Section 4 Fire Safety Measures for Submersibles

4.1.1 As far as practicable all materials used in the construction and outfitting of submersibles are to be non-combustible. Consideration may be given to the use of combustible materials for specific applications in order to take advantage of unique properties possessed by these materials which make them especially suitable for specific applications. The risk of fire is not to be significantly increased thereby, either intrinsically or by the provision of compensating factors.

4.1.2 As far as possible, fire loads and sources of ignition are to be avoided. Electrical heating appliances and heaters are to be fitted with protection against overheating.

4.1.3 All exposed surfaces including those in concealed or, inaccessible spaces are to have low flame spread characteristics.

4.1.4 As far as practicable all materials having surfaces exposed to oxygen enriched atmospheres are to have fire retardant characteristics in addition to any other required fire-resistance properties.

4.1.5 Materials are to be selected to minimize as far as practicable the omission of toxic and noxious combustion products.

4.1.6 Materials are to be selected with a view to minimising the danger of static charges.

4.2.1 Machinery and equipment identified as potential sources of ignition are to be enclosed by Class ‘A-0’ divisions or equivalent non-load bearing divisions.

4.2.2 Where a submersible is subdivided into one or more spaces the divisions separating the spaces is to be Class ‘A-0’ divisions of equivalent non-load bearing divisions.

4.2.3 The fire-resistance of doors and inspection panels is as far as practicable to be equivalent to that of the division in which they are fitted.

4.2.4 Where ‘A-0’ divisions or equivalent non-load bearing divisions are penetrated by ventilation ducts they are to be fitted with fire dampers. The fire dampers are to operate automatically but are also to be capable of being closed manually from both sides of the division. It is to be possible to open fire dampers manually from the closed position from both sides of the division.

4.2.5 Special attention is to be given to maintaining the integrity of ‘A-0’ divisions or equivalent non- load bearing divisions in way of penetrations by pipes and electric cables. Transit devices containing components which release flammable or toxic gases are not to be used.

4.3.1 A fixed fire detection and fire-alarm system of an approved type complying with the requirements of Pt 6, Ch 1, 2.8 Earth leakage trip override facility of the Rules for Ships is to be installed in all compartments which are not regularly occupied or in which it is unreasonable to expect a continuous watch to be maintained and inside the enclosures referred to in Pt 5, Ch 8, 4.2 Divisions 4.2.1.

4.3.2 The occurrence of fire must be signalled visually and audibly in at least one permanently manned control room.

4.3.3 The fire alarm may be actuated manually from the permanently manned control room or may be automatically activated by the fire detection system.

4.4.1 Means for extinguishing fire are to be provided in all spaces and inside the enclosures referred to in Pt 5, Ch 8, 4.2 Divisions 4.2.1. They are to be ready for immediate use.

4.4.2 The use of a fire-extinguishing medium which either by itself or under expected conditions of use could endanger persons inside the submersible is not permitted. The use of water inside the enclosures referred to in Pt 5, Ch 8, 4.2 Divisions 4.2.1 is acceptable. Proposals to use other extinguishing media will be considered only where it can be shown that they will not contravene the requirements of this paragraph. CO2 and dry powder are not acceptable for use in submersibles.

4.4.3 The quantity of extinguishing media to be provided, application rates and the means of storage and application will be specially considered in each case having regard to the nature and the extent of the fire-risks in the spaces to be protected.

4.4.4 Special consideration will be given to the suitability of extinguishing equipment for use in spaces where isobaric pressure is not maintained.