But just how effective are those thermal scanners? The cameras were purchased several years ago. The old models were designed for industrial testing of overheated switchboards and their accuracy is +- 2 deg. C.
Typically you would have a suspected case of flu if a person has temperature of 38 deg. C. Now imagine what you will detect with such low accuracy… In addition to that, as far as we know those particular models had no alarm output.
Studies show that CCTV operators can comprehend only 5% of information after staring at a CCTV display for just 20 minutes. Combine that fatigue factor with +/-2 deg. accuracy and you can get an idea of the effectiveness of thermal scanning currently deployed in Australian airports.
Better technology exists now, it was developed after previous SARS scare specifically for health inspections.
For example, NEC AVIO (Japan) makes IS7800 camera system with +/-1 deg. (Japanese conservative) accuracy, audible alarm and in addition to that mixing of thermal image on visual so operator can easily identify a suspected case of swine flu with much greater probability.
If a person’s temperature is higher than set temperature on IS7800, alarm display appears on the LCD screen. Mixing(Fusion) function is useful to identify that person.
Specifications of IS7800 system
* Accuracy ??1.0??C
* Dimensions 102(W) x 217(H) x 205(D)mm
* Weight (including battery) 1.3kg
* Frame Rate 60 frames/second
* Focus 50cm to infinity
* Uncooled focal plane array – VOX material (stable and low drift)
* Detector size (320 x 240)
* Environmental temperature: 20 to 30??C, at 30 to 42??C Black body)
* Resolution 0.1??C (at 30??C Black body) 0.06??C (at 30??C ?16)
* Measurement range 0 to 50??C (Human body)
IS7800 is lightweight: 1.3kg. It is easy to carry into an airplane or vessel for inspections.
Applied Infrared Sensing – VIC
Building 22 / 270 Ferntree Gully Road
Notting Hill 3168 VIC, AUSTRALIA
Tel. +61 (03) 9501 2777
Fax +61 (03) 9501 2788
Applied Infrared Sensing – NSW
Ground Floor / 810 Pacific Highway
Gordon 2072 NSW, AUSTRALIA
Tel. +61 (02) 9416 0626
Fax +61 (02) 9416 2583
Why such a series?
This series of stories highlights the suppliers of Temperature measurement devices intended and specially designed for screening people for elevated body temperature, a likely indicator of fever and possible an infection, such as SARS, Avian Flu, Swine Flu, Dengue and others.
We do this for several reasons:
1. Most people are unskilled in selection and use of Infrared Thermal Imagers and thermometers. Consequently there are often serious mistakes made in both choosing and using such devices. We feel it is important to use our knowledge of them to try to save us from those who rush to judgment on technical matters without adequate input and thought. We are highlighting equipment suppliers who make devices tailored for this use as evidenced by product details on their web pages. (This is not an endorsement of those suppliers but rather an information resource to help cull out those who have some experience and products intended for this use.)
2. Please be aware there are now some international standards for these devices, their performance, and introductory standardized practices for their use. You can get the best help in selecting and using them, we believe. from experts at your National Measurement Institute (NMI) who specialize in the infrared field. There is a list of all the NMIs in the world at the website of the International Bureau of Weights & Measures (Le Bureau international des Poids et Mesures – BIPM) and a selected list on www.TempSensor.net.
3. Some vendors are more careful and experienced than others and we recommend that you check the experts at more than one of them before making any decisions plus run your views past the NMI experts before finalizing them.
4. Although the use of these devices doesn’t directly detect infection or all who are infected, it has been demonstrated that their careful use and selection during the SARS crisis of 2003 can help screen for and locate some who have the illness. The individuals then get more rapid treatment and are quarantined to reduce their possible effect on others. (See the SARS pages on www.temperatures.com for some details, reference stories and article links)
5. Yes, there were undoubtedly false negative as well as false positives in earlier uses. There will always likely be some of both. However, misuse, mostly though improvised practices and hasty, ill considered equipment choices, will increase the probability of more false negatives.
6. An effort to finalize ISO Standards for equipment performance and use will go a long way to improving the situation. Until a viable set of standards, developed by world experts are in use, we shall see continued mis-specification and misapplication of equipment and subsequent squandering of resources, in our opinion.
Note In late 2008, IEC published the standard: IEC 80601-2-59 Ed. 1.0 “Medical electrical equipment – Part 2-59: Particular requirements for the basic safety and essential performance of screening thermographs for human febrile temperature screening”. It provides many performance and calibration requirements for devices used in this application.
In March 2009, the ISO standard, ISO/TR 13154:2009 “Medical electrical equipment — Deployment, implementation and operational guidelines for identifying febrile humans using a screening thermograph”, was published. It bears directly on this use, and while not perfect, does represent a major milestone completed since SPRING Singapore began their effort to create workable standards in 2003.
The standards may be purchased and downloaded online at: www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=51236 and webstore.ansi.org RecordDetail.aspx?sku=IEC+80601-2-59+Ed.+1.0+b%3a2008 respectively.
(Kudos to John Snell of Snell Infrared for advising about the links for the online availability of these standards)