Why inspection needs its own standards
Most coating failures are built in not when the material is chosen but during the work: the paint was applied over a dusty or salt-contaminated surface, during condensation, below the specified thickness or without stripe-coating the edges. To catch such errors before acceptance, every parameter has its own measurement method and its own standard, and the acceptance criteria are written into the specification and the inspection plan in advance. Below is what is checked in the corrosion protection of steel and concrete, to which documents of the different systems, and how the results are recorded. How we organise inspection on site is described on the coating inspection and testing and quality control pages.
What is measured and to which standards
| Parameter | ISO | ASTM, AMPP | GOST and Uzbek codes |
|---|---|---|---|
| Application conditions: air and surface temperature, humidity, dew point | ISO 8502-4 | ASTM E337 (humidity by psychrometer) | QR 04.01-23 — minimum application temperatures |
| Steel cleanliness grade | ISO 8501-1 … 8501-4 | SSPC-SP and NACE, SSPC-VIS reference photographs | GOST 9.402-2004, GOST R ISO 8501-1-2014 |
| Residual dust | ISO 8502-3 | — | — |
| Water-soluble salts on the surface | ISO 8502-6, ISO 8502-9; chloride — ISO 8502-2, ISO 8502-5 | — | — |
| Abrasive and compressed air | ISO 11124, ISO 11126 | ASTM D4940, ASTM D4285 | GOST 9.010-80 |
| Surface profile | ISO 8503-1 … 8503-5 | ASTM D4417 | — |
| Wet film thickness | ISO 2808 | ASTM D4414 | GOST 31993-2024 |
| Dry film thickness | ISO 2808, ISO 19840, ISO 2178, ISO 2360 | SSPC-PA 2, ASTM D7091; on concrete — ASTM D6132 | GOST 31993-2024, GOST 35271-2025 |
| Adhesion | ISO 4624, ISO 16276-1, ISO 2409, ISO 16276-2 | ASTM D4541; on concrete — ASTM D7234; ASTM D3359 | GOST 32299-2025, GOST 31149-2014, GOST 32702.2-2014, GOST 15140-2026; criteria — ShNK 2.03.11-24 |
| Continuity | ISO 29601 | ASTM D5162, NACE SP0188; on concrete — ASTM D4787 | checked on acceptance under QR 04.01-23 |
| Cure | — | ASTM D4752 (ethyl silicate zinc-rich primers), ASTM D5402 | — |
| Appearance and defects | ISO 4628 | ASTM D610, ASTM D714 | GOST 9.407-2015 |
| Concrete before coating | — | SSPC-SP 13/NACE No. 6, ASTM D4258, ASTM D4259, ASTM D4263, ASTM F2170 | — |
The table gives designations without the year. Current editions and recent replacements are listed on the pages on ISO, US and Russian standards.
How acceptance criteria are set
A test method standard answers the question “how to measure”, but not always “how much is enough”. The numbers come from three sources:
- Codes. In Uzbekistan, ShNK 2.03.11-24, for example, sets adhesion requirements for paint coatings on steel structures: up to 250 µm — no more than 2 points by cross-cut; for thicker coatings — no more than 1 point by X-cut or at least 4 MPa by pull-off.
- Acceptance standards. ISO 19840 and GOST 35271-2025 set the sampling plan and the rules for assessing thickness on rough steel, ISO 16276-1 and ISO 16276-2 do the same for adhesion, and in American practice SSPC-PA 2 sets the frequency of thickness measurements and the thickness restriction levels. ISO 16276-1 applies only if the required value and the type and manufacturer of the instrument are specified in advance: results from different pull-off instruments are not comparable.
- Specification and data sheet. The nominal thickness of the coats, the permissible limits for salts and dust, the surface profile, the voltage for continuity testing and the application conditions are set by the design, the client’s specification and the material manufacturer’s documents.
If a criterion is not written down before work starts, a dispute at acceptance is almost inevitable: the contractor and the client will measure with different instruments and calculate by different rules.
Inspector qualification
| Certification scheme | Operated by | Levels |
|---|---|---|
| Coatings Inspector Program (CIP) | AMPP | Basic Coatings Inspector (CIP Level 1), Certified Coatings Inspector (CIP Level 2), Senior Certified Coatings Inspector (CIP Level 3) |
| FROSIO | Norwegian certification body for surface treatment and insulation inspectors | Inspector Level I (candidate), Level II, Level III |
| Protective Coating Inspector | Institute of Corrosion (ICorr), United Kingdom | Level 1, Level 2, Level 3 |
| BGAS-CSWIP Painting Inspector | TWI Certification Ltd | Grade 2 and Grade 1 (highest) |
Which scheme is needed on a facility is decided by the client — the requirement is usually written into the specification. According to AMPP, its programme will eventually take the place of the former NACE CIP and SSPC PCI programmes in standards and requirements. ISO is developing a separate standard on the competency of coating inspectors, ISO 24959; as of October 2026 it is a draft on which voting has closed. General guidance for painting inspectors on metal substrates is given in ASTM D3276-21, and the execution and supervision of paint work in ISO 12944-7. In American practice, the qualification of painting contractors is confirmed by the AMPP QP 1 and QP 3 programmes, and NORSOK M-501:2022 specifically clarifies the qualification requirements for paint shops and operators.
Inspection records
- Inspection and test plan (ITP) — checks by stage: what, by which method and to which standard, how often, against which criterion and by whom; points after which work does not continue without acceptance (hold), with the client present (witness) and with document review (review). How we prepare it is described on the painting specifications page.
- Daily reports — climate and dew point over time, surface preparation, material batches, wet and dry film thicknesses, deviations and the action taken.
- Log and reports under QR 04.01-23 — in Uzbekistan, the regulation requires a corrosion protection work log, reports on intermediate work and a protective coating acceptance report.
- Reference areas — ISO 12944-8 provides for them to assess the quality of the work and the performance of the system in service.
- Final dossier — measurement records, material documents, acceptance reports, the list of non-conformities and the records of their close-out.
Common inspection mistakes
- The thickness gauge has not been checked and adjusted for a rough surface, so the thickness is systematically over- or under-stated.
- The specification says “pull-off adhesion” but gives neither the instrument nor the required value — there is nothing to compare the result with.
- The surface was assessed only visually: salts and dust invisible to the eye were not checked.
- Acceptance on the average value without a sampling plan — thin spots on edges and at connections go unnoticed.
- Continuity was not checked on immersion coatings and chemical-resistant linings, although a single pore can become the starting point of under-film corrosion.
Need an inspection plan for your specification or independent coating inspection? We will prepare the ITP, carry out the measurements and issue reports to the requirements of the codes and the client. Phone, WhatsApp, Telegram: +998 94 094 52 27. E-mail: info@ognezashita.uz.