inspection equipment THE USE OF PULSED DC HOLIDAY DETECTORS   FOR FIELD TESTING PIPELINE COATINGS                         ...
inspection equipment THE USE OF PULSED DC HOLIDAY DETECTORS   FOR FIELD TESTING PIPELINE COATINGS          Presented by Cr...
Content  Introduction  The Problem - Flaws & Defects  Standards for Porosity Detection  Continuous DC High Voltage Testing...
IntroductionHigh Voltage Holiday Detection is used oncured coatings to ensure there are no flaws  Two main high voltage eq...
IntroductionContinuous AC High Voltage Testers are alsoavailable but these are often mains operated,which is inconvenient ...
The ProblemFlaws in cured coatings reduce servicelife:  Pipeline – internal and external coatings  Tank linings  Immersion...
The Problem   Some Examples of Coating Flaws     Runs & Sags     Pinholes     Cratering     Cissing     Incorrect Coating ...
The ProblemRuns & Sags  Caused by excessive  local thickness prior  to cure
The ProblemPinholes  Caused by air or blast  media inclusion in the  coating
The ProblemCratering  Caused by air release  from the partially cured  coating
The ProblemCissing  Caused by contamination  of substrate by oil or  grease  (also known as crawling  or fisheyes)
The ProblemIncorrect Coating Thickness  Profile peaks through  thin coatings  Cracking due to excess  coating thickness
Test Standards       NACE         SP0188:2006         “Discontinuity (Holiday)         Testing of New Protective         C...
Test StandardsNACE  RP0274:2004                V  7,900 T                             Where: V = test voltage  “High Volt...
Test StandardsNACE SP0490:2007                     V  104 T “Holiday Detection of Fusion-   Where: V = test voltage      ...
Test StandardsASTM D5162:2008                    V  M Tc “Practice for Discontinuity   Where: V = test voltage,          ...
Test StandardsASTM D4787:2008                        V  M Tc “Continuity verification for      Where: V = test voltage,  ...
Test Standards     ISO       BS EN ISO29601:2011       “Paints and varnishes –       Corrosion protection by       protect...
Test Standards       Test Voltage Comparisons     Standard          Test Voltage for 500 µm (20                           ...
Continuous DC TestingTest Set-up  Signal return connected to  substrate  DC Voltage from 0.5 to 30 kV  Conductive Electrodes
Continuous DC TestingTest Electrodes  Insulated Handle  Rolling Spring  Internal Pipe Brush  Metal or Conductive Rubber  B...
Pulsed DC Testing     Test Set-up       Capacitive Signal Return Cable
Pulsed DC TestingTest Set-up  35 kV Test Voltage  Range  Menu operated standards  Voltage calculator
Pulsed DC TestingFull Set of Electrodes  Band brushes  Wire brushes up to 1 m wide  Internal pipe brushes  Conductive Rubb...
Pulsed DC TestingSignal Return Conductive Mat
THE USE OF PULSED DC HOLIDAY DETECTORS FOR      FIELD TESTING PIPELINE COATINGS           CONCLUSIONS                     ...
ConclusionsThe key to successful high voltage holiday detectionis the selection of the correct test voltage:  Too low a vo...
ConclusionsCare must be taken with lowdielectric strength coating:  Thin sections may not resist the  high voltage if the ...
ConclusionsContinuous DC vs. Pulsed DCTesting  Determined by practical issues  Pulsed DC when direct connection  to substr...
ConclusionsContinuous DC vs. Pulsed DCTesting  Continuous DC recommended when  accurate voltage setting required –  low di...
ConclusionsCare when referencing a standard  The different standards produce different test voltages for  the same thickne...
THE USE OF PULSED DC HOLIDAY DETECTORS  FOR FIELD TESTING PIPELINE COATINGS              THANK YOU         FOR YOUR ATTENT...
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Craig Woolhouse - The Use of Pulsed DC Holiday Detectors for Field Testing Pipeline Coatings

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Craig Woolhouse - The Use of Pulsed DC Holiday Detectors for Field Testing Pipeline Coatings

  1. 1. inspection equipment THE USE OF PULSED DC HOLIDAY DETECTORS FOR FIELD TESTING PIPELINE COATINGS Author: John Fletcher FICORR Technical Support Manager Elcometer Limited© Elcometer Limited 2011 60 years of excellence www.elcometer.com
  2. 2. inspection equipment THE USE OF PULSED DC HOLIDAY DETECTORS FOR FIELD TESTING PIPELINE COATINGS Presented by Craig Woolhouse Regional Sales Manager Elcometer Limited© Elcometer Limited 2011 60 years of excellence www.elcometer.com
  3. 3. Content Introduction The Problem - Flaws & Defects Standards for Porosity Detection Continuous DC High Voltage Testing Pulsed DC High Voltage Testing Conclusions
  4. 4. IntroductionHigh Voltage Holiday Detection is used oncured coatings to ensure there are no flaws Two main high voltage equipment types Continuous DC Pulsed DC
  5. 5. IntroductionContinuous AC High Voltage Testers are alsoavailable but these are often mains operated,which is inconvenient for site work Surface contamination & moisture cause AC sparks High AC voltage is more hazardous than DC
  6. 6. The ProblemFlaws in cured coatings reduce servicelife: Pipeline – internal and external coatings Tank linings Immersion Service
  7. 7. The Problem Some Examples of Coating Flaws Runs & Sags Pinholes Cratering Cissing Incorrect Coating Thickness
  8. 8. The ProblemRuns & Sags Caused by excessive local thickness prior to cure
  9. 9. The ProblemPinholes Caused by air or blast media inclusion in the coating
  10. 10. The ProblemCratering Caused by air release from the partially cured coating
  11. 11. The ProblemCissing Caused by contamination of substrate by oil or grease (also known as crawling or fisheyes)
  12. 12. The ProblemIncorrect Coating Thickness Profile peaks through thin coatings Cracking due to excess coating thickness
  13. 13. Test Standards NACE SP0188:2006 “Discontinuity (Holiday) Testing of New Protective Coatings on Conductive Substrates” Test Voltage Table
  14. 14. Test StandardsNACE RP0274:2004 V  7,900 T Where: V = test voltage “High Voltage Electrical and T is the thickness in Inspection of Pipeline mm Coatings” Voltage Formula or Table V  1,250 T Where: V = test voltage and T is the thickness in mil
  15. 15. Test StandardsNACE SP0490:2007 V  104 T “Holiday Detection of Fusion- Where: V = test voltage and T is the thickness in Bonded Epoxy External µm Coatings of 250 to 760 µm (10 to 30 mil) ” V  525 T Voltage Formula or Table Where: V = test voltage and T is the thickness in mil
  16. 16. Test StandardsASTM D5162:2008 V  M Tc “Practice for Discontinuity Where: V = test voltage, Tc is the thickness in (Holiday) Testing of mm or mil and M is a Nonconductive Protective constant dependant on the range of the Coating on Metallic thickness Substrates ” Voltage Formula or Table
  17. 17. Test StandardsASTM D4787:2008 V  M Tc “Continuity verification for Where: V = test voltage, Tc is the thickness in liquid or sheet linings applied mm or mil and M is a to concrete substrates ” constant dependant on the range of the thickness Voltage Formula or Table
  18. 18. Test Standards ISO BS EN ISO29601:2011 “Paints and varnishes – Corrosion protection by protective paint systems – Assessment of porosity in a dry film” Test Voltage Table
  19. 19. Test Standards Test Voltage Comparisons Standard Test Voltage for 500 µm (20 mil) Coating NACE SP0188 2.5 kV NACE RP0274 6.0 kV NACE SP0490 2.3 kVASTM D4787 (Formula) 2.3 kV ASTM D4787 (Table) 2.7 kV BS EN ISO 29601 2.9 kV
  20. 20. Continuous DC TestingTest Set-up Signal return connected to substrate DC Voltage from 0.5 to 30 kV Conductive Electrodes
  21. 21. Continuous DC TestingTest Electrodes Insulated Handle Rolling Spring Internal Pipe Brush Metal or Conductive Rubber Brush Electrodes Extension rods
  22. 22. Pulsed DC Testing Test Set-up Capacitive Signal Return Cable
  23. 23. Pulsed DC TestingTest Set-up 35 kV Test Voltage Range Menu operated standards Voltage calculator
  24. 24. Pulsed DC TestingFull Set of Electrodes Band brushes Wire brushes up to 1 m wide Internal pipe brushes Conductive Rubber Strip Electrode adaptors Steel rolling springs Phosphor-Bronze Rolling Springs
  25. 25. Pulsed DC TestingSignal Return Conductive Mat
  26. 26. THE USE OF PULSED DC HOLIDAY DETECTORS FOR FIELD TESTING PIPELINE COATINGS CONCLUSIONS .
  27. 27. ConclusionsThe key to successful high voltage holiday detectionis the selection of the correct test voltage: Too low a voltage and flaws will be missed Too high a voltage and the coating will be burnt .
  28. 28. ConclusionsCare must be taken with lowdielectric strength coating: Thin sections may not resist the high voltage if the dielectric strength is low Breakdown voltage of air is: 4 kV/mm Some coatings have a dielectric strength of 6 kV/mm .
  29. 29. ConclusionsContinuous DC vs. Pulsed DCTesting Determined by practical issues Pulsed DC when direct connection to substrate is not possible Pulsed DC when coating is damp or dirty .
  30. 30. ConclusionsContinuous DC vs. Pulsed DCTesting Continuous DC recommended when accurate voltage setting required – low dielectric strength coatings .
  31. 31. ConclusionsCare when referencing a standard The different standards produce different test voltages for the same thickness .
  32. 32. THE USE OF PULSED DC HOLIDAY DETECTORS FOR FIELD TESTING PIPELINE COATINGS THANK YOU FOR YOUR ATTENTION Any Questions? .

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