Hi,
I have come across a practice where ESD Trays containing sensitive devices, where the trays are place one on-top another. These are then sealed in ESD Shield Bags and shipped.
DO the trays need to be checked at 12% RH as the shielding bags provides ESD protection already and it qualified at 12% and 50% based on packaging standards.
Sukhbeer,
Since the ESD trays are used as part of your ESD packaging, they should meet the product qualification resistance requirements for conductive or dissipative packaging per table 4 of ANSI/ESD S20.20. This requires that the packaging is tested per ANSI/ESD STM11.11, 11.12, or 11.13. All 3 standards require that samples of the packaging be pre-conditioned to 12% +/- 3% and temperature of 23°C +/- 3°C for at least 48 hours. They do not need to meet the shielding requirements of table 4 of ANSI/ESD S20.20 if they are only used inside the EPA.
If the ESD trays meet the product qualification limits, then they would only need to be periodically verified to the compliance verification resistance limits of table 4 of ANSI/ESD S20.20 following the packaging section of TR53 which only requires you to test the packaging at ambient temperature and humidity.