Coating Condition Survey
Coating Assessment of Defects and Failure Modes
Determining the condition of existing protective coatings is necessary for maintenance of assets and project planning,
- Accurately identify defects
- Measure coating film properties
- Prioritize and recommend action
- Tests for coating integrity
- Field sampling of coating for analysis
The primary objective of an assessment is to determine the current physical and performance condition of the existing coatings
“Assessment of the condition of aged coated surfaces strengthens decisions on when coating maintenance is required, aids in the selection of effective coating maintenance procedures, and provides a means to characterize performance of coating systems.” (ASTM D5065 Standard Guide for Assessing the Condition of Aged Coatings on Steel Surfaces)
The categories of services shown below include a summary list of standards (for reference only) which will detail all aspects of the assessment task. An official citation of the standards and links can be found in the Reference tables. This is an overview of all available services which apply to a wide range of projects. A specific scope of work can be created according to individual project details. Please see Contact if more information is needed.
Visual Assesment
Identify existing conditions for failure analysis and planning
Corrosion Trap
Edges – Flame Cut
Edges – Sharp
Loss of Metal
Loss of Topcoat
Mill Scale
Oil Contamination
Skip Weld
Slag
Surface Deteriorated
Surface Preparation Commentary for Metal Substrates – SP COM
Accurately identify defects for analysis and planning
Adhesion Failure
Alligatoring
Aluminium Corrosion
Blistering
Bloom
Bridging
Brush Marks
Bubbles or Bubbling
Chalking
Checking
Cracking
Cratering
Delamination
Dry Spray
Efflorescence
Erosion
Fading
Filiform
Flaking
Grinning
Grit Inclusions
Growth
Impact Damage
Laminations or Shelling
Misses; Skips; Holidays
Missing Topcoat
Mud Cracking
Orange Peel
Overspray
Peeling
Pinholes
Rot
Runs or Sags
Rust Rashing
Rust Spotting
Rust Staining
Saponification
Solvent Lifting
Solvent Popping
Tackiness
Undercutting
Water Spotting
Wrinkling
Zinc Carbonates
Fitz’s Atlas 2 of Coating Defects – NACE International
Terminology and Acronyms Relating to Corrosion – NACE/ASTM G193
ASTM D5065 Standard Guide for Assessing the Condition of Aged Coatings on Steel Surfaces
Rate condition of common defects
Rust – SSPC-VIS 2, ASTM D 610
Under-Film Condition – D610
Peeling – ASTM D610
Blistering – ASTM D714
Checking – ASTM D660
Cracking – ASTM D661
Chalking – ASTM D4214
Evaluating Degree of Rusting on Painted Steel Surfaces – ASTM D610
Evaluating Degree of Checking of Exterior Paints – ASTM D660
Evaluating Degree of Blistering of Paints – ASTM D714
Standard Method of Evaluating Degree of Rusting on Painted Steel Surfaces – SSPC-VIS 2
| Rust Grade | (% of Surface Rusted) |
|---|---|
| 10 | (≤ 0.01 %) |
| 9 | (> 0.01 % – 0.03 %) |
| 8 | (> 0.03 % – 0.1 %) |
| 7 | (> 0.1 % – 0.3 %) |
| 6 | (> 0.3 % – 1.0 %) |
| 5 | (> 1.0 % – 3.0 %) |
| 4 | (> 3.0 % – 10.0 %) |
| 3 | (> 10.0 % – 16.0 %) |
| 2 | (> 16.0 % – 33.0 %) |
| 1 | (> 33.0 % – 50.0 %) |
| 0 | (> 50 %) |
| Rating | Blister Size |
|---|---|
| 10 | None |
| 8 | < 1mm seen with unaided eye |
| 6 | 1mm |
| 4 | 2mm – 3mm |
| 2 | 4mm – 5mm |
| 0 | > 5mm |
| Rating | Chalking |
|---|---|
| 1 | 20% |
| 2 | 40% |
| 3 | 60% |
| 4 | 80% |
| 5 | 100% |
Measure coating film properties
Thickness
Adhesion
Measurement of Dry Film Thickness by Destructive, Cross-Sectioning Means – ASTM D4138
Nondestructive Measurement of Dry Film Thickness Applied to Non-Ferrous Metals – ASTM D7091
Pull-Off Strength of Coatings Using Portable Adhesion Testers – ASTM D4541
Pull-Off Adhesion Strength of Coatings on Concrete – ASTM D7234
Condition Rating
The overall condition of the coating is rated categorically
| Rating | Condition | Description |
|---|---|---|
| 5 | Excellent | No visible defects, new or near new condition, may still be under warranty if applicable |
| 4 | Good | Good condition, but no longer new, may have some slightly defective or deteriorated component(s), but is overall functional |
| 3 | Adequate | Moderately deteriorated or defective components; but has not exceeded useful life |
| 2 | Marginal | Defective or deteriorated component(s) in need of replacement; exceeded useful life |
| 1 | Poor | Critically damaged component(s) or in need of immediate repair; well past useful life |
Facility Condition Assessment – Federal Transit Administration, U.S. Department of Transportation
Priority and recommended action assigned for each condition catagory
| Condition | Priority | Recommendation |
|---|---|---|
| Excellent | None | No action needed |
| Good | Low, can be deferred | No action needed, unless noted for localized conditions |
| Adequate | Low, discretionary (not essential) | Maintenance coating needed |
| Marginal | Medium, can be done as routine maintenance | Maintenance coating, or rehabilitation needed |
| Poor | High, should be done as soon as possible | Maintenance coating, or rehabilitation needed |
Facility Condition Assessment – Federal Transit Administration, U.S. Department of Transportation
Field Testing
Tests for coating integrity
Film Adhesion
Thickness
Brittleness
Under-Film Corrosion
Identification of Generic Type – Laboratory Service
Patch Tests to Establish Compatibility
Removal
Rating Adhesion by Tape Test – ASTM D3359
Pull-Off Strength of Coatings Using Portable Adhesion Testers – ASTM D4541
Evaluating Adhesion by Knife – ASTM D6677
Pull-Off Adhesion Strength of Coatings on Concrete – ASTM D7234
Dry Film Thickness (DFT) by Cross-Sectioning Means – ASTM D4138
Dry Film Thickness (DFT) Applied of Non-Ferrous Metals – ASTM D7091
Field Identification of Coatings – ASTM D5043
Patch Test to Assess Coating Compatibility – ASTM D5064
Assessing the Condition of Aged Coatings – ASTM D5065
Solvent Resistance of Organic Coatings – ASTM D5402
Overcoating Existing Coating Systems – SSPC-TU 3
Maintenance Painting Programs – SSPC-PA 5
Data fields for sample collection (may vary according to laboratory service)
Type of Analysis
Project Name
Project Number
Client
Sample Number
Date & Time Sampled
Location/Material Type
Special Instructions
Sample Collector
Relinquished by
Date-Time
Sampling Chain-of-Custody Procedures – ASTM D4840
Field Sampling of Coating Films for Analysis – ASTM D5702
Sampling of Coating Films – ASTM D6206
| Property | Test |
|---|---|
| Film integrity cross-section | Optical Microscopy |
| Coating type and component characterization | Infrared Spectroscopy |
| Metals content, lead and zinc | Atomic Absorption Spectroscopy |
| Detection of non-metals | X-ray Fluorescence |
| Multi-element analysis of surface layers | Electron Spectroscopy for Chemical Analysis (ESCA) |
| Volatile organic solvents | Gas Chromatography |
| Detecting additives | High-Performance Liquid Chromatography |
Resources
ICI is an online, self-paced course that consists of 8, 30-minute modules introducing the fundamentals of coatings, as well as the purpose and role of a coating inspector on a coatings project. Students may either choose to complete the modules in sequential order or those with more experience or with specif ic interests, may select the modules that would most benefit them in their career.
Module 7: Coating Defects
Identify the types of defects that may occur when the specification is not followed or when problems occur during the coatings installation and how to identify them
Comprehensive visual guide to coating and surface defects. Compiled by coating specialists to provide a useful pictorial reference to all who use and encounter paint coatings, their defects and failures. 2011 MPI Group
Product Number: 38335
ISBN: 0951394029
Author: By Brendan Fitzsimons
Publication Date: 2011
Fitz’s Atlas is a 200 page, pocket-sized ring binder including more than 190 illustrations to provide the most comprehensive visual guide to coating and surface defects. Each section has been compiled by coating specialists who understand paint coatings and their application and as such will provide a useful pictorial reference to all who use and encounter paint coatings, their defects and failures.
Surface preparation. Salt contaminated abrasive. Effect of peak density on performance. Galvanizing. Silane-modified, polyurea & powder coatings. On dry spray. Polyaspartics. Scientific background & advice. Theory & applications. 2009 Wiley
Product Number: 38388
ISBN: 9780470697535
Author: By D. G. Weldon
Publication Date: 2009
Entirely devoted to the failure analysis of coatings and paints – an “excellent reference to a select market”. Latest edition contains new material on surface preparation, transfer of salt to steel from contaminated abrasive, effect of peak density on coating performance, on galvanizing, silane-modified coatings, polyurea coatings, polyaspartics, and powder coatings and on dry spray. Balances scientific background and practical advice, giving both the theory and applications in a slim, easily readable form. Includes case studies of laboratory tests. Written by an author with over 25 years of experience in the paint and coatings industry.
https://store.nace.org/failure-analysis-of-paints-coat-rev-edition
Assessment of Existing Protective Coatings
“An assessment is necessary for evaluating alternative coating strategies, selecting coatings to meet the specific facility and condition requirements, and preparing and executing maintenance specifications.
The type of data collected includes:
Location of area inspected
Service environment in area
Coated items rated
Coating identification and condition
Practical restrictions on maintenance
Physical test results
Physical testing of coating may contain:
Adhesion
Coating thickness
Hardness
Coating removal to expose substrate
Take samples for laboratory analysis (lead, asbestos, generic type)
Analysis of Coating Condition Data:
Type, extent, and distribution of corrosion
Type, size, and distribution of coating defects
Estimating costs for immediate and future work
Establishing priorities and coating schedules
General maintenance coating strategies are:
Deferral of coating for two years or more
Spot repair (touch-up) only
Spot repair and full topcoat (overcoating)
Complete removal and replacement of the existing coating system”SSPC Planning and Specifying Industrial Coatings Projects (C2), SSPC: The Society for Protective Coatings, Pittsburgh, PA
Coating Failure Analysis
Many of the procedures and tests listed above apply to failure analysis and forensic investigation.
Coatings are not permanent. They are subject to such forms of deterioration as erosion, corrosion, weathering, and abrasion. It is important to distinguish between coating failure and expected degradation. Failure occurs when a coating no longer performs its intended function, whether its function is corrosion protection, appearance (e.g., color and gloss retention), control of marine fouling, etc. Catastrophic failure is one that occurs shortly after application and results in obvious loss of function (e.g., extensive delamination, or paint chip contamination of stored chemicals).
Degradation is the gradual loss of functional properties through aging of the coating film and the effects of the environment. It is a matter of interpretation as to whether degradation results in failure.SSPC Planning and Specifying Industrial Coatings Projects (C2), SSPC: The Society for Protective Coatings, Pittsburgh, PA
Questions?
Please contact me if you have any questions regarding Coating Condition Surveys, and if you would like to learn more about the NACE Certified Inspector Program see the Information page.