- Are divisions forming bulkheads and decks that are;
- Constructed of steel or equivalent
- suitably stiffened
- Prevent passage of smoke and flame to the end of one hour standard fire test
- Insulated using non-combustible material so that average temperature on un-exposed side does not rise above 139oC and point temperature above 180o The time duration for which the bulkhead complies with this , governs its class
A-60— 60 Min
A-30— 30 Min
A-15 —15 Min
A-0 —0 Min
- These are divisions formed by bulkheads, decks, ceilings and lining
- Prevent passage of flame for first half hour of standard fire test
- Insulated so average un-exposed side temperature does not rise more than 139oC above original and no single point rises more than 225oC above original .
- B-15 -15 Min
B-0 -0 Min
- Constructed of non-combustible material and all materials entering the construction are similarly non-combustible except where permitted.
- These are divisions constructed of approved non-combustible materials. Combustible veneers are allowed where they meet other criteria
- Main vertical zones Divided by Class A bulkheads and not exceeding 40m in length
You may also know :
- Transverse Bulkheads serve to :
- Subdivide a ship against flooding and spread of fire
- Support Decks & Superstructures
- Resist racking stresses
- “Margin line” means a line drawn at least 76mm below the upper surface of the bulkhead deck at the side of a ship, and assumed for the purpose of determining the floodable length of the ship
- Bulkhead Deck :
- It is usually the freeboard deck
- For Collision Bulkhead it is the uppermost continuous deck
- For Afterpeak Bulkhead it may be one deck above load water line, provided this deck is made watertight to the stern or to a watertight transom floor.
Please do correction for class A
…average temperature of the unexposed side does not rise above 140C of the original temperature, nor will the temperature at any point including a joint rise above 180C above original temperature.
Collision bulkhead definition and freeboard definition.
Very useful notes. Thanks very much.