STM9.1 and STM97.1 section 6.2.1 call for a sample size of 3 pair (6 total) as the minimum quantity for product qualification. How do we handle the situation where we won’t have 3 pair of the same footwear for PQ? The prime example would be employee purchased ESD shoes. Can it be as simple as noting on the PQ data report the test was done on a single pair?
J.D.,
I suggest you either purchase two more pairs of this shoe type for product qual testing or you don’t allow this ESD shoe type in your system and ask the employee to use one of the approved footwear items. Three pairs of shoes were determined to be the minimum required to ensure repeatability across the shoe type.
Situations like this have happened many times where an employee wants to use a certain pair of ESD shoes they have or like that are not part of the ESD control program. Unless many others in the organization are also asking for this new footwear to be approved, the request is usually rejected because the effort and cost to do the qualification testing is high (i.e. test lab availability or waiting for factory relative humidity to be at the lowest, test equipment, etc.).
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If an ESD control program is maintained and followed strictly and if your program has Footwear-floor facility for mobile personnel and mobile equipment then you are supposed to have all types of footwear used on the floor **qualified prior to use per the standard test method.and conditions **
In general no pvt footwear of the working staff be allowed in an EPA with Footwear -Floor facility including any VVIP or head of the organization even .
But ,as VVIPs or head of the organization just visit the plant on casual basis but normally do not touch any device or component many use a disposable ESD safe shoe cover with a conductive tape which is inserted inside socks or tied around the ankle .
Thanks for the reply esdtekniks. I agree with what you are saying except the private footwear would be qualified prior to use.
Thanks for the reply AndyN. There is the consideration of supporting an employee and minding a budget. I understand how 3+ pair would establish good data of repeatability across a shoe type or foot grounder that will be used by the dozens. With the one-off though, I think the qualifications would be akin to a go/no go for that particular pair of shoes.
J.D.,
If you are not trying to get ANSI/ESD S20.20 facility certification, then this approach may work for you as long as you are willing to accept the additional risk of using footwear that is not fully qualified per the STM’s.