A Human independent protection layer (IPL) can be a valid and valuable IPL. A human can be combined with an SIS-based alarm, but the human would then be part of the Logic Solver (decides what to do) and is part of the final control element. The criteria for counting human IPLs will be more completely [...]
IEC 61511 mentions systemic errors should be controlled and also estimated in the SIL Verification. But, ISA folks say they found it too complicated to include a calculation method for systemic error in TR84.00.02 guidance; which is why we almost never see it considered in actual practice. There is systemic error for process-related failures (such [...]
A team is neither necessary nor required (this is true for 95% of the LOPA we have done since 1996). If the PHA/HAZOP was documented well, a single analyst can complete the LOPA in about 20-60 minutes; with a phone call or two to a team member for some of the LOPA. The originators (or [...]
Before we start, note that the priority for Process Safety issues is much more skewed toward the engineered features in process safety. For Occupational Safety, the priority should be: Optimize human factors to as good as possible to consistently achieve the lowest average base human error rate of 1/100 (ish)... this residual error rate is [...]
It is important to know what certification means. Mostly, certification is just a way for the certifier to make money off of the unsuspecting purchasing. Certification in this or that is big business. But in most cases, certification of proficiency is not easily possible. This is why the folks in the Chemical Process Safety field [...]