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Inspection and controlInspection and control

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What is QA - QC ?What is QA - QC ?

QA = Quality Assurance

(A documented management system)

QC = Quality Control

(Inspection and testing routines)

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The tasks of the paint inspectorThe tasks of the paint inspector

• To ensure that the requirements of the coating specification are met.

• Verify the quality of work carried out by the contractor/yard.

• Prepare written records of the standard of work - Approval (Satisfactory ? / Conforming ?) - Non-conformance

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An inspector’s work includes:An inspector’s work includes:

• Be capable of interpreting

the specifications

• Understand the objective

of the inspection

• Inspect all structures to be painted

• Ensure that all specified requirements are met

• Document the results from the inspections

• In case of non-conformance: Issue written reports

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Daily logsDaily logs

• Steel temperature

• Air temperature

• % Relative Humidity

• Dew point

• Object no. and name

• Exact specification

• Pre-treatment, specified and actually conducted.

• Film thickness (to be measured also at spot repair)

• Area, m²

• Product name, place of production and batch no.

• Name of relevant persons

• What was discussed

• Non conformance report (remember signatures)

• Other comments

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• All paints that will be used

• All relevant inspection

methods and inspection tools

• Relevant standards

• Relevant TDS and MSDS

• Methods involved in cleaning, pre-treatment and paint application

• The equipment used for pre-treatment and application: Benefits and limitations

An inspector needs to knowAn inspector needs to know

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What needs to be inspected ?What needs to be inspected ?

• Shop-priming of the steel• The steel work (Pre-blasting preparation)• Cleaning and surface preparation prior

to paint application • Application of paint • The applied paint film and its

curing/drying conditions.

If relevant, the following stages of the production need to be inspected

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Inspection toolsInspection tools

Cd-4932-80

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Inspection tools. Inspection tools. Mirror and flash lightMirror and flash light

• Visual inspection

• Important tools for inspecting areas difficult to access

• For inspection in confined spaces: Use Ex approved equipment

Cd-4932-83

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Using Inspection tools.Using Inspection tools.Mirror and flash lightMirror and flash light

• Visual inspection

• Important tools to be able to inspect areas difficult to access

Cd-4932-84

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Inspection of steel work Inspection of steel work (Pre-blasting preparation)(Pre-blasting preparation)

Rounding of sharp edges. Smoothing of rough welding seams. Removal / grinding of weld spatter

and beads. Cracks and pittings. Surface faults like laminates etc. ISO 12944 - 3 , or ISO 8501 - 3

The following items need to be inspected during construction

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0589-5

C3

0589-6

Pre-blasting preparationPre-blasting preparation

• Rounding of edges

• Removing of weld spatters etc.

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Inspection of cleaning and surface Inspection of cleaning and surface preparation prior to application preparation prior to application

Cleanliness (salt, oil, grease and dust/dirt) Evaluation of present condition (rust grade) Surface preparation (e.g. blast cleaning) Cleanliness of prepared surface

(salts, oil, grease, dust and dirt) Climatic conditions

(temperature, relative humidity etc.)

If relevant, the following conditionsmust be inspected / verified

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Relevant standards for assessing Relevant standards for assessing surfaces prior to paint applicationsurfaces prior to paint application

Standard AreaISO 8501 Visual assessments of surface cleanliness.

ISO 8502 Tests for the assessment of surface cleanliness.

ISO 8503 Surface roughness characteristics of blast-cleaned steel substrates.

ISO 8504 Surface preparation methods.

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ISO 8501 - 1 ISO 8501 - 1

Surface preparationSurface preparation

• Visual assessment of surface cleanliness after blast cleaning, hand or power tool cleaning or flame cleaning

• Rust grades and preparation grades of uncoated steel

• Photographic examples of steel when blast cleaned with different abrasives

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ISO 8501 - 1

Rust grade A, B, C and D

Surface preparationSurface preparation

Standard for deciding rust grades Standard for deciding rust grades

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Cd-0631-59 Cd-0631-58

Cd-0631-57 Cd-0631-56

ISO 8501-1 ISO 8501-1 Evaluation of rust grades Evaluation of rust grades

Rust grade A

Rust grade D

Rust grade B

Rust grade C

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Sa: Blast cleaning (grades 1, 2, 2 ½ and 3)

St.: Hand and power tool cleaning

(grades 2 and 3)

Fl: Flame cleaning (one grade)

ISO 8501 - 1ISO 8501 - 1Standard for deciding preparation gradesStandard for deciding preparation grades

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ISO 8501 - 2ISO 8501 - 2

Surface preparation Surface preparation

As for ISO 8501-1, but:

For steel where previous coating has been removed locally, not completely.

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PSa : Localised blast cleaning

(grades 2, 2 ½ and 3)

PSt : Localised hand and power tool cleaning

(grades 2 and 3)

PMa : Localised machine abrading (one grade)

ISO 8501 - 2 ISO 8501 - 2 Standard for deciding preparation gradesStandard for deciding preparation grades

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ISO 8502 ISO 8502 Assessment of surface cleanlinessAssessment of surface cleanliness (1 of 2)(1 of 2)

Part 1 Field test for soluble iron corrosion products

Part 2 Laboratory determination of chloride on cleaned surfaces.

Part 3 Assessment of dust on steel surfaces prepared for painting (pressure- sensitive tape method)

Part 4 Guidance on the estimation of the probability of condensation prior to paint application.

Part 5 Measurement of chloride on steel surfaces prepared for painting. Ion detector tube method.

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ISO 8502 ISO 8502 Assessment of surface cleanlinessAssessment of surface cleanliness (2 of 2)(2 of 2)

Part 6 Extraction of soluble contaminants for analysis.

The Bresle method.

Part 9 Conductometric measurements of soluble salts

Part 7, 8 and 10 are not prepared

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Filter paper impregnated with Potassium Hexacyanoferrate

Blast cleaned steel

Blue spots

ISO 8502-1. Annex. 3 ISO 8502-1. Annex. 3 Water soluble salts on blast cleaned steel Water soluble salts on blast cleaned steel

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Approved

Not approved

Tape Blast cleaned steel

ISO 8502-3ISO 8502-3Assessment of dustAssessment of dust

Steel Surfaces Prepared for Painting.

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1. Quantity ratings 1, 2, 3, 4 and 5 corresponding to pictorial references

2. Dust size classes 0, 1, 2, 3, 4 and 5

ISO 8502 - 3ISO 8502 - 3Assessment of dustAssessment of dust

Assessment of dust on steel surface prepared for painting

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ISO 8502 - 3ISO 8502 - 3Assessment of dustAssessment of dust

Assessment of dust on steel surface prepared for painting

1. Quantity ratings 1, 2, 3, 4 and 5 corresponding to pictorial references2. Dust size classes: 0, 1, 2, 3, 4 and 5

Inspection / Dust_control1

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ISO 8502-4 ISO 8502-4 Estimating probability of condensation Estimating probability of condensation

Wet cotton

Psychometer Thermometer

Guidance on estimating probability of condensation prior to paint application

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1. Air temperature

2. % Relative humidity

3. Steel temperature

4. Dew point

ISO 8502 - 4ISO 8502 - 4HumidityHumidity

Guidance on the estimation of the probability of condensation prior to paint application

Steel temperature min. 3 oC above the dew point

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ISO 8502-4ISO 8502-4Measuring the relative humidityMeasuring the relative humidity

• Photo: Sling psychrometer for measuring:

- Dry temperature

- Wet temperature

• Measure the temperature in the vicinity.

• Calculate the relative humidity

• Use together with dew point calculator

Cd-4932-88

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Contact thermometerContact thermometer

• Electronic instrument for measuring the steel temperature

• Other types of thermometres are also available. E.g. magnetic thermometers

Cd-4932-87

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ISO 8502-4ISO 8502-4Dew point calculatorDew point calculator

• For calculation of dew point

• To be used together with surface temperature thermometer and sling psychrometer.

• Use this frequently during pre-treatment, application and drying of the paint.

• Recommendation: Every 6 hours and when weather conditions are changing

Cd-4932-89

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Surface temperature of the

structure must be minimum

3 °C above the dew point

of the surrounding atmosphere

Atmospheric conditions.Atmospheric conditions.Requirement during blasting and paintingRequirement during blasting and painting

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B-24/2-4

4847-693

ISO 8502 - 4ISO 8502 - 4

Estimating probability of condensationEstimating probability of condensation

• Cold liquid inside hull and warm air outside causes condensation

• See how frames inside keeps the cold longer

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Relative humidity, RHRelative humidity, RH

% R.H.:

% water vapour in the air as percentage of the total amount water vapour the air can contain at the same temperature.

Example

Air at 20 oC can contain 17.31 g. water/m3, but contains 15 g/m3. What is the R.H. ?

R.H. = = 86.65 %15 x 100

17.31

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• Ambient temperature will influence:

– shelf life

– pot life

– viscosity/sprayability

– steel temperature

• Steel temperature will affect:

– speed of cure

– degree of cure

– recoating interval

– service life of the coating

Ambient temperature andAmbient temperature andsteel temperaturesteel temperature

Is the temperatures important ? YES !

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Determination of water soluble saltsDetermination of water soluble salts

• Conductivity

• Titration

• Colour-reactions

Other Methods:

• SCM 400 Salt Contamination Meter

The most frequently used methods are:

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ISO 8502 - 6 ISO 8502 - 6

The Bresle method.The Bresle method.

A method for extraction of

soluble contaminants on

steel substrates for analysis:

The Bresle method

This is a quantitative test

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ISO 8502-6ISO 8502-6Salt test equipment - Bresle testSalt test equipment - Bresle test

• ISO 8502 - 9 (Conductivity)

• Equipment for measuring content of water soluble salt on substrate

• Bresle method Cd-4932-96

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ISO 8502 - 9 ISO 8502 - 9 Conductometric measurement of soluble salts.Conductometric measurement of soluble salts.

Field method for measuring soluble salts

by conductivity ( S) of solutions

containing water soluble salts

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How to measure the How to measure the salt level on a surfacesalt level on a surface

• Water soluble salts will be removed by water jetting

• Here: The substrate is cleaned at a pressure of 2000 bar

• Salt level is measured by the Bresle method

• Dissolve the salt inside the frame of the patch

• Measure the conductivity of the water sample

Pre-treatment: Wj_saltlevel1

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Calculation of salt level Calculation of salt level on the substrateon the substrate

(L(L22 - L - L11) x 6 = mg salt per m) x 6 = mg salt per m22

L2 = µS after cleaning

L1 = µS before cleaning

Water sample, ml.: 10 15 20 50

Constant in formula: 4 6 8 20

Formula:

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Instruments for measuring Instruments for measuring surface roughnesssurface roughness

• Stylus instruments

• Elcometer Mod. 123

• Testex Press-O-film

• Microscope

• Comparator

–Rugotest No. 3

–ISO 8503 etc.

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ISO 8503 ISO 8503 Surface roughness Surface roughness

• Example of a reference comparator

• Surface profile comparator comprising four segments.

• Grit (G)

• Shot (S)

• Check if the profile is according to specification and the paint manufacturer’s recommendation

Cd-4932-86

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ISO 8503 - 1ISO 8503 - 1

Limits of profile gradesLimits of profile grades

a) Comparators for steel. Blast-cleaned with grit abrasives

Fine (G) Profiles equal to segment 1 and up to,but excluding segment 2Profiles equal to segment 2 and up to, but excluding segment 3Profiles equal to segment 3 and up to,but excluding segment 4

Medium (G)

Coarse (G)

b) Comparators for steel. Blast-cleaned with shot abrasives

Fine (S)

Medium (S)

Coarse (S)

Profiles equal to segment 1 and up to,but excluding segment 2Profiles equal to segment 2 and up to, but excluding segment 3Profiles equal to segment 3 and up to,but excluding segment 4

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Contamination of abrasivesContamination of abrasives

• Water

• Oil and grease

• Chlorides

• Sulphates

The abrasives can be contaminated with

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• According to ASTM D 4940

• Mix 300 ml of abrasive and 300 ml water

• Stir for 1 min. let stand for 8 min., stir again for 1 min.

Oil content (AB-1)

No presence of oil, either on top or as an emulsion after 30 min.

Oil content (AB-1)

No presence of oil, either on top or as an emulsion after 30 min.

How to check the abrasivesHow to check the abrasives

Conductivity (AB-1)

Fill the liquid for test and measure the conductivity.

Max 25 mS/m

Conductivity (AB-1)

Fill the liquid for test and measure the conductivity.

Max 25 mS/m

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Inspection during applicationInspection during application

Record name of coating and batch no. Ensure proper mixing of 2-pack paints Ensure use of the correct thinner Measuring the wet film thickness (WFT) Number of coats as given in the specification Cleanliness between coats (salts, dust, oil etc.) Drying time / recoating intervals Control of equipment: Pressure, nozzle etc. Climatic conditions (Ventilation, Air and steel

temperature and the relative humidity)

The following must be verified, inspected or tested:

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Information to be found from the Information to be found from the technical data sheet, TDStechnical data sheet, TDS

• Product description

– Generic type etc.

• Recommended use

– Where to use the product

• Technical information

– Solids by volume, WFT, DFT

• Application data

– Methods, mixing, potlife

• Surface preparation

– Different methods given

• Conditions during application

• Drying and overcoating time at different temperatures

• Typical recommended system

• Storage

• Handling

• Packing control

• Health and safety

– Details in MSDS

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Wet paint

Steel

ISO 2808 - 97 Method No.1 ISO 2808 - 97 Method No.1 Wet film measuring combWet film measuring comb

Microns250 225 200 175 150 125 100 75 50 25

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Inspection after applicationInspection after application

Climatic conditions (Ventilation,

Temperature and humidity) Curing / drying of the film Dry film thickness (DFT) Adhesion Holiday detection (if required)

After application the following must be checked

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• Electromagnetic instruments

• Calibration on a smooth steel surface min. 1,2 mm thick

• For DFT measurement, not less than 25 and preferably above 50 microns

• Number of readings, as a guide:

– 1 reference area: At least 3 readings evenly

– 2 reference areas for every square meter for flat plates

– 4 reference areas for every length for a web

– 2 reference areas every metre length for a flange

– 2 reference areas every metre length for a pipe

ISO 2808 - 97 ISO 2808 - 97

Determination of film thicknessDetermination of film thickness

Method No. 10 - On blast cleaned steel substrates

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ISO 2808 - Magnetic and electromagnetic ISO 2808 - Magnetic and electromagnetic Dry film thickness gaugesDry film thickness gauges

• Dry film thickness gauge

• Calibrate on smooth surface to zero and to thickness similar to be measured

• Check with your calibration foil frequently

• Plastic material foils wear easily. Replace frequently.

• No internal memory in gauge

Inspection \ Dryfilmthickness1

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Glove RagMEK

Rubbing 50 x

No Zinc on the Rag:CuredApproved

ASTM D 4752-87 ASTM D 4752-87 Curing test of Zinc - ethylsilicate with MEK. Curing test of Zinc - ethylsilicate with MEK.

A lot of Zinc on Rag:Not curedFurther curing / Reblasting

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Glove

Rag

MEK

ASTM D 4752-87 ASTM D 4752-87 Curing test of Zinc - ethylsilicate with MEK. Curing test of Zinc - ethylsilicate with MEK.

Inspection / Zincsilicate_curing1

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ISO 2409 ISO 2409

Cross-cut test Cross-cut test Cutting tool

Single bladed knife

or

Multi-blade cutting tool with 6 cutting

edges spaced 1 mm or 2 mm apart

Spacing of cuts

0 - 60 microns: 1 mm spacing, hard substrates

0 - 60 microns: 2 mm spacing, soft substrates

60 - 120 microns: 3 mm spacing, hard/soft substrates

121 - 250 microns: 3 mm spacing, hard/soft substrates

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ISO 2409ISO 2409Cross cut adhesion testCross cut adhesion test

• Cross cut adhesion test

• Cut vertical and horizontal lines to form a grid

• Apply a strong tape

• Pull off the tape

• Evaluate according to the standard

Inspection / Adhesion_crosscut1

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ISO 2409ISO 2409Classification of Cross-cut testClassification of Cross-cut test

Classi-fication

Description Appearance of surface Six parallel cuts

0 Completely smooth: none of the squares detached

1 Small flakes at the Intersections. Area affected 5 %

2 Flaked along the edges and/or at theIntersections. Area affected: 5-15%

3Flaked along the edges, wholly in large ribbons, and/or partly or wholly on different parts of the squares. Area affected: 15-35%

4Flaked along the edges in large ribbons and/orsome squares have detached partly or wholly. Area affected: 35-65%

5 Any degree of flaking that cannot even be classified by 4.

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Instruments:

• Elcometer Adhesion Tester

• Saeberg Adhesion Tester (pneumatic)

• Hate Adhesion Tester (hydraulic)

• PAT

ISO 4624ISO 4624

Pull-off test for adhesionPull-off test for adhesion

Failure:Adhesion failure: Between coats or between or substrate and 1st coatCohesion failure: Inside a coat

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ISO 4624ISO 4624

Pull-off test for adhesionPull-off test for adhesion

Procedure:

• Test dollies glued onto the coating

• Adhesive: Cyano-acrylate or solvent free epoxy

• Remove adhesive and coating around the dollies

• Pull off test-dollies vertical to the surface

• Read adhesion value and report the type of fracture

Fractures:• Adhesion failure - fracture between coats or substrate and 1. coat

• Cohesion failure - fracture within a coat

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ISO 4624ISO 4624Pull-off dollies glued to the structurePull-off dollies glued to the structure

• Pull off adhesion test

• Dollies are glued to the structure with a strong glue

• Prior to pull-off:

Cut around the dolly, through the paint film and down to the substrate material

Cd-4932-102

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ISO 4624ISO 4624Pull-off testing of paint on a structurePull-off testing of paint on a structure

• Pull off adhesion test.

• Destructive test method

• Here, connecting of the device for pulling off the dollies

• Read and note the value

• Several types of instruments are available

Cd-4932-101

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ISO 4624ISO 4624Area after pull-off testingArea after pull-off testing

• Pull off adhesion test

• The adhesiveadhesive failure - fracture between coats - or between coating and substrate must be evaluated

• Note adhesion failure, %

• The cohesivecohesive failure - fracture within the coating- must be evaluated.

• Note cohesion failure, %

• Also: Note glue failure, %

Cd-4932-103

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ISO 4624ISO 4624Pull-off dollies glued to the structurePull-off dollies glued to the structure

• Pull off adhesion test

• Dollies are glued to the structure with a strong glue

• Prior to pull-off:

Cut around the dolly, through the paint film and down to the substrate material

• Record the pull-off value

• Evaluate the failure

Inspection / Adhesion_pulloff1

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ASTM G 62 - 85 Method A ASTM G 62 - 85 Method A

Pinhole detection. Pinhole detection. Low Low voltage.voltage.

• Low voltage: < 75 V DC

• To detect pinholes, voids or metal particles to be in the range of 25-250 microns.

• Effective for paint films up to a DFT of 500 microns if a wetting agent is used in the water.

• This is a non-destructive test.

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ASTM G-62-85, method AASTM G-62-85, method ALow voltage pinhole detectorLow voltage pinhole detector

• Detecting pinholes, voids or metal particles in paint film up to 250 microns

• Non destructive test method

• Will only detect defects down to bare metal

• The sponge must be wetted

• Do not use excessive waterInspection / Pore_detection1

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ASTM G 62 Method B ASTM G 62 Method B

Holiday detection. Holiday detection. HighHigh voltage. voltage.

High voltage: 900 - 20.000 V

Used to detect pinholes, voids andareas with thin paint films

This is a destructive test.

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ASTM G 62 Method B ASTM G 62 Method B

Holiday detection. Holiday detection. HighHigh voltage. voltage.

Inspection / Holiday_detection1

• High voltage: 900 - 20.000 V

• Used to detect pinholes, voids and

• areas with thin paint films

• This is a destructive test.

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ISO 12944ISO 12944 General standard for corrosion protection:General standard for corrosion protection:

Part 1 General introduction.

Part 2 Classification of environments.

Part 3 Design considerations.

Part 4 Types of surface and surface preparation.

Part 5 Protective paint systems.

Part 6 Laboratory performance test methods.

Part 7 Execution and supervision of paint work.

Part 8 Development of specifications for new work and maintenance.

Paints and varnishes - Corrosion protection of steel structures by protective paints systems.