All you need to know about Thermal Imaging Systems

The following sections discuss scientific evidence supporting the use of tele thermographic systems in determining skin temperature. A thermal camera and temperature reference source may be used in these systems. Thermal Detection system imaging are referred to in this document.

Infrared thermometers (NCITs) and thermal imaging systems both use infrared technology to measure temperature. For more information about NCITs, please see the Non-contact Infrared Thermometers fact sheet.

Thermal Imaging Systems

• Temperature measurement systems, when used properly, have shown to accurately measure someone's surface skin temperature without being physically close. Thermography is a method of measuring temperature without needing to measure it close to the body (as opposed to non-contact infrared thermometers or oral thermometers that require contact).

• It is not possible to determine whether someone with COVID-19 definitively has it using temperature-based screening methods, such as thermal imaging. One reason for this is that a COVID-19 patient may not have a fever. COVID-19 is diagnosed through a diagnostic test.

• Multiple people being taken temperature at the same time using thermal imaging systems has not been proved accurate. For these systems to be accurate, they must be set up and operated correctly, along with the evaluation subject being properly prepared.

• The use of thermography during epidemics has been reported by several countries, yet the effectiveness of these systems has been mixed.

• A guidance to expand the use of thermal imaging systems and mitigate thermometer shortages during the Coronavirus Disease 2019 (COVID-19) Public Health Emergency has been issued by the FDA. The guidance provides a directive to enforce for the duration of the COVID-19 public health emergency, and also recommends that thermal imaging systems be labeled and performed according to standards.

A thermal imaging setup that demonstrates how individuals can be tracked in a public area is shown in Figure 1.

Thermal Imaging Systems: Benefits

• Physical proximity to the person being evaluated is not necessary for the person handling the thermal imaging system. People who handle thermal imaging systems may actually be located elsewhere.

• Thermal imaging systems have the ability to measure surface skin temperature faster than typical forehead thermometers and oral (mouth) thermometers, which require an individual to be within close proximity to them.

• Thermal imaging systems can accurately measure the skin's surface temperature when used correctly, according to scientific studies.

Thermal imaging systems have limitations

• However, these systems have not been shown to be effective when used to take the temperature of multiple individuals simultaneously, even in high throughput areas (such as airports, businesses, and sporting events). "Mass temperature screening" should not be conducted with them.

• The temperature measured by these systems is usually lower than that measured orally. Correcting for this difference in measurements requires thermal imaging systems to be set up properly.

• Only when all the following conditions are met will these systems work effectively:

  • Environments or locations are right for the use of the systems.

  • System setup and operation are correct.

  • Preparation for assessment follows instructions.

  • Thermal imaging systems are handled by appropriately trained personnel.

Thermal imaging systems: proper use

To ensure that the system can measure surface skin temperature accurately, the person handling it should follow all manufacturer instructions.

Both the location where the system will be used and the person being evaluated must be prepared properly by the person handling the system. Refer to the following standards and scientific papers for more information.

• You need a room temperature of 68-76°F (20-24°C) and humidity of 10-50 percent.

• Consider controlling other factors that may impact the measurement of temperature:

  • Minimize reflections of infrared radiation by avoiding reflective surfaces (e.g., glass, mirrors, metallic surfaces).

  • The room should be without any draft (air movement), away from the sun and away from radiant heat sources (such as portable heaters).

  • Keep out excessive lighting (e.g., incandescent, halogen, quartz tungsten halogen).