The standard does not give universal values. Instead, it requires that minimum adhesion values be agreed between contractor and client before testing.
You might also find a PDF for ISO 4624 (Paints and varnishes — Pull-off test). This causes confusion.
Think of it this way: ISO 4624 tells you how to pull. ISO 16276-1 tells you how to pull, what to accept, and where to apply it on a bridge or ship.
| Standard | Scope | Relationship to ISO 16276-1 | |----------|-------|-----------------------------| | ISO 4624 | Pull-off test method on rigid substrates | The how – referenced normatively | | ISO 19840 | DFT measurement on rough steel | Used to verify coating thickness near test sites | | ISO 12944 (Parts 1–9) | Corrosion protection system design | ISO 16276-1 provides the field adhesion check for systems qualified under ISO 12944 | | ASTM D4541 | Pull-off strength of coatings (elastomeric & rigid) | Similar method, but no built-in acceptance criteria |
For ISO 12944-compliant projects, ISO 16276-1 is the mandated field adhesion acceptance test. pdf iso -16276-1
ISO 16276-1 specifies procedures for assessing the adhesion and cohesion of protective paint coatings on steel structures using pull-off testing (generally per ISO 4624 or ASTM D4541). Its unique value lies in providing acceptance criteria specifically for corrosion protection systems on structural steel—something earlier standards avoided.
Key distinction: ISO 4624 describes how to perform the test. ISO 16276-1 describes how to pass/fail based on that test, in the context of an anti-corrosion coating system.
It applies to:
It does not apply to:
ISO 16276-1:2007 specifies procedures for assessing the adhesion of protective paint coatings on steel structures using pull-off tests (per ISO 4624) in the field. It is part of a two-part standard (Part 2 covers cross-cut testing).
This standard is critical for industries like:
During my years as a NACE/FROSIO inspector, I saw most validation failures come from three specific violations of the ISO 16276-1 PDF guidelines.
A compliant report must include:
No “pass/fail” decision is complete without the failure mode.
Many specifiers write “minimum 5 MPa pull-off”. But that alone is dangerous. A coating could achieve 7 MPa but fail adhesively at the substrate—meaning corrosion will creep under the film. Another might give 3 MPa but fail cohesively deep within a thick layer, still providing a protective barrier.
ISO 16276-1 requires both:
Example from the standard: For a given coating system, the acceptance criterion could be: Fracture strength ≥ 5 MPa and failure mode not A or C (adhesive failures) more than 20% of the tested area. The standard does not give universal values
This dual requirement prevents false passes and false fails.