This paper investigates the effect of ventilation on mould growth in a typical Japanese bathroom byuse of the fungal index which indicates the growth rate of a mould, Alternaria alternata S-78. Thebathroom was set in an artificial climate where the temperature and relative humidity (RH) werekept constant. The temperature, RH and fungal index in the bathroom were measured under severalventilation methods after taking a bath.
The paper deals with a numerical investigation of the influence of ventilation and airconditioning on the distribution of pollutant concentrations in buildings. The model used is acoupled thermal and airflow model where the room is divided into 18 sub-zones.Temperatures and pressures are determined from the mass and energy conservation equationsin each sub-zone, while airflow rates between two adjacent sub-zones are determined from theBernoulli equation.
After several cases of health problems in French schools, a methodology for health riskassessment related to indoor air quality (IAQ) was required. Based on measuredconcentrations in schools where acute symptoms possibly due to exposure to airborne sensoryirritants were reported, an index quantifying the sensory irritation potential was built andused. This paper focuses on one classroom where the index was successively applied withoutany ventilation system, after the implementation of passive ventilation grids and with amechanically controlled ventilation.
A combined windcatcher and light pipe (SunCatcher) was installed in the building of theSchool of Construction Management and Engineering in the MSc Seminar Room (2N09).Monitoring of indoor environment in real weather conditions was conducted to evaluate theperformance of windcatchers in the room and to conduct occupant survey. External weatherconditions and internal indoor environment and air quality indicators were recorded. Thetracer gas decay method using SF6 was used to establish the air change rate for variousconditions.
This paper is a keynote address presented at Ventilation, Humidity Control and Energy 24th AIVC Conference.It is a warning for HVAC professionals that are however walking a tightrope. How provide sufficient ventilation for IAQ that yet maintain an appropriate moisture balance without using excessive energy ?Mold is having a severe impact upon us; excessive ventilation and reducing the energy to control the humidity are oftentimes being blamed. Claims have skyrocketed for mold , mildew and humidity-related problems cases.
The goal of this study was the determination of the existing situation in houses with regard to air quality and energy used for ventilation in relation to the health of inhabitants. For the energy policy the Government is considering increased energy requirements for dwellings. They are permanently opposed in doing so by people who are concerned about negative health effect due to increased requirements on for instance air tightness of buildings. To have at least a reference point, they are interested in the existing situation.
A concept is investigated for the energy efficient control of residential mechanical ventilation in response to outdoor air temperature and the corresponding stack-driven infiltration. The control concept takes advantage of the natural air leakage characteristics of a house and the ability of temperature-driven stack infiltration to provide ventilation air to the house. As the outdoor to indoor temperature difference increases and natural infiltration increases, the fan operation is reduced, thereby minimizing over-ventilation.
In recent years, poor indoor climate has caused health problems for building occupants. Sometimes these problems have been so serious that these buildings have, quite rightly, been labelled sick buildings.Today, there is good evidence in some areas as to why such problems arise. Unhealthy substances given off by various building materials, the existence of mould and general air pollution are the main causes. Another important factor is the high level of humidity in buildings and indoor air.In general, the most important way to remedy the problem is to improve ventilation.
This is a personal set of comments giving the author's impressions of the papers presented at the conference. A great concern of him is the difference between building scientists and health scientists as indoor air quality issues are investigated.
In moderate climates, adventitious ventilation helps in keeping the water vapor balance in a building under control. This does not hold in hot and humid climates, where the outside air is a moisture source. Adventitious ventilation should be avoided in such climates and intended ventilation flows must be dried before entering the space. Anyhow, could adventitious ventilation also generate moisture problems in moderate climates? To get an answer, a reference case was analyzed with the air leakage distributed over facades and roof.
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