humidity

The problem of indoor air pollution has many facets, ranging from excess humidity, mould and insects over emissions from gas boilers to high levels of various chemicals in tight buildings. The common denominator of all these problems is the existence of several sources of pollution inside a volume of relatively low dissipative capacity. Where the resulting concentration from a single substance exceeds an already established hygienic standard regulatory measures are straightforward. Assessing the risk of several substances being present at the same time is still difficult.

Results of air quality measurements are presented for a group of low-leakage houses located in Saskatoon, Saskatchewan. A total of 46 houses were tested for formaldehyde, nitrogen dioxide, radon, and humidity levels. The median level of formalde

Examines the causes of condensation problems and ways of reducing or eliminating them. Deals with diffusion through the building envelope, mechanical dehumidification and ventilation. Considers condensation inside cavities and roof spaces.

Notes the trend to installing windowless kitchens, bathrooms and W.C.s in the internal zones of dwellings. Describes a research project to measure for internal kitchens the energy consumption and emission of equipment, the total daily energy consumption, air temperatures, air humidity values during cooking, comfort and air speed. Illustrates the test kitchen and gives the results of measurements of around 100 days of simulated operation for a household of four. Notes the consequences for recommended normal and peak ventilation rates.

Fan pressurization tests on 2 unoccupied houses have been conducted once every 2 weeks for a period of a year to determine the seasonal variation in air tightness. House no.1 was built with more insulation than is required by the local building

To simulate time-dependent interior humidity, a moisture mass balance is applied to the control volume of the envelope of a residential structure. Moisture transport mechanisms incorporated include infiltration, cooling coil condensation, int

DEscribes the ventilation system which supplies outdoor air into the living room and extracts air in the kitchen and bathroom as a function of measured air humidity. Explains how air pollution by carbon dioxide and odours from occupants is associated with the production of water vapour. The only pollutants not so associated are in the kitchen and WC, which can have supplementary air evacuation.

Describes large-scale field studies to investigate the effectiveness of measures to prevent condensation in some 4-storey blocks of walk-up flats in Stirling. The remedial measures in the blocks of flats are improvement of thermal insulation

Compares measured hourly data on indoor humidity with data obtained by calculative values for NBS Houston test houses and for the high mass test building in an environmental chamber. Measured values are usually very different from the calculated values if no considerations are given to moisture absorption and desorption phenomena that take place at the interior surfaces. Introduces the Tsuchiya model that permits the evaluation of room surface moisture absorption capability.

Assesses the efficacy of an engineered mechanical ventilation system in controlling indoor humidity in one of the HUDAC Mark XI houses. Develops a mathematical model of the home, which is used to demonstrate the interaction between outdoor humidity, infiltration and ventilation rates, and indoor moisture generation and their influence on indoor humidity levels. Discusses the operating effectiveness of the rotary heat exchanger and the energy saved through its use.