The coatings inspector is the one ultimately responsible for ensuring that the specified degree of surface cleanliness is actually achieved.

Coatings experts often say that surface preparation is the most important part of a coating system.

Effective surface preparation is of paramount importance to the success and longevity of a coating system.

Surface preparation affects the performance of the coating more than any other variable. Given that the proper coating system has been selected, if the surface preparation is poor, coating performance is usually going to be poor.

If surface preparation is good, then the coating applied over it is likely to perform well.

For you, the applicator, it is useful to know the reasons why surface preparation is so important, because knowing why can help you to do a better job.

Surface Preparation Is a Foundation

First, we can express the reason for the importance of surface preparation in a broad, general way, with the help of an analogy or comparison.

Surface preparation is to a coating system what a foundation is to a building. If a building has a poor foundation it can collapse altogether.

If a coating system has a poor foundation / surface preparation), it will fail faster than expected (say, after 5 years rather than 10 years); or it can fail catastrophically, within the first year of application.

Both reduced service life and catastrophic failure, great financial losses occur to a facility owner.

The contractor may be held responsible for these losses if the surface preparation work is found to be faulty.

Surface preparation creates a foundation in 2 important ways: mechanically, by providing an anchor for the coating (adhesion-surface area) ; and chemically, by allowing intimate contact of coating molecules with the steel surface (bonding).

An inspector is likely to examine in the inspection of a coatings project following.

Scrutinize accurately the specification to make firm

1  the standard against which the work is to be measured;

2  the required level of surface cleanliness;

3  the maximum allowable surface profile;

4  special tests that may be required in the contract.

Identify the area being tested and

1  ensure that it is correctly identified in the daily inspection report and

2  ensure that the daily inspection report matches with the progress chart.

Inspect the pre-surface preparation condition of the steel to ensure that the requirements of the specification will be achieved.

Prior to blast cleaning, confirm that:

1  the surfaces are free from oil and grease;

2  the abrasive to be used is suitable and that it is recorded in the daily inspection report;

3  sieve analysis has been carried out, if necessary;

4  the abrasive is free from contamination, especially in cases of shop preparation where recycled media are used.

Beyond the obvious requirement that the abrasive should produce a clean steel surface that is free from contamination, it also should provide an adequate surface profile, a working mix of particle sizes, and particles only within the grading required.

Information should be obtained from datasheets about chemical analysis, hardness, density, chloride content, and conductivity. Conformity of the product to national or international safety regulations is typically indicated as well.

Carry out inspection of the prepared surfaces as necessary and when requested by the coating contractor’s supervisory staff to ensure that:

Carry out, when necessary, special tests (e.g., soluble salt, rogue peaks, etc.) required by the specification.

1  Overwhelming the adverse of dirt; dust; grease; oil; rust; moisture; and, in some cases, mill scale.

2  Overwhelming the adverse of Non Visible chemical Contaminants

The most dangerous forms of Non Visible contaminants are soluble salts: chlorides and sulfates.

When chlorides and sulfates are painted over, they are hygroscopic and draw moisture to cause detachment, blistering, and enhanced corrosion of the steel substrate lying beneath .

Blistering caused by underfilm corrosion is a more gradual process, taking many months to appear, but the presence of conductive salts under the paint film and/or in corrosion products will greatly accelerate this.

It is prudent to examine for the presence of soluble salts with approved field test kits before paint application and then to apply further cleaning stages for salts purging, if they are present in negative amounts.

Certain projects conductivity/soluble salt contamination testing is mandatory.

The results of osmotic blistering salt contamination has a significant effect on coating performance and it is critical that monitoring of salt levels on the substrate is undertaken in Cargo, Water Ballast, Potable and Grey Water tanks .

The International Maritime Organisation “Performance Standard for Coatings (PSPC) for Dedicated Sea Water Ballast Tanks in All Types of Ships and Double-side Skin Spaces of Bulk Carriers” specifies a maximum allowable water soluble salt substrate contamination level of 50mg/m2 (5 micrograms/cm2) expressed as Sodium Chloride.

Adhesion is a primary function of paint.

Wet and dry adhesion of a coating system are two very different things with adhesion being significantly decreased in immersed conditions.

Contamination and adhesion, depend exclusively on the method used to prepare the substrate before coating application.

Surface defects unnoticed for normal service, can quickly result in coating failure when painting tanks.

Delamination on an artificial scribe after salt spray exposure should be considered as a one of a set of measurable factors representative of the corrosion protection performance of coatings.

It is absolutely necessary that for immersed environments the highest standard of preparation is achieved, this is the reason Sa 2 ½ blast, or equivalent, is normally required for such applications.

Record the results of the inspection, confirming that the areas inspected may be recognized from the reports.

Where remedial work is necessary, make sure that:

1  the areas are appropriately marked up so that the contractor’s supervisor can recognize them;

2  the supervisor and workers are aware of any reasons for rejecting the work and the requirements for further work;

3  the contractor’s supervisor is informed in writing of remedial work; and

4  the area under preparation is rechecked to make certain that it meets the requisite standards.

·Measure and record the surface profile using the appropriate standard method.

·Ensure that the prepared surface is coated within the maximum over-coating intervals. Over-coating interval related problems are more likely to occur with coatings which cure by cross linking, such as epoxies or polyurethanes.

·Inspect the steel prepared surfaces and ensure that the specified standards have been achieved prior paint application

When the specification calls for surface preparation by mechanical cleaning methods, in addition to the above inspection requirements, it will be necessary to confirm that:

1  excessive burnishing of the metal is avoided; Polishing of actual steel surfaces may also be a problem if brushing is carried out over zealously, because smooth polished surfaces can be detrimental to coating adhesion and

2  any visible peaks produced by power tool cleaning methods are removed. If this type of surface is painted without further preparation, the rough peaks can protrude through the coating and cause rash rusting and coating failure

The company should provide the coatings inspector with the most appropriate European standards relevant to the general activities in the surface preparation and painting process.

The Coatings Inspector job is to inspect the prepared surfaces, advise on whether the specified standards have been achieved, and then to accept or reject them as suitable for painting.

Following is a limited range of relevant standards:

SURFACE PREPARATION STANDARD BOOKS that are in common use in the shipbuilding and repair industry.

They are as follows:-

STANDARD ISO 8501 Corrosion Protection of Steel Structures by Painting

This standard is divided into 4 parts.

ISO 8501-1:2007 - Rust grades and preparation of uncoated steel substrates and steel substrates after overall removal of previous coatings.

ISO 8501-2:2001 - Preparation grades of previously coated steel substrates after localised removal of previous coatings.

ISO 8501-3:2007 - Preparation grades of welds, edges and other areas with surface imperfections.

ISO 8501-4:2006 - Initial surface conditions, preparation grades and flash rust grades in connection with high pressure water jetting.

• ISO 8502 series—Tests for the assessment of surface cleanliness.

Covers field methods for sampling moisture, dust, and chemical products and contaminants;

• ISO 8503 series—Surface characteristics of blast cleaned steel;

• ISO 8504 series—Methods for surface preparation;

ISO 1124-1127Abrasives Standards

• ISO 11124 series—Specification Metallic blast-cleaning abrasives;

• ISO 11125 series—Test methods for metallic blast-cleaning abrasives;

• ISO 11126 series— Specification Non Metallic blast-cleaning abrasives;

• ISO 11127 series—Test methods for non-metallic blast-cleaning abrasives; (Note that although some of these standards have been replaced, they may still be referenced in customer specifications, usually with the comment “or latest revision.”)

ISO 4628, Part 1Rating of Paint Defects

The ISO standard is called "Evaluation of Degradation of Paint Coatings—Designation of Intensity, Quantity and Size of Common Types of Defects. General Principles and Rating Schemes."

ISO 4628, Part 2Degree of blistering

ISO 4628, Part 3Degree of rusting

ISO 4628, Part 4Degree of cracking

ISO 4628, Part 5Degree of flaking

ISO 4628, Part 6Degree of chalking

Specific tests (i.e., adhesion pull-off ISO 4624 , cross-hatch ISO 8780-5 & ISO 787/16, paint film thickness ISO 2178 ,ISO 2808-6Aa & ISO 19840 and Measuring Dry Film Coating Thickness According to SSPC-PA2 for PSPC, holiday detection on painted surfaces ISO 2746, (etc.) are covered in ISO standards.

If specified in the customer’s specifications, these standards should be provided by the company when required.

The PSPC denotes to SSPC-PA2 when film thicknesses measurements are stated.
One important aspect of SSPC-PA2 is that it requires readings to be taken on the bare substrate, prior to any paint being applied, since surface varies from point to point as a result of blast-cleaning.
This methodology is designed to provide a consistent way of assessing coating thickness.
The readings are then corrected to allow for the profile / rough surface on the steel.

In addition to previously issued standards for solvent cleaning, hand and power-tool cleaning, abrasive blast cleaning, water-jetting, coating materials, paint and coating application, and related topics, there are new, revised, and recently issued documents for the following topics.

• Wet abrasive blast cleaning, industrial blast cleaning, and chemical stripping

• Newly manufactured, re-manufactured, and recycled metallic abrasives

• Surface preparation and coating of concrete

• Containment of debris generated during coating removal operations

• Sampling of environmental air, soil, and water during coating removal operations

• Application of thermal spray coatings (Metal Coatings)

• Shop, field, and maintenance painting of steel

In addition

• Primary Surface Preparation and Shop Primer Application

• Newbuildings

The International Maritime Organisation (IMO) Performance Standard for Protective Coatings (PSPC) for Dedicated Sea Water Ballast Tanks In All Types of Ships and Double-side Skin Spaces of Bulk Carriers

IACS have indicated that use of the standards will be mandatory under their Common Structural Rules.

Consequently the coating inspector needs to be familiar with these standards.

Environmental conditions for paint application

Although contracts are specific, the lack of documented quality control is sometimes terrifying.

Prior to the start of any project, there are a number of initial records or documents that you should have, or be able to refer to either at a central location or at the job site.

Equally important are the records that you create of the actual work progress and of the working conditions.

All fine points of coating application should be recorded clearly in the daily inspection reports, which should be submitted to the inspection company and customer weekly.

Precise and succinct reporting of all inspections is a major responsibility of a coatings inspector.

In addition to the technical phases of the project, information related to the work progress, project delays, the number of people working and equipment levels, and project paint materials should also be recorded as well.

Records can be kept in the format of a daily diary, or they can be kept on pre-printed forms, which might be preferable because they are organized with labelled spaces for all the kinds of information required. There are sample forms that could be used to record in-process data about work performed.

An inspector is likely to examine in a coatings project as part of the daily inspection report following:

At the beginning of a project, prepare appropriate tables or computer software by to track maintenance programs and painting projects so the progress of the work can be satisfactorily monitored.

Such tables or computer software should include in detail:

i) general progress in the preparation and painting programme , and

ii) daily progress with identification of the appropriate daily inspection reports.

Ensure that the daily inspection reports are correctly and filled in by the end of each working period.

At the end of the project, ensure that all tables, plans, the log book, specifications, etc., are returned to the office or the customer.

Attend all site meetings, called to plan or advance the progress of the works or to resolve a particular problem that has arisen. Take notes of the main points discussed.

Identify the areas being treated and

i) ensure that they are correctly identified in the daily inspection report;

ii) enter the area on progress chart; and

iii) ensure that the daily inspection report is tied in with the progress chart.

Re-check that the areas/items under treatment which have been identified can also be identified by another inspector or person coming onto the site at a later date.

Record in simple terms

i) the surface preparation carried out at all areas, and

ii) the results of such surface preparation.

Record the contractor’s the number of people working and equipment levels and whether the equipment was operating properly.

Record equipment breakdowns, malfunctions and material shortages and include the action taken by the contractor to overcome these problems.

Record time lost and an analysis of the causes (e.g., weather; breakdowns and malfunctions; lack of equipment, materials, staffing; etc.).

The types of information typically recorded as part of a daily inspection report are:

·weather conditions,

·substrate conditions,

·surface preparation,

·equipment

·the number of people working,

·coating materials, and coating application.

It should never be assumed that the correct coating materials for a project have been delivered to the work site or the paint shop.

·Ensure that the paints provided to the site or shops match with the requirements of the specification and that all paints to be used on a surface are supplied by one Paint manufacturer.

·Ensure that the paint is the correct type for the application method being used by the contractor.

·Record the batch number, and date of manufacture of the paints.

·Examine the storage conditions and make sure that they are in line with the requirements of the specification and the manufacturer’s product data sheets.

·Make sure that there are sufficient materials in storage for the completion of the contract or that there are sufficient materials earmarked for the contract in a central storage area.

·Be present to observe the subject of the coatings from the storage area at the start of the work period.

The success or failure of a paint coating is often determined before a drop has even been applied.

The apparently simple tasks of mixing and thinning are often found to be the root cause of many coating failures.

The primary goal of mixing paint is obviously to provide a homogeneous liquid. Serious problems result when this is not achieved.

Ensure that:

1) all coatings are thoroughly stirred by mechanical means with an electric or air powered stirrer so that there is no residue on the bottom of the container;

2) two-pack (multi-component) materials are handled as noted below.

Two-pack (multi-component) coating materials require special attention.

Two-component paint materials, such as most epoxies and urethanes, are normally supplied by the manufacturer in two containers of correct, pre-measured proportions. It is important when mixing that complete rather than partial kits are used to avoid creating the wrong volume of one component with relation to another.

Best results are generally achieved by mixing each component separately before they are mixed together, but once again, the application data sheet should be the first port of call before mixing.

It is often important that the two components be combined in a particular manner. The data sheet may detail whether Component A is to be added to B or vice versa. It is always advisable to add and mix the two components of a paint gradually to achieve an homogeneous mixture and to avoid areas of high and low concentrations.

1)  Ensure that any induction time is strictly followed.

Some two-component materials, such as epoxies, require a specific induction or “sweat-in” time, generally about 15-30 minutes. This time allows the two components to start reacting chemically before the paint is applied.

2)  Ensure that no material is used after the expiration of its pot life.

Pot life is the length of time after mixing during which two-component paints can be successfully applied. After too much time has passed, the paint reacts chemically to a point where it should no longer be used.

3)  Thinning

Occasionally, it is necessary to decrease the viscosity of a paint by adding a thinner so it can be applied effectively. When the need for thinner arises, it is very important that you follow the manufacturer’s recommendations in the data sheet exactly.

Just enough thinner should be added to give the desired application viscosity. Over-thinning will produce a runny material and cause problems achieving the required film thickness.

·Ensure that any additions to the coatings are strictly in accordance with the manufacturer’s recommendations.

·Ensure that all necessary sampling procedures and testing have been carried out prior to the start of the work.

·Ensure that all necessary material sampling and testing procedures required by the specification during the course of the work are completed satisfactorily.

Paint Application

The durability of paint material depends on:

•the quality of its manufacture as well as

•surface cleanliness,

•uniformity of application, and

•conditions during application, curing, and service.

Inspect that the coating is applied only to surfaces suitably prepared to the specified standard of cleanliness.

1) Confirm that the environmental conditions are acceptable for the application of the coatings.

2) Confirm that the particular coating being applied does not have any special limitations on its application.

3) Confirm that the surface to which the coating is being applied is free from moisture, oil, grease, dust, grit , corrosion products, debris , or other contamination that would advesrsely affect its performance.

4) Confirm that the coating is applied within the minimum and maximum over-coating intervals.

·Confirm whether a stripe coat has been specified and applied correctly.

·Confirm that each coat of paint is uniformly applied and free from runs, sags, etc.

·Ensure that any areas of defective coating are marked for remedial attention and that the contractor’s supervisor is aware of the areas marked as well as the repairs required.

·Re-check areas previously marked as defective to ensure that remedial work has been done.

·Inspect predominantly the areas that are less accessible to ensure complete coverage of all surfaces.

·Pay particular attention to areas around edges, weld seams, cut-outs and scallops throughout, difficult corners on angle beams, areas where water might accumulate, and areas that are difficult to see without an inspection mirror.

·Measure the wet film thickness of the coating immediately after application to ensure that it is in accordance with the recommendations of the data sheet and that the dry film to be obtained will meet the requirements of the specification.

·Measure the dry film thickness to ensure that it meets the requirements of the specification.

·Ensure that the dry film thickness measurements are in agreement with the expected value calculated from the wet film thickness measurements.

In the event of a serious discrepancy between the dry film thickness measurement and the expected measurement based on the wet film thickness reading, the coating material should be checked in order to ensure that only authorised additions were made.

Complete any special tests (e.g., adhesion DIN EN ISO NF 6860 & DIN EN ISO NF 2409, cure ASTM D5402 & ASTM D4752 , salt ISO 8502-6 & ISO 8502-9 Bresle - salt contamination test by conductivity measurements , pinhole/ holiday ISO 2746 & BS EN ISO 829 A , etc.) that may be prerequisite by the specification.

·Confirm that the completed work is uniform in colour.

·Confirm that the equipment is adjusted and maintained as recommended by the equipment and material manufacturers

·Confirm that the handling of items during and after painting is carried out in such a way that the coatings are not damaged.

·Confirm that the handling of items are not moved before the coating is sufficiently hard to withstand handling damage.

·When damage does occur, ensure that remedial work is carried out properly and to the satisfaction of the specification requirements.

The Paint Inspector has a responsibility to organize his time in order to be available when requested by the Shipyard Quality Control or Contractor for the purpose of inspecting work that has been performed.

Many contractors have implemented elaborate QA/QC procedures and consider this to be adequate. But are the procedures being followed? Are the persons in charge of quality responsible and reliable? Do they have sufficient authority? Are they unbiased?

Experience tells us that the answers to the questions above are often “No.”

Although contracts are specific, the lack of documented quality control is sometimes terrifying.

Basically, a coatings inspector is part of a group that includes the customer, coatings manufacturer, and contractor.

All members of the group share the common purpose of preventing corrosion by means of adequate preparation and application of coatings materials to industrial and marine structures.

Implementation of basic coating quality control procedures, could exclude many potential problems that can appear during a painting project and could effect in both direct and indirect benefits.

•Direct benefits relate essentially to savings in effort, time, and paint material costs for rectification of non-compliant work.

•Indirect benefits relate principally to repeat business by reliably reassuring the customer, by external quality control procedures, that their requests are being accomplished.

Following may be used as the basis for improving quality control procedures or for communicating customer requirements for external inspection services.

The subjects to be dealt are:

1)  Surface preparation,

2)  Environmental conditions,

3)  Paint coatings,

4)  Paint application,

5)  Daily inspection reports, and

6)  Inspection Equipment & instruments.

The primary responsibility of a coatings inspector is to ensure that all work is carried out in accordance with the customer’s written specifications and the material manufacturer’s recommendations, and that it is accurately reported.

This primary responsibility, leads to successive responsibilities, which are established through watchful review of the objectives of the specification and the inspection procedures used.

Specifications and standards communicate a customer’s requirements, but different understanding of these requirements or non-compliance with them can lead in failure to succeed the customer’s expectations or, premature failure of the coating system.

To adequately achieve their obligations, inspectors must have documentation applicable to the specific job.

Whether this documentation may comprises of customer or organization’s specification describing,

ISO standards of quality of skill or sequences of informal statements, it should unmistakably communicate the requirements of the customer and the responsibilities of the coating contractor.

Following are topics and guidelines an inspector might consider regarding the specification for a coatings job.

The main responsibility of an inspector is to confirm that all work is carried out in line with

1.the customer’s specification and

2.the paint maker’s technical procedures and recommendations, and

3.that it is precisely recorded in daily inspection reports.

Prior to the start , the inspector should confirm that he has available

1  the customer’s specification;

2  the work scope of the project,

3  manufacturer’s product data sheets and health and safety data sheets;

4  the application contractor assessment report related health hazards from harmful substances being used; and

5  Reference standards.

The specification, which forms part of the legal agreement between the customer and the coating contractor, will be the main document for supervising the works.

In the event of a dispute between the customer and the contractor, the specification delivers the source against which the work actually performed will be judged.

The information recorded by the inspector in the daily inspection reports and other reports that may be required will be of particular value in the case of disputes or potential claims.

All changes in Specification are necessary for the technical department of customer and inspector on site to confirm in writing.

The inspector must take into consideration:

1)  the customer’s requirements,

2)  prospective critical areas of the project, and

3)  the obligation of safeguarding that no unnecessary delays of the project are occurring.

By adopting a rationalized approach to the inspection of the hull structure and a methodology on:

-what to inspect,

-when to inspect,

-where to inspect