Hello Mr Raul
I am also a new user in thermography like you and I inspect only electrical panels and trafo. we have a large facility and so we decided frequency 6 month. right now we not utilize baseine trending but using just to see problem or temp difference.
With seeing the temperature on Cable termination , you have to note the ambient temp,emissivity( which is nearly 0.95 of cable insulation) and running load ).
For baseline trending you check the InspecTrend software which have different level of utilization. Right now i am using initial virsion of inspectrend and may be within short time we will go for Baseline trending but before that i need to learn InspecTrend well. Lookin for satisfied user of inspectrend who is well familiar with features of this software.

We all are here for learning and request to share as much knowledge as we can.

thanks & Regards

Hello for everybody.

I would like to receive some comments about the criteria of severity that I made in order to improve the inspections by Thermography (The file is attached).

Regards.

Severidad_en_la_medicion_de_Termografia.xls (18 Kb, 12 downloads) Standard

Raul,

I think you are thinking in the correct ways that will lead to success because you are asking the right questions about frequency and load and are also using different alarm points for different types of equipment.

MANY factors influence the surface temperatures we see. For equipment that is inside, load is probably the biggest factor. You must consider the present load and where the load my go in the future. Outdoors load is still a factor but wind and other ambient changes are also important to consider. The question, of course, to ask: "Is the problem getting worse or have the conditions simply changed?" It is for these reasons that I don't suggest relying only on temperature.

We also have a very poor understanding of what a good alarm temperature is, especially for electrical equipment. I suggest we not ANY variation from normal and then, depending on resources, investigate as many as possible to understand the root cause and the severity.

It is vital that you prioritize your equipment so that the most critical is inspected at an optimal frequency. In all cases, you should also let your findings help guide you as your refine the frequencies. If you continue to find many problems, increase your frequency. If you find fewer problems, decrease the frequency.

Furnaces, once you have established a baseline signature, may behave more predictably in most cases. The frequency of inspection should take into account the history and typical operating considerations you have. The alarm temperatures you set depend on your risk tolerance and your resources to monitor and repair findings. I would strongly suggest you involve your furnace engineer, who will have heat transfer experience on that furnace, in setting these alarms.

Remember, infrared is just a tool, even if it is an amazing one, and the real work is in using the tool intelligently. In your brain, or those of your co-workers, are the answers—the imaging system just helps us see them more easily!

I look forward to meeting you at some point in the future.

John has a good point that most people agree with. We should acknowledge there are so many unknowns that we really can't predict anything resembling a time to failure. And prioritizing findings, while not as bold as predicting time to failure, is a similar type activity.

But, I find that in my plant environment my plant customers do repeatedly request guesstimates of risks of not repairing a certain item for a certain length of time. They also ask for prioritization like hi, medium, low. And they don't like it when I factor anything resembling my opinion based on specific circumstances into that prioritization. Instead they would rather have the logic all laid out ahead of time in a relatively simple set of "rules" that they can look at and confirm the prioritization independently without my input. The fact that so many standards susggest a simple single scale of temperature rise criteria for all equipment (no mention of indirect heating) under all load and wind conditions etc and that these type standards are so widely used, is a very strong indication that there are many people that want that type of simple rule-based system. I'm not saying that is the right approach or the smart approach, but that is the kind of box that we sometimes get pushed into.

One reference that I think is a very good starting point is John's article "So Many Problems, Which Ones to Fix?" here:
http://www.thesnellgroup.com/storage/fck/File/thinkther...rmally_2003_July.pdf

This message has been edited. Last edited by: electricpete,