This is the determination of the temperature value at which condensation forms.
This value allows you to determine the localization condensation, which is located on the surface of the wall or inside it. The feasibility of its calculation is associated with determining the thickness of the wall to save heat.
The importance of determining the dew point is determined by the fact that this process affects whether the wall will be wet on the outside or inside. The condensation temperature depends on following factors indoors:
- humidity level;
- air temperature.
For example, at an air temperature of +20 o C and a humidity of 60% in a room, the temperature value of condensation on any surface is below +12 o C. If the temperature has dropped outside, but inside it is stably constant, then dew point will move in the thickness of the wall closer to the room.
The more precisely the value of the indicator is determined, the higher the probability of creating comfortable microclimate in buildings and structures. The dew point calculation allows you to calculate the segments of the highest humidity.
It is advisable to prevent these processes in order to avoid the development of decay processes and the appearance fungus and mold.
This is achieved dew point shift closer to the outer surface, that is, measures for warming the outside.
Competent calculation the thickness of the insulation will prevent freezing of the walls as a result of freezing and thawing of condensate. Optimally, if the condensate will fall inside the insulation layer.
The main indicators needed for the calculation are humidity and indoor temperature. They are used to determine household psychrometer.
This device determines both indicators. His work based on a thermometer combination cooled by a humidifier. The higher the humidity percentage, the higher the thermometer readings.
For construction needs, electronic devices have been developed that instantly calculate the values of temperature and humidity and display them on the display. Also, some models have the function of calculating the dew point. thermal imagers.
There are several dew point calculation methods:
- according to the formula;
- according to the table;
- using an online calculator.
Formula calculation
Dew point calculation T using a formula, it is carried out at known indicators of humidity and temperature. The final value will be considered approximate due to the neglect of some factors.
t is room temperature o C, φ is humidity%, and 17.27 and 237.7 are constant values.
For example, for a room, normal values are 60% humidity and room temperature 21 o C, calculation will look like in the following way:
So the dew point calculation looks like this:
The condensation temperature is 12.92 o C. Thus, the insulation of the walls from the outside prevent losses heat from the room and freezing of the wall.
Table calculation
The dew point can be determined using a table created by specialists. In order to determine the dew point, for example, for 21 o C at 60% humidity, we are looking for line crossing temperature with a column of humidity and we get a value of 12.9 o C.
Table 1. Dew point definitions. 
Calculation with an online calculator
How to work with an online calculator to calculate the dew point in a wall, look at the video:
Regulations
The need to calculate the dew point is regulated by building codes and regulations. SP 23-101-2004 "Design of thermal protection of buildings", as well as SNiP 23-02 "Thermal protection of buildings". Insufficient insulation shifts the dew point closer to the room.
Since the temperature in the area of window blocks or doors is lower than the total calculated dew point, condensation in these segments is inevitable during the cold season. Dew point determination important for the implementation of the solution which side to carry out insulation work and what thickness it is more expedient to purchase a heater.
Important! The lower the thermal conductivity of the insulation, the thinner the insulation layer will be required. For example, a mineral wool insulation thickness of 0.12 m will be enough, when you need more than 5 meters of reinforced concrete to keep the heat in the room.
table 2. Dependence of wall material thickness on thermal conductivity
| wall material | Coeff. thermal conductivityI, W/(m*oC) | Required thickness in meters |
| 0,039 | 0,12 | |
| 0,041 | 0,13 | |
| Reinforced concrete | 1,7 | 5,33 |
| Silicate solid brick masonry | 0,76 | 2,38 |
| Perforated brick masonry | 0,5 | 1,57 |
| Glued wooden beam | 0,16 | 0,5 |
| Expanded clay concrete | 0,47 | 1,48 |
| gas silicate | 0,15 | 0,47 |
| foam concrete | 0,3 | 0,94 |
| slag concrete | 0,6 | 1,88 |
Minimizing heat loss and maintaining a comfortable microclimate are priorities in the design and insulation of buildings. Compliance with building rules and regulations, as well as sanitary and hygienic standards, will allow you to competently prepare engineering documentation and calculate the volumes of required building materials.