building materials

The influence of natural convection on the thermal properties of insulating porous medium with air cavity is studied. Here, the combined effect of air movement in the air cavity and the air movement inside the insulation is evaluated with the help of numerical analysis. The influence of total natural convection on the thermal properties of mineral wool, loose-fill insulation, insulation made of small and large polystyrene ball with air cavity are studied. The results are presented in terms of dimensionless numbers and the temperature distribution across the insulation.

Investigation the modelling of the mathematical model of expediency of project decisions of building materials including the human safety the asbestos. The asbestos is most widely used in the production of roof cover-slate. At this moment the building materials in which composition the asbestos is used, become the actual ecological and economical problem of the country.

The Paper deals with numerical computations, carried out, in order to predict the effects of natural convection on the thermal performance of porous material. In this paper the effect of natural convection in a horizontal porous layer will be discussed. The study of the above configuration is essential to understand the functioning of insulation of the type used in attics. The influence of natural convection on the thermal properties of mineral wool, loose-fill insulation, insulation made of small and large polystyrene balls are studied.

The necessity to provide and maintain high cleanness of air in the rooms of the highestcleanliness classes requires a proper adaptation of selection and designing methods for airfilters. The level of air cleanliness for such rooms is defined numerically by the determinationof the permissible number of dust particles whose diameters are equal or higher than the givenlimit values.

Recently well-insulated and well-airtightened houses are increasing in Japan. Those houses havesome problems of air quality because of formaldehyde from construction materials. Ventilationsystems have possibility to solve these problems. The authors have developed a simulation programfor designing building elements, equipment elements to keep balance among comfortabletemperature and humidity, good air quality and energy conservation. The effects of some ventilationsystems in multiple dwellings are revealed by the developed simdation program.

The objectives of thisinvestigation were to examine the dynamic water vapour sorption offurnishing materials and to compare the experimental results withpredictions obtained from the Moisture Admittance Model. Dynamic sorption measurementswere carried out for common building materials. The measurements were made by placingspecimens of the materials in a humidity chamber and varying the ambient humidity between46% and 90% RH at constant 22C. The weight of the specimens was monitored in situduring this procedure.

Airborne particulate matter is an important form of pollution, which has generated increasing concern in recent years. As well as contributing to poor visibility and surface soiling, airborne particulate matter can have adverse effects on human health. Construction and other civil engineering sites have been perennial sources of nuisance dust (that is, dust deposited on surfaces and generating complaint). However, there is currently no formal advice or Code of Practice for regulating the emission of particles from construction activity.

Source/sink models of volatile organic compound (VOC) emissions from building materials are reviewed and a multi-zone ventilation model is developed to predict concentrations of contaminants in rooms. The source model based on the principles of mass transfer and fluid flow presented by Zhang et al. (1995, 1996) is integrated into the multi-zone ventilation model. The characteristics of the parameters related to voc concentration, i.e. Schmidt number, ventilation rate and air velocity at the free stream are investigated by the sensitivity analysis.