Each of us has repeatedly witnessed the formation of water droplets on the surrounding objects and structures.This is explained by the fact that on the subject, brought by a cold, cool the surrounding air.It is saturated with water vapor and dew condensation on the subject.
the same nature is fogging the windows in the apartment.The reason that the "window crying" are condensation processes that are affected by humidity and ambient temperature.
Condensation is closely linked with the concept of the dew point.For a better understanding of the phenomena described in more detail just need to consider this factor.
dew point.What is it?
dew point - the temperature is cooling the surrounding air, in which the water vapor that it contains starts to condense, forming dew, that is a temperature of condensation.
This figure depends on two factors: air temperature and relative humidity.The dew point of the gas is higher, the higher the relative humidity, that is, it is close to the actual ambient temperature.Conversely, the lower the humidity, the lower the dew point.
How to calculate the dew point?
Calculation of the dew point is important in many aspects of life, including in the construction.From the correctness of the determination of this parameter depends on the quality of life in the new building and has long handed over the premises.So how to determine the dew point?
to determine this indicator are approximate formula for calculating the dew point temperature Tr (° C.), which is determined by the dependence of relative humidity Rh (%) and temperature T (° C.):
With some devices it calculated?
So how, in practice, is calculated dew point?The definition of this indicator is made by a psychrometer - device consisting of two alcohol thermometer that measures the humidity and air temperature.Nowadays mainly used in laboratories.
for inspection of buildings used by portable thermohygrometers - electronic devices, the digital display which displays the data on the relative humidity and air temperature.On some models, even the dew point displays.
also a function of calculating the dew point have some thermal imagers.When this is displayed thermogram which real time visible surface with a temperature below the dew point.
Table calculate the dew point
With household psychrometers easy to measure humidity and temperature of the surrounding air.Using the display of this unit, the temperature of condensation can be found using the table.Through the estimated parameters of temperature and humidity determined dew point.TABLE its calculation is as follows:
How is the temperature of the dew in the building?
dew point measurement - a very important stage in the construction of buildings to be carried out at the stage of project development.From its accuracy depends on the possibility of condensation of the air inside the room, and therefore the further comfort of living in it, as well as its durability.
Every wall has a certain moisture content.For this reason, depending on the material quality and wall insulation thereon can condense.Dew point temperature is dependent on:
- humidity in the room;
- temperature.
Thus, using the reduced above table, it can be determined that the room temperature to 25 degrees and relative humidity of 65% condensate will be formed on surfaces having a temperature of 17.5 degrees and below.It should remember pattern: the lower the humidity in the room, the greater the difference between the dew point and the temperature in the room.
The main factors that affect the location of the dew point, belong:
- climate;
- temperature inside and outside;
- humidity inside and outside;
- regime stay in the room;
- quality functioning of heating and ventilation systems in the room;
- thickness and material of manufacture of the walls;
- insulation of floors, ceilings, walls, and so on. D.
Features neuteplёnnyh
walls in many rooms wall insulation is completely absent.In such circumstances, the following behaviors dew point depending on its location:
- between the outer surface and the center of the wall (the inner part of the wall always remains dry).
- between the inner surface and the center wall (on the inner surface condensation can occur, provided a sharp cooling of air in the region).
- on the inner surface of the wall (the wall will remain wet throughout the winter period).
How to insulate the wall?
warmed wall At the dew point can be located in different places of a heater that depends on several factors:
- Thermal insulation properties of the insulation is reduced with increasing the level of its humidity, as water - an excellent conductor of heat.
- presence of insulation defects and gaps between the insulation and the wall surface creates good conditions for the formation of condensation.
- Droplets of dew significantly reduce the insulating properties of insulation, as well as help for the development are the fungal colonies.
Thus, it is understood the risk of using the walls for insulation materials, moisture passing because they are susceptible to loss of heat-shielding properties and the gradual destruction.
Also, be sure to pay attention to the ability to choose materials for thermal insulation of walls to resist fire.It is better to opt for the materials with organic content of less than 5%.They are considered to be non-flammable and the most suitable for thermal insulation of residential buildings.
External wall insulation
ideal option protect the premises from the damp and cold is external wall insulation (provided that it is made in compliance with the technology).
In that case, if the thickness of insulation is chosen optimally, the dew point will be in the insulation.The wall will remain completely dry throughout the cold period, even at sharp cooling dew point reaches the inner wall surface.
If insulation thickness has been calculated incorrectly, you may experience some problems.Dew point is moved to the boundary interface heat insulating material and the outer side wall.The voids between the two materials can occur condensate and accumulate moisture.In winter, when the temperature drops below freezing, the moisture will expand and turn into ice, contributing to the destruction of thermal insulation and partially walled.In addition, the surfaces of constant humidity leads to the formation of mold.
With complete disregard of technology and gross errors in calculations of possible options to offset the dew point of the inner surface of the wall, leading to the formation of condensation on it.
internal wall insulation
insulate the wall from inside - initially not the best option.If the insulation layer is thin, the dew point will be located on the boundary of the insulating material and the inner wall surface.Warm air in the room when a thin layer of insulation practically will not reach the inside of the walls, leading to the following consequences:
- high probability of wet and freezing the wall;
- hydration and, as a consequence, the destruction of the insulation;
- excellent conditions for the development of mold colonies.
However, this method of warming the room can be effective.To do this, you must comply with certain mandatory conditions:
- ventilation system must comply with regulations and avoid excessive moisture of the ambient air.
- thermal resistance of the construction fence, in accordance with regulatory requirements, must not exceed 30%.
What is fraught with neglect of condensation in the construction?
In winter, when the temperature is almost always below freezing, warm air inside the room, contact with any cold surface, supercooled and falls on its surface in the form of condensate.This occurs when the condition that the respective surface temperatures below the dew point calculated for the data of temperature and humidity.
If condensation occurs, the wall is in a wet state is almost always at a lower temperature.The result is the formation of mold and development in its wide variety of harmful microorganisms.Later they moved to the surrounding air, which leads to various diseases tenants are often indoors, including in asthmatic disorders.
addition, homes ravaged by mold and fungal colonies, is extremely short-lived.The destruction of the building inevitably, and begin this process is to dampen the walls.That is why it is important to make correct calculations with respect to all the dew point at the stage of design and construction of the building.This will make the right choices about:
- thickness and material of the walls;
- thickness and insulation material;
- method of insulating walls (interior or exterior insulation);
- choice of ventilation and heating system that will provide an optimal indoor climate (the best ratio of relative humidity and temperature).
Calculation of the dew point in the wall, you can make yourself.It should take into account the climatic characteristics of the region of residence, and other nuances The given previously.Still, better to turn to specialized construction companies, are engaged in similar calculations in practice.And the responsibility for the correctness of the calculations will be based not on the client, and representatives of the organization.
