1. Investigating Failure: Security Barrier with Compromised Corrosion Protection
Welcome
Speaker: Robert Ikenberry,
California Engineering Contractors
Organizers: Larson Electronics and JPCL
Welcome
Speaker: Rob Lanterman, KTA-Tator, Inc.
Moderator: Josiah Lockley, Paintsquare
Organizers: Paintsquare

2. Investigating Failure: Security Barrier with Compromised Corrosion Protection
Agenda
Rob Lanterman, KTA-Tator, Inc (45 minutes)
Questions and answers (about 10 minutes)

3. Recording
Investigating Failure: Security Barrier with Compromised Corrosion Protection
Recording and Reference
This presentation is being recorded, and will be available soon by visiting
Copy of reference slides will also be available for download

4. Recording
Recording
Investigating Failure: Security Barrier with Compromised Corrosion Protection
Today’s Speaker
Rob Lanterman
Coatings Consultant, KTA-Tator, Inc.
A coatings consultant with KTA-Tator Inc. He is an SSPC Certified Protective Coatings Specialist and a NACE Level 2 Certified Coatings Inspector with over 10 years of coatings engineering experience

5. Presented by: Jayson L. Helsel, PE, PCS KTA-Tator, Inc.
investigating FAILURE: Security barrier with compromised corrosion protection
Presented by:
Jayson L. Helsel, PE, PCS
KTA-Tator, Inc.

6. Learning Objectives
Comprehension of the webinar will enable the participant to:
Understand the typical steps for conducting a coating failure investigation
Describe some typical field coating tests or measurements when investigating a coating failure
List some typical types of lab testing used for analyzing coating samples
Understand the primary cause of the security fence failure

7. BACKGROUND Security barrier was installed at electrical power station
Coating was failing after several months
Facility within view of residential area

8. COATING FAILURE INVESTIGATION
Data collection
Field investigation
Laboratory analysis
Review, conclusions and report

9. Data Collection Specification Construction sequence Structure history
Painting history

10. Specification Surface preparation Coating materials Film thicknesses
Method of application
Product data sheets

11. Construction Sequence
Which components were erected first?
Which components were erected last?
How much time lapsed between the beginning and the end of a project?

12. Structure History
How long has the existing system been in place? Have there been other failures? Were failures isolated or widespread?

13. Painting History Was the system or primer applied in the shop?
Was the finish coat or entire system applied in the field?

14. Data collection
Barrier constructed of galvanized sheet formed in corrugated shape
Perimeter barrier was roughly rectangular

16. Data collection Primary surface preparation was degreasing
Powder coating applied in fluidized bed process (i.e. shop applied)
Low density polyethylene (LDPE)
Field touch-up with acrylic primer/finish

17. Data collection Barrier installed in late fall
Coating failure reported in following spring
Failure worsened over year

18. Field investigation Patterns of failure (visual exam)
Coating thickness
Adhesion
Substrate condition
Sample collection

19. Looking for Patterns
Is the system failing everywhere or in a single, isolated location?
Directional exposure differences, e.g. south facing sun exposure

20. Looking for Patterns
Failure/delamination from substrate along vertical edges
Cut edges in majority of cases
Field touch-up but poor coverage
Often at inward bends
Sometimes at vent openings
Occurred on both sides, all exposures

24. Coating Thickness Gages for Different Surfaces
Gages to measure thickness on ferrous and non-ferrous metal surfaces
Micrometer measures thickness on disbonded coating chips
Tooke gage measures thickness by observation into the coating system

25. Dry Film Thickness Gages
Measuring over ferrous metal (Magnetic pull-off or magnetic flux)
Measuring over non-ferrous metals like aluminum and copper (eddy current)
Measuring over non-ferrous, non-metallic surfaces like concrete and wood (ultrasound)

26. Electronic/magnetic DFT gage

27. Micrometer

28. Tooke Gage

31. Coating thickness Electronic gage measured 10 to 55 mils
Typical range 12 to 25 mils
Thickness varied along panel
Low end typically 12 to 15 mils
High end typically 22 to 25 mils
Higher thickness often at cut edge

32. Measuring Adhesion
ASTM D3359 – Tape test
ASTM D6677 – Knife adhesion

33. Measuring Adhesion by Tape Test
ASTM D3359
Method A - The “X” cut (>5 mils)
Method B - The “Cross-Cut” (< 5 mils)

35. Evaluating the X-Cut 5A No peeling or removal
4A Trace peeling along incisions
3A Jagged removal along incisions up to /16” on either side
2A Jagged removal along most of incisions up to 1/8” on either side
1A Removal from most of the area of the X under the tape
0A Removal beyond the area of the X

36. Measuring Adhesion by knife
ASTM D6677
“X” cut
Probe cut with knife to remove coating

38. Evaluating knife Cut 10 Coating extremely difficult to remove
Fragments no larger than 1⁄32” by 1⁄32” removed with great difficulty
8 Coating difficult to remove
Chips from 1⁄16” by 1⁄16” to 1⁄8” by 1⁄8” removed with difficulty

39. Evaluating knife Cut 6 Coating somewhat difficult to remove
Chips from 1⁄8” by 1⁄8” to 1⁄4” by 1⁄4” removed with slight difficulty
4 Coating somewhat difficult to remove
Chips in excess of 1⁄4” by 1⁄4” removed by exerting light pressure with the knife blade

40. Evaluating knife Cut 2 Coating easily removed
Once started with knife blade coating can be grasped with ones fingers and easily peeled to a length of at least 1⁄4”
0 Coating easily peeled to length >¼”

41. knife Cut ADHESION 0 rating and poor adhesion near failing areas
4 to 6 rating and fair adhesion for intact coating when thickness was greater (e.g. 20 mils)
8 rating and good adhesion for intact coating when thickness was lower (e.g. 12 mils)

44. Substrate Condition Remove coating
Determine presence of mill scale, rust or contamination
Level of surface preparation (power tool cleaning, blast cleaning, etc.)

45. Substrate Condition No evidence of contamination
Galvanized surface was smooth, no roughening obvious

47. Sample Collection Coating chips Corrosion samples Blister liquid/caps
Failing & non-failing areas
Corrosion samples
Blister liquid/caps
Coating retains

48. Laboratory Analysis Optical microscopy Infrared Spectroscopy
Pyrolysis/Gas Chromatography/Mass Spectroscopy
SEM/EDS

49. Optical Microscopy Visual examination of coating samples
Cameras attached to the microscope
May direct or alter the course of a failure investigation

50. Fourier Transform Infrared Spectroscopy
Produces a fingerprint of coating
Can determine if coating specified was the one actually applied

51. Pyrolysis/Gas Chromatography/ Mass Spectroscopy
Detects presence of solvents trapped in a coating or in blister liquid

52. Scanning Electron Spectroscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS)
Uses magnification up to 10,000x
Examines defects in the coating surface
Compares failing and non-failing areas
Provides an elemental analysis of the surface

53. Holiday Detection Two types:
Low voltage (wetted sponge) – coatings that are less than 20 mils thick
High voltage (spark testers) – coatings that are greater than 20 mils thick

54. Pinholes and Holidays
Holidays – skips or misses in the coating/lining system
Pinholes – tiny voids in the coating or lining
Testing found many holidays

58. conclusions
80% of failure at cut ends of panels – allowed moisture to travel beneath coating
Significant thickness variation – 12 to 25 mils
Poorer adhesion at high thickness
Failure at ends typically at higher thickness
Numerous holidays at edges and openings

59. Repair RECOMMENDATIONS
Remove poorly adhered coating
Abrade/sand existing intact coating and exposed galvanizing
Apply acrylic primer and 1 or 2 acrylic finish coats
Consider an elastomeric acrylic coating

60. other RECOMMENDATIONS
Simpler barrier design
Better galvanizing surface prep
Chemical cleaning
Phosphate conversion coating
Evaluate/improve application process to achieve uniform thickness
Better field touch-up

61. Coating failure investigation
Questions?

62. Recording
Recording
Investigating Failure: Security Barrier with Compromised Corrosion Protection
Recording and Reference
This presentation has been recorded, and will be available soon by visiting paintsquare.com/webinars
Copy of reference slides available for download

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