Training needs

Published:  15 March, 2007

There is a worrying misconception that because users increasingly think the subject of thermal imaging is easy to understand they consequently draw the conclusion they don't need training.

Jon Willis - thermography technical support/training manager at  Flir Systems" Infrared Training Center (ITC),  says he sees this many times as a trainer: "So called experienced people with many years experience not even knowing the basics.  Specifically on a level 1 course a comment I hear many times is 'I know all that needs to be known and am attending because I need the certificate'.

"It"s amazing how many people back track the comment they have made on the first day and realize that they have learnt many new tricks and approaches to thermal imaging.”

It is understandable that thermal imaging cameras are viewed similarly to visual cameras in that once a two dimensional image has been produced the operator can use the equipment effectively. This would not require much training. The reality is that producing the image is relatively easy compared to the task of interpreting the thermal data.”

Austin Dunne, European training manager at the Institute of Infrared Thermography - a training provider for companies such as Fluke - told PWE through education, seminars and training, industry will start to understand that knowledge of the equipment and the theory behind its operation is imperative to achieve a return on investment. "The infrared community as a whole can play a part by communication to industry through articles, seminars, training and sharing knowledge when talking to clients.”

Willis told me: "A thermal imaging camera is a precision instrument but if it has been setup incorrectly temperature measurement can be 100°C or more out.  In any situation this level of error is unacceptable. ITC not only tries to educate the camera operator and in many cases it will be the end user as well.

Willis says that to any customer asking about thermography the company recommends a 1 day training course to start with, these are based all around  the UK on a monthly schedule. This will give the customer an insight into the Infrared Industry, hands on with the camera and guidance on how to set the camera correctly.”

Willis highlights there are six very important factors to consider when you take a thermal image: “You need to be aware of viewing angle, distance, humidity, reflected radiation, emissivity and focus.  Many inexperienced users may only get emissivity and then not fully understand what this means and what effect it has when entered into the camera.  This lack of knowledge can lead to misdiagnosis of problems and in extreme cases cause downtime at a factory when it is unnecessary.”

Thermal anomalies are not always apparent, a good technician, like a detective has to develop an inspection technique. Dunne explains that initially the user should have full control over the manual adjustments on the camera to thermally focus the image of the equipment that is under inspection. This allows the user to remove saturation of the thermal energy levels that prevents the operator from viewing the correct energy levels required for proper interrogation of the image.

“As objects do not emit 100% of their energy, the trained technician will be aware that in some cases only a small amount of the true energy will be emitted to the camera detector. The technician can manually adjust the camera to account for the reduction in energy.

Another factor often mis-diagnosed is energy reflected from the background impacting on the target object giving an apparent temperature change. It is not commonly understood by new users that reflections occur in the infrared spectrum very similar to the visual spectrum.”

If a user cannot determine the fraction of energy emitted from a material, then they introduce an error into their measurement. As several materials have a very low emittance value, the error can be substantial. Dunne emphasises: “To use infrared cameras for quantifying measurements it is fundamental that the user has the knowledge to perform emissivity testing on materials (when safe to do so) to determine a specific value for a given material. As emittance can change with material, temperature and wavelength, emittance tables found in books and provided by camera manufacturers will usually only give a guideline.”

Therefore infrared thermography training is vital for inexperienced users for a number of reasons:

  • Incorrect operation of the camera can lead to mis-diagnosis of anomalies or potentially overlooking important thermal details in the scene viewed by the user.
  • Knowledge of infrared theory would be required to interpret the thermal information. A good understanding of the 1st and 2nd laws of thermodynamics focuses the user towards accurate evaluation of data.
  • An outline of inspection procedure can be useful for the novice both from a safety point of view and efficient camera technique in the field. 

Austin Dunne recommends a minimum of a short camera operation course (2 days) would allow users to manually operate a unit providing high quality thermal data that can be useful for qualitative assessment. To carry out remote infrared temperature measurement the user should seriously consider an L1 certification course to fully understand infrared theory and how it impacts on measurements. It also provides a certificate of competence upon completion of the course requirements. 


Employer reluctance

Speaking to a number of attendees on a recent basic thermography training course, I learnt many had a difficult time persuading their employers of the necessity for attending such a course. Some companies, I was told, were reluctant to send employees on a training course for a camera that cost only a few thousand pounds. Many of the attendees were experienced engineers, but were obviously not getting the most out of their cameras, and some may have been misinterpreting the images with potentially serious consequences.

So is it really necessary to send someone on a training course for a relatively inexpensive thermal imaging camera?

Willis explained: “Customers have said training is expensive and that camera control and image interpretation can be passed on from operator to operator. For this reason we offer a free 1 day training place with any new camera purchase, there is no excuse not to attend and be shown how to get it right first time. In larger companies and organisations I have trained engineers who have been out in the field with a camera for more that ten years. Nearly all of these engineers are shocked at how little they know for the amount of time they have spent with their camera.”

Dunne told PWE infrared theory is applicable to all makes and models of camera. Initially a camera operation course can be provided at relatively low costs, but as the technology can provide substantial information regarding the safety and security of clients' assets, a high level of training and camera skills will allow the user to exploit the technology to a high standard.

It should be emphasised that inexperienced users are not the only ones who can benefit from training. Willis told PWE: “With our experienced customers it"s always good to try and keep in touch with new methods, applications and technologies.” ITC's training courses are broken down into three levels of training. Level 1 through to level 3. Level 1 which complies with ISO18436 CMGEN appB (IRT) will give an engineer around 70% of the knowledge he requires to go out into the field and practice as a thermographer, this course teaches camera handling, image interpretation, emissivity factors, T Reflected and many more core subjects.

He adds that Level 2 builds on level 1 and includes a core of knowledge 3 day element then splits three ways, electrical, mechanical and a civil engineering element. Level 2 is where engineers can specialise in particular subject.  Level 3 builds on the level 2 and looks at building on program management. This course is really designed for supervisors or managers.

Additionally seminars, user group meetings and engineering exhibitions are all a wealth of information for engineers and companies.

Dunne adds: “Typically a one week course will not make users expert in the technology. Attending courses not only allows for reinforcement of the theoretical aspect of the technology, but also allows the user to improve their skills techniques and move from passive to active techniques. State of the art equipment and software advances at a fast pace and to keep in touch with changes, new applications and market forces, it is desirable to continue users" education.

“Once passed L1 with site experience, a user can take specialised application courses in Electrical, Mechanical and Petro/Chemical applications. More specialised courses include Medical, Equine and building investigations. Active techniques can also be investigated to deliver a variety of non-destructive testing activities. Active thermography can inspire users to look at the use of pulse thermography (adding energy to a material and documenting how the energy flows through the material). This can provide information on sub-surface defects in materials. Users can look at the use of filters and camera lenses to maximise specific data.”


Overcoming barriers

So what barriers need to be overcome to put training at the top of the agenda? Willis says, many companies assume that because they have taken temperature measurement via contact methods, that Thermal Imaging is very similar: “It is true that a thermal image can be interpreted quite intuitively because the image has a lot of detail - The problem lies in the fact that for example people assume that colour has relevance in the image - it doesn’t - the colour is there merely to help the eye and unless the temperature scale is visible in the image the colour means nothing.”

He continues to explain traditionally companies that invested in the cameras a few years ago would automatically invest in training for at least one person because it was a significant investment. Then if that person left or was promoted, the training was passed down by word of mouth – leading to insufficient knowledge transfer and incorrect application.

Today, Willis explains, with cameras starting from £2995, people are just buying them and going out and taking images, and expecting the measurement to be accurate – which Willis says it is, based on the settings in the camera – but the effects of distance and emissivity need to be accounted for to make an accurate measurement. Although he adds it is worth noting that not all problems need measurement to diagnose – the image itself can give sufficient information to suggest a particular problem in some cases – such as a leak or a blocked pipe, or damaged insulation.

Dunne says the infrared industry actively promotes the use of thermal imaging cameras to be used to increase the safety and security of industrial systems. The focus has been guided towards a 'state of the art’ piece of equipment and determination of industrial applications that the camera can be used on. As the technology is widely known by industry, an emphasis has to be made on the ability of the user to extract the best out of the equipment. “A good technician should be trained, have an enthusiastic approach to the work and a commitment to continual improvement as they develop their skill and experience. This has to be endorsed by management and initially it is important to inform management of the complexity of the technology. Effective Infrared technicians are highly skilled individuals.”


Continual improvement

In conclusion recent rapid advances in thermal imaging technology have brought about a significant reduction in product cost and also simplified the controls of the instrument. Sat Sandhu at Irisys says “manufacturers have worked on the two areas of cost and ease of use to increase the benefits of thermal imaging to a larger audience, for a wider range of applications”.

But as this article highlights, camera price should not enter into the equation in terms of whether training is cost effective. There are many other issues which inexperienced users need to understand to get the most out of their thermal imager. Ease of use is one thing in terms of control but understanding how to interpret the emissivity of an object is another.


For further information please visit:
www.flirthermography.co.uk
www.fluke.co.uk
www.irisys.co.uk  
www.infraredinstitute.com 


Thermal anomalies are not always apparent, a good technician, like a detective has to develop an inspection technique

Thermal anomalies are not always apparent, a good technician, like a detective has to develop an inspection technique


Jon Willis –  thermography technical support/training manager at  Flir Systems’ Infrared Training Center (ITC)

Jon Willis – thermography technical support/training manager at  Flir Systems’ Infrared Training Center (ITC)


The effects of emissivity - two containers filled with fluid at the same temperature. One emits very effectively and the outside of the vessel displays the same energy level as the fluid. The other vessel emits a small proportion of its energy and appears to be cooler. As it is a metallic vessel with high thermal conductivity we know it will be the same temperature as the fluid.

The effects of emissivity - two containers filled with fluid at the same temperature. One emits very effectively and the outside of the vessel displays the same energy level as the fluid. The other vessel emits a small proportion of its energy and appears to be cooler. As it is a metallic vessel with high thermal conductivity we know it will be the same temperature as the fluid.

Common problems faced by inexperienced users include: 

  • Incorrect use of the camera (camera setup incorrect).
  • Mis-diagnosis of thermal data (inability to interpret data).
  • Lack of experience to develop inspection technique.
  • Inability to report anomalies effectively in a report format.

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