5. hydrostatic test exemptions

7/28/2019 5. Hydrostatic Test Exemptions

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Hydrostatic TestHydrostatic Test

Exemptions for TanksExemptions for TanksRepaired to APIRepaired to API--653653

Credit: Ken Erdmann Matrix Service


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OutlineOutline

Reason for Hydrostatic Tests.Reason for Hydrostatic Tests.

When a hydrostatic test is not needed.When a hydrostatic test is not needed.

Major Repairs / Alterations.Major Repairs / Alterations.

Hydrostatic test required but exempted.Hydrostatic test required but exempted.

The ultimate out (or is it).The ultimate out (or is it).

Hydrostatic Test Trade SecretsHydrostatic Test Trade Secrets


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Reason for APIReason for API--650 Hydro Test650 Hydro Test

Test shell for leaks.Test shell for leaks.

Finding of bottom leaks is unlikelyFinding of bottom leaks is unlikely


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Reasons for theReasons for the

API 653 HydroAPI 653 Hydro--TestTest

Avoid catastrophic failure while containingAvoid catastrophic failure while containing

product.product.

Test the soundness of repairs.Test the soundness of repairs.

Test for any missed leaks.Test for any missed leaks.

Limit questions of liability for future failures or leaks.Limit questions of liability for future failures or leaks.


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Reasons for the HydroReasons for the Hydro--TestTest

APIAPI--653 12.3.1653 12.3.1

Reconstructed TanksReconstructed Tanks Any tank that has undergone major repairsAny tank that has undergone major repairs

or alterations unless exempted by 12.3.2or alterations unless exempted by 12.3.2

for combination of materials, design andfor combination of materials, design andconstruction features.construction features.

Tank that has an increase in severity ofTank that has an increase in severity of

service including higher pressure, lowerservice including higher pressure, lower

temperature or damaged tank.temperature or damaged tank.


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When is the hydroWhen is the hydro--test not needed?test not needed?

Since hydro is testing against catastrophicSince hydro is testing against catastrophic

failures and testing soundness of repairs onlyfailures and testing soundness of repairs only

major repairs need to be tested.major repairs need to be tested.

Repairs not exposed to liquid are not critical.Repairs not exposed to liquid are not critical.

Repairs that donRepairs that dont put extra stresses into partst put extra stresses into parts

exposed to liquid are not critical.exposed to liquid are not critical.

Repairs that are exposed to the liquid may be aRepairs that are exposed to the liquid may be a

problem unless they are small repairs.problem unless they are small repairs.


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APIAPI--650 Hydro Not Needed If...650 Hydro Not Needed If...

If water is not available for testing, the tank canIf water is not available for testing, the tank can

be leak tested by:be leak tested by: Vacuum box test all shell seam.Vacuum box test all shell seam.

Penetrant oil test all shell seams.Penetrant oil test all shell seams.

Combination of vacuum box and penetrant oil testCombination of vacuum box and penetrant oil testshell seams.shell seams.

New tank hydro listed in APINew tank hydro listed in API--650 Par.5.3.5,650 Par.5.3.5,

Testing of the shellTesting of the shell..


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Examples:Examples:

Repairs Not Requiring HydroRepairs Not Requiring Hydro--TestingTesting

Seal replacements or repairs.Seal replacements or repairs.

Any floating roof replacement or repairs unless door sheetAny floating roof replacement or repairs unless door sheetrequired.required.

Any carbon steel floating roof needs a water floatation test. ThAny carbon steel floating roof needs a water floatation test. This isis isnot a shell high hydro test.not a shell high hydro test.

APIAPI--650 H.6.4.1 refers to a float test to check for leaks. H.6.4.2650 H.6.4.1 refers to a float test to check for leaks. H.6.4.2refers to initial fill to confirm it travels full height freely.refers to initial fill to confirm it travels full height freely.

APIAPI--650 C.4.3 refers to a float test again to test for leaks while t650 C.4.3 refers to a float test again to test for leaks while thehetank is being filled with water and emptied. No full height travtank is being filled with water and emptied. No full height travel isel ismentioned in Appendix C.mentioned in Appendix C.

Interior bottom repairs.Interior bottom repairs. Limited shellLimited shell--toto--bottom weld repairs.bottom weld repairs.

Max 12Max 12shell inserts (without nozzles).shell inserts (without nozzles).

Max 12Max 12nozzles with no inserts.nozzles with no inserts.


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Major Repairs and AlterationsMajor Repairs and Alterations

Hydro test is required when major repairs orHydro test is required when major repairs or

alterations are made to the tank.alterations are made to the tank.

These are repairs that could potentially causeThese are repairs that could potentially cause

failure if not properly completed.failure if not properly completed.

These repairs could also cause failure if doneThese repairs could also cause failure if done

properly in brittle material.properly in brittle material.


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APIAPI--653 Major Repairs653 Major Repairs

Any shell fitting largerAny shell fitting largerthan 12than 12below DLL.below DLL.

Any bottom fitting withinAny bottom fitting within1212of shell.of shell.

Shell plate replacementShell plate replacementbelow DLL or annularbelow DLL or annular

plate replacement whenplate replacement whenlongest dimensionlongest dimensionexceeds 12exceeds 12..

More than 1/2 removal /More than 1/2 removal /replacement of shellreplacement of shellvertical weld or annularvertical weld or annularring radial weld.ring radial weld.

Installing new bottomInstalling new bottomunless the following isunless the following is

met:met: Tank has annular ring thatTank has annular ring that

stays in tact.stays in tact.

Tank has no annular ringTank has no annular ring

but no welding is donebut no welding is donewithin the critical zonewithin the critical zone(within 3(within 3 inside of shell)inside of shell)

Removal andRemoval andreplacement of any partreplacement of any partof the shellof the shell--toto--bottombottomweld.weld.

J acking of the tank shell.J acking of the tank shell.


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When Required HydroWhen Required Hydro--TestTest

Can Be ExemptedCan Be Exempted Each of the following must be met:Each of the following must be met:

Repair reviewed and approved by engineerRepair reviewed and approved by engineerexperienced in APIexperienced in API--650 tank design. Engineer must650 tank design. Engineer must

concur in writing with taking hydrostatic testingconcur in writing with taking hydrostatic testing

exemption.exemption.

Tank owner has authorized exemption.Tank owner has authorized exemption.

Plus appropriate portion of 12.3.2.2 throughPlus appropriate portion of 12.3.2.2 through12.3.2.6 or 12.3.2.7 must be met.12.3.2.6 or 12.3.2.7 must be met.


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Shell Repair ExemptionsShell Repair Exemptions

Weld procedures for existing material to repairWeld procedures for existing material to repairmaterial must be developed including impactmaterial must be developed including impacttesting per APItesting per API--650 7.2.2.650 7.2.2.

New material used must meet APINew material used must meet API--650.650.

Existing material must meet one of following:Existing material must meet one of following: Meet current APIMeet current API--650.650.

Fall within safe for use area of Figure 5Fall within safe for use area of Figure 5--2.2.

Stress in repair area shall not exceed 7,000Stress in repair area shall not exceed 7,000 psipsi..

New vertical and horizontal shell welds shall beNew vertical and horizontal shell welds shall becomplete penetration and fusion.complete penetration and fusion.


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APIAPI--653 Figure 5653 Figure 5--22


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Shell Repair Exemptions (Shell Repair Exemptions (concon tt ))

New shell welds shall have root and final pass examinedNew shell welds shall have root and final pass examined

by magnetic particle or liquid penetrant testing. Finishedby magnetic particle or liquid penetrant testing. Finished

weld shall be fully radiographed.weld shall be fully radiographed.

Neck to shell and neck to pad welds shall be completeNeck to shell and neck to pad welds shall be complete

fusion and penetration. Root pass shall be back gougedfusion and penetration. Root pass shall be back gougedand examined by magnetic particle or liquid penetrantand examined by magnetic particle or liquid penetrant

methods. The final weld shall be magnetic particle ormethods. The final weld shall be magnetic particle or

liquid penetrant and ultra sonic tested.liquid penetrant and ultra sonic tested.

Door sheets must meet insert exemptions and cannotDoor sheets must meet insert exemptions and cannot

extend to the corner weld.extend to the corner weld.


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Bottom Repair In Critical ZoneBottom Repair In Critical Zone

Repairs to bottom and annular rings withinRepairs to bottom and annular rings within

critical zone must meet the following:critical zone must meet the following: Use weld procedures, new and existing materials asUse weld procedures, new and existing materials as

required to exempt shell repairs.required to exempt shell repairs.

Examine repair visually prior to welding.Examine repair visually prior to welding.

Examine after root and final pass by visual andExamine after root and final pass by visual and magmag..

particle or liquid penetrant methods.particle or liquid penetrant methods.

Examine annular plate butt welds by ultrasonicExamine annular plate butt welds by ultrasonic

methods after final pass.methods after final pass.


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Shell to Bottom Weld RepairShell to Bottom Weld Repair

Repair of shell to bottom or annular ring weldRepair of shell to bottom or annular ring weld

shall meet one of the following:shall meet one of the following:

A portion of the weld (of any length) may beA portion of the weld (of any length) may be

removed and replaced as long as size meets APIremoved and replaced as long as size meets API--

650 and 50% or less of weld area is replaced.650 and 50% or less of weld area is replaced.

More than 50% of weld area can be removed andMore than 50% of weld area can be removed and

replaced along length of no more than 12replaced along length of no more than 12. Must. Must

not be closer than 12not be closer than 12from each other includingfrom each other including

repaired welds on opposite side of the shell.repaired welds on opposite side of the shell.

Root and final pass examined visually and byRoot and final pass examined visually and by magmag..

particle or liquid penetrant method.particle or liquid penetrant method.


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Bottom Repair by ReplacementBottom Repair by Replacement

Plates Outside Critical ZonePlates Outside Critical Zone Any or all plates of a bottom can be replaced ifAny or all plates of a bottom can be replaced if

subgradesubgrade is in acceptable condition and theis in acceptable condition and thefollowing are metfollowing are met

If annular ring exists it stays in place and supportIf annular ring exists it stays in place and support

under annular ring remains intact.under annular ring remains intact.

If tank has no annular ring repairs do not result inIf tank has no annular ring repairs do not result in

welding of remaining bottom plate in the critical zone.welding of remaining bottom plate in the critical zone.

Support under critical zone remains intact. (CriticalSupport under critical zone remains intact. (Critical

zone = within 3zone = within 3of shell).of shell).


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Minor Shell JackingMinor Shell Jacking

Tank shell and critical zone materials shall meet APITank shell and critical zone materials shall meet API--

650,650, safe for usesafe for usearea in Figure 5area in Figure 5--2 of API2 of API--653, or653, or

stress must be less than 7,000stress must be less than 7,000 psipsi..

Engineer must consider all pertinent variables includingEngineer must consider all pertinent variables including

but not limited to: the magnitude of jacking required,but not limited to: the magnitude of jacking required,material, toughness, quality control, inspection beforematerial, toughness, quality control, inspection before

and after repair, material temperature, future foundationand after repair, material temperature, future foundation

stability, and jacking technique. Careful consideration tostability, and jacking technique. Careful consideration to

potential stresses and damage from jacking.potential stresses and damage from jacking.


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FitnessFitness--ForFor--Service EvaluationService Evaluation

The owner/operator may utilize a fitness for service orThe owner/operator may utilize a fitness for service or

other appropriate evaluation methodology based onother appropriate evaluation methodology based on

established principles and practices to exempt a repairestablished principles and practices to exempt a repairfrom hydrostatic testing. The procedures and acceptancefrom hydrostatic testing. The procedures and acceptance

criteria for conducting an alternative analysis are notcriteria for conducting an alternative analysis are not

included in this standard. This evaluation shall beincluded in this standard. This evaluation shall beperformed by an engineer experienced in storage tankperformed by an engineer experienced in storage tank

design and the evaluation methodologies used.design and the evaluation methodologies used.


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In a NutshellIn a Nutshell

Does repair include major repair?Does repair include major repair?

If so, is a hydro exemption met?If so, is a hydro exemption met?

Impact test can be used to verify existing materialImpact test can be used to verify existing materialmeets APImeets API--650. Cost ~ $400.650. Cost ~ $400.

If not, advanced fracture mechanics test canIf not, advanced fracture mechanics test can

insure brittle material is safe for use.insure brittle material is safe for use.

Install flaw in weld between existing and newInstall flaw in weld between existing and new

material.material.

Find critical flaw size needed for failure.Find critical flaw size needed for failure.

Verify NDE can detect critical flaw size.Verify NDE can detect critical flaw size.

Cost ~ $8,000.Cost ~ $8,000.


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Indirect HydroIndirect Hydro--Test RequirementsTest Requirements

Repairs in the critical zone are limited unless theRepairs in the critical zone are limited unless the

entire sketch plate is removed and replaced.entire sketch plate is removed and replaced.This is a major repair requiring a hydroThis is a major repair requiring a hydro--test.test.

Shells over 1/2Shells over 1/2thick of unknown toughnessthick of unknown toughness

must use inserts that are 12must use inserts that are 12 larger than nozzlelarger than nozzle

diameter. This is a major repair requiring adiameter. This is a major repair requiring a

hydrohydro--test.test.


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Hydro Tricks of the TradeHydro Tricks of the Trade

Evaluate hydro requirement before performingEvaluate hydro requirement before performingany repair.any repair.

Can repairs be made to stay away from major repairCan repairs be made to stay away from major repairdefinition.definition.

Remove 12Remove 12shell sample for impact testing. If it doesshell sample for impact testing. If it doesnot pass replace the sample with insert. Not a majornot pass replace the sample with insert. Not a majorrepair, still no hydro test.repair, still no hydro test.

Be prepared for failed test, have alternate plan.Be prepared for failed test, have alternate plan.


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Do not use inserts automatically. All tanksDo not use inserts automatically. All tanks oror

less can use nozzles installed in the shell with aless can use nozzles installed in the shell with arepadrepad (no insert). This allows up to a 12(no insert). This allows up to a 12nozzlenozzle

with no need for hydro since no major repair.with no need for hydro since no major repair.

Shells overShells over thick can avoid inserts if theythick can avoid inserts if they

have known toughness.have known toughness.


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The use of a hot tap for nozzles up to 4The use of a hot tap for nozzles up to 4whenwhen

the shell is overthe shell is over thick and of unknownthick and of unknowntoughness can avoid a hydro test.toughness can avoid a hydro test.

Hot taps are restricted when shell is overHot taps are restricted when shell is over and ofand of

unknown toughness except nozzles up to 4unknown toughness except nozzles up to 4areareallowed.allowed.

A 4A 4repair nozzle in the same tank would require anrepair nozzle in the same tank would require aninsert of a size that would be a major repair requiringinsert of a size that would be a major repair requiring

a hydro test.a hydro test.


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Nozzles can be installed in new cover plates toNozzles can be installed in new cover plates toavoid shell work that would result in a hydro test.avoid shell work that would result in a hydro test.

Evaluate the loads that go into the cover.Evaluate the loads that go into the cover.

Insure otherInsure other manwaysmanways are available for future access,are available for future access,

egress and venting.egress and venting.

Stay away from the shellStay away from the shell--toto--bottom weld andbottom weld andcritical zone. Any repairs in these areas mustcritical zone. Any repairs in these areas mustpay close attention to details to avoid invoking apay close attention to details to avoid invoking ahydrohydro--test.test.


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SummarySummary

Certain repairs require hydro testing. APICertain repairs require hydro testing. API--653 may653 may

guide the type of repair to force the repair to meet theguide the type of repair to force the repair to meet the

major repairmajor repairdefinition.definition.

If a major repair is performed, APIIf a major repair is performed, API--653 allows653 allows

exemption based on material, design andexemption based on material, design and

construction factors.construction factors.

All exempted hydrostatic tests must be able to pointAll exempted hydrostatic tests must be able to point

to the justification for exemption.to the justification for exemption.

In general this justification is aimed at assuring thereIn general this justification is aimed at assuring there

is a very low risk of brittle failure.is a very low risk of brittle failure.


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SummarySummary

Prior to any repair the hydro test connotations should bePrior to any repair the hydro test connotations should be

considered.considered. If impact or other testing is performed in an attempt to eliminaIf impact or other testing is performed in an attempt to eliminate ate a

hydro test be prepared for poor results.hydro test be prepared for poor results.

If possible, choose repairs to avoid a hydro.If possible, choose repairs to avoid a hydro.

Fitness for service evaluations should not be treated as guarantFitness for service evaluations should not be treated as guaranteedeedexemptions. They provide a method for using advanced analysisexemptions. They provide a method for using advanced analysisand additional NDE to justify legitimate exemptions.and additional NDE to justify legitimate exemptions.

5. hydrostatic test exemptions

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