RELIABILTY AND OF EDDY CURRENT TESTING

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RELIABILTY AND OF EDDY CURRENT TESTING

• ANMOL BIRRING
• NDE ASSOCIATES, INC
• WWW.NDE.COM

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MY PERSONAL EXPERIENCE

• PERFORMING ECT FOR OVER 15 YEARS
• WORKED IN SEVERAL PETROCHEMICAL AND FOSSIL PLANTS
• CONDUCTED ECT TRAINING IN USA, KOREA, JAPAN,
  MEXICO, TAIWAN

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PAPER ADDRESSES

• INSPECTION IN PETROCHEMICAL PLANTS
• INSPECTION OF HEAT EXCHANGER TUBING

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TUBING INSPECTION METHODS
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CONVENTIONAL ECTNON-FERROMAGNETIC TUBING

• STARTED IN 1950s
• FIRST MAJOR APPLICATIONS BY NAVY NUCLEAR
• STEAM GENERATOR INSPECTIONS IN THE 1960s

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ECT INSPECTION
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DEFECT TYPES
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OD CRACK
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ECT STRIP CHART
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CALIBRATION
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ECT INSPECTION
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ID PITTING BRASS TUBING
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FINAL RESULTS
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DEFINITION - RELIABILTY

• POD PROBABABILTY OF DETECTION. MUST BE HIGH
• POFA PROBABILTY OF FALSE ALARMS. MUST BE LOW
• RELIABILTY POD x (1-POFA). MUST BE HIGH
• ACCURACY SIZING ERRORS

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EPRI AND SHELL TESTS ON RELIABILTY

• POD CAN VARY 50 TO 95
• POFA CAN VARY 0 TO 20
• RELIABILTY POD x (1-POFA) CAN VARY 40 TO 90
• TECHNICIAN DEPENDENT
• NOT EQUIPMENT DEPENDENT

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PETROCHEMICAL VS. NUCLEAR

• NUCLEAR - WELL DEFINED MATERIALS
• NUCLEAR WELL DEFINED DAMAGE MECHANISMS
• PETROCHEMICAL RANGE OF MATERIALS AND DAMAGE
  MECHANISMS WE HAVE OVER 150 CAL TUBES AND WE
  STILL ADD

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MAJOR PROBLEM WITH ECT INSPECTIONS

• LARGE VARIATION AMONG TECHNICIANS IN RELIABILTY
  AND ACCURACY

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WHAT CAUSES SUCH VARIATIONS

• EDUCATION ?
• TRAINING ?
• TESTING ?
• CERTIFICATION ?
• APTITUDE ?

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CERTIFICATIONS AND EXPERIENCE

• LEVEL II AND III DO NOT MEAN ANYTHING IN TUBE
  TESTING
• PAST EXPERIENCE MAY NOT BE OF MUCH SIGNIFICANCE

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EDUCATIONHOW MUCH ?

• MUST HAVE HIGH SCHOOL EDUCATION
• BASIC MATH SKILLS MUST BE GOOD
• COMPUTER SKILLS ARE A NECESSITY
• Note I have run into students who do not know
  what is 20 of 80 - This is the problem of our
  high school students

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TRAINING

• GENERAL ECT TRAINING - OK
• SPECIFIC ECT TRAINING
• PRACTICAL ECT TRAINING

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GENERAL TRAINING

• MUST UNDERSTAND IMPEDANCE PLANE

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SPECIFIC TRAININGTECHNIQUE SELECTION

• CONVENTIONAL ECT
• REMOTE FIELD ECT
• IRIS
• MFL
• TECHNIQUES AND LIMITATIONS

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SPECIFIC TRAINING

• SELECTION OF PROBE FREQUENCY AND SIZE
• CALIBRATION TUBE MUST BE SAME MATERIAL AND SIZE
• HOW TO VERIFY TUBE MATERAIL
• DETERMING ECT FREQUENCY WITHOUT KNOWING MATERIAL
  CONDUCTIVITY

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VERIFY TUBE MATERIAL
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PRACTICAL ECT TRAININGMUST ADDRESS REAL WORLD
PROBLEMS

• MATERIALS
• DEFECT TYPES
• METALLIC DEPOSITS

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MATERIALS

• STAINLESS STEEL, HASTELLOY, INCONEL
• AD. BRASS, Cu-Ni Alloys MOST DIFFICULT
• TITANIUM
• ALLOY 2205

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DEFECT TYPES

• PITTING
• CRACKING AXIAL AND CIRC
• WALL LOSS
• DAMAGE AT SUPPORTS

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METALLIC DEPOSITSWEAKEST AREA

• METALLIC DEPOSITS IN TUBES CAN JUST LOOK LIKE
  DEFECT SIGNALS
• THIS ARE IS RARELY ADDRESSED IN ANY TRAINING
• MAJOR CAUSE OF POFA

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METALLIC DEPOSITS
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ID GROOVE
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METALLIC DEPOSITS CAN LOOK LIKE ID DEFECTS
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SIZNG ACCURACY

• ASME CAL CURVE IS NOT ACCURATE
• ECT PHASE DEPENDS BOTH ON DEFECT DEPTH AND
  DIAMETER

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CURRENT PRACTICAL TRAINING

• BASICALLY THERE IS MINIMAL PRACTICAL TRAINING
• LIMITED TO ASME CAL TUBES

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PRACTICAL TRAINING

• MUST BE ON ACTUAL DATA
• MULTIPLE ID PITS
• DEFECTS UNDER SUPPORTS
• METALLIC DEPOSITS
• RANGE OF MATERIALS

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TRAINING ON TEST BUNDLESNOT EFFECTIVE

• THIS APPROACH IS VERY LIMITED
• LIMITED SAMPLES
• LIMITED DEFECTS

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WHAT ABOUT TESTS ON BUNDLES ?LIMITED TESTS

• MOST OF THEM HAVE MACHINED FLAWS
• MOST OF THEM TEST CAPABILTY TO TEST UNDER
  SUPPORTS

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WHAT IS NEEDED ?

• MORE INTENSE PRACTICAL TRAINING ON ACTUAL DATA
  OVER 10,000 SIGNALS
• TESTING ON ACTUAL TUBE DATA

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PRACTICAL TEST ON ACTUAL DATA20 SIGNALS EACH

• MULTIPLE ID DEFECTS IN BRASS
• ID DEFECTS IN BRASS
• OD DEFECTS IN BRASS
• WEAR AT SUPPORTS
• CRACKS AT SUPPORTS
• METALLIC DEPOSITS
• VIBRATION DAMAGE

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CONCLUSIONS

• ECT IN PETRMOCHEMICAL PLANTS IS CHALLENGING
• RANGE OF MATERIALS
• VARIETY OF DAMAGE MECHANISMS
• PRACTICAL TRAINING AND TESTING THAT ADDRESSS
  THESE ISSUES IS THEREFORE REQUIRED

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FINALLY !!

• IT BOILS DOWN TO THE ATITUDE OF THE INSPECTOR
• WILLINGNESS TO LEARN
• SELF MOTIVATON
• INTEGRITY

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FOR MORE INFORMATIONWWW.NDE.COM

• NDE 01-01  Detection of MIC Damage in U-Bends
• NDE 02-01  Detection of Axial ODSCC under
  supports
• NDE 03-01  Why ECT Technicians Make False Calls ?
• NDE 03-02 Detection of Cracks in Tubesheet
  Expansion Roll
• ECT vs IRIS
• Typical Defects in Heat Exchanger Tubes