The dew point defines one of the major characteristics indicating state of environment. It is temperature at which the moisture which is airborne begins to be condensed. This situation is considered when calculating construction projects, climatic systems and design of various household and industrial appliances, by production of paint and varnish products and anticorrosive structures.
Temperature of the environment at which there is a condensation of the moisture which is available in air is called a dew point. It is not a constant and it depends on humidity of air and the actual ambient temperature. For each value of air temperature there is the limit of amount of moisture which can keep in the form of steam. At the same time the higher air temperature, the more water can contain in a type of steam. Everything that over this quantity, is condensed. At decrease in temperature and invariable amount of moisture at some point in air this moisture cannot keep any more, and the surplus is condensed. Such temperature is also called a dew point.
When in temperature about one environment, humidity and value of a dew point material with a temperature below a dew point gets, on the surface of its material condensate because in a boundary zone the air cools down drops out.
Dew point in construction
During the winter period on the street temperature is much lower, than indoors. The outer surface of walls is cooled, and internal heats up. In a wall temperature of material accepts transitional values between external and internal. It is important that the point in which temperature equal to value of a dew point for air indoors is formed was as it is possible further from an internal surface and in the thickness of a uniform layer of material of a wall. If it is close located to an internal surface or the internal surface is colder than value of a dew point, then on it moisture will be condensed that promises many problems. The excess of moisture in a plaster coat and on its surface can lead to damage of internal finishing and formation of a fungus and mold. Because of arrangement of a dew point it is not necessary to warm walls from within the room. The dew point will be displaced closer to an internal surface, as a result, condensate and dampness indoors is formed.
Dew point and microclimate
Important components of a comfortable microclimate is air temperature 18-24os and relative humidity of 40-60%. At relative humidity of 100% the actual temperature is just equal to value of a dew point. To raise humidity, various evaporators, humidifiers are used. For decrease in humidity it is possible to use the conditioner at which the heat exchanger has temperature below, than value of a dew point. Thereof moisture is condensed on a radiator and taken away from the room.
Dew point and corrosion-resistant coatings
When drawing a corrosion-resistant coating it is important that the painted surface was heated to temperature above a dew point. Otherwise the formed condensate will interfere with a dense adherence of a corrosion-resistant coating.