What Is a Fire Compartment?

The ship's bulkhead is a structural part made of many rows of steel plates arranged and combined and welded. It divides the interior space of the hull into a number of cabins. A watertight bulkhead is a bulkhead that is impermeable to water at a specified water pressure. Watertight bulkheads are a major invention in ancient Chinese shipbuilding technology. The emergence of watertight bulkheads has resulted in watertight bulkheads, which enable ships to have sufficient buoyancy and stability when damaged. The role of watertight bulkheads is to strengthen the hull and increase the structural strength of the hull. The second is that the watertight bulkheads closely separate the tanks from the tanks. During the voyage, even if one or two tanks are damaged and enter the water, the water will not flow to the other tanks. Third, the watertight bulkhead is used to divide the cabin into many cabins, which is convenient for cargo handling and management. The number of watertight bulkheads varies according to the type and size of the ship. There are at least 3-4 watertight bulkheads in the cargo holds and engine rooms of large ships to ensure the ship's unsinkability.

1. Fireproof bulkhead 1. Overview

In recent years, during the inspection of multiple large cargo ships by the Port State Supervisor and Inspector, it was found that the fire doors of the bulkhead of the separated bridge deck are not completely consistent, and there are some defects that do not meet the requirements of the Convention. The crew confirmed on the ship. The inspector consulted with a number of classification societies, consulted the provisions of the relevant conventions, traced the source, and made every effort to clarify the origin and original intention of the convention's requirements for the classification of the fire door of the bulkhead of the bridge, providing reference for the next inspection.

2. Fireproof bulkhead 2.Introduction to the layout of the bridge

Generally speaking, the layout of the bridge can be divided into two cases: one is the overall layout, the entire bridge is a whole without partitions; the other is the partition layout, which is "named" for navigation according to the different equipment placed in the partitions. Equipment room (nav. Locker), electrical equipment room (electrical equipment room), converter equipment room (converter room), etc., as shown in Figure 1. In addition, some large tankers are also equipped with "back" shaped bridges.

3. Fire bulkheads 3. Fire integrity requirements for separated bridge bulkheads

Chapter II-2 Construction of the SOLAS Convention-Fire Prevention, Fire Detection and Extinguishment provides a more detailed division and regulation of the fire integrity of bulkheads and decks between different compartment spaces of ships. In general, for cargo ships other than tankers, the bridge should be considered as a control station, which must meet the fire integrity requirements of at least Class A fire compartments in the surrounding bulkheads and lower decks, and more detailed for the bridges that are arranged separately. Combing of judgments.

First of all, the bridge is clearly a control station, and the electrical equipment room can be clearly defined as other machinery spaces; but for the navigation equipment room and the conversion equipment room, different considerations need to be made according to the equipment installed in it. A control station may be considered as defined in accordance with the premises provided with ship radio equipment under the category of control station.

Secondly, referring to Section 9.2.3.3 of Chapter II-2 of the SOLAS2000 Amendment, Table 9.5-Fire-resistant integrity of bulkheads separating adjacent spaces, it can be seen that the bulkhead between the control station and other machinery spaces should meet the "A-15" separation requirement ; The basic requirement between the control station and the control station is "A-0", but the entry has an additional note, "the bulkhead separating the cabin, chart room and radio room can be" B-0 " ". It can be seen that the common bulkheads of the navigation equipment room, the conversion equipment room and the bridge can be arranged according to "B-0" class separation.

Furthermore, the Convention also requires that where a thing and use in a premises makes it questionable to classify under this article, or it is possible to assign two or more categories to a premises, the premises shall be considered to have the most restrictive interface The relevant category of space required. ", Refer to Table 9.5. It can be seen that the requirements for the fire integrity of the bulkhead of the control station and any other spaces are at least Class A, which is very different from the previous requirements of" B-0 ". For example, if a large number of spare parts are stored in the navigation equipment room, and the area of the enclosed compartment is less than 4 square meters, which meets the definition of "Convention Service Areas with Lesser Fire Risk", the fire integrity of the bulkhead shall meet "A-15" If the storage area is larger than 4 square meters and meets the definition of "service premises with greater risk of fire", it shall meet the requirements of "A-60" level.

4. Fireproof bulkhead 4. Independence requirements of compartment division

Separated bridges consider the navigational equipment room, conversion equipment room and the bridge as separate separate spaces. For this, the convention requires: "Smaller, enclosed rooms within a space that have less than 30% communicating openings to that space are considered separate spaces.". According to the principle of dimensional analysis, 30% is a dimensionless quantity, that is, the two quantities to be compared should have the same unit. Therefore, "communicating openings" and "that space" should be the same values for area or volume units. This article here tends to the ratio of the area of the opening to the area of the common bulkhead where the opening is located. Such considerations are in line with the fire safety goal of Article 2.1.1.4 of the Convention "Suppression, control and suppression of fires and explosions in the fire source compartment.

In particular, note the interpretation of the requirements for fire integrity of bulkheads in cargo ship separation spaces, as explained in Article 44.2 of the MSC / Circ.847 Circular, which entered into force on June 12, 1998: "if the separating bulkheads of such spaces have at least 30% openings, these spaces are not considered to be separate spaces. " Comparing the two, it can be found that the Convention further clarifies the requirements of this clause, and uses 30% of the opening area as a limit for the independence of the premises.

In summary, the identification of the category of the enclosed cabin in the bridge is a key factor in assessing the fire integrity of the bulkhead. However, a few classification societies consider that the bridge as a control station can be considered as a whole, and the boundary has been surrounded by at least Class A fire integrity. The internal bulkheads are optional and the fire doors on the bulkheads are optional. There is no strict level requirement. This article also analyzes the necessity of separating bulkheads from aspects such as electromagnetic compatibility, and does not agree with such fuzzy treatment methods.

5. Fireproof bulkheads 5. EMC requirements for separate bridge deck bulkheads

From the very beginning of ship design, the bridge has occupied an extremely important position among them. In order to ensure the navigation safety of the ship, the main system of the bridge is always retained, and it continues to evolve to modernization and information. For example, communication systems, distress alert systems, driving assistance systems, fire alarm systems, etc., and gradually increasing VDR (Navigation Data Recorder), BNWAS (Bridge Watch Duty Alarm System), LRIT (Remote Tracking Identification System), etc. But with it, the increasingly high-power transmitting and receiving equipment has turned the originally small and crowded bridge space into a strong magnetic field space, especially the beep sounds from the transceiver equipment, the conversion unit, etc. The " " current noise poses a potential threat to the physical and mental health of the crew members on the bridge. Aiming at the electromagnetic interference between the ship's electronic equipment, the SOLAS Convention and its resolution specify the electromagnetic compatibility requirements. For example, Chapter 5.2.1 of SOLAS states that "Each radio device should be installed in a place where harmful interference from mechanical, electrical or other sources of interference will not affect its normal use, thereby ensuring electromagnetic compatibility and avoiding interference with other equipment and systems Harmful mutual interference. "; Article 17.1-3 clearly states" It shall be ensured that it is installed on ships constructed on or after July 1, 2002 and that electromagnetic compatibility is provided for all electrical and electronic equipment located on or near the bridge. Sex test. "

Resolution A.813 (19) [2] entered into force on November 23, 1995, where Article C.2.2 states that "equipment and devices need effective shielding, ie: installed in metal housings; use of shielded cables, including A suitable cable stuffing box, especially where the cable enters the metal shell; use metal bulkheads and decks for shielding, and ground the shield at the cable crossing point as low as possible. "The third point is clear The shielding requirements for bridge equipment include metal bulkheads and decks separating the bridge.

Furthermore, the resolution A.694 (17) on November 6, 1991 clarified the basic requirements for ship equipment that composes the GM DSS system. Article 6.1 of it stipulates that "All reasonable and practicable steps should be taken to ensure electromagnetic compatibility" between the equipment concerned and other radio-communication and navigational equipment carried on board in compliance with the relevant requirements of chapter IV and chapter V of the 1974 SOLAS Convention ". Sexual requirements; and Mechanical noise from all units should be limited so as not to prejudice the hearing of sounds on which the safety of the ship might depend. aims.

In summary, the navigation bridge (nav. Locker), electrical equipment room, converter room, etc. mentioned in the previous paragraph can be used to comply with electromagnetic compatibility standards for various types of bridge equipment Separate arrangements can also be used to separate the crew on duty from strong radiation equipment, current noise, etc. This measure is desirable and necessary, in accordance with the Convention's long-term consideration of the safety protection of ships and crew.

6. Fireproof bulkhead 6.Conclusion

Therefore, in accordance with the principle of "the original meaning of the provisions of the Convention", for ships with the aforementioned navigation equipment room and conversion equipment room inside the bridge, and meeting the requirements for treating them as separate premises, Under the premise of the category of the change, the common bulkhead should meet the B-0 separation requirement at least, and the electrical equipment room should be divided according to A-15. At the same time, it is also a fire door that constitutes the structural integrity of the separation bridge bulkhead. Should meet the corresponding level requirements.

7. Fireproof bulkhead 7. Recent developments

After more than two years, the inspectors and classification societies "you come and go" by mail, discussions, telephones, etc., to promote the classification societies through the International Classification Society Association (IACS) The fourth meeting of the IMO Marine System and Equipment Subcommittee submitted a draft unified interpretation of the topics discussed in this article. If successfully passed, it will be submitted to the 98th Hai'an Conference (MSC) discussion scheduled for June 2017 to form a formal unified interpretation. text. The draft proposes to unify the fire protection class of the navigation equipment room (considered as a control station) that can only be accessed by the bridge from the bridge to the B-0 level. In the process of soliciting opinions from the inspectors, I Fang made the following comments for reference.

(1) The draft intends to integrate navigation locker, navigation equipment, and navigation equipment into the concept of navigation locker, even if they are uniformly explained. , It is still easy to cause the contradiction of the mixed use of the concepts of size.

(2) The unified interpretation of the draft did not take into account that during the operation of the ship, the crew members improperly stored the debris to the navigation locker, which may substantially change the general objective reality of the category to which the department belongs, and it is also easy to trigger the inspector during the ship safety inspection. Identification of the danger of fire in the bridge space. ^[1]