In ship design and construction, fire - resistant divisions play a vital role. Current conventions and regulations highly emphasize the crucial position of fire - resistant divisions in ship fire prevention.
Ships are divided into several main vertical zones by fire - resistant divisions. Meanwhile, accommodation spaces are also separated from machinery spaces, cargo spaces and other spaces by fire - resistant divisions. Such divisions can effectively prevent the large - scale spread of fire when a fire occurs. In addition, fire - resistant divisions can also protect escape routes and entrances and exits, ensuring structurally that all kinds of spaces on the ship are under protection commensurate with their fire hazards. In the event of a fire, fire - resistant divisions can confine the fire to a local area, thereby minimizing the fire hazard and the resulting losses.
Fire - resistant divisions are classified into Class A, Class B and Class C divisions according to their performance in preventing fire and smoke and the temperature rise in fire - resistance tests.
Class A divisions consist of bulkheads and decks that meet specific requirements. Firstly, they should be made of steel or other equivalent materials and should have appropriate stiffening against flexure. In a standard fire - resistance test, Class A divisions can prevent the passage of smoke and flame within a specified time. For example, Class A - 60 needs to meet the corresponding requirements within 60 minutes, Class A - 30 within 30 minutes, Class A - 15 within 15 minutes. Although Class A - 0 does not need to undergo a standard fire - resistance test, it is allowed to be strengthened with 4.5 - millimeter - thick steel plates and anti - flexure members of specific dimensions. At the same time, Class A divisions should be insulated with approved non - combustible materials to ensure that the average temperature on the unexposed side and the temperature rise at any point are within the specified range.
Class B divisions consist of bulkheads, decks, ceilings or linings that meet the requirements. At the end of the initial half - hour standard fire - resistance test, Class B divisions should be able to prevent the passage of flame. They have a certain insulation value to ensure that the average temperature on the unexposed side and the temperature rise at any point are also within specific ranges. For example, Class B - 15 meets the requirements within 15 minutes, and Class B - 0 does not need to undergo a standard fire - resistance test. Class B divisions should be made of approved non - combustible materials. Although the use of combustible inserts is not excluded, it must comply with relevant regulations.
Class C divisions should be made of approved non - combustible materials. Different from Class A and Class B, it does not need to meet the requirements of preventing the passage of smoke and flame and limiting the temperature rise, nor does it need to undergo a standard fire - resistance test.
In addition, continuous Class B ceilings and linings refer to Class B ceilings or linings that terminate only at Class A or Class B divisions. Main vertical zones refer to the sections into which the hull, superstructure and deckhouses are divided by Class A divisions, and the average length on any deck generally does not exceed 40 meters. Different spaces on ships are also clearly defined. Accommodation spaces include public spaces, corridors and other similar spaces; cargo spaces are all spaces used for loading cargo; service spaces include kitchens, pantries with cooking facilities, etc.; ro - ro cargo spaces are special spaces where cargo can be normally loaded and unloaded in the horizontal direction.
In conclusion, the scientific classification and reasonable arrangement of fire - resistant divisions on ships provide a solid guarantee for ship fire safety, ensuring the maximum protection of the lives of personnel and ship property in the event of a fire.