Safety 9 Detecting leaks in unexpected locations
According to Schiller one of the advantages of using optical gas imaging is that you will be more likely to detect the leaks in unexpected locations. "Leaks can really turn up in the strangest of places. There was one case where a support pipe was welded onto a bend in the pipework, but the welder had been overenthusiastic and his welding had caused a leak from the pipework into the support. With the optical gas imaging camera it was very easy to locate the gas escaping from the pipe support, since it stood out very clearly in the thermal image, but with a sniffer it would have taken ages to detect the leak, if we would have ever detected it at all, for who would look for leaks in a pipe support?"
team of people with sniffers a whole week to inspect the whole plant. With the optical gas imaging camera this takes one person one day. Now that we have the optical gas imaging camera we inspect the entire plant twice a year and we also perform a quick inspection at every startup. So the inspection frequency has gone up considerably."
Light temp deviation along ceiling probably due to deposits inside the piping
The GF306 optical gas imaging camera is compact, relatively lightweight and ergonomically designer, to prevent back and arm strain.
Infrared absorption
The FLIR GF306 optical gas imaging camera contains a cooled Quantum Well Infrared Photodetector (QWIP) that produces thermal images with a resolution of 320 x 240 pixels at a thermal sensitivity 25 mK (0,025 °C). The gas visualisation functionality of the FLIR GF-Series optical gas imaging cameras is based on infrared absorption. Gases absorb electromagnetic radiation in certain parts of the spectrum. FLIR GF-Series optical gas imaging cameras contain a spectral filter, a focal plane array and optics that are specifically tuned to such a part of the spectral range. Since the gas absorbs infrared radiation it blocks radiation from objects behind the gas, causing gas leaks to show up as either a black or a white plume in the thermal image, depending on whether the user opted for the 'white hot' or the 'black hot' settings.
Recording video footage
Apart from real time visualisation the FLIR GF306 optical gas imaging camera is also capable of recording both visual light video and thermal video footage. "This is very important, because the moving smoke like plume shows up much more clearly in a video than in a still picture", explains Schiller. "For leak reports we usually start our video recording in the visual video mode, to show the location to the maintenance crew, then we switch to the gas detection mode to show the leak and then we switch back to visual video mode to verify the leak location. This method has worked really well for us."
This HSM footage clearly shows a gas leak.
A tool that is used as often as the FLIR GF306 optical gas imaging camera is being used at Borealis in Stenungsund needs to be lightweight, compact and ergonomically designed to prevent back and arm strain. All FLIR GF-Series optical gas imaging cameras are ergonomically designed. With its rotating handle, direct access buttons and tiltable viewfinder and LCD screen the FLIR GF306 optical gas imaging camera is designed from the end-user's perspective, offering advanced ergonomics to improve worker safety. With a weight of 2.4 kg the FLIR GF306 optical gas imaging camera is also relatively light and compact.
"Another example of an unexpected leak location was when I found gas escaping from insulation material. Due to a leak in a connection at the other end gas leaked in behind the insulation and at the other end it leaked out again. And this is just one of a list of leaks detected with the optical gas imaging camera that would have been nigh impossible to detect with a sniffer. A sniffer has to be held exactly in the right spot to detect a leak, so the inspector will only hold in locations where leaks may be expected. With an optical gas imaging camera you see all leaks within the camera's field of view. You can use it to spot leaks easily, quickly and it makes your inspections more thorough."
This valve is leaking ethylene, showing up as white smoke in the black hot thermal image.
Worth the investment
"Some companies might be reluctant to buy an optical gas imaging camera due to the price tag, which is understandable as a sniffer is much cheaper", continues Schiller. "But the difference in purchase cost is deceptive. For one thing, inspecting with sniffers is much more labour-intensive and man hours do not come cheap, well not here in Europe at least. Secondly leaks in unexpected locations are difficult to find and easy to miss with sniffers, so using optical gas imaging cameras will help ensure the safety of personnel and of the inhabitants of the surrounding area and in my opinion safety is definitely worth investing in. Using optical gas imaging also increases the sense of safety for the plant's workers. They feel safe in the knowledge that no gas leak escapes my attention with the FLIR GF306 optical gas imaging camera."
Leaks can pop up in unexpected locations, such as in this pipe support.
The FLIR GF306 optical gas imaging camera can detect even smaller leaks from a distance, such as this leak spotted using the HSM.
"This plant is relatively new, it was opened a few years ago to replace, the old polyethylene plant" adds Schiller. "The new polyethylene plant had a few teething problems, but with the help of the optical gas imaging camera we have been able to make it into one of the leak-tightest polyethylene plants in the world. To give an idea this new plant produces twice as much polyethylene as the old plant did, but the amount of VOC's escaping due to leakage is ten times less. In my opinion the FLIR GF306 optical gas imaging camera has helped to make this very low leakage rate possible."
"Last but not least the use of optical gas imaging will help reduce amount of gas lost to the atmosphere", continues Schiller. "Given the fact that these gases are our base material it is a waste to lose it due to leakage. I would much rather turn it into plastic. So gas leakage is in fact throwing away money. By reducing the leakage the optical gas imaging camera will earn back its purchase cost. So all in all I would definitely say that an optical gas imaging camera is worth the investment."
Another unexpected leak location. Due to a leak in a connection the gas escapes from the insulation material.
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APRIL / MAY 2013 •
WWW.PETRO-ONLINE.COM
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