Bayles_TankCleaning

8/17/2019 Bayles_TankCleaning

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API 2006 Storage Tank ConferencePresentation

Doug BaylesEngineering Manager

HMT Inc.

Tank Cleaning For Inspection Purposes

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3.12 owner/operator: The legal entityhaving both control of and/orresponsibility for the operation andmaintenance of an existing storagetank.

API 653 Section 3 - Definitions


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3.4 d. An independent organization orindividual under contract to and underthe direction of an owner/operatorand recognized or otherwise not prohibitedby the jurisdiction in which theaboveground storage tank is operated.The owner/operator’s inspectionprogram shall provide the controls

necessary for use by authorizedinspectors contracted to inspectabove-ground storage tanks.

API 653 Section 3 - Definitions

Tank Cleaning

• How are you going to achieve a tankbottom clean enough to provide yourinspection vendor the opportunity tomeet your needs?

And finally why this is so Important…


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Ask Yourself

• What would your answer be to thefollowing question:

“What is the most important step you cantake to insure a quality tank bottominspection?

It’s Not a Trick Question

A) Remaining Plate Thickness

B) Corrosion Rate

C) Type of Scanner Used

D) Tank Bottom Surface Preparation /Cleanliness


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What to Ask for from your Cleaner !

• The Society for Protective Coatingsprovides excellent standards of cleaningperformance.

• Key specifications would be:

SSPC-SP 6 - Commercial Blast

SSPC-SP 7 - Brush-off Blast

SSPC-SP 14 – Industrial Blast

SSPC-SP 6

• “ A commercial blast cleaned surface,when viewed without magnification,shall be free of all visible oil, grease,dust, dirt mill scale, rust, coating,oxides, corrosion products, and otherforeign matter, except for staining…Random staining limited…”


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SSPC-SP 7

• “A brush-off blast cleaned surface, whenviewed without magnification, shall befree of all visible oil, grease, dirt, dust,loose mill scale, loose rust, and loosecoating. Tightly adherent mill scale,rust and coating may remain on thesurface.”

Example of Original Condition


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Blast Cleaned to SP 6



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SSPC-SP 14

• An industrial blast cleaned surface,…shall be free of all visible oil, grease,dust, and dirt. Traces of tightlyadherent mill scale, rust, and coatingresidues are permitted…”



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Wet Blast Alternative

• When you have the need to use a wetblast instead of the dry blast method fortank surface preparation …

• SSPC provide a similar standard for wetblast options

Why is cleaning so Important

• “What an inspector cannot seecannot be effectively inspected.”

• The visual portion of the API Standard653 inspection is critical.

• Additionally, items such as vacuum box,helium testing or other NDE methodscan be severely limited without propercleaning.


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MFL Considerations

• These issues haven’t even mentionedthe overwhelming problems created bypoor tank bottom preparation for theMFL inspection. Issues such as:

1)Loose material clogging MFL scannermagnets

2)Material packed into pits that make UTprove-up nearly impossible, butcertainly un-reliable


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Wish Everyone Would

• The following slides are some examplesof good surface preparation using eithera dry blast or wet abrasive blast:


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In Contrast

The following are typical examples of what we encounter:


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“Just do the best you can!”

• Think back – have you asked the aboveof your inspection vendor?

• Under the pressure of trying to get yourtank back in service – believe me mostof you have either used these words orhave been very tempted.

How will Inspection vendor react?

• My hope is that all of the inspectioncommunity would tell you that acomprehensive inspection cannot bepreformed under the conditionspresented. Without proper cleaning theinspection company should decline the

work since they cannot perform to thelevel required.


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• Should you then persist with the “justdo the best you can…” approach

• The inspection company should be dutybound to inform you that the inspectionwill be severely limited and that you willbe assuming all risks associated withany inspection under such conditions.

• In other words … the inspection reportwill have disclaimers that will make thereport worth less than the paper it iswritten on…


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In Summary

• Cleaning to a reasonable industrystandard is a must to insure that youare getting a “quality” tank bottom MFLinspection – to say nothing of the APIStandard 653 visual portion of theinspection.

• I would like to thank the Society of Protective Coating (SSPC) for theirassistance with this presentation.

• Additionally, SSPC provides a wonderfulvisual reference guide you can use towork with your tank cleaner.

Documents

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