Thermal Detection ...

... helps you to uncover potential weak points and to find the source of the problem faster. We will be talking about thermal imaging in general, use cases and tipps and tricks for the application.

What is thermal detection?

Thermal detection is a method of measuring the surface temperature of objects by using infrared radiation.

A thermal imaging camera measures the surface temperature of an object and shows this as a thermal image in the display. This provides a clear and simple overview of heat distribution and differences in temperature.

Thermal Cameras and Infrared Thermometers

Thermal imaging example photo

What is thermal imaging?

A thermal imaging camera makes thermal radiation visible. A thermal image shows the distribution of temperatures within a measuring range. Each pixel of the camera contains information about a temperature point. A thermal imaging camera measures the surface temperature of objects and shows this as a thermal image in the display. This provides a clear and simple overview of heat distribution and differences in temperature.

Infrared temperature measuring example photo

What are infrared thermometers?

The spot thermometer always measures the average of a circular area between the two laser points. The temperature measurement is only punctual at this specific point. The average temperature inside this area is shown as the measured value on the display. In addition to surface temperature, the infrared spot thermometer from Bosch Professional can also measure relative humidity and ambient temperature.

What is Infrared-Thermography?

Infrared thermography is the contact-free measuring and imaging of an object's surface temperature.

Example: Perception of light vs. perception of heat or thermal energy

Perception of light

  • Perceiving the reflection caused by an external source of radiation. In this example: the light reflects on an object, therefore we are able to see it
  • Visual perception: eyes or photography

Perception of thermal energy

  • Perceiving the self-radiation, independent of an external source
  • Perception over skin or IR thermography: the thermal energy can be felt or made visible with a thermal detector

Infrared radiation

  • Thermal energy is stored in every body at its own temperature T above absolute zero (-273.15 °C = 0 Kelvin)
  • Part of the thermal energy is emitted from the surface in the form of electromagnetic radiation (= self-radiation)
  • Infrared radiation lies in the infrared range of the electromagnetic spectrum, which is invisible to the eye

Where is infrared radiation to be found in the spectrum of electromagnetic radiation?

What is emissivity?

Emissivity is a parameter that provides information about how much thermal radiation an object emits and how strongly the reflected temperature influences the measurement. The emissivity has a substantial influence on the accuracy of the temperature measurement that can be achieved. In order to obtain the most accurate measurement result, the emissivity must be adapted to the material of the measured surface in the settings.

The highest measuring accuracy can be achieved:

  • For surfaces with high emissivity
  • When the correct emissivity is set
  • When the correct background temperature is set

How does emissivity influence a thermal image?

High degree of emissivity

  • Most of the energy comes from the object
  • Reflection → less relevant

Low degree of emissivity

  • Majority of energy comes from the reflected object
  • Reflection → important to consider!

Advantages and things to consider

Infrared measuring (Thermal imaging)

Infrared measuring (Thermal imaging) example photo

Advantages

  • Contact-free, therefore measuring is possible with objects that ...
    • ... are resting and moving
    • ... are heavily accessible
    • ... are very hot and
    • ... are current-carrying
  • Non-reactive and destruction-free measuring
  • Very short measuring time
  • Area-measured temperature information

Consider!

It is necessary to ...

  • ... have knowledge about the surrounding conditions
  • ... adjust your tool
  • ... be aware that only the surface temperature is measured

Contact measuring (Thermocouple)

Contact measuring (Thermocouple) example photo

Advantages

  • Direct and therefore precise measurement
  • Avoid measuring mistakes via sensor (no adjustment of emissivity degree)
  • Possibility for measurements ...
    • ... of heavily reflecting surfaces
    • ... within liquids and objects
    • ... of air temperature
    • ... of small and rounded object fields

Consider!

  • No thermal image, only punctual measurement
  • Measurement is not non-reactive (sensor is changing the temperature of the measuring point, consider acclimatization time; security)

Why is thermal detection needed?

Applications for thermal detection

Insulation check of roof

Routing of the floor heating

Verify floor heating distribution

Window and door insulation

Heating in- and outflow of radiators

Radiator

Electric cabinet

Examination of exhaust system

Side mirror heating

Front window heating

Heat detection engine bay

Fields of application for thermal detection

Electricians

  • Regular inspection and preventive maintenance (finding and documenting abnormalities)
  • Fault detection and inspection of electrical components (e.g. cable connections, fuses)

Electricians

HVAC

  • Check floor heating
  • Locate heating pipes, pipe blockages and leakages
  • Check radiators, heating- and AC-systems

HVAC

Window installer

  • Insulation evaluation
  • Visualize energy losses
  • Detect thermal bridges and sources for leakages

Window installer

Renovation

  • Detect construction failures
  • Find leakages in insulation
  • Pinpoint water intrusion
  • Find pipes to avoid drilling into them

Renovation

Automotive

  • Inspection of engine compartments (e.g. fuse boxes, the catalytic converter and the coolant cycle)
  • Checking of comfort heating systems (e.g. windshields, mirrors, seats)

Automotive

Industrial Applications

  • Checking air circulation, oil pumps and insulation of hardening plants
  • Inspect rollers in conveyer belts
  • Monitor fill levels
  • Inspect low voltage installations such as switches, fuse boxes etc.

Industrial Applications

Agriculture

  • Thermal imaging on animals (for veterinary usage please check country-specific regulations)
  • Check machinery (e.g. prevent overheating)
  • Beekeeping
  • Check temperature in silage

Agriculture

Veterinary Medicine

  • Monitoring of inflammation and healing processes
  • Localization of infections or inflammations in the area of tendons, ligaments, muscles, nerves and teeth
  • Horses: inspection of hoof and checking of saddle fit
  • For veterinary usage please check country-specific regulations on our homepage

Veterinary Medicine

Use cases for thermal detection

Potential user problem – Apartment does not heat up well

Potential situation:

  • Radiator hot water input is not set properly. Need to readjust the central heating system.
  • Radiator contains air, so it cannot reach the full heating performance. Need to vent the system.

Relevant for:

  • HVAC (Heating, Ventilation, Air Conditioning)

Potential user problem – Where are the heat pipes in the floor?

Potential situation:

  • Drywall installer wants to build a new drywall and needs to fix the profiles for the new wall. He knows there is a floor heating but does not know location of heat pipes.
  • Parquet is laid but baseboards need to be installed. Most heat pipes are located close to the floor. Danger to drill into it.

Relevant for:

  • Dry Wallers
  • Parquet layers
  • Window & door installation businesses

Potential user problem – Power breakdowns

Potential weakness:

  • Defective or weak fuse
  • Lose screw / cable leads to overheating
  • Cable diameter too thin (voltage to high - more heat danger of burnt cables)
  • Overheated machine due to missing oil in ball bearings

Relevant for:

  • Electricians
  • Maintenance services
  • Industrial maintenance & machine control

Potential user problem – Apartment does not heat up well

Potential situation:

Floor heating is not working as it should because

  • the pipes contain dirt and do not heat up evenly. Might have to be cleaned.
  • there is leakage and the floor gets moist.

Relevant for:

  • HVAC
  • Sanitary (e.g. want to install a bigger bathtub but do not want to hit the floor heating pipes)

Tipps & Tricks

Emissivity

Problem:

  • Measurement of the exact temperature of the heating element

Consider Emissivity:

  • Make sure to set the emissivity value and the reflected temperature to get the precise value of Degrees Celcius.
  • This way, a corruption of measured values by strong reflection will be prevented

Reflected temperature

Problem:

  • Measuring the wall temperature

Consider reflected temperature:

  • Make sure to set the emissivity value and the reflected temperature to get the precise value of Degrees Celcius.
  • This way, a corruption of measured values by strong reflection will be prevented.

Consider reflection

Problem:

  • Temperature measuring at stainless steel cover

Low emmissitiy value: usage of black matte sickers of special sprays

  • When measuring on strongly reflecting surfaces like bare metal it is strongly recommended to use black, matte stickers or specific sprays
  • Shortly after applying on the reflecting object they take on its temperature, which can now be precisely measured due to its high emissivity value.

Consider timing and surroundings

Consider timing and surroundings

  • Rainfall and warming solar irradiation influence the surface temperature, they have to be avoided (as well as high humidiy and wind)
  • It is not recommended to measure in direct surroundings of hot temperature sources (e.g. ovens)

Possible influence of surroundings when measuring outside.

Example: Reflection of the sun

Problem:

  • Measuring of objects in sunshine

Reflection of the sun

  • Initial situation: Only the heading vent is the only thing that it warm by itself --> Other objects reflect the radiation of the sun
  • Without solar radiation: Avoiding the influence of sun reflection by taking the measurement during the night --> Precise measuring of temperature

FAQ

The closer the tool is to the measurement object, the more precise the measurement. From further away, the measuring results can become less precise, e.g. small differences in temperature become less easily visible or cannot be perceived at all. A minimum distance of 30 cm should be adhered to, since the tool requires at least this distance to be able to focus correctly.

For optimum results, configure the tool by selecting the material you are measuring (emissivity). A selection list of the most common materials and their associated emissivity is stored on the GTC. However, it is possible to enter user-defined values.

Thanks to the built-in real image camera, for every thermal image (…X.jpg) a real image (…Y.jpg) is also saved. This makes it easier for you to identify any objects which are unclear in the thermal image. On the GTC 600 C Professional, you can also record a voice memo. This is then saved along with the corresponding thermal image with the extension "...Z.wav". This means that you will then have all the information correctly assigned to the corresponding thermal image. In addition, the raw data of the temperatures is also stored in the real image. Each pixel therefore has a temperature value stored in it and if you like, you can easily edit the real images (…Y.jpg) in our free GTC Transfer Software. You can also effortlessly create an evaluation or report.

In principle, neither the thermal imaging camera nor the infrared thermometer need to be calibrated on a regular basis. However, if the tool has been subjected to significant drops or impacts, we can offer a re-calibration service via Bosch Service. This means you can ensure that your measurement results continue to be exact.