Indoor air pollution is defined, and some of the causes are listed, all of which can be harmful to health. The problem is accentuated by recent insulation measures aimed at economising on energy costs, which lead to a dramatic reduction in natu
A handbook of constuction techniques for achieving a low air change rate and good insulation in steel buildings. Insulating materials and how to avoid cold bridges are discussed. Air leakage, moisture problems and comfort questions are also considered. Examples are presented of a small industrial building andof a tennis hall.
A transient simulation method TRATMO with applications to the analysis of the hygrothermal behaviour of timber frame constructions with additional thermal insulation is discussed. This method makes it possible to evaluate the hygrothermal behaviour with respect to risks of mouldering since it gives simultaneous information on moisture content and temperature at certain sections of the construction. Based on the computer simulations and experiments a number of practical aspects to be considered in additional thermal insulation of timber frame constructions are introduced.
Test structures were constructed near Madison, Wis, USA and Gulfport, Miss, USA for exposure of eight types of insulated wall panels at controlled indoor conditions and typical outdoor weather conditions. Panels were instrumented with moisture sensors and tested without and with penetrations (electrical outlets) in the indoor surface. Continuous internal vapour barriers effectively prevented cold weather condensation in all panels. Installation of an electrical outlet changed moisture patterns in both the cold winter climate and the hot, humid summer climate.
Measurements reported in this paper demonstrate the increase in heat transfer due to convective air flow that can occur in wood-frame walls containing air-permeable mineral wool insulation with air spaces in contact with both sides. The effect of this air interchange between the air spaces increases with increasing temperature difference, air space height and air permeability of the insulation. Use of mid-height blocking and higher density insulation thus resulted in some reduction in the heat flow through the insulation, although convective effects were still significant.
Theoretical relationships have been developed to describe the heat transfer by combined fluid conduction-convection through air-permeable insulation with vertical air spaces adjacent to both surfaces. The fluid conduction-convection is shown to be a function of fluid properties, air flow coefficient of the insulation, insulation height and thickness, and temperature difference. A correlation in terms of dimensionless groups has been derived. Results of measurements on a 4-ft high insulation specimen over a temperature difference range from 30 to 90F were in agreement with the theory.
Domestic demands account for about 40% of total energy supplies in Sweden. This article reviews research by the Building Technology Division of the Swedish Royal Institute of Technology over many years into the thermal behavior of houses. It highlights the importance of effective insulation and of solar heat gains in particular situations, entailing modifications to conventional design calculations.
The current German Standard specifies a minimum thermal insulation. However even with excellent insulation, if the air change rate is too low, condensation can form. High humidity emissions in dwellings can require air change rates of more than 2/hour. The use of mechanical ventilation, possibly humidity-controlled and with a heat recovery system, is suggested to minimize ventilation heat losses. The user has to be educated to provide adequate ventilation in spring and autumn, but during the cold season the ventilation rate can be reduced to two thirds of the minimum value.
The Linford project involved designing, building and monitoring 8 low energy passive solar houses. The houses were insulated to current Danish Regulation standards. Seven occupied and 1 unoccupied test house were monitored over two years.