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APAC Inspections

APAC Inspections

Independent technical inspections are conducted before, during and after application.

Examples of Technical Inspection:

ISO: Preparation of steel substrates before application of paints and related products:

  1. SURFACE ROUGHNESS: (Comparative + Electronic Gauge)

ISO: Tests for the assessment of surface cleanliness:

  1. SOLUBLE SALT CONCENTRATION (Conductivity Test)
  2. RELATIVE HUMIDITY & DEWPOINT (Dewpoint Meter)
  3. DUST ASSESSMENT (Dust Tape Test Kit)

ISO: Paints and varnishes — Corrosion protection of steel structures by protective paint systems:

  1. DRY FILM THICKNESS (Coating Thickness Gauge)
  2. PINHOLE & POROSITY (Holiday Test)
  3. ADHESION (Pull Off Test)

Visual Inspection:

1. Surface Roughness

Test: Comparative + Electronic Gauge.

Reading: Visual and electronic surface roughness comparison.

ISO: ISO 8503-1 (Surface roughness characteristics of blast-cleaned steel substrates).

Surface comparators are used to compare freshly blasted profiles to pre-defined profiles. Standard comparators are available as either grit, shot or sand. Surface comparators provide four reference profile grades. Profiles are recorded in microns. The hole in the middle of some comparators enables clear visual comparisons with the reference profiles. Electronic gauges are also used.

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2. Soluble Salt Concentration

Test: Conductivity Test.

Reading: Visual and electronic surface roughness comparison.

ISO:  ISO 8502-6 (Extraction of soluble contaminants for analysis — The Bresle method).
        ISO 8502-9 (Field method for the conductometric determination of water-soluble salts).

It is essential that the level of contaminants on a surface is measured before the application of the coating. If the coating is applied to a contaminated surface, which is not properly prepared, it could fail prematurely resulting in costly re-coating and high maintenance costs.
A portable meter measures the conductivity of a single drop from a sample taken from a ‘test patch’. The conductivity is automatically converted to show the density of salts.

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3. Relative Humidity & Dew Point

Test: Dewpoint Meter.

Reading: Climatic Parameters.

ISO: ISO 8502-4 (Guidance on the estimation of the probability of condensation prior to paint application).

A Dewpoint Meter is designed to measure and record climate parameters to determine whether the conditions are suitable for painting including relative humidity; air temperature; surface temperature and dewpoint temperature.

4. Dust Assessment

Test: Dust Tape Test

Reading: Quantity and Size of dust particles.

ISO: ISO 8502-3 (Assessment of dust on steel surfaces prepared for painting).

Dust on blast cleaned surfaces can reduce coating adhesion, leading to premature coating failure and sub-standard coating finish.

Dust Tape Test kits allow assessment of the quantity and size of dust particles on surfaces prepared for painting.

Dust Assessment

5. Dry Film Thickness

Test: Coating Thickness Gauge

Reading: Coating thickness

ISO:ISO 19840 (Measurement of, and acceptance criteria for, the thickness of dry films on rough surfaces)

Dry Film Thickness is probably the most critical measurement in the coatings industry. It provides vital information
as to the expected life of the substrate and ensures compliance with many international standards.

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6. Pinhole & Porosity

Test: Holiday Test.

Reading: Porosity.

ISO: ISO 29601 (Assessment of porosity in a dry film).

Premature corrosion of a substrate usually happens due to a coating failure. A major cause is the presence of flaws in the finished coating, collectively referred to as porosity. The Holiday test is used to detect holes in a coating. The test involves checking of an electric circuit to see if current flows to complete the electrical circuit. The Holiday test detects the smallest coating flaws invisible to the naked eye.

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7. Adhesion

Test: Pull-Off Test.

Reading: Numerical value for adhesion strength.

ISO: ISO 16276-1  (Assessment of, and acceptance criteria for, the adhesion/cohesion (fracture strength) of a coating: Pull-off testing).

A test dolly is bonded to the coating using an adhesive. The adhesion tester houses a spring arrangement which applies a lift force to the dolly as the tension is increased. When the coating is pulled off the surface, an indicator on the scale shows the numerical value of adhesion strength. An inspection of the dolly face is required to determine success.

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