The aims of that study were on the one hand to find out how relative humidity can be reduced by optimal selection of ground covers and air change rates, and on the other hand to evaluate the acceptability of achieved moisture conditions by means of mould growth analyses. Two buildings (one relatively warm and the other relatively cold) were studied with the resistance-capacity network model. Simulations of thermal and moisture buffering effects of air change rates and various ground covers were made.
The aim of that study was to find out if a potential air flow from crawl space has an influence on the indoor air quality : is there a potential risk for the first floor apartments ? A balanced ventilation system is recommended.
The work of Task Force IX started in 1997 at a workshop in Washington Healthy Buildings conference. It continued at the Indoor Air ‘99 conference in Edinburgh, Scotland, and the following workshops took place at Healthy Buildings ‘00 in Helsinki, Finland
Microclimates in moisture chambers and environment in houses were evaluated using afungal index. The index was calculated from the growth rate of a sensor fungus in a test piece,fungal detector, during an exposure period to the test environment. In the constant climates inthe moisture chambers, higher indices were obtained at higher relative humidity. In the roomswith higher fungal indices, the densities of airborne fungi were higher, indicating arelationship between the index and fungal contamination.
The aim was to study changes of symptoms and signs in an office exposed to flooding fromheavy rain. All 18 workers participated in medical investigations in January 1998. Thesubjects were first investigated on a Monday in a reference building and then all moved backand were reinvestigated in a damp building after 2 days of exposure.
A questionnaire on e.g. building characteristics including dampness, and allergic symptomsamong children from 8 918 homes was carried out in the year 2000. 18-24 months later, 6professional inspectors visited 390 of the homes and made inspections and measurements.Questionnaire reports on building characteristics, type of ventilation system, and buildingmaterials were in good agreement with observations from the inspectors (K=0.68-0.87). Individualkappa-values for the inspectors varied in the range of 0.33-0.96.
During the research, air samples were taken by exposure of agar plates and taking smearsamples from the AC equipment. Sampling took place during the autumn because theconcentration of spores at that time reaches its peak.
In two school buildings, concentrations of viable fungal spores in air, material and insurface samples were high indicating moisture and mould damages. Microbesincluded numerous moisture indicating species (e.g. Aspergillus versicolor,Trichoderma, Fusarium, Stachybotrys, Chaetomium, Streptomyces). After renovation,the school buildings were thoroughly cleaned. Surfaces still had abundant anddiversiform microflora. After repeated cleaning, abundance and diversity ofmicroflora diminished.
Moisture-related indicators indoors are, e.g. visible mould and damp spots, condensation onthe inside of window panes, detached floor covering materials, flooding and bad odours. Suchindicators are frequently found and are reported to appear in 25-80% of the buildingsworldwide (Bornehag et al., 2001). Dampness has also been identified as a major risk factorfor, e.g. respiratory symptoms such as asthma, cough and wheezing among both children andadults (Bornehag et al., 2001).
Thermal and moisture performances of whole buildings are rather well understood today andvarious models exist for simulating those. However, models for calculating VOC emissionsfrom or through building envelope parts are still rare and often need specific materialproperties for each transported compound.
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