Safe Operating Limits - API 754

[ivani1]

What exactly safe operating limits reporting be based upon as per API 754? Design limit excursion itself, right?
And how that should be reviewed? Every time the limit exceeds, without any delays?

[opo21]

Safe Operating Limits are not always identical to absolute engineering design limits (such as maximum allowable working pressure - MAWP or ultimate design temperatures). Instead, SOLs are operational boundaries established by the facility, often incorporating Integrity Operating Windows (IOWs), control limits, and process safety information, beyond which the plant should not intentionally be operated.

[chem51]

In simple words, "SOLE-Max & SOLE-Min process values in the system is defined as HH/LL alarm value which is safe operating limit or SIS activation value."
"OWEL is the process value which will be measured between 50% of high/low alarm valve and of high-high/low-low alarm value ( SIS activation value)."
Reportable value is exceedance of SOLE as per API 754.

[jeem]

The central principle is that an SOL is a defined process safety boundary, not simply an alarm setpoint or the equipment's maximum design rating.
That has to be correctly defined, documented, approved and applied at plants.
Controlled procedures should be made available enabling the system to generate an exceedance on daily basis so that those can be reviewed and acted upon in time.