Describes three test high-rise buildings and the pressure measurements made on buildings. Gives results of internal to external pressure differences against height within building both with and without the ventilation systems in operation, compared with theoretical predictions. Discusses pattern of pressure differences. Suggests feasibility of pressurizing ground floor to reduce stack effect. NOTE Futher measurements of wind on two of these three buildings are given in 'Pressure differences caused by wind on two tall buildings' Tamura G.T. Wilson. A.G. ASHRAE trans. 74 no 2 p170-181.
Describes laboratory test performed on four steel swing windows and one steel double-hung window to determine leakage rates at different values of pressure and humidity. Concludes there is a wide variation in leakage rates of well constructed windows. Test results depend on the method of closing and latching windows, leakage for steel swing windows is found to differ when determined with ascending and descending pressure differences because the window is closed more tightly after completion of the ascending pressure difference.
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.
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.
Discusses theoretical pattern of pressure differences inside a tall building and describes measurement of pressure made on anine-storey building in Ottawa. Pressure differences were measured across external walls, vertical shafts, stairwell doors and elevator doors with the mechanical ventilation system both on and off. Concludes that pressure differences across external walls depend on the distribution of openings in the exterior wall and of the ratio of resistance to air flow inside the building to that across the exterior wall.
Describes measurements made of wind speed and direction and pressure differences across the exterior walls of two multi-storey buildings in Montreal. Regression coefficients are obtained and show better correlation for higher levels than forlower ones and for the taller building "A" than building "B", indicating that shielding by adjacent buildings has an important effect. The variation in wind velocity between the site and a meteorological station was recorded.
Developes mathematical model of air infiltration based on crack flow equations. Describes measurements made on test house. Shows that actual pressure distributions in walls deviate considerably from values in guidebooks. Finds background leakage area of house by pressurizing house with electric fan and measuring pressures. Suggests two distributions for leakage areas. Measures infiltration rate using helium tracer gas, recording temperature and pressure differences. Concludes that comparison between prediction and experimental results is encouraging.
States that it is usual to assume a certain pressure difference across a window for a given wind velocity. Describes method of recording and instrumentation used to record wind speed and direction and pressure difference across two windows. Gives results of measurements showing dependence of pressure on winddirection. Shows that stack effect, even in buildings of moderate height, may be of sufficient importance to require a different allotment of heating capacity between lower and upper floors.
Discusses control from outdoors and gives a formula for the heat required to maintain indoor design temperatures. Outlines the twofold effect of wind, i.e. the increase in the heat transmission coefficient for outside walls, and increased ventilation and air infiltration caused by pressure differences. Explains the solar effect by formulating the heat load on the outer walls and through the windows. An example illustrates the calculation procedure. Tabulates the increase in heat consumption due to wind; this varies with wind speed, building location and height.
A number of cases of water and frost damage in masonry and non loadbearing walls have been examined. This damage could not have resulted from vapour diffusion or rain penetration and is primarily caused by condensation due to exfiltration of air. Air exfiltrates through the many cracks and joints and in this connection the result of chimney action and wind is explained in some detail, including the pattern and magnitude of building pressure differences that induce ex-filtration together with a discussion regarding the moisture that is transferred.
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