“Another article about healthy indoor climate”, some readers will think. The author finds it necessary to shed light on this important aspect of building and living in detail as a good indoor climate is often reduced to only heating and ventilation. But it must be observed even more aspects. The building- biology takes nature as a model. The aim of planning must be to produce as much as possible natural conditions in the interior.
What makes a healthy indoor climate?
Indoor air quality can be measured by several parameters. The carbon dioxide content in the ambient air amounts to between 350 ppm and 400 ppm (parts per million). Increases the level of carbon dioxide in the interior than 1,000 ppm, a significant deterioration compared to the outside air has already occurred. Measurements in classrooms showed, for example, CO2 levels up to 2,500 ppm.
Another parameter for good indoor climate is the relative humidity. A value below 30% is considered to be extremely dry. The dust content increases. Electrostatically charged surfaces provide space for single positively ionized air. A relative humidity of greater than 70% is considered to be too moist. On cold wall surfaces or behind closets moist air can condense. The resulting surface moisture encourages mold growth.
A hygrometer combined with a thermometer belongs in every household. After all, the room temperature must be checked. At high temperatures, pollutants accumulate increased. Too cold air combined with moisture production in the home creates an excessively high relative humidity with the problems described above. For a sufficient supply of fresh air, an air change rate of 0.5 is required. This means that every two hours, an air circulation is preferably effected by cross ventilation.
Construction and surface design
To avoid accumulation of pollutants and achieve optimum humidity is to pay attention to a diffusion-open design. EIFS can cause trouble in this respect. Insulating material made of polystyrene is relatively vapor-tight. The use of mineral foam board or wood fiber panels is preferable.
The room surfaces are important for a good indoor climate in several ways. Floor and walls should have a high surface temperature. The best condition is when room temperature and surface temperature is the same. The tolerable deviation would be a difference of two degrees Celsius. Wood has a relatively high surface temperature and is as flooring the first choice.
Material inside the room must be hygroscopic, have the ability to absorb water vapor and discharge delay of the room air. A very good assessment in this context, has the building material clay. Also lime plasters are recommended. Very bad rank wall coverings made of plastic. These are also problematic with regard to electrostatic charges.
Building materials and furnishings should, at best, themselves emit no pollutants. Ideally, they have also absorption capacities, that is, they can bind and neutralize gaseous toxins.
Stay on the best smoke-free
The worst killer of indoor climate is and remains the tobacco smoke. This is a whole list of pollutants present, for example PAH = polycyclic aromatic hydrocarbons, particulate matter, benzene, hydrogen cyanide, formaldehyde and carbon monoxide. But, for heaven’s sake, it has now spread throughout our society so.
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