MeridexionClass certificates are required for a small, specific set of parts: the ones that hold pressure, carry load, or get welded into the structure. For most other items they are paperwork nobody asked for. Knowing which side of the line a part sits on saves both money and time.
Lead time quoted without a shipping term is not really a lead time.
The document types, in plain terms
The comparison, in one table:
| Document | Issued by | What it proves |
|---|---|---|
| Mill / material certificate | Steel mill or foundry | Chemical composition and mechanical properties of the material |
| Manufacturer’s certificate of conformity | The part manufacturer | The part was made to the stated specification |
| Test report | Manufacturer or test house | Pressure, hardness, NDT, balancing results |
| Class certificate | Classification society (LR, DNV, ABS, BV, NK, RINA, CCS) | The part is accepted for the intended service under that society’s rules |
These are cumulative, not alternatives: a class certificate normally requires the material and test documentation underneath it.
Which parts usually need class certification
- Components of the propulsion train — crankshafts, thrust components, propeller shafting
- Pressure vessels and their safety fittings
- Steering gear and essential auxiliary system components
- Parts covered by a specific survey requirement in the society’s rules
Consumables and routine wear parts generally don’t, though the surveyor may ask for material certificates. When in doubt, ask the attending surveyor before ordering — not the supplier.
The timing problem
Certification isn’t a paperwork step added at the end. It usually requires:
- The manufacturer to hold the relevant approval, or the society to agree to survey the item.
- Inspection at defined stages of production.
- Documentation issued before the part leaves the factory.
Starting this after the part is made is often impossible, which is why “class certificate” must appear on the enquiry, not on the shipping instruction.
Practical sequence
- Confirm with the class surveyor which parts require certification.
- State the requirement in the RFQ, including the society.
- Confirm the supplier can obtain it before accepting the order.
- Ensure inspection points are scheduled into production.
- Check the certificate against the part number and serial before dispatch.
For the wider sourcing sequence see how sourcing works, and for the enquiry fields see the RFQ checklist.
A few things people ask
Which marine spare parts need class certificates?
Those the classification society surveys — typically propulsion train components, pressure vessels and their safety fittings, steering gear, and items named in the society’s rules. Routine consumables and wear parts usually need only material certification.
Can a class certificate be obtained after the part is manufactured?
Rarely. Certification usually requires approval of the manufacturer and inspection at defined production stages. It must be arranged before or during production, not after dispatch.
Is a mill certificate the same as a class certificate?
No. A mill certificate proves the material grade; a class certificate confirms the finished part is accepted for the intended service. The class certificate normally depends on the mill and test documents underneath it.
Talk to us about this part
One email with the engine details and the part is enough to start. We reply with availability, options and a realistic lead time.