One of our sites is currently undergoing an ESD audit and was questioned about our verification methods for testing flooring. Within our documentation for troubleshooting we specify to clean the electrodes. But we also allow cleaning of the floor.
We were asked why we would allow cleaning the floor and what specification this came from. After some digging I found that cleaning the floor was included in TR53-01-18, but was removed from TR53-01-22. Am I missing something?
So if we are to only follow TR53, than we would need to replace the floor when it was dirty resulting in a failed test. Of course, that wouldn’t happen… but was there a reasoning behind removing this obvious troubleshooting step.
Additionally, it appears ALL instances of cleaning the item being tested was removed. Work surfaces, ESD Seating, etc… I can only assume this was due to the “common sense” factor. However, now there is no longer a “documented” reasoning for why we are cleaning these items and as we are seeing some auditors will question our methods.
Please refer to Section 5.0 of TR53 for this statement:
Compliance verification of the ESD control item should be performed where the electrostatic
discharge sensitive (ESDS) item is likely to reside or to be handled in the process. The intent is to assess the as-found condition of the ESD control item being verified. There should be no modification (for example, cleaning, rubbing, moving, etc.) of the ESD control item prior to verification.
There is allowance in each of the sections to “trouble-shoot” your measurement set up to ensure that the measurement set-up or chain is functioning properly and then you can re-test.
Remember - the goal of compliance verification measurements are to "verify that your control element is working properly and doing what it is supposed to do. If you don’t get the expected results, then that is a key that further investigation into either the measurement set up, or there is in fact something wrong with your control element.
Thanks Matt for pointing out section 5 of TR53. However… this puts into writing to not modify the item prior to test. Which I completely agree with, as yes you are proving that your system is sufficient to obtain passing results. But what is doesn’t address is “the item failed” now what?
Section 5.1 even points out that troubleshooting is meant to help with “common potential failure modes”. Maybe items being dirty creating failures is no longer an issue in the industry? I can maybe see that. In our case, we didn’t even have a failure. We are just being questioned on cleaning the item prior to retest after a failure. If the item fails, every one of us WILL try cleaning it and retest. Now what we do with that data point will vary greatly I imagine. But none of us will replace an item that can be cleaned and pass. Obviously, I can’t speak for everyone and every situation. But what would you do if you had a failure testing your floor, you checked all your equipment and the only thing left was “is the floor dirty” causing the failure?
I guess I would have liked to see the cleaning statement left in TR53 and if anything added a note. “If cleaning is required to achieve a passing result, you should consider reviewing your PM scheduled for compliance and or effectiveness”.
If anyone else has been asked about this topic I am very interested in how it was handled?
Section 5.1 is ESD TR53 states: “Troubleshooting procedures are provided within this technical report to assist the end-user in determining common potential failure modes within the compliance verification procedure and/or test equipment.
For troubleshooting common ESD control item failure modes, see ESD TR20.20 - Handbook for the Development of an Electrostatic Discharge Control Program for the Protection of Electronic Parts, Assemblies, and Equipment.”
The intent of the troubleshooting procedures is only to address the testing process or test equipment, not the actual ESD control item being tested as there could be many different possibilities and it is left to the operator to figure these out (including possibly cleaning the floor or electrodes). If we left in something like cleaning or other troubleshooting steps like repair, rework, etc., we would also need to explain how to do it (i.e. clean with water, isopropyl alcohol and to what percentage). Since this would be outside the scope of ESD TR53, it was best to leave them out.
It does reference ESD TR20.20 for more information on how to troubleshoot the ESD control items. Although there isn’t anything specifically on cleaning flooring that I could find, it does mention cleaning worksurfaces and other ESD control items.
I did look at TR20.20 as well because of that reference to do so. I can respect the decision to remove the cleaning based on your comments. It just leaves a gap for those of us that followed that part of the specification. We will have to add content into our documentation to explain the omittance of this in TR53. Thank you again