This customer was finishing commissioning from a line upgrade that included new safety functionality across the line. The customer was originally performing a line speed upgrade. They also wanted to identify and address existing safety issues for the full length of the line, from the uncoiler to the recoiler, during this process.
Validation services from our machine safety consultant is a routine part of our complete safety services, and this situation demonstrates why that is so important. It is critical to verify that safety functions operate as outlined by the risk assessment and truth tables, and that analysis and testing processes adhere to ISO 13849-2 standards. Just as redundancy and monitoring are required to maintain various safety ratings, the human portion of this process should also have redundancy.
During the validation process, we found several emergency stop buttons that did not initiate an emergency stop at all.