humidity

This paper summarizes two sets of activities that were undertaken in a Subtask on “Indoor Boundary Conditions”, as part of the International Energy Agency Annex 41. Field monitoring in Europe, Scandinavia and Canada provided new information on moisture ex

Field measurements of the indoor climate have been carried out in 128 lightweight timber-framedetached houses in Finland and in Estonia during the years 2002-2005. The temperature and relativehumidity were continuously measured in bedrooms, living rooms and outdoors for each house at 1-hourintervals over a 1-year period.

Heat and mass transfers in building materials influence the thermal properties and performances ofthe materials more especially as they are porous. This paper deals with the case of various porousbuilding materials (Aerated Autoclaved Concrete, Hemp Concrete and Vertically Perforated Brick)studied by an experimental approach. A cell of exchange makes it possible to impose on a sample,gradients of temperature and relative humidity variables as function of time. The performances ofthese materials are thus deduced from the evolution of T and %RH in several positions.

This study aims at demonstrating that semi-quantitative dampness/mold exposure indices can predict existence of excessive building-respiratory symptoms and diseases. Those findings justify action to correct water leaks and repair water damage in ordre to prevent them.

The distribution of the humidity in a dwelling unit is the key factor determining the condensationrisk and the mold growth, as well as the dryness problem. As the first stage of the research project aiming at the understanding and the solutions of the above problems, the experiment on humidity distribution in multiple rooms with the simulated occupancy was carried out in a full-scale research house. The effects on the humidity distribution of the ventilation, etc. are described and compared with the numerical predictions.

The performance of a passive cooling system was evaluated as part of design works for theproject of an auditorium. The passive cooling system incorporates an array of buried pipes together with a solar chimney. The natural ventilation is enhanced with the help of the solar chimney and fresh air is cooled by circulation within the buried pipes. The application of this system to the acclimatization of an auditorium was evaluated. A model was developed on this purpose, which allows foreseeing the temperature and relative humidity of the air in the auditorium.

Subjective experiments were conducted during the summer season and the winter season in order toclarify the multiplied effects of humidity and indoor chemical pollutants on subjective comfort and productivity. Lower concentration of formaldehyde was observed at low humidity than at high humidity. Subjects rated the acceptability of air lower at the beginning of the exposure in the environments polluted with formaldehyde. On the other hand, lower humidity caused subjects to rate air quality higher in clean air.

In order to clarify the effects of humidity on subjective comfort and productivity under transient conditions in summer, subjective experiments were conducted. Subjects were exposed to 30C/70%RH for 15 minutes in Chamber 1. Then they moved to Chamber 2, in which 4 different conditions were set, and stayed for 180 minutes. For all 4 conditions, SET* was kept constant at 25.2C. Skin wettedness on left chest and skin moisture on left forearm decreased more at low relative humidity. No significant difference in subjective task performances was found among all conditions.

Temperature and humidity changes can affect building materials and the building structure (deformation or breakage). A research was carried out by a holographic interferometer.Thanks to those investigations of temperature and humidity deformation, it has been made possible to give recommendations on maintenance in Russian churches and cathedrals.

The Sint-Pieterschurch in the city of Ghent is one of the largest churches of the city. It was built in the 17th century. The city council wants to use the church not only for its religious functions, but also for cultural activities as concerts and exhibitions. To be able to do this the thermal comfort of the visitors has to be guaranteed. At this moment the church has no central heating system. Gas heaters are used during services. Installing a central heating system will influence the humidity and moisture behaviour of the church.