We have all watched the US troopers with their ‘night-vision’ /infrared capability enjoying an advantage over insurgents in Iraq and Afghanistan or firemen able to see through smoke and find victims in a blaze. The spin-off of a US$500-million US Defence Department investment is now also being applied to improve preventive electrical maintenance in New Zealand commercial properties. Kevin Kevany reports.
Bill Mitchell, a qualified, highly-experienced electrician, an ITC-certified infrared thermographer, and accredited user professional infrared cameras, is a man with a double mission – to convert building owners and managers to the value of this cost-efficient, effective preventive maintenance, using a specialist camera, and to eliminate “the cowboy users of infrared technology”. As a seasoned electrician, Mitchell is passionate about how the latest generation of infrared cameras enhances his ability to deliver highly accurate preventive maintenance, quickly and unobtrusively, during office hours. Being a qualified electrician too, he is uniquely capable of fixing the problem there and then – what he calls his “we need to do something NOW” moment. “Basically, nearly everything gets hot before it fails, making infrared cameras extremely cost-effective, valuable diagnostic tools in many diverse applications in the electrical industry,” he says.
Jeff Mclaren, CEO of the Singer Group, has welcomed the infrared capability and Mitchell’s professional skills’ package to the company, particular to building maintenance, which is managed by long-serving manager, Kevin Dunbar. “Kevin has been on about us adding a thermographic capability to our maintenance services for some time now. I’ve seen a few demonstrations of it, of varying standards and application. But I was bothered by the fact that the operators involved seemed to be totally reliant on the cameras and had to then brief an electrician to fix any problem.
“That seemed like too many links in the chain. When Kevin introduced, Bill, a long-standing friend, and made the point that he was fully qualified to both diagnose and fix, I was sold. And that has been the case with our customers, who have to-a-man, welcomed the combination of leading-edge technology; an operator trained to the international standard; and a qualified and experienced electrician.
“’Technology-for-technology’s sake’ has never done anything for Singer. But this is the only way to go. I’m very supportive of the New Zealand Association of Professional Thermographers looking to enforce standards and lobbying the insurance industry to recognise the difference through premiums.
“We don’t need a ‘towering inferno’ experience in a New Zealand CBD, before we recognise the dangers of having unskilled and unsupervised operators passing off incomplete information. The last time we allowed that to happen, New Zealand ended up with the leaky houses disaster – something we are all still paying for,” Mclaren adds.
Mitchell is Secretary of the professional association and is working to support the efforts of its president, Ken Jackson, who is the country’s top professional trainer of certified thermographers, delivering courses approved by The Infrared Training Center (ITC), the world's largest thermography training organisation, which last year trained more than 7,000 infrared users, worldwide. “Finding a problem with an infrared camera is sometimes not enough. In fact, an infrared camera image alone, without accurate temperature measurements says very little about the condition of an electrical connection or worn mechanical part. Many electrical components are operating properly at temperatures that are significantly above ambient. An infrared image without measurement can be misleading because it may visually suggest a problem that does not exist,” Mitchell says.
That can lead to unqualified or inexperienced operators, with very basic gear and knowledge, bringing a building to a standstill, only to find that a switchboard component was functioning within the correct parameters, and that an outside factor, like a setting sun was to blame. “There is constantly a fine line that we have to tread between being officious (and mistaken) and erring on the wrong side, when safety could be compromised. The operator/electrician not the camera makes the call, based on the information accumulated.
“At all times, you have to be using your own brain and skills in conjunction with this superb equipment. You and the camera need to analyse what is being emitted by the ‘target’; what is coming off you as the operator and being reflected back; and what is being reflected in from the outside. Getting a proper reading is the first step. You also have to understand what is in that calculation. You must be able to ‘contextualise’ the information from the camera, the environment and your electrical training and experience, to really get the correct answer,” says Mitchell, who was trained in the Royal New Zealand Navy, where the environment is the primary consideration – every time.
Your first thought, as a lay-person, is that the camera looks ominously like a cop’s radar gun. But it is far more sophisticated. Mitchell explains: “Take the camera I use. It’s a Flir – ‘forward looking infra red’ – which delivers two images. The first is a digital shot of the item being assessed. The second is an image which is, if you like, the top of a massive ‘mathematical box’, which contains, in my case, an image resolution of some 320 x 240 (a whopping 76,800 pixels) or individual temperature detectors, generating a seemingly-static surface snapshot of all those simultaneous calculations. And those 70-oddK detectors get calibrated into a calculated narrow range, to bring the detail on a potentially faulty cable coupling or circuit-breaker into a macro-range where nothing can escape the probing eye. Remember, thermal imaging doesn’t ‘see through walls or cabinets or equipment’; it measures what is on the surface, which in turn is a product of what is beneath it,” he notes.
Being a qualified and experienced electrician, Mitchell adopts a belt-‘n-braces approach, keeping a thermocouple handy for when he wants to check a reading which he thinks might be misleading. He describes it as a thermoelectric temperature sensor which consists of two dissimilar metallic wires, e.g. one chromel – an alloy made of approximately 90 percent nickel and 10 percent chromium -- and one constantan – an alloy, also known as Eureka, usually consisting of 55-percent copper and 45-percent nickel – coupled at the measurement-junction or probe-tip and extended to the reference junction or “known temperature”.
The temperature difference between the probe tip and the reference junction is detected by measuring the change in voltage or electromotive force at the reference junction. The absolute temperature reading can then be obtained by combining the information of the known reference temperature and the difference of temperature between probe tip and the reference.
The final thought from Mitchell: “I believe there are three critical variables which have to line-up in applying thermography to ensure that it delivers for the customer. One: the quality of the camera. A 60 x 60 pixel camera only gives you 3,600 temperature detectors versus say 50,000 and upwards. Two: the competence of the ‘driver’. The training and the other qualifications and experience of that person are as critical as the technology. You’d prefer a trained astronaut to a bus-driver to fly your rocket, most times.
“And three: look at the company and the resources it has to stand behind the individual using the technology. If you suddenly find yourself facing a major problem, you want to be able to draw on as many qualified electricians and even engineers that might be needed – seamlessly. That’s why I brought my skills and training to Singer.”
Email: Jeff Mclaren, J.Mclaren@singer.co.nz