Briefly surveys past work on wind tunnel measurements on the surface pressures on low rise buildings. Describes experimental investigation of the surface pressures on an isolated model. Discusses results of flow around a model of varying height and aspect ratio, and the influence of upstream fetch on surface pressures. Gives figures showing recorded pressure coefficients and details of pressure tappings on the various models.
Describes use of an acoustic method developed by Keast to detect air leaks. A loud source of sound is placed inside the building and a microphone, stethoscope, rubber hose or sound meter is used to detect places where anincrease in sound indicates air leakage. Finds method is effective in detecting simple leaks but will not spot complex paths through walls.
In projects to rehabilitate old buildings in Canada, it is general practice to clear out the entire interior of a building, leaving only the structure and some or all of the exterior walls and roof. The new interior conditions impose more severe loads on the building envelope and hence walls and roofs must be upgraded. Discusses improvement of walls and roofs to increase airtightness, reduce rain penetration and conserve energy use. Discusses the effect of insulation and the location of insulation on the envelope performance and possible types of wall and roof modification.
Reports comparison of three computer programs designed to calculate room air temperature and heating loads. The programs are:< BRIS - a swedish program using a finite difference method< BYVOK - a norwegian program using the thermal response factor method
Discusses condensation within dwellings. Treats conditions conducive to reducing risk of condensation, factors which control concentration of water vapour in the air in a building and temperature of building fabric. Distinguishes between those under control of occupier and those controlled by design of building fabric. Considers in particular effect of ventilation on dewpoint of the air in bedrooms and humidity and temperature conditions in a bedroom during the day. Provides several case histories which illustrate relationship between ventilation and condensation.
Discusses acceptable levels of CO2 contamination in occupied rooms. Describes measurements in a classroom over 3 days using an infra-red analyser with natural ventilation via the windows. Illustrates curves for CO2 concentrations in 8 graphs for closed windows. Notes that limiting value of 0.1% by volume CO2 (1000ppm) is reached in from 5 to 15 minutes. Repeated sudden ventilation by opening windows is not practicable. Evaluates air change rate. Concludes energy saving for ventilation in heavily populated rooms is only attainable by mechanical ventilation with heat recovery.
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.
Presents the results of a series of wind tunnel tests in which the surface pressure fields of low-rise buildings have been studied. These tests start with an examination of how the body shape influences the surface pressures for a range of isolated bodies. The test results then go on to describe how theparameters which describe an array of such model buildings influence the surface pressures.
Reports results of a project to assess energy conservation measures in a group of typical three-storey, naturally ventilated, blocks of flats, built in 1940 in Stockholm. The measures were:< 1) Improvement of boiler efficiency< 2) Weatherproofing of windows and doors< 3) Adjustment of the heating system and reduction of indoor temperature< 4) Additional insulation of attic floor<5) Additional insulation of external walls< Discusses the energy conservation effect and profitability of each measure.
Presents a long term calculation method for indoor air temperature and moisture variation related to the water vapour condensation problem in a detached residence. In this method, the multi-room infiltration calculation is developed. Furthermore the effect of sorption and description of a room, which is evaluated by means of a short term experiment, is introduced.