Here are answers to some common questions regarding temperature screening for coronavirus in our COVID-19 FAQs. 

What can thermal imaging cameras do?

Thermal cameras use infrared radiation to detect radiating heat from a body and estimate the core body temperature. These cameras commonly have an accuracy of 0.5°C.

Thermal imaging is a powerful technology, often used by emergency services to see through smoke in a house fire or locate people at night. But how can they be applied during the COVID-19 pandemic?

Although thermal cameras give a reasonable measure of skin temperature, traditional medical device thermometers, such as ones you place in your ear, are more accurate, to at least 0.1°C.

Thermal imaging cameras are being installed in many public buildings, schools, airports and offices. They are used to check people entering for an elevated body temperature indicating a fever, a common symptom of COVID-19 (coronavirus).

What is considered normal body temperature?

Normal body temperature fluctuates around 37 °C. A high temperature or fever is usually 38°C or over. But normal temperature can vary from person to person and changes depending on time of day or what activities we have been doing. It is also influenced by a woman’s monthly cycle.

Taking an accurate reading of body temperature can be difficult. The most accurate method is a rectal temperature measurement but the forehead, mouth, ear and armpit are commonly used. This involves close proximity to the person checking your temperature.

This can be avoided by the use of thermal imaging. Even if it does result in a small reduction in accuracy, thermal cameras can check someone’s temperature very quickly.

If used in an automated system that does not require human operation, thermal imaging reduces the risks and costs associated with temperature screening. This can also be seen as a less intimidating alternative to a security guard pointing a portable infrared thermometer at each visitor’s forehead.

Do thermal cameras detect coronavirus?

This is the most common question we get asked of our COVID-19 FAQs.

Thermal cameras DO NOT detect coronavirus. They are only used to measure temperature. A high temperature or fever is just one common symptom of the virus. Others include cough, nausea, headaches, fatigue and loss of taste or smell. But many people with the virus are asymptomatic and will not have a fever.

This means thermal cameras alone will not identify infected people with no fever or symptoms. These are called false negatives. They will also identify people who have a fever for another reason e.g. bacterial infection – known as false positives.

So are thermal cameras useful?

On its own, temperature screening will not guarantee a building or area is COVID-19 free. But it will reduce the risk of infectious people entering the premises, providing peace of mind to those inside. 

Temperature screening is used by all hospitals in Singapore and Taiwan and the UK is beginning to follow suit through trials such as ours at Chelsea and Westminster.

To be truly effective, temperature screening should be combined with other tools such as symptom screening, face shielding and COVID-19 testing.

Can I wear a mask during temperature screening?

Most temperature measurements (including ThermaFY Protect’s) are taken from points on the forehead, which is usually exposed. However, plastic face shields must be removed because they obscure forehead temperature measurement significantly.

Will I be hotter if I have been exercising?

Not necessarily because your body can regulate its temperature very effectively, even after exercise and surface skin temperature actually goes down during exercise as you sweat. To avoid any fluctuations caused by exercise, we recommend waiting five minutes after exercise before having your temperature checked.

At work, do I have to submit to a temperature test?

Under UK employment law, employees must agree before an employer can temperature screen their staff. Some work contracts will already allow for this type of testing.

Taking an employee’s temperature without their consent is unlawful, according to the professional body for HR and people development. Employers must also process any medical information they gather fairly and transparently.


thermal image temperature checkA thermal picture indicating a forehead temperature of 36.4°C taken with the ThermaFY Protect Screen.

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