14B                  STRUCTURAL FIRE PROTECTION - VESSELS OF 500 GT AND OVER

                 The purpose of this section is to ensure that a consistent level of structural fire protection. The principles of the section aim to achieve a level of fire protection compatible with the requirements of SOLAS for passenger ships carrying up to 36 passengers. These have been adapted where appropriate to fit in the general yacht design philosophy. Much emphasis is placed on the provision of sprinkler/mist systems as trade-off for certain aspects. Also the provision for fire engineering for equivalent standards is outlined

14B.1               Definitions

                                    Terms used in this section should have the same meaning as defined in SOLAS, except as defined in Section 14.1 and as follows:

                                    "Not readily ignitable" means that the surface thus described will not continue to burn for more than 20 seconds after removal of a suitable impinging test flame;

14B.2               Table 14B.2 is a guide to the major requirements of this Section. The Table is intended as a quick reference to the requirements and is not to be used in isolation when designing the fire safety arrangements.

Table 14B.2

                        All vessels should comply with the following: -

14B.2.1            Structure

                        Purpose

                        The purpose of this section is to contain a fire in the space of origin. For this purpose, the following functional requirements should be met:

•  the ship should be subdivided by thermal and structural boundaries;

•  thermal insulation of boundaries should have due regard to the fire risk of the space and adjacent spaces;

•  the fire integrity of the divisions should be maintained at openings and penetrations.

14B.2.2.1         The hull, superstructures, structural bulkheads, decks and deckhouses should be constructed of steel or other equivalent material.

14B.2.2.2         However, in cases where any part of the structure is of aluminium alloy, the following should apply: -

                        .1          Insulation of aluminium alloy components of "A" or "B" class divisions, except structure which, in the opinion of the Administration, is non-load-bearing, should be such that the temperature of the structural core does not rise more than 200 ° C above the ambient temperature at any time during the applicable fire exposure to the standard fire test.   This insulation is to be applied on all sides except for the upper sides of decks and the outside of the vessel

                        .2          Special attention should be given to the insulation of aluminium alloy components of columns, stanchions and other structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" class divisions to ensure that for members:

                                   (a)        supporting lifeboat and liferaft areas and "A" class divisions, the temperature rise limitation specified in .1 above should apply at the end of one hour; and

                                   (b)        supporting "B" class divisions, the temperature rise limitation specified in .1 above should apply at the end of half an hour.

           .3          Aluminium alloy components of divisions that are required to be equivalent to steel (identified by an * in tables 1 and 2) should be insulated with 25mm of mineral wool approved for use in A class divisions or with an equivalent insulation acceptable to the administration.

14B.2.2.3         For composite structures, the insulation is to be such that the temperature of the laminate does not rise more than the minimum temperature of deflection under load of the resin at any time during the specified fire exposure. The temperature of deflection under load is to be determined in accordance with the requirements of a recognised international standard.   This insulation is to be applied on all sides except for the upper sides of decks and the outside of the vessel.

                        .1          Special attention should be given to the insulation of composite components of columns, stanchions and other structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" class divisions to ensure that for members:

                                   (a)         supporting lifeboat and liferaft areas and "A" class divisions, the temperature rise limitation specified in .1 above should apply at the end of one hour; and

                                   (b)         supporting "B" class divisions, the temperature rise limitation specified in .1 above should apply at the end of half an hour.

                        Special attention is to be given to the fixing of fire door frames in bulkheads constructed of materials other than steel. Measures are to be taken to ensure that the temperature of the fixings when exposed to fire does not exceed the temperature at which the bulkhead itself looses strength.

14B.2.2.4         Crowns and casings of a machinery space of category A should be A60 divisions and openings therein, if any, should be suitably arranged and protected to prevent the spread of fire.

14B.2.2.5         For structures in contact with sea-water, the required insulation should extend to at least 300 mm below the lightest waterline.

14B.2.2.6         Fire divisions using steel equivalent, or alternative forms of construction may be accepted if it can be demonstrated that the material by itself, or due to non-combustible insulation provided, has the fire resistance properties equivalent to the A or B class standard required.

14B.2.2.7         Insulation required by 14B.2.2.6 is to be such that the temperature of the structural core does not rise above the point at which the structure would begin to lose its strength at any time during the applicable exposure to the standard fire test. For 'A' Class divisions, the applicable exposure is 60 minutes, and for 'B' Class divisions, the applicable exposure is 30 minutes.

14B.2.3            Main vertical zones and horizontal zones

14B.2.3.1         Hull, superstructure and deckhouses in way of accommodation and service spaces should be subdivided into main vertical zones by "A" class divisions.   These divisions should have insulation values in accordance with tables 1 and 2.

14B.2.3.2         As far as practicable, the bulkheads forming the boundaries of the main vertical zones above the bulkhead deck should be in line with watertight subdivision bulkheads situated immediately below the bulkhead deck. The length and width of main vertical zones may be extended to a maximum of 48 m in order to bring the ends of main vertical zones to coincide with watertight subdivision bulkheads or in order to accommodate a large public space extending for the whole length of the main vertical zone provided that the total area of the main vertical zone is not greater than 800 m 2 on any deck. The length or width of a main vertical zone is the maximum distance between the furthermost points of the bulkheads bounding it.

14B.2.3.3         Such bulkheads should extend from deck to deck and to the shell or other boundaries.

14B.2.3.4         When a main vertical zone is subdivided by "A" class divisions for the purpose of providing an appropriate barrier between spaces protected and not protected by a sprinkler system, the divisions should be insulated in accordance with the fire insulation and integrity values given in tables 1 and 2.

14B.2.4            Bulkheads within a main vertical zone

14B.2.4.1         All bulkheads within accommodation and service spaces which are not required to be "A" class divisions should be at least "B" class or "C" class divisions as prescribed in the tables 1 and 2 .

14B.2.4.2         All such divisions may be faced with combustible materials

14B.2.4.3         All corridor bulkheads where not required to be "A" class should be "B" class divisions which should extend from deck to deck except:

                        .1          when continuous "B" class ceilings or linings are fitted on both sides of the bulkhead, the portion of the bulkhead behind the continuous ceilings or lining should be of material which, in thickness and composition, is acceptable in the construction of "B" class divisions but which should be required to meet "B" class integrity standards only in so far as is reasonable and practical in the opinion of the Administration;

                        .2          the corridor bulkheads of "B" class materials may terminate at a ceiling in the corridor provided such a ceiling is of material which, in thickness and composition, is acceptable in the construction of "B" class divisions. All doors and frames in such bulkheads should be so constructed and erected to provide a "B" class standard.

14B.2.4.4         All bulkheads required to be "B" class divisions, except corridor bulkheads, should extend from deck to deck and to the shell or other boundaries unless continuous "B" class ceilings or linings are fitted on both sides of the bulkhead, in which case the bulkhead may terminate at the continuous ceiling or lining.

14B.2.5            Fire integrity of bulkheads and decks

14B.2.5.1         In addition to complying with the specific provisions for fire integrity of bulkheads and decks mentioned elsewhere in this section, the minimum fire integrity of bulkheads and decks should be as prescribed in tables 1 and 2.

14B.2.5.2         The following requirements should govern application of the tables:

                        .1          Tables 1 and 2 should apply respectively to the bulkheads and decks separating adjacent spaces.

                        .2          For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such spaces are classified according to their fire risk as shown in categories (1) to (9) below.   The title of each category is intended to be typical rather than restrictive.   The number in parentheses preceding each category refers to the applicable column or row in the tables.

(1)                    Control stations

•  Spaces containing emergency sources of power and lighting.

•  Wheelhouse and chartroom.

•  Spaces containing the vessel's radio equipment.

•  Fire-extinguishing rooms.

•  Fire control rooms and fire-recording stations

•  Control room for propulsion machinery when located outside the machinery space.

•  Spaces containing centralized fire alarm equipment.

(2)                    Corridors and lobbies

•  Guest and crew corridors and lobbies.

(3)                    Accommodation spaces

•  Cabins, dining rooms, lounges, offices, pantries containing no cooking appliances (other than equipment such as microwave cookers and toasters), and similar spaces . .

(4)                    Stairways

•  Interior stairways, lifts and escalators (other than those wholly contained within the machinery space(s)) and enclosures thereto.

•  In this connection, a stairway which is enclosed only at one level should be regarded as part of the space from which it is not separated by a fire door.

(5)                    Service spaces (low risk)

•  Lockers and store-rooms not having provisions for the storage of flammable liquids and having areas less than 4m² and drying rooms and laundries.

(6)                    Machinery spaces of category A,

•  Spaces so defined.

(7)                    Other machinery spaces

•  Spaces so defined, excluding machinery spaces of category A.

•  Sprinkler, drencher or fire pump spaces.

(8)                    Service spaces (high risk)

•  Galleys, pantries containing cooking appliances, paint and lamp rooms, lockers and store-rooms having areas of 4m² or more, spaces for the storage of flammable liquids, workshops other than those forming part of the machinery spaces, and spaces containing vehicles or craft with fuel in their tanks, or lockers storing such fuels storage lockers for gaseous fuels for domestic purposes.  

(9)                    Open decks

•  Open deck spaces and enclosed promenades having no fire risk. Air spaces (the space outside superstructures and deckhouses).

14B.2.5.3         Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted as contributing, wholly or in part, to the required insulation and integrity of a division.

14B.2.5.4         External boundaries which are required to be of steel or other equivalent material may be pierced for the fitting of windows and portlights provided that there is no requirement for such boundaries to have "A" class integrity elsewhere in this section.   Similarly, in such boundaries which are not required to have "A" class integrity, doors may be of combustible materials, substantially constructed.

Table 1 - Fire integrity of bulkheads separating adjacent spaces

Notes: To be applied to both tables 1 and 2, as appropriate.

a                       For clarification on which applies, see 14B.3.4 and 14B.3.7.

b                       Where spaces are of the same numerical category and subscript b appears, a bulkhead or deck of the rating shown in the tables is only required when the adjacent spaces are for a different purpose, e.g in category (9).   a galley next to a galley does not require a bulkhead but a galley next to a paint room requires an "A-0" bulkhead.

c                       Bulkheads separating the wheelhouse and chartroom from each other may be "B-0" rating.

e                       For the application of 14B.3.3.1, "B-O" and "C", where appearing in table 1, should be read as "A-0".

f                        Fire insulation need not be fitted if the machinery space in category (7), in the opinion of the Administration, has little or no fire risk.

*                       Where an asterisk appears in the tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class standard.

                        For the application of 14B.3.3.1 an asterisk, where appearing in table 2, except for category (9),   should be read as "A-0".

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