Have you been questioned by your quality manager about shelf life on ESD bags? Maybe it’s an internal quality procedure that is being written and you would like to know where the manufacturer stands on the shelf life of ESD packaging. Well today we will address the topic of ESD Static Control bag storage and the expected shelf life.
There are many ways to manufacture an ESD shielding bag with low charging properties on the inner and outer layers. This is the first factor to consider so I will address only the items that I convert here at SCS. In our process, I achieve shielding values via a buried metal layer. The metal layer is laminated between two layers of polyethylene. This process makes a very robust and long- lasting product in terms of shielding values as per ANSI/ESD S541-2018, the electronic industry’s most recognized standard for ESD packaging. Still the metal layer is exposed to oxidization if not stored properly and subject to extreme climate or moisture.
How does all this pertain to shelf-life you ask? SCS provides a Static Control Bag Storage document with a 1 year warranty from the date of purchase. I have witnessed SCS ESD bags stored in a controlled climate, well-ventilated area that have maintained passing surface resistance results after 5 yrs. on the shelf. Some customers have relied on our Moisture Barrier products to archive various critical products for as long as 20 yrs. They found through extensive testing that SCS had the highest quality and most repeatable results to trust with their archived product.
End users cannot always provide a climate and humidity-controlled atmosphere for our raw material, so it is recommended that you test
your bags periodically per the S541 standard and dispose of any materials that are found to be questionable. As a best practice, you can log your products by purchase date or lot number and create an annual spot check audit to assure that your bags are still in compliance. Using a FIFO First In First Out process is critical in keeping your inventory fresh. You can imagine that there are 1000’s of variations to consider when we discuss shelf life. Heat, storage rack conditions, travel method and local climate to name a few, so the points to take away are this