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A-60 vs B-15: marine fire classes explained
A-60 and B-15 are fire classes for ship divisions defined in SOLAS Chapter II-2 and tested under the IMO FTP Code. An A-60 division is steel-based and must stop smoke and flame for 60 minutes while keeping the unexposed side cool for 60 minutes. A B-15 division must stop flame for 30 minutes and keep the unexposed side cool for 15 minutes. A-class is used around stairways, machinery and control spaces; B-class is used for cabin and corridor partitions.
The fire classes side by side
| Class | Integrity (stops smoke and flame) | Insulation time | Construction |
|---|---|---|---|
| A-60 | 60 minutes | 60 minutes | Steel or equivalent, insulated |
| A-30 / A-15 | 60 minutes | 30 / 15 minutes | Steel or equivalent, insulated |
| A-0 | 60 minutes | None | Steel or equivalent |
| B-15 | 30 minutes | 15 minutes | Approved non-combustible materials, e.g. mineral wool panels |
| B-0 | 30 minutes | None | Approved non-combustible materials |
Insulation means the average temperature rise on the unexposed side stays below 140 °C and no single point rises more than 180 °C during the stated time.
Where each class is used
- A-60: boundaries of machinery spaces, stairway enclosures, control stations, galleys (as SOLAS tables require)
- A-0: steel divisions where integrity is needed without insulation
- B-15: cabin-to-corridor bulkheads and many accommodation partitions
- B-0: cabin-to-cabin partitions and linings where the tables allow
What this means when you order
- Order doors in the same class as the division they sit in
- Check that the door model is certified for that bulkhead type
- For EU-flagged ships, require the MED wheelmark; for others, the class type approval the vessel needs
- Ask for certificate numbers in the quotation and verify them
B-15 / B-0 panels · A-60 and B-15 doors · How certificates work
Frequently asked questions
Is A-60 better than B-15?
A-60 is a higher fire class: it applies to steel divisions and must resist fire for 60 minutes with 60 minutes of insulation. B-15 divisions resist fire for 30 minutes with 15 minutes of insulation. The class required for each bulkhead or door is set by SOLAS Chapter II-2 tables, not by choice.
Can a B-15 panel be used where A-60 is required?
No. A-class divisions must be steel or equivalent and pass the A-class test. A B-class panel system cannot replace an A-class division.
Which test standard applies?
Both are tested to the IMO 2010 Fire Test Procedures Code (FTP Code), Part 3, with the standard fire curve.
Need a quotation?
Send your specification or deck plan and the delivery port. We reply with certified options, lead time and price.