(123b) PHA: Common Misses with Significant Risks

This paper will discuss common Process Hazard Analysis (PHA) misses with potentially significant risk. Specifically, 10 common misses noted from the authors’ 40+ year career in process safety will be evaluated and opportunities for improvement in PHA documentation will be identified. This paper is of significant interest to industry leaders responsible for Process Safety and Risk Management (RM), as these are common PHA misses seen across multiple industries within different companies that have the potential to result in catastrophic incidents. The first instance of Process Hazard Analysis (PHA) can be traced to 1949 as a military procedure in MIL-P-1629 “Procedures for Performing a Failure Mode, Effects and Criticality Analysis”.^[1] Hazard and Operability Studies (HAZOPs) origins have been described by Trevor Kletz as stemming from when a three-person team from Imperial Chemical Industries (ICI) met for several days a week over several months in 1963 to study design of a new phenol plant.^[2,3] This method was originally known as Operability Studies and then evolved into Hazard Analysis with Kletz using the term “HAZOP” in formal publications in 1983 within Institute of Chemical Engineers (IChemE) course notes.^[2] HAZOP usage grew exponentially after promulgation of Occupational Safety and Health Administration’s (OSHA) Process Safety Management (PSM) standard in 1992. And what, you may ask, is the point of this little history lesson? Well, in simple terms, given 75 years of PHA, have we mastered these analyses? While we have clearly “upped our game”, common PHA misses with potential significant risks remain. The remainder of this paper will discuss the following 10 common PHA misses and how to address these opportunities for improvement.

No.	PHA Common Misses
1	Stopping at Overpressurization
2	Not Evaluating Relief Discharge Location
3	Sampling Omissions
4	Fire Scenarios and Facility Siting
5	No Leakage and Egress
6	No Previous Incident Identification or Documentation
7	Lack of Management of Change (MOC) Documentation
8	Inadequate or Non-Existent Communication of PHA Results
9	Inadequate Discussion of Maintenance Activities
10	Insufficient Frontline/Operator Participation