How marine equipment gets and keeps class-society type approval from the five IACS members most commonly asked for on merchant fleets: DNV (Norway), ABS (USA), Lloyd's Register (UK), Bureau Veritas (France), and ClassNK (Japan). Covers the type-approval application flow, the difference between type approval and product approval, unit certificates (Form 3, PCoC), scope-of-approval limits, and how to keep the certificate current across firmware releases and material changes. Written for buyers verifying that a delivered spare part is covered by the vessel's classification survey.
Class societies covered
Society
Country
IACS founding member
Fleet share (approx)
DNV (formerly DNV GL)
Norway
Yes
~22%
ABS (American Bureau of Shipping)
USA
Yes
~14%
Lloyd's Register (LR)
UK
Yes
~12%
Bureau Veritas (BV)
France
Yes
~11%
ClassNK (Nippon Kaiji Kyokai)
Japan
Yes
~19%
KR (Korean Register)
South Korea
Yes
~8%
CCS (China Classification Society)
China
Yes
~11%
RINA
Italy
Yes
~2%
PRS (Polski Rejestr Statków)
Poland
Yes
~1%
Type approval vs. product approval vs. unit certification
The three terms are often used interchangeably but carry different technical meanings.
Type approval — a certificate against a manufacturer's design (drawings, materials, test results) confirming that the equipment TYPE meets the applicable class rules. Type approval is granted once per design revision and covers all units built to that design.
Product approval / Product Design Assessment — issued by ABS as their equivalent to type approval. Same technical intent as type approval.
Unit certificate (Form 3, Product Certificate PCoC) — issued per individual unit built. Confirms that this specific serial number was built to the type-approved design and passed factory acceptance test (FAT) witnessed by the surveyor.
Common type-approval scopes
Equipment category
Common class rule / annex
Ballast Water Management System (BWMS)
IMO MEPC.279(70) + USCG 46 CFR 162.060 + class annex
Fuel oil / diesel engine components
IACS UR M53 + class engine chapter
Cargo pumps and inert-gas systems
Class cargo-piping chapter + IACS UR P
Electrical machinery (motors, generators)
Class electrical chapter + IEC 60034
Marine automation and control (IAS)
Class automation chapter + IEC 60945 EMC
Refrigerated cargo plant
Class refrigeration chapter
Firefighting equipment
SOLAS Chapter II-2 + MSC.98(73) FSS Code
Life-saving appliances
SOLAS Chapter III + MSC.81(70) LSA Code
Bridge equipment
Class navigation chapter + IMO SN.1/Circ.243
Application flow (typical)
Pre-application meeting — manufacturer identifies which class rules apply and confirms scope with the surveyor.
Documentation submission — general arrangement drawings, wiring diagrams, materials list, EMC test reports, FMEA (for safety-critical systems), software life-cycle documentation (for control systems).
Prototype testing — witnessed environmental tests (vibration IEC 60068-2-6, shock IEC 60068-2-27, temperature IEC 60068-2-1/-2, humidity IEC 60068-2-30, salt mist IEC 60068-2-52) and functional performance tests.
Certificate issuance — type approval certificate valid for a defined period (usually 5 years) subject to notification of design or material changes.
Renewal — reapplied before expiry; requires re-testing only if the applicable rules have changed.
How buyers verify the certificate at goods-in
Each class society publishes an online type-approval register. Buyers verifying a delivered spare part enter the certificate number and confirm it is (a) still valid, (b) covers the specific part number delivered, and (c) is issued by the vessel's classification society or by an IACS member with mutual recognition. If the certificate lists a design revision (e.g. "Rev. 3.2") the delivered nameplate must match that revision — a Rev. 4.0 part supplied against a Rev. 3.2 certificate is not covered and can be rejected at the next class survey.
Which classification society has the largest share?
DNV classes roughly a fifth of the world fleet, ahead of ABS (~14 %) and Lloyd's Register (~12 %) — all three are IACS members.
Is type approval from one society valid for another?
Not automatically. Mutual-recognition exists for some certificate types within IACS, but a DNV type approval does not by itself satisfy an ABS-classed vessel's requirement — the certificate must match the classing society or be accepted by it.
When does equipment need class type approval at all?
When it serves a classed function (structural, propulsion, safety, main electrical). Commodity parts outside the classed scope ship on manufacturer certificates such as EN 10204 3.1 instead.