Discusses problem of assessing wind loads on buildings. Describes general properties of the wind and suggests wind can be described by its mean velocity with superimposed gusts. Suggests averaging period of 10-15 minutes for the mean velocity. Gives empirical expression for wind spectra. Considers relationship between extreme value of wind speed and the parent distribution. Suggests influence of gusts is not best determined by maximum gust speeds. Finds mean wind speed profile and turbulent structure are strongly dependent on terrain.
Describes experimental techniques used to produce turbulent boundary layers in a wind tunnel. Gives model law for velocity profile in a turbulent flow over a rough surface. Describes wind tunnel, five tunnel coatings used to generate turbulence, themodels and instrumentation. Gives as an example the test results from a model of house with desk roof.
Reviews some previous work on the measurement of wind pressures at full-scale. Deals with some of the problems arising. Describes pilot investigation being made at State House, Holborn to develop suitable techniques and to study the effect of gusts on pressure distribution. Gives preliminary results and mentions problem of establishing a suitable reference pressure.
Gives method for calculating air infiltration through window cracks. Calculates pressure drops across windows in buildings for four types of building and discusses resulting pressure differences. Gives values for crack width and length. Recommends design values for rates of air change due to infiltration in buildings heated by off-peak electricity.
Describes method of estimating roughness required to generate velocity profile of a given shape with a boundary layer of agiven depth. Uses data correlation for the wall stress associated with very rough boundaries and a semi-empirical calculation method to calculate the shape of boundary layers in exact equilibrium with the roughness beneath them. Results can be summarized in a single figure which relates shape factor of boundary layer to height of roughness elements and their spacing
Reports natural exposure test on vertical joints in open-jointed rain screen cladding. Describes test rig and gives results of water penetration tests. Gives design recommendations for screens.
Discusses some problems of providing weathertight joints between window and wall. Mentions sealing failures, condensation, frame defects and poor dpc detailing as important reasons for water penetration around windows. Refers to some principles of weather protection. Makes recommendations for the design of window-to-wall joints.
Reports tests made to examine moisture problems in a flat roof of cold deck construction. Tests simulated the effect of normal, wet and very wet conditions below the roof with no ventilation of the roof. Found that without ventilation there is a substantial risk of moisture degrade and condensation problems. Roof was then ventilated at five air changes per hour and this was found to be effective in solving moisture problems. Suggests this as a minimum ventilation rate and that where it is difficult to provide ventilation in a flat roof, a warm deck design should be considered.
Outlines the problem of assessing the rate of heat loss from dwellings due to ventilation. Discusses the mechanisms and pathways of ventilation and ways of controlling air infiltration. Reviews methods of measuring ventilation using tracer gases. Discusses qualities of ideal tracer gas and three automated measuring systems. Reviews some experimental results obtained from the SEGAS test house. Describes house and measurement method. Finds sealing house reduced ventilation rates by between 30 and 45 per cent.
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