Infrared Testing Techniques

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J oe Grelish

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Orange County, Florida, Facilities Management has a few questions for your esteemed staff.

They are listed below.

If further clarification is required please contact me.



1. What are the expectations (recommended frequencies, types of equipment, locations, etc ) for conducting Infrared (Thermography) Testing on electrical equipment and components?



2. Who/What is the governing body of this type of testing? Is it under NFPA, NEC or another agency? What NEC reg. is it?



3. Are there viable studies comparing the use of private contractors conducting testing, versus using trained in house personnel to conduct the same testing?



4. Are there industry leaders in this field? Who are they?



5. Any other considerations/recommendations?



Thank you,

Joe Grelish

Orange County Facilities Management

Removed the e-mail address and other personal contact information. Please use the PM system to exchange personal information and e-mail addresses. To use the Private Mail system, click on the :D

[ June 28, 2005, 09:28 PM: Message edited by: charlie ]
 
Re: Infrared Testing Techniques

Thermography testing is an excellent preventative maintenance technique. I have used it many times and found unseen problems that would of never been expected. It is something that needs to be done on a trend analysis basis though. Usually once something burns up it's to late for thermography :D

1.Frequencies, up to you. How often do you use the equipment? How vital is it? How much transient temperature does it undergo? I am used to running a quarterly thermography check, but check different things each time. I would rotate it around so that each piece of equipment I wanted checked would be done once a year but with having them come back each quarter, then if there were any other concerns I could have them check those also. I was in a very large plant though and it was quite easy to keep a thermographor busy for an entire day.

2. No real governing body except for yourself, big thing is safety. Thermography has to be done while the equipment is running and the more fully loaded the better. That's when you will see your problem spots or for that matter the things that are working correctly.

3. Depends on how much you want to spend. The equipment is quite expensive for the good stuff. Better than $50,000. You can pick up a cheap thermal camera for about $20,000 and can even just get an infrared gun and try to do some monitoring but if you want something easy to interpret and make nice reports it will cost. My personal recommendation. Use a contractor or spend the money to get the high end equipment. I've been down both roads. It's much better to give the guy that needs to fix the problem a good clear picture of where he needs to work than just going "hey, it's hot in this area, take everything apart and clean it up and make sure all the connections are tight". Also makes it much better for reporting and proving the nice cost reductions, and problems that were avoided ahead of time. Training is a big thing, it's not as easy as it seams to just take the picture and go there's the problem. Emistivity set points, where to gain access and other things are key to finding problems.

4. Industry leaders, there are a lot of them on the market. I would just do a search on the web and look for someone in your area. A lot of power companies will even do survey's for you, and most any industrial electrical contractor, or I even used a motor repair shop before, depends on who has the best equipment.

You should take off all your personal information from here.
 
Re: Infrared Testing Techniques

Dear Sir,

Thank you for your very timely response. You have provided me with a wealth of information.
Sincerely,
Joe Grelish
 
Re: Infrared Testing Techniques

I don't know much about it but I thought I'd post an image.

electrical%20thermography%20IR%20image.jpg
 
Re: Infrared Testing Techniques

Excellent picture physis, now all the Questions come up. Believe it or not with all the adjustments that can be made with these cameras you can make something that is not to bad look real bad. First is there really a problem? The temp. I see is only around 150. Check the actual load on the breaker, how much current difference is there? Is this breaker feeding a three phase balanced load, or a panel that has single phase loads on it? How has it been before? Does anything look burned? At first glance it looks like an obvious overheating on the middle lug.

These are just tools that need to be evaluated just like any other indication. Don't just run off thinking there is a major problem.

Anyway, I'm getting carried away myself but this is a very good example of what you can find and use to help evaluate the condition of your electrical system.

By the way thermography can be used for many other things too. Check motor bearings, gear boxes, furnaces, steam leaks, thermal insulation break down, leaks around window's, doors..... the list can go on and on.


Is it error A????

[ June 28, 2005, 02:46 PM: Message edited by: 69boss302 ]
 
Re: Infrared Testing Techniques

This is an image I borrowed from the internet. My thoughts are the same as yours. The temperature on this terminal isn't necessarily critical. I'd certainly raise an eyebrow at it. It does demonstrate how useful of a tool thermography is. If I had the dough I'd buy a gadget. :(

[ June 28, 2005, 03:00 PM: Message edited by: physis ]
 
Re: Infrared Testing Techniques

And the sensitivity you can get too.

I'm gonna say that the ambient temperature's in the nieborhood of 105? F, the adjacent terminals are about 110? F and the hot one is around 145? F.

Those are really some fairly close values.

Cool things are cool. :cool:
 
Re: Infrared Testing Techniques

Originally posted by physis:

Cool things are cool. :D ;) :cool:

Edit: Don't forget, george keeps hookers in his trunk!

[ June 28, 2005, 03:30 PM: Message edited by: 69boss302 ]
Click to expand...
 
Re: Infrared Testing Techniques

I don't believe that guy when he's telling the truth. ;)

Edit: I think Error B is leaving a word out.

[ June 28, 2005, 03:42 PM: Message edited by: physis ]
 
Re: Infrared Testing Techniques

joe,
i have recently retired and was a certified infrared thermographer since 1989 and also a florida state certified electrical contractor. i have always used top of the line equipment and only provided these services to our service customer base. the certification process in the early days of this equipment was more adapted to roof repairs than electrical problems. our customer base was mainly the largest high rise office buildings in south florida. and most of my expieriance was gathered within these buildings over the years of scans and problem areas. you ask some very good questions concerning this technology.

and as noted above, some things can be made to look hot when it not, and just as important, some things are hot but they are supposed to be hot!!
many times i have followed behind other thermographers and false alarms are common especially when the thermographer is not electrically knowledgable! it is also important to know what to concentrate within the scope of the scan. originally(1989) i would report on a two pole breaker with a 40 degree rise that was feeding a computer room a/c unit. over the years, i have realized this is a normal result since the heat load in the average computer room is high and the compressor rarely shuts down! and this is important to the tenant, but not the building owner. the building owner is concerned in issues that can directly effect the normal operation of his/her building! our scan covers the entire electrical distribution system and will find a bad main breaker or termination, but i avoid branch circuit problems.

as an example, the typical office building may come up with 30 infrared items in need of repair the first time we scan. and if these items are repaired according to our recommendations, usually the following year you can expect to find less than half this number--say 13 or so. the following year this number may drop to seven. at this point you may consider a scan every two years?? some are required by insurance companies, and many give a lower insurance rate when infrared scans are schedualled yearly. and some of the building's rate savings more than paid for our scans. motor loads are prime problem areas.

we have found problems that your eye or touch can effectivily evaluate -- consider a 4000 amp bus duct with a 1 1/2 degree rise on a joint --looks brand new, and your hand cannot determine only 1 1/2 degrees! now the building owner has enough faith in your equipment and knowledge to order thirty thousand dollars worth of parts and schedual a shutdown to change the effected sections out! it sure is a relief when you cut it open and find the bus sections damaged! an electrician makes a good thermographer because he knows what is supposed to be hot and what is not. if you find a hot internal contact on a 200 amp circuit breaker, and find using an amprobe that the current drawn across this phase is 20 per cent higher, the high temperature would be justified. but if the amprobe showed a equal current draw on all phases it would indicate the breaker has an internal problem and should be replaced....

i recently reviewed a infrared scan report which was required by a certain insurance company and also performed by this insurance company. and it was very demanding with their recommendation for repair and a time in which this repair was to be accomplished!!! i did not find one item in this report critical to the building's operation nor actually alarming to me! there was thirty items listed and the highest temp. rise was 11 degrees!!!

i cannot recommend another company - i never found one that provided educated electricians along with top of the line equipment to perform their scans. if you need any additional information concerning this service for you facility you can e-mail me. charlie tuna
 
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