Thermal cameras vs handheld thermometers

Many workplaces are now thermally screening staff and visitors as one level of protection against COVID-19. This trend is also as part of a growing realisation that preventing potentially infectious people entering the workplace makes a lot of sense irregardless of the COVID threat. It protects the health and safety of staff and has a financial benefit through reduced sick leave.

This article looks at the relative merits of using hand held forehead thermometers vs thermal cameras for doing thermal screening.

Hand held thermometers

On the face of it (excuse the pun) using a contactless infrared thermometer seems like cheap and easy way to do this. You can buy one for under $100 and you just point it at a forehead and get a reading.

However there are a few points to consider if you are going to go down this route. The first is whether you will have people measure their own temperature or have an operator do it for them. In either case you will need to make sure you have sufficient training.

This is easier to do if you have an operator. Often an operator will be a receptionist, security guard, or someone employed specifically for this task.

The key thing is to ensure the operator understands how close the thermometer should be held to the forehead. For example the Berrcom non contact infrared thermometer should be held between 3 and 5 cm from the forehead. If you get this too close or too far then you will get inaccurate readings.

With the need to get this close, the operator is at risk if the person being scanned is infectious. To mitigate this risk you need the operator to wear adequate personal protective equipment (PPE) - probably a mask and maybe gloves. They also need to be trained in how to use this PPE correctly. To be safe, the person being scanned should also wear a mask.

If you are going to have more than one operator use the thermometer then you need to ensure each operator is trained and the thermometer is cleaned between use by operators.

You probably want an auditable record of the temperature checking so that you can confirm that the thermal screening is happening and that everyone is being screened at the frequency dictated by your health and safety policy. The most common way of doing this is with a pen and paper. The problem with this is that because it's not digital it is difficult to automatically check compliance against a policy (is everyone being checked daily).

Even if the results are being typed into a spreadsheet there is another risk of the keyboard - or the pen and paper being transmission vectors. If the person being scanned doesn't have a mask then the operator's hand gets close enough to be breathed on and the virus so the hand should be cleaned before picking up the pen or going to the keyboard. A manual record is also very likely to contain errors. These will increase if you have spend time washing hands between taking a reading and filling in the form.

The one other negative aspect of forehead thermometers is that it is invasive having someone put something that close to your face. Even though it's not touching you, we don't normally let people get that close to our head. On top of this the person being scanned can't see the result - they have to ask the operator to tell or show them.

Self screening with a hand held thermometer

We have heard of some organisations asking their staff to take their own temperature and filling it out on a form. This poses a number of challenges:

• each staff member needs to be trained on how to operate the thermometer accurately
• staff members need to be trained to sanitise their hands before picking up the thermometer and the pen to write down their temperature so the thermometer or pen don't become vectors for transmitting a virus.
• There needs to be a routine for cleaning the thermometer and pen.
• There lacks the opportunity for someone else to check that everyone is being honest. There may be financial incentives for staff to hide the fact they have a fever if they have no more sick leave owning to them. 

Thermal camera

In contrast to a hand held thermometer when a thermal camera is used no one needs to touch anything or get close to the person being scanned.

The person being scanned simply stands on a spot on the floor and they can see their temperature.

An "operator" can be nearby listening for the optional sound of a safe temperature or a fever temperature. Alternatively the operator can have a mirror of the camera screen so they can see exactly what the person in front of the screen can see. Or the camera can operate un-manned with the option of alerts being sent if someone is recorded as having a fever.

A thermal camera can automate the recording of temperatures, storing each temperature in the cloud. This can be viewed and downloaded at will, making compliance with your health and safety policies much easier to audit.

Although a thermal camera costs a lot more up front (the Te Kahu Ora Camera is $3999 ex GST, plus a monthly cost), there is considerable costs saved from not having to have an operator or the costs involved in training an operator, or the staff. A thermal camera also does a better job, with less risks reducing the likelihood of staff passing on infections or the more catastrophic outcome of the business needing to be closed if COVID-19 has be transmitted at your work place.

Some of these features are not yet available on the Te Kahu Ora screening - but are being developed with the support of a government grant and will be available shortly.