Thermal imager for construction: types and rules of house inspection
Objectively evaluate the work performed on the insulation of a private house can be a number of signs. In most cases, this is the amount of energy spent on heating and the readings of thermometers. But if the insulation proved to be ineffective, it is difficult to find the reasons without special equipment.
In such situations, a thermal imager is used for construction. In our article, the principle of operation and design features of the device are described in detail. The rules of use and processing of data obtained during thermal imaging are given.
The content of the article:
Why do thermal imaging?
Inspection by a building thermal imager of a cottage, cottage or residential building makes it possible to see on a thermogram what is happening inside various objects and structures of the building, without touching them at all. This is called non-destructive testing.
This kind of inspection will show the condition of the heating pipes in the walls and underfloor heating without opening the plaster or tile.
The sensitivity of some models reaches hundredths of a degree, thanks to which you can not only see the thermal footprint on the surface of structures, but also find out what is happening inside.
The unique advantage of modern thermal imagers over other means of control is precisely the ability to look inside objects without violating their integrity. Even a minimal deviation of temperature indicators from the norm will indicate a malfunction, for example, in the power grid.
Checking a private house with a thermal imager will help solve a variety of problems:
- localize places of heat leakage and determine the degree of their intensity;
- monitor the effectiveness of vapor barrier and detect the formation of condensation on various surfaces;
- choose the right type of insulation and calculate the required amount of insulation material;
- detect leakage of the roof, pipelines and heating mains, leakage of coolant from the heating system;
- check the airtightness of window double-glazed windows and the quality of installation of door blocks;
- diagnose ventilation and air conditioning systems;
- determine the presence of cracks in the walls of the structure and their size;
- to find places of blockages in the heat supply system;
- diagnose the condition of the wiring and identify weak contacts;
- detect habitats of rodents in the house;
- Find sources of dryness / moisture inside a private building.
The thermal imager makes it possible to quickly verify the compliance of the parameters of the erected building with technical requirements, evaluate the quality of an immovable object before purchasing it and diagnose the operation of internal communications.
And after the completion of work, thermal imaging will allow us to control the final result and detect installation flaws that create heat loss. The check will also show the cold bridges, which can be quickly removed in preparation for the winter season.
Before reconstructing or repairing old structures, an infrared camera device will come to the rescue to identify the coldest areas and places of leakage, problems with underfloor heating, and objectively evaluate the amount of planned construction work.
Device and principle of operation
A sensitive element of any thermal imager is a sensor that transforms the infrared radiation of various inanimate and living objects, as well as the background into electrical signals. The information received is converted by the device and displayed on the display in the form of thermograms.
In mechanical devices, the heating of the individual constituent parts occurs due to constant friction at the points of contact of the moving elements. In equipment and systems of electrical type, conductive parts are heated.
After pointing and shooting an object, the infrared camera instantly generates a two-dimensional image containing complete information about temperature indicators. Data can be saved in the memory of the device itself or on external media, or can be transferred using a USB cable to a PC for detailed analysis.
Some models of thermal imagers have built-in interfaces for instant wireless transmission of digital information. The recorded thermal contrast in the field of view of the thermal imager allows you to visualize the signals on the device screen in half-tones of a black-and-white palette or in color.
Thermograms show the intensity of infrared radiation of the studied structures and surfaces. Each individual pixel corresponds to a specific temperature value.
On the black and white screen of the thermal imager, the warmest areas will be displayed with the lightest. All cold objects will be almost indistinguishable.
On a color digital display, areas that emit heat more than others will light up in red. As the radiation intensity decreases, the spectrum will shift toward the violet. The coldest zones will be marked in black on the thermogram.
To process the results obtained by the thermal imager, just connect the device to a personal computer. This will allow you to reconfigure the color palette on the thermogram so that the required temperature range is best seen.
Modern multifunctional devices are equipped with a special detector matrix, which consists of a huge number of very miniature sensitive elements.
The infrared radiation captured by the thermal imager lens will be projected on this matrix. Such IR cameras are capable of detecting temperature contrast equal to 0.05-0.1 ºC.
Most models of infrared imagers are equipped with a liquid crystal control display to display information. However, the quality of the screen does not always indicate a high level of infrared equipment in general.
The main parameter is the power of the microprocessor involved in encoding the received data. The speed of information processing plays a major role, since pictures taken without a tripod may be blurry.
Another important parameter is the resolution of the matrix. Devices with a large number of sensitive elements give better two-dimensional images than thermal imaging devices with a lower resolution of the detector matrix.
This difference is explained by the fact that one sensitive cell accounts for a smaller surface area of the studied object. In high-resolution graphics, optical noise is almost invisible.
Types of thermal imaging devices
Checking a private house for heat loss with an infrared camera makes it possible to conduct the most accurate measurements and a qualitative analysis of all temperature indicators. And after that, based on the promptly received data, competently perform repair work and / or modernization of the residential facility.
For thermal imaging diagnostics, two types of devices are used:
- stationary thermal imagers;
- portable infrared cameras.
Stationary appliances are used mainly in manufacturing enterprises. They are designed to regularly check the status of power grids and constantly monitor complex technical equipment. Stationary thermal imaging systems are made on semiconductor arrays of photodetectors.
Using portable thermal imagers, energy audits of residential multi-apartment buildings and private buildings are carried out. These devices are used both for a one-time local check, and for complex diagnostics of houses.
Portable thermal imagers are developed on the basis of silicon uncooled microbolometers and are excellent for use in hard-to-reach places.
Depending on the functionality, there are three types of thermal imagers:
- Observational instruments - provide only visualization of various heat-contrasting objects, often in monochrome.
- Measuring devices - create a graphic image within the infrared radiation and assign each point of the light signal a specific temperature value.
- Visual pyrometers - designed for non-contact temperature measurements and visualization of the thermal field of specific objects in order to detect areas with deviations from normal values.
The price of good functional thermal radiation receivers starts at $ 3,000. Their purchase for a one-time examination at home is simply unprofitable. Many companies today offer building imager for rent for a day. This is a very convenient service.
You can also order a full professional thermal imaging survey of the cottage / house. The average cost of shooting a thermal imager is $ 5 per 1 square meter of area of a private residential facility.
As a rule, the cost of thermal imagers is an indicator of their functionality. But even budget models effectively perform infrared diagnostics. Therefore, when choosing, it is worth focusing on basic technical characteristics and the ability to solve specific problems.
A big plus is the availability of additional functions, namely: digital scaling, laser pointer, annotation of thermograms, customizable color alarm, definition of areas with maximum and minimum temperature indicators.
Significantly simplify thermal imaging diagnostics at home and various accessories - removable optical wide-angle lenses for consideration of the general plan and telephoto lenses for detailing critical areas, folding tripods, storage containers for batteries.
Thermal imager application rules
The main task of a thermal imaging survey is to accurately identify heat losses and defects in the operation of engineering systems, as well as to detect possible weak points of a residential facility at the construction stage.
Thermal diagnostics of buildings includes:
- examination in the long-wave IR region in the range of 8-15 microns;
- building a temperature map of the studied objects and surfaces;
- monitoring the dynamics of thermal processes;
- accurate calculation of heat fluxes.
Inspection of a residential property is performed both outside and inside the building. In the first case, infrared photography allows you to detect gross defects in the infiltration of air flows through the building envelope and defects in thermal insulation. In the second - to identify errors in functioning heating system and power networks.
The higher the temperature difference, the more accurate the test results. In addition, in order to obtain the correct data, the surveyed residential facility must be uninterruptedly heated for at least 2 days. In the summer, it is practically useless to examine the building with a thermal imager due to the minimum temperature difference.
Inspection of buildings by heat radiation receivers shows the distribution of temperature fields on the surfaces of objects or structures at a particular point in time. Therefore, shooting with an infrared camera is highly dependent on a number of conditions, the observance of which is critical for obtaining correct results.
The device is affected by strong wind, sun and rain. Under their influence, the house will cool or heat up, which means that the check can be considered ineffective. The examined structures and surfaces should not be in the area of bright direct rays of the sun or reflected radiation within 10-12 hours before the start of thermal imaging diagnostics.
It is recommended that door and window blocks be kept in a fixed position for 12 hours before shooting with an infrared camera and during building verification.
Before the start of the examination at home on the device, you need to set the basic settings, namely:
- set the lower and upper temperature limits;
- adjust the range of thermal imaging;
- choose intensity level.
Other indicators are regulated depending on the type of insulation, wall materials and ceilings. An energy audit of a private house begins with a check of the foundation, facade and roof of the building.
At this stage, it is very important to conduct a thorough diagnosis, since the areas on the same plane are significantly different and the heat radiation detectors will definitely show this.
The shooting is carried out in the direction from the window blocks to the doors, slowly exploring all technological openings and walls. At the same time, the doors between the rooms are left open in order to stabilize the flow of heated air and minimize the probability of measurement errors.
Thermal imaging control involves the phased verification of different areas of the enclosing structures, which must be open for shooting with an infrared camera. To do this, you need to free up the window sill, organize unhindered access to skirting boards and corners.
Walls for the duration of the building’s internal thermography must be freed from carpets and paintings, exfoliated old wallpaper and other objects that impede the direct visibility of the object under study.
Houses equipped with heating radiators are usually removed only from the outside. Facade diagnostics are carried out under favorable weather conditions - the absence of wet fog, smoke, and precipitation.
Interpretation of received data
Thermal imaging devices capture a temperature difference of 3 ºC, and this will be displayed on the thermogram as an anomalous zone in the characteristic color spectrum. However, the spectrozonal image itself is insufficient justification to consider the diagnosed area defective.
That is why instrumental software for qualitative and quantitative analysis of thermograms, as well as reporting, is supplied with portable thermal imagers.
All this means that special training is not required to work with an infrared camera. Having studied the user manual, it is easy to independently conduct thermal imaging verification and processing of the results in the proposed program. After analyzing the obtained indicators, the application will give an expert assessment of the images.
In addition, the information collected by the equipment can be transferred to programs for processing statistical data - table processors or special engineering utilities, for example, MathLab.
It is also worth noting that the thermal imager may give incorrect results in case of incorrect settings. Similar situations occur when examining such surfaces as glass, glossy tiles, mirrors.
Infrared radiation from nearby objects will be reflected in these surfaces, which will lead to distortion of thermograms. To correctly determine the temperature of the mirror surfaces in thermal imaging devices, it is necessary to additionally adjust the correction factors.
A quantitative method for analyzing the distribution of temperature fields over the surface of structures does not take into account the emissivity and background radiation of the environment. Moreover, it does not matter whether the IR camera is shooting on the spot or the results are processed by software.
When carrying out diagnostic measures inside the building, more reliable results are obtained, since external climatic conditions do not affect the surfaces under study. The resulting thermograms after processing with appropriate programs are true.
Using a building thermal imager allows you to objectively assess the quality of thermal protection of a building, detect cold bridges and insulation subsidence, as well as find hidden damage and defects in the installation of window blocks, doorways, poor-quality joints of the roof, walls and ceilings.
Infrared diagnostics makes it possible to correctly, and therefore economically, perform work to minimize heat loss in a residential facility, reduce costs by floor insulation and thermal insulation of other structures.
Conducting a research procedure will provide an opportunity to correctly select insulation for walls and the ceiling private built. As a result, the cost of heating a private house will decrease.
Conclusions and useful video on the topic
The principle of the thermal imager, checking the building after insulation for defects and the correct interpretation of images in infrared rays in the video:
Functionality of thermographic scanners:
Video on how to analyze and create a technical report for diagnosing a home with a thermal imaging device using the Testo IRSoft software module:
Today, infrared imaging with an infrared camera is an advanced non-destructive monitoring technology that allows you to monitor the status of various structures, communication networks and electrical equipment.
The study of heat loss with the help of a thermal imager is carried out in order to prevent emergencies, to detect defects in thermal and waterproofing, to identify malfunctions of engineering systems at home.
Do you have experience using a thermal imager to study weaknesses in your country house / apartment? Perhaps you can share useful information on determining heat loss by a building structure? Please write comments, ask questions, post a photo on the topic of the article in the block below.
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When we built our skeleton, we called a specialist with such a thermal imager. Very comfortably! Our house is ecological, instead of insulation, sawdust is dry, so it was necessary to look where they normally fell asleep, where not. They called two times, as they built and flooded the stove inside (it was December) and the next fall, when a steady 0º on the street. We looked through everything, eliminated heat leaks. Of course, I took the money normally, but I do not regret it. If they didn’t go through a thermal imager, then they would go bankrupt on heat loss and on a remake.
Even if you are building a budget house, do not save on the quality of insulation. Let sawdust or fashionable ecowool. It is better to go twice with the appliance than to patch it later and think about why it blows and where the heat goes.
The thermal imager is a useful little thing, but here's the problem: it costs a lot. And you will use it from strength 2-3 times. And then, in general, it will come in handy once to check the quality of insulation, and that’s all. I ordered thermal insulation in a company that has been doing this for more than a year. He came to the site himself and checked how the work was being done. The superintendent had a thermal imager, he checked the house with me with him. In general, it is not suitable for home use.
Is it possible to check a house with a thermal imager for hunting, or are they radically different from a building something?
Hello. Each device has its own purpose. They have completely different characteristics, indicators and non-universal application. Therefore, we still advise you to purchase a construction device.