FLORIDA POWER & LIGHT CO — Hazardous liquid — incident on 2003-12-06

Hazardous liquid incident in RIVIERA BEACH, PALM BEACH County, FL. Reported cause: 1. Reported consequences: 0 fatalities, 0 injuries, YES #6 FUEL OIL released, $200,250 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20040002.

Operator ID: 26039.

Reported incident date: 12/6/2003.

Cause detail: CORROSION, EXTERNAL

Cause detail: AT THE CONCLUSION OF A FUEL OIL TRANSFER THE OPERATOR DISCOVERED A POOL OF OIL ABOVE THE PIPELINE. THE PIPELINE SEGMENT WAS ISOLATED AND SURFACE CLEAN-UP STARTED. THE PIPELINE SEGMENT WAS EXCAVATED AND A SPOT OF LOCALIZED CORROSION WAS FOUND TOP DEAD CENTER OF THE PIPE. THIS CORROSION AND RESULTING HOLE APPEARED TO BE AT THE LOCATION OF A CAD WELD FOR A POLARIZATION CELL LEAD. THE COATING AT THIS LOCATION HAD BEEN REMOVED TO MAKE THE CAD WELD. THE LINE WAS REPAIRED AND THE FAILED PORTION IS BEING SENT TO OUR LAB FOR FURTHER METALLURGICAL ANALYSIS. THE CONCLUSIONS OF OUR CORROSION PERSONNEL AND METALURGISTS IS AS FOLLOWS:THE FAILED SECTION OF THE 30" OIL LINE WAS SHOWN TO OUR METALLURGIST AT THE LAB AND HE SAID THAT UNFORTUNATELY THE NATURE OF THE CORROSION OF THE PIPE PRECLUDES A DEFINITIVE ANALYSIS OF THE FAILURE MODE, DUE TO THE COMBINATION OF DIFFERENT TYPES OF CORROSION PRESENT. THE PRESENCE OF GENERAL CORROSION ON THE PIPE AND GROSS MATERIAL LOSS ESSENTIALLY PRECLUDES EXAMINING THE STEEL FOR CORROSION CAUSED BY A SPECIFIC EVENT, SUCH AS AC CURRENT ARCING AT THE FAILURE POINT (WHERE THE STUD FOR THE GROUNDING CABLE WAS LOCATED). THUS WE ARE LEFT WITH PIECING THE FAILURE MODE TOGETHER BASED ON THE HISTORY. OUR UNDERSTANDING OF THE HISTORY IS: �H THE 30" LINE WAS INSTALLED ABOUT 1976, WITH THE BURIED ISOLATION JOINT AT THE PORT OF PALM BEACH UTILIZING THREADED STEEL STUDS WELDED TO BOTH SIDES OF THE ISOLATION JOINT. A ZINC / COPPER GROUNDING CELL WAS WIRED TO THE JOINT VIA THE STUDS. CATHODIC PROTECTION (CP) WAS NOT PROVIDED FOR THE SHORT, ISOLATED SECTION OF THE LINE (EAST SIDE OF THE JOINT). �H IN 1980, A POLARIZATION CELL WAS INSTALLED ACROSS THE ISOLATION JOINT. 4/0 POLARIZATION CELL CABLES WERE CONNECTED TO THE LINE USING THE EXISTING STUDS AT THE ISOLATION JOINT. COPPER COMPRESSION RING TERMINALS WERE USED FOR THESE CABLE CONNECTIONS. NOTE THAT THE THERMAL INSULATION HAD TO BE REMOVED TO RETROFIT THESE CABLES; PROPER SEALING OF THE INSULATION AND JACKET MAY NOT HAVE OCCURRED ONCE THESE CABLES WERE RETROFITTED TO THE PIPES. �H WITH THE INSTALLATION OF THE RIVIERA PLANT FUEL OIL STORAGE TANK CP SYSTEM IN 1997, THE ISOLATED SECTION OF THE 30" LINE AT THE PORT OF PALM BEACH BEGAN RECEIVING CP, SINCE THIS SECTION OF THE LINE IS GROUNDED COMMON TO THE PLANT TANKS. �H IN DECEMBER 2003, THE 30" LINE LEAKED ON THE EAST SIDE OF THE ISOLATION JOINT. UPON VISUAL INSPECTION OF THE LEAK, THE STEEL STUD HAD CORRODED AWAY, AND THE COMPRESSION RING TERMINAL OF THE 4/0 CABLE APPEARED TO HAVE EXPERIENCED ARCING (THE RING PART OF THE TERMINAL NO LONGER EXIST; ONLY THE CRIMP PORTION WAS REMAINING). THE STUD & 4/0 CABLE CONNECTION ON THE WEST SIDE OF THE JOINT WAS FOUND INTACT AND IN GOOD CONDITION. GIVEN THE TIMELINE OF THE EVENTS, IT IS LIKELY THAT GENERAL CORROSION OF THE SHORT, ISOLATED SECTION OF THE LINE (EAST SIDE OF THE JOINT) PROCEEDED FOR ABOUT 21 YEARS (1976 TO 1997). GENERAL CORROSION IS EVIDENT ON THE ISOLATED PART OF THE REMOVED SECTION OF PIPE. SINCE THE ISOLATED SECTION OF LINE WAS NOT PROTECTED WITH CP DURING THIS TIME, A BIMETALLIC CORROSION CELL EXISTED BETWEEN THE STEEL STUD AND SURROUNDING PIPE, AND THE COPPER CABLE AND COPPER RING CONNECTOR, WITH THE STUD AND SURROUNDING STEEL PIPE BEING ANODIC (CORRODING) TO THE COPPER COMPONENTS. VISUAL INSPECTION INDICATES THAT THE COATING AND THERMAL INSULATION AT THE LEAK LOCATION WAS NOT IN GOOD CONDITION, WHICH ALLOWED GROUNDWATER TO BE PRESENT AT THE STUD CONNECTION, AND ALLOWED THE BIMETALLIC CORROSION TO PROCEED. THE 30" POLARIZATION CELL AT THE PORT PASSES AC CURRENT BACK TO THE RIVIERA PLANT GROUND; AC EXISTS ON THE 30" BECAUSE IT IS LOCATED IN THE TRANSMISSION RIGHT-OF-WAY, AND VOLTAGE IS INDUCED ON THE LINE FROM THE TRANSMISSION LINES. IT IS BELIEVED THAT THE BIMETALLIC CORROSION CELL AT THE STEEL STUD EVENTUALLY DEGRADED THE ELECTRICAL CONNECTION AT THE STUD, RESULTING IN A HIGH RESISTANCE CONTACT. CONSEQUENTLY THE AC CURRENT PA SSING THROUGH THIS CONNECTION EVENTUALLY BECAME AN ARCING CONDITION; THIS WAS EVIDENT FROM THE DAMAGE SEEN ON THE RING CONNECTOR. THE ONGOING ARCING AC MAY HAVE BEEN A CONTRIBUTING FACTOR TO THE PIPE CORROSION, BUT UNFORTUNATELY THIS CANNOT BE MEASURED DIRECTLY. THE FACT THAT THE LINE LEAKED SOME SIX YEARS AFTER CP WAS APPLIED TO THE ISOLATED SECTION OF LINE FURTHER SUPPORTS THE POSSIBILITY THAT ARCING AC CURRENT AT THE STUD CONTRIBUTED TO THE CORROSION. AS COUNTERMEASURES TO THIS EVENT, THESE INSULATORS THAT STILL EXIST WITHIN OUR SYSTEM ARE GIVEN SPECIAL ATTENTION WHEN IN-LINE INSPECTIONS ARE CONDUCTED FOR SIGNS OF METAL LOSS. AN ILI WAS CONDUCTED ON THIS PIPELINE AFTER THE EVENT TO INSURE INTEGRITY GOING FORWARD. ADDITIONALLY, THIS INSULATING FLANGE WAS MOVED ABOVE GROUND AND THE POLARIZATION CELL LEADS WERE CONNECTED WHERE THEY WERE EASILY INSPECTED VISUALLY.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $200,250 reported total cost, $127,627.874 in 1984 dollars, $314,308.174 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.