Dear ESD experts,
For qualification of item only use within the factory, the ANSI/ESD S20.20 state that we shall test under the annual lowest RH% of the factories (if not to follow standard test method conditioning).
How ever in our factories, the Rh% is control in the range of 40%-60% (typical above 47%).
Is it acceptable if we declare a tailoring statement to accept the product qualification to be conducted under ambient RH% (any within the range of 40%-60%) as follow:
Tailoring Statement: Product qualification for items used within facility shall be conducted at Relative humidity (RH) range 40%-60% instead of Annual minimum RH for items are used within EPA.
ANSI/ESD S20.20
Requirement Affected: Item 7.3 Product Qualification Plan “Organizations with facilities where the annual minimum relative humidity (RH) is above the environmental conditioning levels identified within the product qualification test method for each ESD control item can use this minimum value to qualify each item used within that facility”.
Technical Rationale for Deviation:
Our factory maintains a controlled RH environment of 40%-60% per Site Facilities Infrastructure & Environment Process. Historical data demonstrates that this RH range effectively supports ESD control for all qualified items. The facility’s annual minimum RH does not drop below 40%, ensuring no conditions occur that would compromise ESD control effectiveness.
Testing under this RH range accurately represents the operational environment within the EPA and aligns with product qualification requirements. This ensures compliance with ANSI/ESD S20.20 while optimizing test conditions for facility-specific environmental factors.
Thank you in advance for your advices.