Covid-19 has forced every business to evaluate their working conditions. At Extronics, we have been asked a lot recently if our Real Time Location System (RTLS) products can be used to provide a contact tracing and social distancing solution.
With so much noise out there online, how do you know you are getting the facts about the different options available to you?
Extronics has been providing RTLS solutions to hazardous industries for over fifteen years.
We specialise in developing and manufacturing ATEX, IECEx, and North American certified equipment for use in hazardous areas, and rugged industrial products for harsh environments. We serve customers around the world from industries such as oil and gas, chemical, pharmaceutical, and mining.
We have created this article as a guide to some of the most common technology available, and the things you should consider before selecting a solution for your social distancing or contact tracing needs.
The World Health Organisation (WHO) have suggested that one metre is an appropriate social distance to reduce the risk of spreading Covid-19. Many governments have increased this to two metres, but how do you ensure personnel maintain this distance on large process industry sites?
With so many use cases, such as confined working areas, scheduled maintenance, turnarounds etc., it can seem like a daunting task to risk assess your site and decide on the right solution.
Governments and health organisations, such as Health Direct Australia, have also stated that the time a person spends in close proximity to another person is a factor when analysing the risk of spread.
Many agree that the risk of spreading the virus increases significantly after a person spends longer that 15 minutes near another person. Matt Hancock, Secretary of State for Health and Social Care in the UK, even went as far to state that within the 2 metre recommended distance, face to face presents the highest risk, side by side lower, and face to back and back to back present almost no risk at all.
When we consider how many people move around a site and the types of day to day roles they undertake, it is worth factoring in government guidance into your decision making process.
There are two main types of social distancing and contact tracing system. One requiring an infrastructure and one that is a standalone solution.
There are several wireless location technologies you could use. The most common of these are BLE, WiFi, GPS and UWB tags.
Infrastructure based RTLS provides data on a worker’s location and proximity to others using the native location accuracy. The data can then be used to determine social distance proximity compliance and tracing.
UWB and BLE AoA (Angle of Arrival) both have a sub-one-metre accuracy level and can even achieve sub-0.5-metre or better – down to 10cm in ideal conditions.
Both technologies use a tag beacon to determine location in a location engine running on a server. An alert is triggered if two or more individuals wearing tags are too close to one another. The alert can be a flashing LED, audio alarms or a vibration alert to the person wearing the tag.
Certain configuration can allow custom alerting that will auto cancel if the individuals move away to a safe proximity.
Should a worker become infected, a report can be run to trace anyone who was within the defined range for a set period. It is also possible to review where an infected worker has been and deep clean these areas.
WiFi or BLE RTLS using the RSSI (Received Signal Strength) location principle to calculate worker location offers similar functionality to the above. However, the native accuracy is typically in the sub-ten-metre range in built up or indoor environments. It is possible to get sub 5 metre location accuracy in some cases, but the better accuracy requires further infrastructure.
It is not possible to use Wi-Fi or BLE RTLS for alerting people when they become too close to one another. Simply put, Wi-Fi or BLE RTLS does not have the required accuracy for social distancing applications.
However, it is feasible to do contact tracing with Wi-Fi or BLE RSSI RTLS, but the density of your infrastructure will have a factor in the level of accuracy you can achieve. In principle, a report can be run for anyone who has tested positive to see where on your site they were between a set time frame. This will allow you to determine who the person was in close contact with, but it would be impossible to see this at a sub-two-metre range. A degree of false positives would need to be accepted to ensure no false negatives were not missed.
Standalone systems that do not require infrastructure work on either BLE or UWB.
BLE tags transmit and receive beacons (Tag ID’s). The RSSI is then used to calculate the proximity of the tags.
The signal strength remains reasonable linear up to a two-metre range. Whilst not as accurate as UWB, BLE offers enough accuracy to be used practically.
It is also worth noting that many governments around the world are introducing apps running on smart phones using the BLE radio. Google and Apple have also developed functionality for their OS using the same principle.
Standalone BLE systems store signal levels and tag ID’s locally in the tag and process the signals to alert the user if they are too close to another tag. The encounters of anyone located within a certain distance for more than 15 minutes can be offloaded at regular intervals, typically daily after a work shift or at any point when a person has tested positive. A report can then be run to trace those that have been in close proximity with that person.
UWB tags use ToF (Time of Flight) to measure distance. This is more accurate than BLE and can typically achieve 0.1 metre accuracy. The solution functionality is typically the same as BLE, but the battery life is poor in comparison. UWB tags are likely to need regular charging, some even daily as this mode of location calculation is power hungry.
There are some solutions that offer both a standalone system for social distancing and contact tracing, but also offer a practical solution for real time location tracking across an entire site. These solutions provide a more robust option for many use cases such as:
Customers that require a solution to social distancing and contact tracing can now benefit from a rapid deployment with the lowest possible costs.
If you would like to discuss your use case, please contact our experts on +44 845 277 5000, or email firstname.lastname@example.org.
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