DNV, ABS and IACS approvals: what they mean for steel products
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How classification-society rules, manufacturer approvals and material certification relate — and why “DNV/ABS approved” is not a steel grade.
“DNV approved,” “ABS approved” and “IACS approved” are phrases often used loosely in steel enquiries. They can refer to very different things.
Most importantly, DNV, ABS and IACS are not steel grades.
DNV and ABS are classification societies
Classification societies publish rules, survey ships/offshore units and certify materials/components within the scope of their rules.
A steel manufacturer can hold an Approval of Manufacturer (AoM) for specified products, grades, processes and dimensional ranges. DNV states that manufacturers of materials need approval when supplying customers seeking DNV classification, and that approval involves verification of manufacturing processes and normally a supervised test programme.
That does not mean every product from that mill is automatically class-certified.
IACS is different
IACS is the International Association of Classification Societies. It develops Unified Requirements (URs) that member societies incorporate into their own rules, subject to the IACS implementation process.
IACS itself is not normally the body that issues the individual material certificate for your plate or pipe.
IACS describes its Unified Requirements as minimum requirements, while member societies remain free to impose more stringent rules.
Three different concepts that buyers should separate
1. Manufacturer approval
The mill has been approved by a classification society for a defined manufacturing scope.
This approval can be limited by:
- product type;
- steel grade/family;
- manufacturing route;
- thickness or diameter range;
- heat-treatment route;
- production location.
2. Material manufactured to a class grade/rule
The steel itself is ordered to a grade defined or recognized by the class rules.
3. Product certification / survey for the actual order
The specific heat, plate, pipe or batch is produced, tested, inspected and certified under the required survey/certification regime.
These three are related, but they are not interchangeable.
“Class approved mill” does not equal EN 10204 3.2
EN 10204 defines inspection-document types. A class approval is a manufacturer qualification. A project may require both, one, or neither.
See EN 10204 3.1 vs 3.2 and EN 10204 certificate types.
Marine rules vs industrial/project inspection
For material that is part of a classed ship or offshore unit, the applicable classification rules and survey requirements can be contractual requirements. For ordinary industrial/offshore equipment outside class scope, a purchaser may instead appoint an independent inspection body under the project specification.
The fact that an inspection company can witness tests does not automatically make the material “DNV certified” or “ABS certified.”
What to ask a supplier
Instead of asking only:
“Are you DNV approved?”
ask for:
- classification society;
- approval certificate number;
- approved manufacturing location;
- product type;
- grade/material family;
- process route;
- dimensional range;
- certificate validity;
- whether the actual order requires surveyor attendance and class-stamped certification.
Procurement takeaway
Use precise language. Manufacturer approval, class grade, class survey and EN 10204 certificate type are different layers. A supplier can legitimately have one without automatically having the others.
References and verification sources
Standards referenced
- IACS Unified Requirements
- DNV Rules / Approval of Manufacturers
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DNV, ABS and IACS approvals: what they mean for steel products
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