This sixteen-page digest provides a guide to why condensation occurs in buildings and how to avoid it. Outlines causes of condensation problems in buildings.Gives 9 case studies. Discusses physical principles of moisture transfer. Describes vapour sources in buildings. Outlines ways of reducing thecondensation risk in buildings. Gives methods for predicting when condensation will occur.

Reports insights from research project "Optimalisatie koelhuisbouw" (Optimisation of cold store buildings) by the Delft Technical University for the Foundation for Cooling Technique Development. Pleads for standardisation of the maximum admissible heat gain by air leakage and yearly averaged pressure differences between the cold room and its surroundings. Gives some numerical examples. Uses theory of specific equivalent leak opening.

Reports experimental measurements carried out in a boundary layer wind tunnel at the University of Western Ontario. Both external and internal pressures on two different models were measured with different porosities for the walls. Discusses results and concludes that mean internal pressures measured in thewind tunnel agree well with analytically predicted values that accurate evaluation of internal pressures is necessary to calculate building air infiltration.

Discusses the use of a regenerative air-to-air rotary heat exchanger (thermal wheel) for heat recovery in residential ventilation systems. Describes a small rotary heat exchanger designed to handle low air flow rates typical of residential houses. The heat exchanger is constructed of a light-weight honeycomb structure made of aluminium foil sheets. Laboratory tests of the heat exchanger showed a high sensible heat recovery effectiveness of the order of 85% with acceptable levels of pressure drop and cross leakage. Cost saving analysis showed significant savings even at today's energy cost.

Reports tests on 4 different windows of air leakage and sound transmission loss. Expresses each of these two quantities by a single parameter and finds reasonable correlation between the parameters. Concludes, within the limitations of the method, that the air leakage class of a window can be deduced from field measurements of sound transmission loss, when the acoustical performance in perfect sealing conditions is known.

Describes the operating characteristics of a small aspirated concentration sensor based on a hot-film anemometer. Constant aspiration velocity past the sensor produces a linear output over a wide range of tracer gas concentrations, and a useful bandwidth of 0-500 Hz. A simple experimental technique for dynamic calibration is presented, with frequency response inferred from a model of the effects of molecular diffusion and hot-film response.

Notes that some of the main contributors to excessive ventilation in industrial buildings are external doors and loading bays. Discusses the choice of industrial doors to minimise energy loss. Discusses flexible doors, strip doors, loading bays, air curtains and door sealing.

Reports a systematic investigation of the wind pressure variations when test models of varying height are surrounded by uniform roughness arrays of various densities in a boundary layer wind tunnel. Describes the effect of the surrounding roughness in shielding the bluff model when the model height is less than the average roughness height and of the degree of exposure experienced by a model taller than the surrounding roughness. Discusses results and gives 24 graphs of pressure coefficients.

Continues an investigation of surface pressures on models in a boundary layer wind tunnel. Part One gave results of measurements on isolated models, Part Two considered the same models in arrays of various densities. Gives vertical distribution of pressure coefficients measured on the centre line of windward and leeward faces of all the models in various layout densities. Discusses the effects of varying layout density, aspect ratio and roughness fetch. Includes 64 graphs of pressure coefficients.