The Baker Panel Report - ABSA

elief system. All five refineries had procedures and administrative controls tomonitor/log the rupture disk/relief valve space pressures.As a part of the technical reviews by the PSM Review Team or through reviewsconducted by BP after the PSM Review Team visited the Whiting refinery in March2006, rupture disk/relief valve spaces at Carson, Texas City, Toledo, and Whitingrefineries were found to have been pressurized without timely follow-up or correctiveaction.A significant example was at the Whiting refinery. At Whiting, the PSM Review Teamreviewed quarterly operator logs for the previous 2 years for a single pressure vessel (afluid catalytic cracking fractionator tower); each such log indicated 7-out-of-8 rupturedisks/relief valves reported higher-than-intended pressure in the space between therupture disk and the relief valve. Despite the elevated pressure in the rupture disk/reliefvalve space, work orders were not written each quarter to repair the problem as requiredby BP procedure. Based on refinery records and interviews, the PSM Review Teambelieves that the refinery operations and maintenance personnel did not understand thehazard/risk significance of a pinhole leak in a disk (i.e., compromising a pressure reliefdevice) even though internal standards clearly defined the issues. As a result, refinerypersonnel did not correct the problem with appropriate urgency. Instead, they intended toaddress the problem at a future unit turnaround by changing the metallurgy of the reliefvalves, thereby eliminating the need for the rupture disks.After the PSM Review Team found the rupture disk/relief valve issue at Whiting inMarch 2006, BP followed its High Potential Incident Reporting (HiPo) procedure andalerted the other refineries of the problem. 11 When the PSM Review Team conducted itswork at Carson in May 2006 and Toledo in May 2006, both refineries had evaluated allof their rupture disk/relief valve installations in response to the Whiting HiPo. At one orboth of the refineries, BP found instances of (1) rupture disk/relief valve spaces withpressure, (2) rupture disk/relief valve spaces with no method of determining if pressureexisted, or (3) the pressure of the rupture disk/relief valve space not regularly monitored.The Texas City refinery did a similar evaluation of rupture disk/relief valve spaces afterthe Whiting HiPo. Even after Texas City had performed its own evaluation, the PSMReview Team identified a deficiency. On one piece of equipment, pressure gaugesindicated that 4 of 11 rupture disk/relief valve spaces had elevated pressure. BP TexasCity operations personnel were aware of the condition but had not responded becausethey believed the pressure gauges were not accurate. When BP Texas City replaced thegauges after the PSM Review Team identified the issue, no elevated pressure wasindicated. The refinery allowed the rupture disk/relief valve space to indicate pressurewithout being certain if the rupture disk/relief valve pressure indication was accurate.System Finding 1 – Rupture disks under relief valves. BP did not recognize the hazardsof pressurized spaces between rupture disks and relief valves and did not evaluate andcorrect identified deficiencies in a timely fashion. These conditions diminished theeffectiveness of the affected pressure vessel relief systems for extended periods of time.(Carson, Texas City, Toledo, and Whiting)18