Inspection Report of CP System (F).pdf

FARWEST CORROSION

CONTROL COMPANY

Annual Inspection of CP System

Natural Gas Piping

June 23, 2021

Prepared for

California Air National Guard Base

F

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CONTROL COMPANY

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5323 East McKinley Avenue Fresno, CA, 93727

144 CES/CEC

Attention: Sheri Chacon TSgt

June 24, 2021 Job Number 85978

Subject: Annual Inspection of Sacrificial Anode Cathodic Protection (CP) Systems, Natural Gas Piping at the California Air National Guard Base, Fresno, California

Dear TSgt Chacon:

On June 23, 2021, Farwest Corrosion Control Company (Farwest) conducted the annual inspection of cathodically protected gas piping at the California Air National Guard Base, Fresno, California. This report serves to document the results of that inspection.

BACKGROUND

The underground gas piping at the California Air National Guard Base (Fresno) was originally of all steel construction. It was reportedly protected by a central impressed current CP system. Over the years, much of the original metallic piping has been replaced by plastic pipe, resulting in isolated and unprotected branches of metallic pipe between newer and older buildings. Farwest was enlisted as subcontractor to install supplemental magnesium anodes to protect the remaining steel gas pipelines during July 2008.

Data from the 2013 annual survey indicated that some of the anode locations had become depleted.

Subsequently, anodes were installed at five locations that indicated depleted anodes. Post-installation testing indicated that three of the five locations met the criteria stated below. Although two of the new anode locations did not satisfy the criteria stated below, the potentials at these locations did increase dramatically, indicating that some level of cathodic protection is being provided (Building 100 South 2.5" riser increased from -251 millivolts to -777 millivolts and Building 110 riser increased from -252 millivolts to -602 millivolts). The 2021 and previous surveys' potential measurements indicate NACE criteria is not being met. Further testing is necessary to determine the cause(s) for this situation.

TEST PROCEDURES

Pipe-to-soil potentials (DC and AC) were measured at pipeline risers using a calibrated Fluke 87 V digital multimeter and a calibrated M.C. Miller portable copper/copper sulfate (Cu/CuS04) reference electrode.

The effectiveness of insulating flanges (IF) or insulating unions were tested using a Tinker & Rasor Model RF-IT Radio Frequency Insulator Tester (RFIT) and/or by measuring and comparing pipe-to-soil potentials on each side of the flange/union.

661.323.2077 I 1120 Carrier Parkway, Bakersfield, CA 93308 I Farwestcorrosion.com

June 24, 2021

Job Number: 85978

CATHODIC PROTECTION CRITERIA

All potential levels measured and recorded are referenced to the criteria for cathodic protection as established by the NACE International Standard SP0169-2013, Section 6, Subsection 6.2.1 which states:

6.2.1 Criteria for Steel and Gray or Ductile Cast-Iron Piping

6.2.1.1 Criteria that have been documented through empirical evidence to indicate corrosion control effectiveness on specific piping systems may be used on those piping systems or others with the same characteristics.

6.2.1.2 A minimum of 100 mV of cathodic polarization. Either the formation or the decay of polarization must be measured to satisfy this criterion.

6.2.1.3 A structure-to-electrolyte potential of -850 mV or more negative as measured with respect to a saturated copper/copper sulfate (CSE) reference electrode. This potential may be either a direct measurement of the polarized potential or a current-applied potential.

Interpretation of a current-applied measurement requires consideration of the significance of voltage drops in the earth and metallic paths.

ELECTICAL ISOLATION

The effectiveness of electrical isolation devices is referenced to the criteria established by the NACE International Standard SP0286-2007, Section 9, Paragraphs 9.2, 9.2.2, and 9.2.7, which state:

9.2 Field Testing

9.2.1 Several tests may be used to determine the effectiveness of an isolating device, depending on the following:

9.2.1.1 The experience and training of the staff conducting the tests;

9.2.1.2 The environment and location of the device; and

9.2.1.3 The local potential and magnitude of any cathodic or anodic electrical currents.

9.2.2 If the isolation device is installed and connected on both sides, a test may be conducted in which current is applied to the pipe on one side of the assembly and effectiveness is judged by the resulting difference in pipe-to-soil potentials measures on both sides of the device. Although not stated in the Standard, a difference~ 100 mV is consider effective isolation.

~~~ FARWEST CORROSION

~,~ CONTROL COMPANY

1120 Carrier Parkway, Bakersfield, CA 93308

(661) 323-2077 I Farwestcorrosion.com 2

Job Number: 85978

9.2.7 Radio frequency meters may also indicate the effectiveness of isolating devices. Once again, although not stated in the Standard, a " 100" on the meter display would indicate an effective device, and conversely, a "O" on the meter would indicate a defective (shorted) device. Anything between " 100" and "O" may indicate some percentage of current passing through the isolation device.

FINDINGS AND RECOMMENDATIONS

The NACE -850 millivolt criterion for cathodic protection was met on gas risers at the Base Master Meter, Buildings 100 (see notes on exceptions below), 102, 117, 123, 124, 125, 130, 135, 145, and 225. Protection does not meet NACE criteria on the south 2" riser at Building 100 and at Buildings 110, 121,122, and 126 risers. Data from the 2020 annual survey is included in order to view trends in potentials. Please see the attached data sheet for pipe-to-soil potentials.

• Building 100

The potential measured on the south 2.5" riser at Building 100 was -671 millivolts, not in compliance with NACE criteria. This pipeline is apparently not dielectrically isolated from one or more foreign structures (isolation is OK at Building 100). This condition became evident after the 2008 anode installations. While some protection is being provided, the -850 millivolt criterion cannot be achieved until this pipeline is located and isolated from building structures, foreign piping, and/or electrically grounded equipment (building heaters, etc.). Testing of the two existing anodes indicated that the anodes are operating as intended, with open-circuit potentials of -1721 and -1633 millivolts.

1. Testing is necessary to attempt to locate any contacts/ connections to foreign structures.

Additionally, performing a current requirement test on the pipeline to see how much current is required to protect this line is recommended. If the current requirement testing data reveals that magnesium anodes can protect this pipeline, installation of additional or larger sized anodes may be required.

• Building 110

Pipe-to-soil potential of the Building 110 riser remains at unprotected levels; poor coating and/or ineffective dielectric isolation from foreign structures are the most likely causes for these conditions.

Drav,ings of the existing gas pipeline system indicate interconnection of the Building 102, 110 and former Building 114 (now demolished) gas lines but the exact layout is unknown. A previous investigation indicated that the Building 110 gas line may be isolated from the 102/ 114 gas lines.

During the anode replacement project, Building 110 was one of the five locations chosen for new anodes. The potentials at the gas riser increased from -224 millivolts to -559 millivo lts. During the 2021 annual pipeline survey, the pipe-to-soil potentials indicate that this pipeline does not meet criteria with a pipe-to-soil potential measurement of -496 millivolts. This same potential was measured on the dov,nstream side of the union, on the water piping, and the building ground. Testing of the insulating union indicated it was good. It is possible that a short exists between the pipe to the

~~~ FARWEST CORROSION

~W CONTROL COMPANY

(661) 323-2077 I Farwestcorrosion.com 3

Job Number: 85978 building and the building ground rod. Testing of the existing anode indicated it is operating as intended, with an open-circuit potential of -1716 millivolts.

1. Testing is necessary to attempt to locate any contacts/connections to foreign structures.

Additionally, performing a current requirement test on the pipeline to see how much current is required to protect this line is recommended. If the current requirement testing data reveals that magnesium anodes can protect this pipeline, installation of additional or larger sized anodes may be required.

• Building 117

Pipe-to-soil potential of the Building 117 riser was found to meet criteria (-898 millivo lts). Testing of the insulating union indicated it was good. There is no above ground anode connection to the riser, therefore, the anode open-circuit cannot be measured. Since the potential is only -48 millivolts above criteria, it is suspected that the existing anode is nearly depleted and replacement is recommended .

1. Install new anode.

• Building 121

Pipe-to-soil potential of the Building 121 riser was found to not meet criteria (-375 millivolts). Testing of the insulating union indicated it was good. Testing of the existing anode indicated it is likely depleted having an open-circuit potential of -379 millivolts (should be around -1700 millivolts). The existing anode is depleted and replacement is necessary.

1. Install new anode.

• Building 122

Pipe-to-soil potential of the Building 122 riser was found to not meet criteria (-509 millivolts). Testing of the insulating union indicated it was good. Testing of the existing anode indicated it is likely depleted having an open-circuit potential of -624 millivolts (should be around -1700 millivolts). The existing anode is depleted and replacement is necessary.

1. Install new anode.

~~~ FARWEST CORROSION ~ -·-

·~ ,~ CONTROL COMPANY

(661) 323-2077 I Farwestcorrosion.com 4

• Building 124

June 24, 2021

Job Number: B5978

Pipe-to-soil potential of the Build ing 124 rise r w as found to meet criteria (-871 millivolts). Testing of the insulating union indicated it was good. There is no above ground anode connection to the riser, therefore, the anode open-circuit cannot be measu red. Since the potential is only-21 mill ivolts above criteria, it is suspected that the existing anode is nearly depleted and replacement is recommended .

1. Install new anode.

• Building 126

Pipe-to-soil potential of the Building 126 riser was found to not meet criteria (-572 millivolts) . Testing of the insulating union indicated it was good. Testing of the existing anode indicated it is likely depleted having an open-circuit potential of -643 millivolts (should be around -1700 millivolts) . The existing anode is depleted and replacement is necessary.

1. Install new anode.

GENERAL

• All tested insulating unions and flanges indicated that they are ope rat ing as intended.

• AC potentials were measured at every riser. The observed AC potentials did not indicate any significant induced AC current on the piping.

• Regulations require that the gas pipeline CP systems be surveyed and inspected annually. Farwest

Corrosion would be pleased to continue scheduling regular inspect ions for the California Air National Guard Base, Fresno.

• Any modifications to structures that may require connection of new equipment should be reviewed by a qualified corrosion engineer to ensure that the electrical isolation and protection of the structures will not be compromised.

We trust that the enclosed information is adequate for your needs. Farwest Corrosion would be pleased to discuss and provide a quote for the repairs and remediation efforts suggested above. 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

C • 1 ::>wSJ -;? Od-oavid Ort

NACE Corrosion Technologist/CP Tester I# 6414

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(661) 323-2077 I Farwestcorrosion.com 5

Location

Master Meter East

West

Bldg. 100 Gas Risers

New 3" riser

North 2" riser

South 2½" riser

4" riser

Bldg. 102 Riser

Bldg. 110 Riser

Bldg. 117 Riser

Bldg. 121 Riser

Bldg. 122 Riser

Bldg. 123 Riser

Bldg. 124 Riser

Bldg. 125 Riser

Bldg. 126 Riser

Bldg. 130 Riser

Bldg. 135 Riser

Bldg. 145 Riser

Bldg. 225 Riser

NOTES:

6/23/2021

Pipe-to-Soil

Potential

(mV)

-1261

-1659

-1653

-1793

-671

-1301

-1084

-496

-898

-375

-509

-1361

-871

-1655

-572

-1373

-1502

-1195

-1172

(1) (2)

Technician: David Ort

6/23/2021

AC Potential

(Volts)

1.973

0.004

0.010

0.006

California Air National Guard - Fresno

Annual Gas Piping CP Inspection

June 23, 2021

8/26/2020 8/26/2020

Pipe-to-Soil

Potential AC Potential 2021 Survey Remarks

(mV) (Volts)

-745 1.966 Does not meet cr it eria - IF OK (PG&E side)

-1671 0.003 Riser protected - IF OK (Base side)

-1325 0.019 Riser prot ected - IF OK

-1888 0.004 Riser protected (bonded to 4 11 riser) - IF OK

June 24, 2021

Job Number 85978

0.037 -707 0.046 Does not meet crit eria - Union OK; Anode OCP: -1721 mV, -1633 mV (2)

0.019 -1.336 0.022 Riser protected (bonded to 2" riser) - Union OK

0.103 -1099 0.157 Riser protected - Union OK

0.009 -516 0 .012 Does not meet criteria - Union OK; Anode OCP: -1716 mV (1)

0.053 -662 0.144 Riser protected - Union OK

0.003 -423 0.003 Does not meet criteria - Union OK: Anode OCP: -379 mV

0.003 -512 0 .007 Does not meet criteria - Union OK; Anode OCP: -624 mV

0.046 -1315 0 .051 Riser protected - IF OK

0.003 -829 0 .007 Riser protected - Union OK

0.003 -1378 0 .007 Riser protected - 2 Unions OK (2" and 1/2")

0.002 -548 0.003 Does not meet criteria - Union OK; Anode OCP: -643 mV

0.004 -1544 0.003 Riser protected - Union OK

0.002 -1501 0.001 Riser protected - Union OK

0.003 -1307 0 .016 Riser protected - Union OK

0.002 -1073 0.001 Riser protected - Union OK

Contin uity between building gas ri ser and ground rod. Further investigation required.

Suspect connection or short to foreign pipeline or structure. Union test ed good w/ RFIT. Further investigation required.

NACE Corrosion Technologist/CP Tester# 6414 Page 1 of 1

INSTRUMENT

Manufacturer: Fluke

Model Number/Type: 87V

Serial Number: 28910189

Certificate Number:

Date of Calibration:

Due for Calibration:

3536 Brian Way Bakersfield, CA 93308

Toll Free: (800) 638-3774 Direct: (661) 327-8681

Fax: (661) 327-1660 www.valleyinstrument.com

062620-28910189

6/26/2020

6/26/2021

Customer Name: Farwest Corrosion Control P.O. Number:

Lab Temperature (°C): 23.9 Lab Humidity (0/oRH): 28

Repair Notes:

Calibration Results

Instrument Received ~ In tolerance, no adjustment required

Instrument Returned 181 In tolerance

□ In tolerance, adjustments made

□ Out of tolerance

Ordered □ with data 181 without data

□ Inoperative or damaged

□ New

Calibration Procedure: OEM Calibration Manual

Standards Used in Calibration (Traceable to NIST)

Standard Serial Number Certificate Number Calibration Date Due Date Fluke 5522A Calibrator 4793903 F8095001 11/21/2019 12/3/2020

Lab Technician: Christopher Angelini Quality Manager: Carlos Angelini

VALLEY INSTRUMENT SERVICE, INC. hereby certifies that the Instrument listed above has been calibrated to meet all published manufacturer specifications using standards with accuracies traceable to the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY OR EQUIVALENT. Records pertaining to these standards are on file and available for examination.

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Reference Electrode Calibration

Facility Ca lifornia Air National Guard - Fresno Base

Technician David Ort / Farwest

Inspection Start Date Inspection Completion Date

6/23/2021 6/23/2021

Meter & Model Meter or DVM Card Serial #

Fluke 87V 28910189

Meter Last Calibration Date

6/26/2020

Was Reference Electrode ✓ YES Reference Electrode prior to Inspection calibrated prior to inspection? NO N/A mVDC

Did Reference Electrode YES Reference Electrode after Inspection Require Maintenance? ✓ NO N/A mVDC

Cu/CuS04 ✓ YES • +/- 5 mVDC Requires Maintenance Reference Electrode? NO

Comments: 2021 Annual Survey

Difference between Field Cu/CuS04 Reference Electrode and Office Reference Cu/CuS04 Electrode was+ 1.8 mV calibrated and documented on 6/23/2021.