Once the flow-pressurization characteristics of a building are known, the largest uncertainty in predicting air infiltration is the effect of wind shelter from nearby buildings. To study the effects of wind sheltering a large data set of hourly air infiltration and meteorological measurements were made for a row of test houses located on an exposed rural site. This configuration produces strong variations in wind shelter as the wind direction shifts from along the row to perpendicular to it.

Conventionally used thermal anemometers are able to measure velocity, but cannot determine direction. In the present study, a new kind of thermal anemometer is presented which consists of a 38mm-diameter sphere with 12 NTC resistances on its surface. Each of them is a single Constant Temperature Anemometer which takes measurements of the local heat transfer on the surface depending on the position on the ball.

Air infiltration and ventilation has a profound influence on both the internal environment and on the energy needs of buildings. In most electrically heated high-rise residential buildings, in cold climates, during the peak winter conditions (below -18 deg C ambient temperature and above 15 km/hour wind velocity), the air infitration component contributes to heating load by 10 to 28 w/m2 - roughly 25 to 35% of peak heating demand. Any reduction in such uncontrolled air infiltration, without sacrificing indoor air quality, will have potential to reduce the peak heating demand.

Simplified, physical models for calculating infiltration in a single zone, usually calculate the air flows from the natural driving forces separately and then combine them. For most purposes-especially minimum ventilation or energy considerations-the stack effect dominates and total ventilation can be calculated by treating other effects (i.e. wind and small fans) as perturbations, using superposition techniques. The stack effect is caused by differences in density between indoor and outdoor air, normally attributable to the indoor-outdoor temperature difference.

Mechanical devices such as exhaust fans and air handlers interact strongly with natural infiltration. In the past, the effects of mechanical systems have either been treated separately from those of natural infiltration or have been combined using simple models. This paper extends the theory of the interaction of unbalanced mechanical systems with stack-driven infiltration. The effects of leakage distribution and the flow exponent on fan efficiency are discussed. A simple model for combining the two effects is presented and compared with two previously proposed models.

This paper describes the application of numerical models to predict the ventilation rate and internal air movement patterns for a naturally ventilated industrial building and compares the results with measured data. Two modelling techniques have been employed. Firstly, a zonal network model (HTBVent), using leakage area data derived from fan pressurisation measurements, was used to predict the time varying ventilation rate in response to variations in wind velocity and internal-external air temperature difference.

The study recommends adoption of the new higher ventilation rates, but with the use of alternative occupancy densities. To verify compliance with Standard 62-89, the study recommends the method of taking a ratio of temperatures to determine percent outdoor air with a total supply air measurement to determine supplied outside air for each air handler serving the building.

This speech comprises a summary of two publications from the Swedish Council for Building Research (BFR); the knowledge survey "Buildings and Health" (BFR T4:90) and "Indoor climate and energy husbandry" (BFR G5:90). One central conclusion presented in both these publications is that the hygienic and climatic requirements are frequently neglected and that they must reassume a central position in the building and building management process.

This paper describes the guidelines prepared by NIST for GSA. These guidelines are organised by envelope construction system and contain practical information on the avoidance of thermal performance problems such as thermal bridging, insulating system defects, moisture migration problems, and excessive envelope air leakage. For each envelope system, both good and bad practice are discussed with an emphasis on the graphical presentation of envelope design details.

Natural ventilation of dwellings is commonly applied, especially in mild and moderate climates. The disadvantage of natural ventilation is the poor control of both flow directions and flow rates within the ventilated building. To improve control, theuse of mechanical exhaust is often recommended. Though this may improve total ventilation, the ventilation of separate rooms often is insufficient still.