All You Need to Know

We have tried to answer almost all the frequently asked questions about our products on this page. If you need information about anything that is not covered here or how it will fit your specific requirements, please feel free to contact us for more information.

LifeGuard ThermoTechnologies TempDefend thermal imaging csystem can be a useful, efficient tool for screening people for signs of elevated skin temperature.

Obtaining actionable data requires adequate thermal resolution, stability, and measurement accuracy, as well as the correct preparation and scanning methodology.

To help clarify the best practices for this non-contact screening option, TEMPDEFEND offers these answers to frequently asked questions.

Q: Can TEMPDEFEND products be used to detect a virus such as the novel Coronavirus (COVID-19)?

A: No, thermal imaging systems cannot be used to detect or diagnose an infection. However, TEMPDEFEND thermal systems are used today in public spaces such as airports and hospitals and by essential services such as manufacturing and shipping as an effective tool for measuring skin surface temperature. People who are identified as having an elevated skin temperature can then be screened by medical professionals using additional tools such as an oral thermometer.

Q: How does thermal imaging technology work?

A: TEMPDEFEND thermal systems detect heat radiation and can be used to identify the surface temperature of objects and people. With this capability, TEMPDEFEND thermal systems are commonly used as a non-contact screening tool to detect differences in skin surface temperatures and pattern changes. In fact, TEMPDEFEND is registered with the U.S. Food and Drug Administration (FDA) to provide a variety of its thermal products to screen for elevated skin temperatures in connection with additional screening tools.

Q: How should skin temperature screening be performed?

A: The U.S. Food and Drug Administration (FDA) provides full recommendations for Thermal Imaging Systems (Infrared Thermographic Systems / Thermal Imaging Systems). Here are several tips to ensure optimal measurement performance from a TEMPDEFEND thermal system:

  • Screen people one at a time to look for temperature anomalies.
  • Screen people from 1 to 2 meters (3 to 6 feet) away.
  • Measure temperature near the tear duct (at the inner canthus) as this location provides the closest temperature correlation to human core body temperature. This is not measuring core body temperature and readings near 35°C (95°F) are common.
  • Perform secondary screening on individuals with elevated skin temperature using a medical device designed specifically for measuring body temperature, such as a thermometer.
Q: How close do you need to be to detect someone with an elevated temperature?

A: In order to obtain a good temperature reading, it is recommended that the intended target be as close to the system as possible (with respect to the system’s minimum focus distance). The location of the system may require a different lens. For instance, if the operator wanted to place the system at a significant distance, TEMPDEFEND may recommend a telephoto lens. Therefore, distance to the target is an important consideration, as is focus.

It is important that the application be set up so that all intended targets are in focus during the screening process, thereby creating a good image. In addition to focus, a good image is dependent on several additional functions and settings, with certain functions and settings affecting the image more than others. Functions and settings that the operator needs to set and/or adjust include the following:

  • Adjust the infrared system focus
  • Adjust the infrared image (automatically or manually)
  • Select a suitable temperature range
  • Select a suitable color palette
  • Change the measurement parameters
  • Perform a non-uniformity correction (NUC)

For the TEMPDEFEND non-contact thermometer (see section below regarding non-contact thermometers), the optimal measurement distance of 5 cm to 15 cm (1.9 in to 5.9 in)

Q: How accurate are the thermal systems?

A: TEMPDEFEND thermal systems “see” or detect the temperature differences with temperature measurements between -20°C and 2,000°C (-4°F to 3,632°F). The standard TEMPDEFEND product accuracy specification of ±2°C or 2% of the temperature reading at 30°C (86°F) ambient environment applies to all temperature ranges it measures and for the multiple applications for which it can be used.

TEMPDEFEND thermal system with screening mode can achieve accuracies of ±0.3°C (0.5°F) at the recommended ambient temperate of 30°C to 45°C (86°F to 113°F).

It’s important to note there are many factors that can affect the accuracy of thermal systems, such as focus, distance, the emissivity* of the target, the ambient environment, and the speed at which the temperatures are acquired.

*A target’s emissivity is its ability to emit thermal radiation. For example, ceramic mugs, clothing, and even human skin have high emissivity, while polished metals have low emissivity.

Q: Do I need to use a black body for skin temperature screening?

A: There are advantages and disadvantages to using a black body when screening for elevated skin temperatures. Including a black body in the system’s field of view can improve the system’s performance in this application. You can use TEMPDEFEND thermal systems with black bodies as part of an elevated skin temperature system setup. In fact, many of our integrators and partners are doing just that, taking TEMPDEFEND technology and developing their own software solution that uses a black body as the reference.

In contrast, using a black body for skin temperature screening can create challenges. The first is the cost and complexity of including an additional piece of hardware in the solution. Black body integration into a system makes mounting, powering, and ultimately maintaining it more complex. Such an addition also introduces another potential point of failure into the overall solution.

Proper focus on the black body is essential to getting accurate measurements. For a black body to be effective, it must be mounted in the same plane as the person being screened. A black body that is significantly closer or farther than the person being screened will be out of focus and not function as an accurate reference source.

If ultimately the screening solution includes the use of a black body, TEMPDEFEND recommends following these requirements, as set forth in ISO/TR 13154:2017:

  • The system of the screening thermograph should be positioned perpendicular, both horizontally and vertically, to the face of the individual being screened so that the inner corner of both eyes can be imaged simultaneously.
  • The individual being screened and the external temperature reference source should be in the correct position and orientation relative to the system for proper focal distance, depth of field and image capture. There should be a means of ensuring that the individual being screened is in this proper position, e.g. a stool, marks on the floor. Consideration should be given to individuals in wheelchairs.
  • The backdrop behind the individual being screened and, when used, side screens should be thermally uniform, high emissivity (non-reflective in the IR spectrum) and light in color (visible spectrum).
  • The operator should be positioned with a clear visual field of the individual being screened and the display of the screening thermograph. The operator may need to intervene to correct the individual’s position. The operator should also be positioned in such a way as to divert individuals to the secondary screening area when required.
  • Operators should be assessed as to their ability to discern the colors of the rainbow scale of the screening thermograph.
Q: Can you name some companies, organizations, and airports that have purchased your products?

A: While we cannot name specific customers or comment on current sales, we can say that our thermal systems are used by customers at ports of entries and high-traffic locations in several countries, including the US, China, Hong Kong, Taiwan, Singapore, South Korea, Thailand, Philippines, and Malaysia.

Q: How long has TEMPDEFEND, been selling thermal systems and non-contact thermometers for elevated skin temperature screening?

A: TEMPDEFEND’s Thermographic Scanning Manufacturer, FLIR noted an increase in the use of thermal systems for skin temperature screening during the SARS outbreak in 2003.

Q: How do you use non-contact thermometers for elevated skin temperature screening?

A: TEMPDEFEND’s Thermographic Scanning Manufacturer, FLIR sells an IR non-contact handheld thermometer. Non-contact thermometers are primarily used in a handheld fashion to screen a person’s forehead. The operator points the non-contact device at the subject from a recommended distance of 5 cm to 15 cm (1.9 in to 5.9 in); the thermometer can measure temperatures from 32°C to 42.5°C (89.6°F to 108.5°F).

Q: What are the minimum specifications for the non-contact thermometer?

A: Requirements for a non-contact thermometer include:

  • Non-contact infrared thermometer/gun type – human body measurement
  • Product must be CE marked or USFDA 510k
  • Product must be produced in accordance to ISO 13485 or equivalent
  • Production must be in accordance to EU standards, ISO 9001 or equivalent

For TEMPDEFEND non-contact thermometers, an adjustable alarm alerts the user—either visually or audibly—when the temperature exceeds the programmed limit. The non-contact thermometer has a large backlit LCD display to display temperatures.

The recommended TEMPDEFEND non-contact thermometer has been calibrated to an accuracy to 0.3°C (0.5°F) with 0.1°C/°F resolution.

This thermometer and thermographic systems area intended for screening individuals or monitoring an individual for potential elevated skin temperatures. It is not a substitute for a clinical thermometer. Always use a clinical thermometer when high accuracy body temperature measurements are required.