Coating Condition Surveys: An Overview
- 5 September 2017
- Posted by: Stm Coatech
- Category: Educational Articles
Coating Condition Surveys: An Overview
I have always expressed my concerns in regard to the health and safety of offshore workers due to oil and gas leaks as well as structural failure caused by corrosion.
The U.K.’s Health and Safety Executive has taken a stronger stance on the significant corrosion issues the offshore oil and industry is still facing. So how far have we come in 2017? Are we now in a safer position with a reduction in leaks and structural failure caused by corrosion?
The U.K. offshore oil and gas industry is now in a position where many of its North Sea platforms have been producing and servicing our needs for 25 to 30-plus years, which in many cases is well beyond many of the assets’ intended lifespans.
I have to say I am afraid we are not, with recent reported accidents occurring offshore resulting in personal injury and attributed directly to corrosion.
We have to face facts: The U.K. offshore oil and gas industry is now in a position where many of its North Sea platforms have been producing and servicing our needs for 25 to 30-plus years, which in many cases is well beyond many of the assets’ intended lifespans, especially taking into consideration the severity of the corrosion environment in which these platforms are situated (C5M in accordance with ISO 12944 in most cases). This in itself creates an abundance of challenges.
Years of neglect through a general lack of risk-based inspection (RBI) and a general lack of fabric maintenance for external corrosion has ultimately led to a number of North Sea assets falling into a serious and potentially fatal state of disrepair.
Because of the increased scrutiny, there has been a significant increase in the demand for coating and corrosion condition surveys on oil and gas installations, and rightly so! However, many are undertaking surveys without the correct knowledge, information, experience and strategic planning required in order to execute a successful coating condition survey, and the result is often major problems for owners and operators from a health and safety and financial perspective.
So why is this happening?
I personally believe it comes down to a lack of general planning, knowledge and experience with regard to coating condition surveys.
In order to execute a successful coating condition survey for asset integrity management, it is essential to develop a strategic pre-planning program of what is to be surveyed, and to decide exactly what data to collect. This is essential to the efficiency and cost effectiveness of both baseline surveys and ongoing inspections for coating facility asset management programs.
To put It simply: It is essential to know what is required before initiating a costly coating condition survey.
Who, What, When, Where, How
There are many factors to consider during the planning stage of any coating condition survey; however, I personally believe that the following are vital in order to execute a successful strategic survey from a fabric maintenance perspective:
- Pre-determine primarily what areas, zones or safety critical elements (SCE) to survey. (Identify scope.)
- Determine survey type (i.e., full, partial or SCE-based).
- Confirm what data is to be collected, how it is to be collected and how it is to be reported.
- Determine the access available or needed in order to survey the coating system.
- Confirm the experience of personnel required for surveying.
- Determine the equipment and resources required in order to execute the survey.
- Confirm a reasonable timeframe for the survey.
- Collate and gather technical drawings such as piping and instrumentation diagrams (P&IDs), as builds, coating specifications and structural plans.
- Determine the type of visual standard to be used for the survey for visual comparison.
- Establish testing methods (i.e., visual, destructive or non-destructive testing).
- Review historical data (if known or present).
Having historical data is very useful for the pre-planning team and the surveyor. Typically, before any coating condition surveys are conducted it will be very useful to the project team to gather some history on the plant or equipment to be surveyed. The age of the plant or equipment, previous coating survey reports, previous maintenance or any outstanding issues such as leaks, corrosion, emergency work should be discussed and identified as priority survey areas. It is vital to establish if technical drawings or specifications exist, as these will be extremely useful in conducting the survey and identifying locations.
Because of the increased scrutiny, there has been a significant increase in the demand for coating and corrosion condition surveys on oil and gas installations.
The above are but a few critical points to take into consideration post-coating survey; however, it is clear from the above factors that a great deal of pre-planning is required in order to determine the correct strategy to implement for the coating condition survey.
To break down the above it is essential to determine what coating condition survey data points will help the asset manager in managing and executing a strategic and successful future fabric maintenance program, as ultimately the data collated will be used for maintenance either reliability-based, safety critical-based or general based.
A full comprehensive coating condition survey is often carried out primarily to:
- Ascertain the actual condition of the coating system which is in place;
- Determine and premature failure areas;
- Confirm the suitability of the original installed coating system;
- Confirm that original coating selections are correct for service and process environments and are performing;
- Evaluate the physical aspects of installed coating systems or to ensure that the coating has been applied as per specification requirements; and
- Provide an ability tool to pre-empt corrosion failure.
About the Surveyor
There has always been great interest in regard to the experience and qualifications required for the coating condition surveyor! Very often, companies request a NACE 3 or ICorr 3 coating or painting inspector as a minimum education requirement.
It is essential that the coating surveyor must have considerable experience in the coatings industry, which is usually attained by coating inspection qualifications coupled with extensive field experience. We have to remember that the surveyor must be able to develop comprehensive field coating condition reports, which will include recommendations and will be used in future maintenance contracts. This means that the surveyor must, at minimum, be able to:
- Follow technical drawings, P&IDS, specifications, as builds and plot plans;
- Evaluate surface areas and identify survey zones;
- Evaluate corrosion breakdown and coating breakdown;
- Identify coating failure types;
- Recommend remedial actions;
- Report accurately and precisely collating comprehensive data;
- Use sensitive inspection equipment usually not used for normal coating inspection; and
- Liaise with senior personnel such as offshore installation managers, plant managers, fabric maintenance coordinators and asset integrity managers.
He or she must also be able to read structural drawings, P&IDs and plant plot plans as well as estimate surface areas and break down percentages. These are not factors usually taught in a protective coating inspection course. What is clear is that the coating condition surveyor should have the necessary experience to be able to conduct the tests, write detailed, comprehensive and unbiased reports and make recommendations that will be required for future coating operations.
On Visual Standards
A great deal of the coating condition survey is visual in nature, and for this reason, various standards exist for evaluating the extent of corrosion and coating failure. These standards should be used extensively by the coating condition surveyor. It is critical that the use of visual standards, and the type of visual standards to be used, be established at the pre-survey discussions or pre-planning stage.
Coating condition surveys play an important role in keeping offshore workers safe and keeping offshore assets secure.
One such visual standard that is commonly used is the SSPC-VIS2: Standard Method of Evaluating Degree of Rusting on Painted Steel Surfaces (also ASTM D 610).
This standard is regularly used for rust evaluation, and it includes reference color photographs and corresponding black-and-white images that depict the percentage of rusting both in general and pinpoint rusting types.
A table is also included to compare against other rust grade scales, such as the ISO and European grades.
Along with the ASTM D610, ASTM has a number of standards that can be used by the coating surveyor:
- ASTM D660 – Degree of checking;
- ASTM D661 – Degree of cracking;
- ASTM D662 – Degree of erosion;
- ASTM D714 – Degree of blistering; and
- ASTM D772 – Degree of flaking.
There are clearly a great number of standards available to the surveyor, and the standards to be used for the coating condition survey should be clarified at the pre-planning stage.
While the SSPC and ASTM standards for evaluation are often specified for coating condition surveys in North America, outside of the United States, the international standards are used more frequently. EN ISO 4628 deals with the evaluation of degradation of paint coatings and designation of intensity, quantity and size of common types of defects.
The document, which contains text and black-and-white illustrations, only has six parts:
- Part 1 – General principles and rating scheme;
- Part 2 – Designation of degree of blistering;
- Part 3 – Designation of degree of rusting;
- Part 4 – Designation of degree of cracking;
- Part 5 – Designation of degree of flaking; and
- Part 6 – Designation of degree of chalking.
The coating surveyor can compile a comprehensive report based on the information that the above standards offer, which is comprehensive and technical guidance to the coating condition surveyor to use once in the field.
The Survey Itself
As we are starting to ascertain, there is a great deal of information to be gathered and taken into account in order to execute an efficient and successful coating condition survey, with much pre-planning and many critical points to consider. Once all of the above factors are established, it should be time to move on to the actual coating condition survey.
Typically, a full coating condition survey usually takes the form of non-destructive testing with a high focus on visual assessment for degradation and deterioration of the protective coating, which is to be assessed and compared to the evaluation standards listed above.
The coating condition survey needs to be thoroughly planned, implemented and executed with a pre-determined scope of work that is thoroughly understood by the coating surveyor.
Dry film thickness readings are often required, in addition to a full pictorial reference catalog of the area/equipment being surveyed. However, there is often a requirement to carry out destructive testing, which may include any of the following tests:
- Adhesion testing;
- DFT assessment using the Paint Inspection Gauge (PIG);
- Solvent rub testing; and
- Sampling (taking paint flakes for laboratory analysis).
The coating surveyor should also detail at minimum the following items within the coating condition survey report, including the location, zone or area:
- Condition of substrate (i.e., factors like contaminated surfaces—grease, oil, etc.—that make the coating survey difficult);
- Rust evaluation;
- Coating assessment or breakdown;
- Any evident rust staining?;
- Loss of gloss retention;
- Metal (section) loss or pitting;
- Missing sections (steel, bolts, nuts etc.);
- Access problems and issues;
- Environmental constraints and issues;
- Coating failures, flaking, blistering, runs, sags, cracking, etc.;
- Discussion on gathered data;
- Recommendation on future works;
- Proposed coating systems and methods of surface preparation; and
- Health and safety issues with conducting future work in line with recommendations
There is clearly a great deal of comprehensive pre-planning and coating engineering required in order to implement and execute a successful strategic coating condition survey, and there is an abundance of factors and issues which need to be taken into consideration. It is not a case of simply turning up with a notepad and a camera: The coating condition survey needs to be thoroughly planned, implemented and executed with a pre-determined scope of work that is thoroughly understood by the coating surveyor.
STM Coatech, SSPC PCI (International Coating Enspektörlüg), and Corroder (MPA Group England), Turkey, Romania, Ukraine, Georgia, Russia, Azerbaijan, Turkmenistan, Kazakhstan, Iraq, Qatar, Kuwait, Oman, the Sudan and Algeria official licensors.
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5.Corrodere Hot Galvanizing
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Paint Square, “Coating Condition Surveys: An Overview”, Erişim Tarihi:30.08.2017