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Home My WebLink About2023 CATHODIC (5-15-2023) May 15, 2023 Job Number: B6352 Golden State Mobil 3200 F Street Bakersfield, CA 93301 1826 Attention: Mr. Monty Singh Subject: Operational Testing of the Cathodic Protection System at Golden State Mobil, 3200 F Street in Bakersfield, California. Dear Mr. Singh: On May 12, 2023, Farwest Corrosion Control Company (Farwest) conducted a cathodic protection system repair and inspection on the Golden State Mobil Gas station’s underground fuel storage tanks. Upon completion of the inspection, repairs and system adjustments, all pipe-to-soil potentials on underground structures met or exceeded NACE criteria for cathodic protection. BACKGROUND: At the request of Golden State Mobil, Farwest Corrosion Control performed an inspection and survey on the impressed current cathodic protection (CP) system designed to protect two (2) underground storage tanks (UST’s) at Golden State Mobil in Bakersfield, California. The purpose of the inspection was to test the effectiveness of the impressed current cathodic protection system on the three underground fuel storage tanks. The 50 Volt, 12 Amp rectifier is located in the storage room within the store. The anode ground bed is located on the south side of the store in the parking lot. Drawings and historical data were not available at the time of this survey. During the first initial visit on May 2, 2023, Farwest Corrosion found the rectifier nonfunctional. Farwest replaced a blown fuse and then turned the rectifier on. Voltage was present but amps were not. Troubleshooting revealed that the main anode lead and the structure lead going to the rectifier had been severed and wire nutted in a plastic electrical box. On May 12, 2023, Farwest returned to Golden State Mobil. After wires were uncovered under the parking lot by another contractor, Farwest spliced the structure lead and the main anode lead from the anode bed back into the leads that ran back to the rectifier. After the splice was completed, Farwest turned the rectifier back on and the rectifier measured both Voltage and Current. Farwest then performed the 3-year CP survey on the UST’s. CATHODIC PROTECTION CRITERIA All potential levels measured and recorded are referenced to the criteria for cathodic protection as established by the National Association of Corrosion Engineers standard SP0285-2021 “External Corrosion Control of Underground Storage Tank Systems by Cathodic Protection,” Section 5.2 which provides the following: May 5, 2023 Job Number: B6352 2 5.2 Criteria for Steel Structures 5.2.1 Corrosion control can be achieved at various levels of cathodic polarization depending on the environmental conditions. However, in the absence of data that demonstrate that adequate CP has been achieved, one or more of the following shall apply: 5.2.1.1 A negative (cathodic) potential of at least 850 mV with the CP applied. This potential is measured with respect to a CSE contacting the electrolyte. Voltage drops other than those across the structure/electrolyte boundary must be considered for valid interpretation of this potential measurement. 5.2.1.2 A negative polarized potential of at least 850 mV relative to a CSE. 5.2.1.3 A minimum of 100 mV of cathodic polarization. The formation or decay of polarization may be used to satisfy this criterion. TEST PROCEDURES: Structure-to-soil potentials were recorded using a calibrated Fluke 87V multimeter and a portable M.C. Miller copper/copper sulfate (Cu/CuSO₄) reference electrode placed in soil on the southwest corner of the parking lot to get the measurements for the vent pipes, dispensers and the storage tanks. Depolarized structure-to-soil potentials were recorded using a calibrated Fluke 87 V digital multimeter and a calibrated portable M.C. Miller copper/copper sulfate (Cu/CuSO₄) reference electrode placed in soil on the southwest corner of the parking lot to get the structure-to-soil potential measurements off the vent pipes, fuel dispensers and the storage tanks. Rectifier current and voltage outputs were measured with the same Fluke multimeter. Rectifier output was interrupted with a Tinker & Rasor TI-50 50-amp current interrupter set at intervals of 19.5 seconds “ON” and 0.5 seconds “OFF” in order to obtain “Instant OFF” potentials on the two protected UST’s. Reliance on the “Instant OFF” survey method confirms compliance with NACE Criteria 5.2.1.2 by measuring polarized potentials independent of voltage influenced by circuit resistance. The “Instant OFF” data also contributes one factor to NACE Criteria 5.2.1.3. The other factor to NACE Criteria 5.2.1.3 is a depolarized potential measurement. On May 2, 2023, the cathodic protection system was found disabled. Considering the cathodic protection system was not functional during the first visit depolarized measurements were obtained by taking structure-to0soil potentials on the vent pipes, dispensers and the UST’s. NACE Criteria 5.2.1.3 states that a minimum of 100 millivolts of polarization is required to fully satisfy this criterion. The 100 millivolts of polarization were established by taking the “Instant OFF” potential and subtracting the depolarized potential. As long as at least 100 millivolts were achieved on all test locations the UST’s are considered to be cathodically protected. May 5, 2023 Job Number: B6352 3 Depolarized structure-to-soil potentials were recorded using a calibrated Fluke 87 V digital multimeter and a calibrated portable M.C. Miller copper/copper sulfate (Cu/CuSO₄) reference electrode placed in soil on the southwest corner of the parking lot to get the structure-to-soil potential measurements off the vent pipes, fuel dispensers and the storage tanks. MAY 12, 2023, RESULTS: 1. All test locations satisfied NACE Criteria 5.2.1.3 with achieving greater than 100 millivolts of polarization ranging from 125 to 402 millivolts. (See attached data sheet). 2. The hour meter on the rectifier at the beginning of the survey was documented at 01687.8. At the end of the survey the documented hour meter reading was 01688.1 indicating that the hour meter was functioning as intended during the 3-year CP Survey on the UST’s. RECOMMENDATIONS: 1. While State of California regulations require that impressed current CP systems protecting underground fuel storage tanks be inspected no less than every 60 calendar days, we recommend you read and record the voltage and current outputs of the rectifier every month. If voltage and/or current outputs change more than ±10% please call us to inspect the CP system. 2. Although the state requires full testing of underground storage tank CP systems every three years, Farwest recommends that a qualified corrosion engineer or technician test the entire cathodic protection system annually. 3. Any electrical or mechanical modifications to these cathodically protected structures should be reviewed by a qualified corrosion professional to ensure that electrical isolation is not compromised. We trust that the enclosed information is adequate for your needs. If you have any questions, or if we can assist you in any way, please do not hesitate to call our office at (661) 323-2077. Sincerely, FARWEST CORROSION CONTROL COMPANY Dennis Clothier NACE CP Technician #40506 May 15, 2023 Job Number: B6352 Job Number B6352 Weather 70° Sunny Date 5/12/2023 Meter Fluke 87V Multimeter Inspector Dennis Clothier Calibration 1/12/2023 Company Golden State Mobil Reference CUCUSO₄ Protected Structure Underground Storage Tanks Calibration 5/12/2023 Rectifier Location Storage Room Comments ±2.1mV Field to Calibration Reference Electrode Please Note if Rectifier is 480 VAC Make/Mfr.JA Electronics BEFORE AFTER -ADJUSMENT Model No.SS-1 Indicated DCV 30.00 Serial No.97175 Indicated DCA 2.00 DC Volt Rating 50 Measure DCV 28.09 DC AMP Rating 12 Shunt Size AC Volt Rating 115 Shunt reading (mV)6.54 AC AMP Rating Not Applicable Calculated Amps 1.96 GPS location N35.38860 W119.02303 GPS Junction Box Anodes in Road Box Tap Coarse B/D GPS Datum WGS 84 Tap Fine 5/6 Structure "ON""OFF"Depolarized Polarization Shift Vent Pipe 1 -774 -559 -275 284 Vent Pipe 2 -674 -524 -272 252 Vent Pipe 3 -1087 -592 -269 323 Vent Pipe 4 -1087 -594 -269 325 Pumps 1 & 2 -850 -526 -343 183 Pumps 3 & 4 -840 -525 -343 182 Pumps 5 & 6 -615 -431 -306 125 Pumps 7 & 8 -610 -430 -303 127 Pumps 9 & 10 -1072 -581 -222 359 Pumps 11 & 12 -1072 -584 -222 362 South East Tank -1072 -473 -220 253 North East Tank -1072 -621 -219 402 Recommendation Next Inspection Date Nace Criteria Satisfied May 2026 Nace Criteria Satisfied Nace Criteria Satisfied Actions Hour meter at Start of survey 01687.8 Hour meter at end of survey 01688.1 Comment Interrupter set at 9.5 seconds "On" and 0.5 seconds "Off". Farwest Corrosion - Cathodic Protection Inspection Sheet General Information Rectifier Data Potential Data (Millivolts - Cu/CuSO4) Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Status of Cathodic Protection Use 1 sheet per Rectifier 50mV/15A Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Data Page 1 of 1 Facility Technician YES NO N/A mVDC YES NO N/A mVDC YES NO Comments: 5/12/2023 5/12/2023 Reference Electrode Calibration Golden State Mobil Dennis Clothier / Farwest Corrosion CP-2 Corrosion Technic Inspection Start Date Inspection Completion Date Require Maintenance? Meter & Model Meter or DVM Card Serial # Fluke Digital Mutimeter Model 87 90960497 Meter Last Calibration Date Was Reference Electrode Reference Electrode prior to Inspection calibrated prior to inspection? Did Reference Electrode Reference Electrode after Inspection Cu/CuSO4 * +/- 5 mVDC Requires Maintenance Reference Electrode? ± 2.1mV measured between Field Reference Electrode and Office Control Reference Electrode. OQ Report Last NameFirstNameCompany NameNumberCourse NameTypeResultCompletedDateExpirationDateProctor /EvaluatorAssigned ByUserGroupClientClothierDennisFarwestCorrosionControl Co.CT01ConductingAnnual CathodicProtectionSurveysKnowledgePass07/07/202016:29:1507/07/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT01ConductingAnnual CathodicProtectionSurveysSkillsPass07/24/202005:00:0007/24/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT02Maintain TestLeadsSkillsPass07/24/202005:00:0007/24/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT02Maintain TestLeadsKnowledgePass07/07/202017:31:0607/07/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT03InspectCathodicProtectionRectifiersSkillsPass07/28/202005:00:0007/28/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT03InspectCathodicProtectionRectifiersKnowledgePass07/14/202021:48:0107/14/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT04CathodicProtectionRectifierMaintenance andRepairSkillsPass07/28/202005:00:0007/28/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT04CathodicProtectionRectifierMaintenance andRepairKnowledgePass07/07/202019:38:2807/07/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT08ConductingCathodicProtectionRemediationKnowledgePass07/07/202021:12:5907/07/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT08ConductingCathodicProtectionRemediationSkillsPass07/24/202005:00:0007/24/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT60GeneralAbnormalOperatingConditionsKnowledgePass07/10/202022:41:1107/10/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT0031Inspect andMonitorGalvanic GroundBeds/AnodesKnowledgePass07/10/202021:35:5007/10/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT1291LocateUndergroundPipelinesKnowledgePass07/10/202018:21:4707/10/2023Schifferle,MichaelClothierDennisFarwestCorrosionControl Co.CT1291LocateUndergroundPipelinesSkillsPass07/24/202005:00:0007/24/2023Schifferle,Michael