Dear ESD experts,
would like to check with you regarding compliance verification requirements. supposed I implement a sampling on my compliance verification, is it acceptable to utilize the sampling method instead of 100%? will i be still compliant to the requirement of ANSI/ ESD S20.20?
let me know your thoughts.
thank you.
Rosalie,
The simple answer to your question, in the words of John Kinnear, is “it depends.” It depends on the ESD control item for which you are doing compliance verification.
For more disposable items, like bags, sampling is acceptable within lots so you don’t have to test them all.
Also, for flooring, sampling different areas of the floor is also acceptable as it would be unreasonable to test every square inch of flooring space.
For something like wrist straps and footwear, you should be doing very frequent tests so sampling would likely not be an acceptable practice.
For something more in between, like ionizers or worksurfaces, you could set up a shorter sampling routine (like weekly) but you would want to make sure each ionizer or worksurface is tested at least over some longer period (like every 3-6 months), so you don’t have a condition where one ionizer or worksurface isn’t tested for many years.
Thanks andy, but the sampling measurement such as for example, worksurface is being check in a monthly basis but 1 sample per month not a 100% being check. is it still acceptable.
Rosalie,
It is up to you to determine the interval between tests for each of your ESD control items. Some facilities may be willing to extend the interval to 3 or 6 months based on the experience and the amount of risk they are willing to take of dealing with the consequences of a failed ESD control item. I know my own organization tests worksurfaces every 3 months.
So, if you wanted to take a sample of a third of your worksurfaces and test them every month, you would check all of them over a 3-month period assuming you keep track of which you tested and which need testing in subsequent months.
I am also interested in this subject but applying it shelving. We have banks of stationary shelving which currently consists of 580 identified shelves. Our organization calls for testing them every quarter. The accumulated data over time shows no failures. Based on that data I would like to sample 290 of the shelves (throughout all the shelves) for the quarter. If there is a failure then all 580 would need to be tested but if there is no failure, just the 290 tests would be recorded. The shelves not tested for this quarter would be tested the next quarter. This means all shelves are tested once every 6 months. Is something like that acceptable? If so, would it require a tailoring statement?
There are no requirements on how often or how to implement a compliance verification program. Each user must evaluate the risk vs the program implemented. As jparkman has a significant amount of data, that can be used to evaluate the risk of implimenting this type of sample plan. There is no need for a tailoring statement as you do have a complaince veriifcation plan.
In gerneral, the complaince verification plan needs to be implemented but the options on how to implement it are left to the user. A sampling plan could be used but again the risk needs to be evaluated.
For example, if everything is fixed and nothing is moving and there is data to show no failures, a sampling plan could be used. If there is a lot of movement or reconfiguring of the manufacturing area, the risk may be to great for a sampling plan.
Dear Experts,
I appreciate you sharing your inputs; they have been very helpful to me.
thank you.
Hello, Greetings of the day to all, from India
Our ESD Guru JK Sir’s two sentence reply at the bottom of his reply is absolutely true.
In general Sampling is only for PQ test and CV test is for all the EPE’s in use subject to an effective grounding or Ionization wherever applicable.
Depending upon the facility floor area- population of personnel- type of your activity -sensitivity of your devices handled-ambient conditions- type of failure -frequency of failure- etc every thing need to be kept in mind to decide the CV frequency as it is up to the user to decide . But , again as per JK Sir, however CV needs to be implemented .
Anyway ,if you have an exclusive dedicated ESD coordinator cum Internal Auditor, as a healthy practice monthly CV audit is very much appreciated as it builds up a good ESD Control awareness for the growth of an organization.