.bulkhead class  .bh

.class A bulkhead

Depending on the extent to which bulkheads can retain the fire and smoke to the affected side, they are classified into three categories. The bulkheads are classified as A B & C class.

The classification is based on fire resistance. So, accommodation bulkheads are classified as

1. Class A Bulkhead
2. Class B Bulkhead
3. Class C Bulkhead

Class A division Bulkhead as per SOLAS

.bulkhead regulation .types of bulkhead .bulkhead type

A” class divisions are those divisions formed by bulkheads and decks which comply with the following criteria:

1. They are constructed of steel or equivalent material.
2. They are constructed to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test.
3. They are suitably stiffened and made intact with the main structure of the vessel, such as the shell, structural bulkheads, and decks.
4. They are insulated with approved non-combustible materials such that the average temperature of the unexposed side will not rise more than 140’C above the original temperature nor will the temperature at any point including any joint rise more than 180’C above the original temperature with the time listed:

class “A-60”	60 min
class “A-30”	30 min
class “A-15”	15 min
class “A-0”	0 min

Class B division Bulkhead as per SOLAS

‘‘B’’ class divisions are those divisions formed by bulkheads, decks, ceilings or linings which comply with the following criteria:

1. They are constructed of approved non-combustible materials and all materials used in the construction and erection of “B” class divisions are non-combustible, with the exception that combustible veneers may be permitted provided they meet other appropriate requirements.
2. They are constructed so as to be capable of preventing the passage of flame to the end of the first half-hour (30 mins) of the standard fire test.
3. They have an insulation value such that the average temperature of the unexposed side will not rise more than 140 degrees C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 225 degrees C above the original temperature, within the time listed below: 

class ‘‘B-15’’	 15 min
class ‘‘B-0’’	 0 min

Class C division Bulkhead as per SOLAS

• C” class divisions are divisions constructed of approved non-combustible materials. They need to meet neither requirements relative to the passage of smoke and flame nor limitations relative to the temperature rise.
• Combustible veneers are permitted provided they meet the requirements.

The Administration required a test of a prototype division in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise.

IMO Symbol A Class Division  IMO Symbol B Class Division 

International shore connection

.isc

The international shore coupling SOLAS requirement under Chapter II-2, regulation 19 says; ships above 500 tons gross tonnage and upwards must have at least one international shore connection.

The international shore connection flange has a standard size and is same for all the countries and ships to ensure that if the ship faces an emergency out of the home port, firefighting assistance from any port is always available

	ISC	Annex 1	Annex 4
Description
Outside Diameter (OD)	178mm	215mm	210mm
Inside Diameter (ID)	64mm	According to pipe, max 125 mm outer dia	According to pipe dia, max 100mm outer dia
Bolt Circle Diameter (PCD)	132mm	183mm	170mm
Slots in Flange	4 holes	6 holes	4 holes
Bolt Hole dia	19mm	22 mm	18mm
Bolt dia	16mm	20 mm	16mm
Flange Thickness	14.5 mm minimum	20 mm	16mm
Bolts & Nuts	4 bolts, 4 nuts	6 bolts, 6 nuts	4 bolts, 4 nuts
Bolt length	50mm	Suitable length	Suitable length
Washers	8 nos	12 nos	8 nos
Pressure	10 bar	6 bar	6 bar

This international shore connection flange is generally kept at a convenient and accessible location (Bridge or in Fire locker) of a ship so that in case of an emergency it is readily available and used.

The connection should be made up of steel or other suitable material and shall be designed for 1.0 N/mm2 services. The flange should have a flat surface on one side and another side should be permanently connected or attached to a coupling that can be easily fitted to ships hydrant and hose connection.

Both ships international shore connection flange is connected together with bolts and each ship fire hydrant is connected to their respective fire main.

Watertight Bulkheads In Ships: Construction and SOLAS Regulations

The safety of a ship in damaged condition is majorly dependent on the strength and integrity of its watertight bulkheads. There are a lot of factors that go into deciding the position of watertight bulkheads in a ship, and designing them structurally.

Watertight bulkheads are vertically designed watertight divisions/walls within the ship’s structure to avoid ingress of water in the compartment if the adjacent compartment is flooded due to damage in ship’s hull.

The position of the bulkheads along the length of the ship is primarily decided by the results of flood-able length calculations during the assessment of damaged stability of the ship. However, once their positions are fixed, there are a lot of factors coming into play, for example: types of watertight bulkheads, their uniqueness based on their position, structural design, etc.

Collision Bulkhead

.collision bulkhead .cbr

A collision bulkhead is the forward-most bulkhead in a ship. The collision bulkhead is a heavily strengthened structure, its main purpose being limiting the damage of a head-on collision. collision bulkhead is watertight bulkhead. It is stiffened by triangular panting stringers.

The final position of the collision bulkhead is decided on the factors below-

Factor 1: Position based on flood-able length calculations.

Factor 2: Position based on the classification society code books.

Factor 3: Position based on SOLAS rule,

which states that

As per SOLAS rules,

• the collision bulkhead should be located aft of the forward perpendicular at a distance not less than 5 percent of the ship’s length of the ship or 10 meters (whichever is less). The distance must also not exceed 8 percent of the ship’s length.
• However, the position of the collision bulkhead should be such that maximum cargo storage volume is achieved.
• The collision bulkhead must be watertight upto the bulkhead deck. A bulkhead deck is basically the deck level upto which all the watertight bulkheads are extended.
• There must be no doors, manholes, access hatches, ventilation ducts or any openings on the collision bulkhead below the bulkhead deck.
• However, the bulkhead can only have one pipeline for pumping to and from forepeak ballast tank.
• The passage of the pipe must be flanged and must be fitted with a screw-down valve which can be remotely operated from above the bulkhead deck. This valve is usually located forward of the collision bulkhead. However, the classification society certifying the ship may authorise a valve aft of the bulkhead provided it is easily serviceable at any condition, and is not located in the cargo area.
• For providing access to chain locker room and the forward part of the bulkhead, steps may be provided on the collision bulkhead.
• In case of ships having superstructures at the forward region, the collision bulkhead is not terminated at the bulkhead deck. It must be extended to the deck level next to the weather deck.
• If the collision bulkhead is extended above the freeboard deck, the number of openings on the bulkhead should be restricted to a minimum in order to ensure sufficient buckling strength. All the openings should be watertight.