that is experienced during the winter in a modern air conditioned office building. Six different methods were employed to estimate the rate of infiltration through the building, four by direct measurement and two by calculation. The methods of direct measurement were,tracer gas decay, measured air flow through one floor, measured air flow through one air conditioning unit and measured change on power demand.

Describes different methods for sealing joints. Gives method for testing permeability of joints to wind and rain. Concludes that two-stage joint seems to offer the greatest advantages which are long life, lack of need for maintenance, lack of sensitivity to tolerances, extensive lack of sensitivity to faulty installation practice and installation independent of the weather. Tests confirm that the wind permeability of two-stage joints can be practically disregarded in the determination of heat requirements.

Describes experiments made to determine the air infiltration rate through revolving doors. Estimates infiltration by combining air leakage past the door seals with infiltration caused by the revolving of the door. Finds that air exchange depends on door speed and temperature differential and somewhat on wind and indoor air velocities. Gives flow past the door seals as function of indoor -outdoor pressure differential and flow related to door movement for a motor- driven revolving door and for a manually operated door for traffic rates up to 2000 people per hour.

Summarises data on air flow characteristics of walls from U.S.A. and Norway. Reports laboratory measurements on four test walls and identifies main sources of leakage for the different test facades. Average air leakage at 200 Pa varied from 5m3/h/m2 to 50m3/h/m2. Shows that wall leakage rate could provide 30% or more of the total leakage rate.

Reports measurements made on windows in old blocks of flats in Sweden. Measurements were taken of air-leakage through 21 windows under different air pressures before and after the renewal of draught excluders between window frame and casement. Concludes that draught proofing of old windows is extremely effective. Heat flow through 18 double-glazed windows is also measured and two systems of converting double to triple glazing are studied. Conversion was found to improve u values by approximately 35%.

Reports of tests on wood windows and doors to determine their thermal performance with and without wind. Additional tests to determine air infiltration effects were made and concludes that air infiltration has very small effect at low pressure differentials. Notes discrepancies between test results and ASHRAE design values especially when a 15m.p.h. wind was present. Recommends development of uniform testing and evaluation methods.