AIVC - Air Infiltration and Ventilation Centre

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Relative humidity is one of the most important parameters which have an influence on human comfortand indoor air quality. Materials exposed to the air can absorb and desorb moisture and thereforeinfluence the relative humidity level. However hygroscopic materials are not always taken into accountin building energy performance simulation codes. The objective of presented work was to improvepredictions of the indoor relative humidity in a well known energy simulation tool TRNSYS.


We already have had theoretical model to predict temperature and humidity variations in a room. Manyworks have estimated the accuracy of the numerical model, but they might be influenced by the airmovement. Thus, theoretically the temperature and humidity variations should be solved with airmovement in a room. In this paper, I calculated the minute temperature and moisture distributions in aroom which has the moisture buffering effects by the porous walls. The room space is regarded asrectangular box which has two hole, inlet and outlet for ventilation.

Dynamic Moisture Behaviour of Materials for Integration into Whole Building Heat Air and Moisture Simulation

Indoor humidity is an important parameter influencing the occupants’ perception of indoor air quality, and is also a cause of harmful processes that may occur on surfaces of materials, such as cracking of walls or microbiological growth. Building material

Assessment of Heat and Mass Transfers in Building Porous Materials

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.

Dynamic spatial three-dimensional thermal comfort analysis underneath a cyclist helmet

Nevertheless the proven benefit of a cyclist helmet in preventing serious head injuries whena crash occurs, many cyclist still refuse to wear a crash helmet. The main reason for not wearing acyclist helmet is the sensation of discomfort encountered when wearing one. This paper evaluates and analyses - for the first time - both local and global temperature levels and moisture production in order to obtain insight in the interaction between both mechanism, as a response to differences in effort level, air velocity and air temperature, and how to improve its thermal comfort features.

Nasal histamine reactivity among adolescents in a remediated moisture-damaged school - a longitudinal study

This paper sums up a longitudinal study carried out on a group of students and teachers in a remediated moisture-damaged school. Registration of subjective data (questionnaires) and objective data (nasal histamine reactivity) has been made. Results and discussion are presented.

How unbalanced return air encourages mold growth

There are two ways for unbalanced return air to produce moisture and mold problems during hot and humid weather : - the increased entry of outdoor air that substantially increases indoor relative humidity. - a negative pressure can draw moist air into wall cavities causing a moist interstitial microclimate, if indoor humidity is relatively low in the conditioned space.To prevent the creation of moisture and mold problems, properly sized return ducts should be provided.

Estimating effects of moisture damage repairs on students' health - long-term intervention study

After the moisture damage repairs, a health symptom questionnaire study was repeated 1 year, 3 years and 5 years on 245 upper secondary and high school students. The data were analyzed. The results indicate that no new cases of symptomatic students occured : in that sense the repairs succeeded.

Setting up a database of indoor climate measurements in recently built Belgian dwellings

One of the major sources of problems in dwellings -if not the main source- is moisture, especially due to surface and interstitial condensation on walls and roofs. For this reason, it seems important to evaluate the current standardisation and reference documents dealing with moisture and eventually to develop new assessment methods. This is the goal of the Belgian project "Moisture problems in roofs", carried out by BBRI, KUL, RUG and W&K. The first step is to collect a large number of indoor climate measurements in recently built dwellings built.

Dampness in buildings and health (DBH) : report from an ongoing epidemiological investigation on the association between indoor environmental factors and health effects among children in Sweden

The aim of this paper is to identify the link between indoor environmental factors and asthma or allergic symptoms among small children and their parents. That four-phases Swedish study will be lasting from 2000 until 2008 : First step : an epidemiological cross-sectional questionnaire on housing and health involving 14,077 preschool children (2000).Second step : a nested case-control study including 198 children with symptoms and 202 healthy controls.