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 Post subject: IR Scanning
PostPosted: Thu Jan 10, 2008 3:32 pm 
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Joined: Thu Jan 10, 2008 2:51 pm
Posts: 3
Performing IR Scanning in the absence of IR windows has raised a number of questions within our own service company and I would like to ask some of the members here what steps they are taking to comply with the NFPA 70E. Of course removing/installing panels, this task is straight-forward and one can follow the tables provided in the NFPA 70E; wearing appropriate PPE based on task or as per lables if provided. However, once panels are removed, technician is exposed to live electrical circuits. If anyone has ever operated an IR camera; it is difficult to operate camera and virtually impossible to look through eye-piece wearing a visor or hood. This is where we are finding it difficult to perform task wearing all the required PPE. A solution to only scan via IR windows is not feasible as many of our customers have not installed windows yet....many have also not completed an arc flash study either. I am looking for input on practises for performing this task or perhaps any articles already written on the subject that we can discuss at our next safety meeting.


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PostPosted: Fri Jan 11, 2008 7:09 am 
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Joined: Mon Aug 06, 2007 10:21 am
Posts: 35
Location: Ellijay, GA
Your timing is impeccable

Larry,

The reason I say that is because I just finished a paper on this very subject. Every January, Snell Infrared hosts an infrared conference call Thermal Solutions. This will be my fourth year attending and my third year presenting a paper. My paper this year is titled "NFPA 70E and IR Thermography, Compliance in a Non-compliant World".

Our company has been providing IR surveys to industrial and commercial facilitites for almost 15 years. We started out like every one else, wearing every day work wear to perform IR. A few years ago we started hearing about 70E and PPE requirements, and it drastically changed our business model. But not in a negative way. We have been providing arc flash analysis as one of our engineering packages for about a year and a half, and most of our business in that sector has come from our IR customers.

To get to your issue...in order to perform an effective IR scan of electrical distribution equipment, the equipment must be energized. If there is no current flow, you have no dissipation of power in the form of heating in the high resistance connections your scanis designed to discover. Another key element is for the equipment to be exposed. It's IR not x-ray, so you can't see what's behind a panel cover. I know there are thermographers out there who will try and convince you that you can surface scan breaker panels and do an effective job, but I know this to be untrue and can prove that assertion. So for the sake of this topic, let's assume you intend to to the scan correctly and open the equipment.

The technician who is operating the camera often is the same technician who is tasked with exposing the equipment. We typically send a two-man team to perform IR. In commercial settings they operate differently than in industrial settings, due in part to the limited access of electrical rooms in a commercial building as opposed to industrial facilities where it's not uncommon for panels and such to be located in common areas. In a commercial property, our team will go from floor to floor, wearing PPE, exposing electrical panels and bus riser disconnects. After a number of floors have had their panels opened, the technician designated as the thermographer for that job will pick up his camera and begin scanning, with the other technician serving as a safety observer. In a number of the buildings where we perform IR we have also performed the arc flash analysis and we know the energy levels so our technicians know exactly what level PPE to wear. We also know the falsh boundaries, so the easy answer is for the camera operator to stay outside the flash protection boundary while he performs the IR scan. We have one technician in complete PPE standing by while the technician operating the camera stays safely outside the flash boundary. As both of them are certified thermographers, if the need arises to take closer look at an anomaly and encroach on the flash boundary, they have he option of passing the camera to the technician still adorned in PPE, or stopping so the camera operator can re-dress in whatever he took off and move closer.

Our approach works for us because we have adapted to the changes 70E makes necessary. Our technicians leave their homes each morning in FR rated trousers and shirts, so that only thing they have to do when they start working is add gloves, safety glasses and a hardhat. We have issues them all PPE kits which include everything they need to achieve any level of required PPE. In environments where we are unsure of the risk levels, we assume risk levels as outlined in the 70E Table 130.7(C)(9)(A) and apply the Simplified, Two-Category FR Clothing System as described in Annex "H" of the 70E. Again in these instances, we will have a technician in PPE at all times while the camera operator stays outside the assumed flash protection boundary.

Additionally, there are devices on the market that make it easier to see the FOV of your camera while wearing PPE. One company makes a small Heads Up Display type device that attaches to the video output of your IR camera and can be worn on the inside of a pair of safety glasses, providing the thermographer with an image of what the camera sees behind a hood or visor. A number of cameras that are equipped with an eyepiece can also support the installation of a small screen. Again, they attach to the video output of your camera and put the FOV image on the external screen. This can be easily seen from behind a faceshield as long as the lighting conditions are agreeable.

I hope I have been some help. If you have a subscription to Uptime magazine, you can watch for an article based on the paper I'm presenting at the conference. Or, if you can break away for a few days, attend the conference yourself. They still have available seats, and its not terribly expensive. The website is ThermalSolutions.org My contact data is in my signature below, feel free to get in touch with me if I can help you any further.


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PostPosted: Fri Jan 11, 2008 9:57 am 
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I appreciate your input as we will be revising the way we approach and perform this task. Additionally, I like the idea of the installation of a seperate screen either attached to one's safety glasses or an external screen and will be checking into these avenues.


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PostPosted: Fri Jan 11, 2008 1:00 pm 
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Joined: Mon Aug 06, 2007 10:21 am
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Location: Ellijay, GA
You're welcome

At the risk of coming off as entirely commercial, we offer consultation if you think you might need that. If we entered into an arrangement with your company in that capacity we would obviously also agree to not snake customers from you. Just something to think about if you have that need.


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PostPosted: Mon Jun 02, 2008 8:22 pm 
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Joined: Mon Jun 02, 2008 11:58 am
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Location: Charlotte, NC
The 2008 70E ROP's address this, the new tables will have different HRC's for persons doing the IR scanning than the person removing panels. I am suprised no one has brought this to your attention yet, everyone really involved with the 70E is aware of this change and has been for over a year.

Or you can do what I have done at past companies that we did IR scanning, outfit our IR crews with the 70E equations in thier smartphones so they can calculate the working distance that HRC1 PPE is sufficient based on the label from the arc flash study if the plant has one (Just work out from 18", if that is the assumed distance for the Ei).


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