API 2008 651 Review Compatibility Mode

8/4/2019 API 2008 651 Review Compatibility Mode

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Pads, Inspections and PitfallsPads, Inspections and Pitfalls

Louis KoszewskiLouis Koszewski

US Tank ProtectorsUS Tank Protectors


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..

New Tank foundation/RW constructionNew Tank foundation/RW construction

Sand Pad MaterialSand Pad Material

Sand Pad ConstructionSand Pad Construction

Ins ection of Sand Pad and CPIns ection of Sand Pad and CP


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..

Rebar in the concreteRebar in the concrete ringwallsringwalls and slabsand slabs

system.system.

Become a significant draw to the CPBecome a significant draw to the CP

sys emsys em Shielding or DeShielding or De--coupling of the rebarcoupling of the rebar

should be considered.should be considered.


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Values listed are from solutionValues listed are from solution

ResistivityResistivity Measures the dissolved saltsMeasures the dissolved salts rr Samples measured as receivedSamples measured as received

ASHTOASHTO


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pHpH very time sensitivevery time sensitive pH < 4.5 very corrosive to steelpH < 4.5 very corrosive to steel

ChloridesChlorides --10 PPM or less10 PPM or less

Sulfate > 200 PPM organic matterSulfate > 200 PPM organic matter

u eu e re uce su a e y ac er are uce su a e y ac er a Sand should be tested at the sourceSand should be tested at the source


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Section 5.3.2.2Section 5.3.2.2 Discussing new tank padDiscussing new tank pad (b) Sand is often installed by loose lifts in(b) Sand is often installed by loose lifts in

maximum layering of 6maximum layering of 6 8 thickness..8 thickness..

Does not mean minimum sand ad to beDoes not mean minimum sand ad to be6 or more.6 or more.

be 6be 6 8 between lifts.8 between lifts.


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7.2.4.37.2.4.3 General concerns in this sectionGeneral concerns in this section Less than 12 successful operation andLess than 12 successful operation and

monitoring shorting out of anodes.monitoring shorting out of anodes.

Installin lastic mesh rock shield willInstallin lastic mesh rock shield willsolve shorting problems.solve shorting problems.

plastic mesh over anodes.plastic mesh over anodes...


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Inspection Testing &Inspection Testing &Maintenance of CP FacilitiesMaintenance of CP Facilities

11.3.2.511.3.2.5 Examination for bottomExamination for bottom--side corrosion mayside corrosion may

be achieved by making coupon cutouts..be achieved by making coupon cutouts..

11.3.2.611.3.2.6 Repair, replacement or adjustment of CPRepair, replacement or adjustment of CP

Reference cell replacementReference cell replacement


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Inspection Testing &Inspection Testing &Maintenance of CP FacilitiesMaintenance of CP Facilities

Why Spend the time to inspect Pad & CP?Why Spend the time to inspect Pad & CP? You wont have the opportunity for 10 yrs.You wont have the opportunity for 10 yrs.

Internal inspections show overall corrosionInternal inspections show overall corrosion

Corrosion is usually averaged over timeCorrosion is usually averaged over time Corrosion may have just startedCorrosion may have just started

Sand ad ma have become contaminatedSand ad ma have become contaminated

Confirms the chemical and electricalConfirms the chemical and electricalProperties of the sand padProperties of the sand pad

Only requires a few hours to completeOnly requires a few hours to complete


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What Information Will I NeedWhat Information Will I NeedTo Perform ECDA?To Perform ECDA?

Internal inspection reportInternal inspection report nk m n r i n l nnk m n r i n l n

Cone up/downCone up/down

Previous tank pad electrical/ chemical testsPrevious tank pad electrical/ chemical tests

sys em es gn con gura onsys em es gn con gura on Anode configuration sizes/ratings (if present)Anode configuration sizes/ratings (if present)

CP operating reportsCP operating reports


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ank crew (1ank crew (1--2 men)2 men) Cut sample coupons (holes or patches)Cut sample coupons (holes or patches)

2 good locations2 good locations 2 corroded locations (if present)2 corroded locations (if present)

Soil resistivity meter (soil box)Soil resistivity meter (soil box) Distilled waterDistilled water hi h resistivithi h resistivit

pH paper or test kitpH paper or test kit SRB test kitSRB test kit

o samp e ars agso samp e ars ags VeryVery High Impedance voltmeter & CellHigh Impedance voltmeter & Cell

Meter > 20 MMeter > 20 M


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NACE RP0502NACE RP0502 Has testing proceduresHas testing procedures Tank Pad ResistivityTank Pad Resistivity Static, SaturatedStatic, Saturated Use high resistivity distilled waterUse high resistivity distilled water

Soil boxSoil box 4 pin method in some cases4 pin method in some cases

pHpH pH paper or field test kitpH paper or field test kit

SRB test kitSRB test kit Send sam les to lab for verificationSend sam les to lab for verification


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Sacrificial SystemsSacrificial Systems Visual testVisual test color, shape, % corrosioncolor, shape, % corrosion Check anode/cable connectionCheck anode/cable connection

Anode potentialAnode potential

Impressed Current AnodesImpressed Current Anodes

Anode potentialAnode potential


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90 Diameter Flat bottom90 Diameter Flat bottom lin rvilin rvi Bottom FailureBottom Failure 4 years of service4 years of service

No cathodic protection reportsNo cathodic protection reports

Sand pad with no chemical/electricalSand pad with no chemical/electricalreportsreports


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Poor sand pad usedPoor sand pad used P r l ri l nn i nP r l ri l nn i n Owner decided to install new clean sandOwner decided to install new clean sand

,,and properly connect the sacrificial anodesand properly connect the sacrificial anodes


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200 diameter200 diameter H rvi 2H rvi 2 F F Bottom Failure 3 yearsBottom Failure 3 years

No CP reportsNo CP reports

No Sand pad electrical/chemical testsNo Sand pad electrical/chemical tests


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Poor sand pad usedPoor sand pad used Im r r n l i nIm r r n l i n Owner decided to:Owner decided to:

IC systemIC system High temperatureHigh temperature

ex nspec on yearsex nspec on years


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100 Diameter100 Diameter Gasoline ServiceGasoline Service

Impressed Current MMO Loop systemImpressed Current MMO Loop system

Annual CP reportsAnnual CP reports Silica sandSilica sand Sand testsSand tests

pHpH 7.47.4

Chlorides 8 PPMChlorides 8 PPM

Sulfides


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Very good sand pad usedVery good sand pad usedV r I mV r I m Patches where no contact and return toPatches where no contact and return to

Next Inspection 10 yearsNext Inspection 10 years


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90 Diamter90 Diamter Gasoline ServiceGasoline Service

Zinc anodesZinc anodes

Annual CP reportsAnnual CP reports Silica sandSilica sand Sand testsSand tests

pHpH 8.48.4

Chlorides 28 PPMChlorides 28 PPM

Sulfides


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Very Good Sand Pad UsedVery Good Sand Pad Used Eff iv P mEff iv P m Installed patch plates and returned toInstalled patch plates and returned to

Next Inspection 10 yearsNext Inspection 10 years


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New Jersey TankNew Jersey Tank

120 Diameter120 Diameter Gasoline ServiceGasoline Service 10 year inspection10 year inspection minor corrosionminor corrosion

Tank leaked 2 years after placed back in serviceTank leaked 2 years after placed back in service Zinc Anode systemZinc Anode system CP Annual surve sCP Annual surve s

No sand pad electrical/chemical testsNo sand pad electrical/chemical tests


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Good sand pad usedGood sand pad used Maybe?Maybe? Pad became contaminated with sea waterPad became contaminated with sea water

Poor CP system selectionPoor CP system selection

Anode attenuationAnode attenuation Anode end effectAnode end effect

Owner decided to:Owner decided to:

Replace tank bottom with RPBReplace tank bottom with RPB Install IC systemInstall IC system


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ConclusionConclusionCauses of Tank Bottom CorrosionCauses of Tank Bottom Corrosion

No Cathodic ProtectionNo Cathodic Protection P N nnP N nn Insufficient Current AppliedInsufficient Current Applied Hot tanksHot tanks

Zinc anodes/hot tankZinc anodes/hot tank Do not useDo not use

rapid anode consumptionrapid anode consumption


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ConclusionConclusionECDA For Tank Bottoms Will:ECDA For Tank Bottoms Will:

eterm ne t e cause s o past corros oneterm ne t e cause s o past corros on Determine the electrical/chemical tank pad conditionDetermine the electrical/chemical tank pad condition

e erm ne e po en a or u ure corros on one erm ne e po en a or u ure corros on onthe tank tested and like service tanksthe tank tested and like service tanks

Establishes a baseline for future inspectionsEstablishes a baseline for future inspections

os mpor an yos mpor an y -- preven very cos y repreven very cos y re--en ryen ryinto the tank before the next internal inspectioninto the tank before the next internal inspection

Documents

API 2008 651 Review Compatibility Mode