Both OSHA’s and EPA’s process safety standards require operating procedures to contain the “steps required to correct or avoid deviation(s)”, but what exactly does this mean? I really wish OSHA/EPA would have phrased it as “avoid or correct” as putting the words in this order is actual reality. Let’s look at a simple process set-up where the process has two (2) alarm levels:
1) Hi-Level Alarm, and
2) Hi-Hi-Level Alarm
When the operator gets the hi-level alarm, he/she responds to this first alarm with the intent of AVOIDING the deviation. The process has NOT YET gone into a “deviated state” (i.e. has not exceeded the safe upper level), so the steps taken are actually to AVOID the deviation of “exceeding safe upper level”.
Now if the operator’s actions, those steps in the SOP that are intended to ensure the process does not exceed the safe upper level, do not actually maintain the process conditions AND the level rises to the Hi-Hi-Level Alarm, the operator will have another set of actions to take to ensure the process is brought back into the safe operating envelope. In essence, we are now operating the process in a deviated state and the actions taken are considered “emergency operations”.
I should also point out that as we progress to this “emergency operations” stage, we need to mention the “conditions under which emergency shutdown is required” (1910.119(f)(1)(i)(D). If these steps to correct our deviated process FAIL, this is a “condition under which emergency shutdown is required”. Look at it like this… we have a process that has exceeded its “safe upper” process limit and the operator has exhausted all of the prescribed steps to AVOID AND CORRECT this deviation and those procedures have failed to bring the process back to its safe operating envelope – this by all definitions is an “out of control process” and one which needs to be shut down via emergency shutdown procedures/systems.
But this all starts with an alarm or some other indication that the process is either on its way to a deviated state or has already entered a deviated stated. If the process had ONLY a single alarm set point at the Hi-Hi-Level then the SOP would NOT contain procedures to AVOID the deviation; only steps to CORRECT the deviation.
And when someone tells you that an alarm condition in a PSM/RMP covered process is not significant, then we need to ask “why have the alarm then?”. We called them “alarm management”, in which each alarm had a prescribed set of procedures the operator was to carry out for that alarm condition. This is, in fact, the “Steps required to correct or avoid deviation”. Granted, some of these procedures were as simple as “notifying the field operator”, who the field operator would have a set of procedures he/she would use to address the alarm condition. Having an alarm (or any process indicator) in place and claims that there needs to be no action taken is an indication that the alarm /indicator should be removed! Having spurious alarms that have no meaning and require no action is a Human Factors nightmare just waiting to happen. But I digress!
So in closing, the “steps required to correct or avoid deviation” are specific procedural steps that a trained operator will execute when the process is on its way to a deviated state and/or has entered the deviated state. And lastly, even when we have a safety instrumented system (SIS) associated with our Hi-Hi process condition, we still need procedures for how the operator(s) will respond to this process condition; especially important are the Start-Up procedures after an emergency shutdown (e.g. the hi-hi level interlock).