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Home My WebLink AboutCATHODIC 2023 661.323.2077 | 1120 Carrier Parkway, Bakersfield, CA 93308 | Farwestcorrosion.com July 28, 2023 Job Number: B6379 76 Wible Road Gas Station 3301 Wible Road Bakersfield, CA 93309 Attention: Mr. Gil Singh Subject: Proposal to Inspect Underground Storage Tank Cathodic Protection System at the 76 Gas Station on Wible Road, Bakersfield, California Dear Mr. Singh: On July 27, 2023, Farwest Corrosion Control Company conducted a cathodic protection system inspection on the 76 Wible Road Gas Station’s (76 Wible) underground fuel storage tanks. Upon completion of the inspection, all pipe-to-soil potentials on underground structures met or exceeded NACE criteria for cathodic protection. All cathodic protection components appeared to be in good repair and functioning normally. BACKGROUND: At the request of 76 Wible, Farwest Corrosion Control performed an inspection and survey on the impressed current cathodic protection (CP) system designed to protect three (3) underground storage tanks (UST’s) at 76 Wible in Bakersfield, CA. 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 rectifier is located in the storage room in the rear of the building, with an unknown number of anodes installed near the pumps. Drawings and historical data were not available at the time of this survey. 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: 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: July 28, 2023 Job Number: B6379 1120 Carrier Parkway, Bakersfield, CA 93308 (661) 323-2077 | Farwestcorrosion.com 2 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 87 V digital multimeter and a calibrated portable M.C. Miller copper/copper sulfate (Cu/CuSO₄) reference electrode placed in soil near the northeast side of the pumps to get the structure-to-soil potential measurements off the 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 three 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 that was achieved by shutting the rectifier off for 1 hour allowing for the depolarizing of the cathodic protection system. NACE Criteria 5.2.1.3 states that a minimum of 100 millivolts of polarization is required to fully satisfy this criteria. The 100 millivolts of polarization was established by taking the “Instant OFF” potential and subtracting the depolarized potential. As long as at least 100 millivolts was achieved on all test locations the UST’s are considered to be cathodically protected. July 2023 RESULTS: Upon arrival, the rectifier was found on and functioning as intended and all other system components were found to be fully functional and operating as designed. All test locations satisfied NACE Criteria 5.2.1.3 with achieving greater than 100 millivolts of polarization ranging from 107 to 180 millivolts. (See attached data sheet). All gas station rectifiers with a built-in hour meter on their rectifiers must be functional to document the July 28, 2023 Job Number: B6379 1120 Carrier Parkway, Bakersfield, CA 93308 (661) 323-2077 | Farwestcorrosion.com 3 time that the rectifiers are operating at. 76 Wible’s rectifier hour meter was found at 788681 upon arrival. After the survey was complete, the rectifier was operating at a new hour, 788689. 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 Ryan Selga NACE CP1 Tester #601676 Reviewed By: Dennis Clothier NACE CP Technician #40506 July 28, 2023 Job Number: B6379 Job Number B6379 Weather 97° Sunny Date 7/27/2023 Meter Fluke 87 V Multimeter Inspector Ryan Selga Calibration 1/12/2023 Company 76 Wible Gast Station Reference CUCUSO₄ Protected Structure Underground Storage Tanks Calibration 7/27/2023 Rectifier Location 35. 3246648, -119.039535 Comments ± 2.75 mV Field to Calibration Reference Electrode Please Note if Rectifier is 480 VAC Make/Mfr.JA Electronics Manufactoring Inc.BEFORE AFTER -ADJUSMENT Model No.SS-I Indicated DCV 30.00 Serial No.98433 Indicated DCA 2.00 DC Volt Rating 50 Measure DCV 31.00 DC AMP Rating 12 Shunt Size AC Volt Rating Not Applicable Shunt reading (mV)6.83 AC AMP Rating Not Applicable Calculated Amps 2.05 GPS location 35. 3246648, -119.039535 GPS Junction Box 35. 3246648, -119.039535 Tap Coarse B of D GPS Datum WGS 84 Tap Fine 6 of 6 Structure "ON""OFF"Depolarized Polarization Shift Pumps 1 & 2 -903 -533 -426 107 Pumps 3 & 4 -930 -543 -430 113 Tank # 1 -1030 -550 -370 180 Tank # 2 -1073 -587 -429 158 Tank # 3 -1047 -548 -426 122 At statrt of survey, hour meter read 788681. At end of survey, hour meter read 788689. Recommendation Next Inspection Date July 2026 Actions Rectifier location is inside the building located behind the counter in the storage room. Comment Interrupter set at 19.5 seconds "On" and 0.5 seconds "Off". Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Nace Criteria Satisfied Status of Cathodic Protection Use 1 sheet per Rectifier 50mV / 15A Farwest Corrosion - Cathodic Protection Inspection Sheet General Information Rectifier Data Potential Data (Millivolts - Cu/CuSO4) Nace Criteria Satisfied Data Page 1 of 1 Facility Technician √YES NO N/A mVDC YES √NO N/A mVDC √YES NO Comments: 7/27/2023 Cu/CuSO4 * +/- 5 mVDC Requires Maintenance Reference Electrode? Difference between Field Cu/CuSO₄ Reference Electrode and Verification Reference Cu/CuSO ₄ Electrode was ± 2.75 mV. Calibrated and documented on Require Maintenance? Meter & Model Meter or DVM Card Serial # Fluke 87 V 28910189 Meter Last Calibration Date 1/12/2023 Was Reference Electrode Reference Electrode prior to Inspection calibrated prior to inspection? Did Reference Electrode Reference Electrode after Inspection 7/27/2023 7/27/2023 Reference Electrode Calibration 76 Wible Ryan Selga / Farwest Inspection Start Date Inspection Completion Date Ryan James Selga NACE CP1 - Cathodic Protection Certified Tester June 22, 2025 11463035 Cert No.201676 OQ Report LastNameFirstNameCompany NameNumberCourse NameTypeResultCompleted DateExpirationDateProctor /EvaluatorAssigned ByUserGroupClientSelgaRyanFarwestCorrosionControl Co.CT04CathodicProtectionRectifierMaintenance andRepairKnowledgePass09/19/202216:32:4809/19/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT02Maintain TestLeadsKnowledgePass09/16/202217:24:5609/16/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT1291LocateUndergroundPipelinesKnowledgePass09/09/202220:49:2309/09/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT60GeneralAbnormalOperatingConditionsKnowledgePass09/09/202218:34:4009/09/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT01ConductingAnnual CathodicProtectionSurveysSkillsPass12/12/202206:00:0012/12/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT01ConductingAnnual CathodicProtectionSurveysKnowledgePass09/16/202216:16:4109/16/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT08ConductingCathodicProtectionRemediationKnowledgePass09/19/202218:04:0409/19/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT03InspectCathodicProtectionRectifiersSkillsPass12/12/202206:00:0012/12/2025Schifferle,MichaelSelgaRyanFarwestCorrosionControl Co.CT03InspectCathodicProtectionRectifiersKnowledgePass09/09/202221:50:2409/09/2025Schifferle,Michael