Section 5 Location and arrangement of spaces

5.1.1 The locations and arrangements of bunkering stations, fuel storage tanks, fuel supply equipment and consumers shall be evaluated in the risk-based studies, see Ch 1, 3 Risk-based studies, and be acceptable to LR. The locations and arrangements shall satisfy the requirements of this Section.

5.1.2 Escape routes shall not pass through hazardous areas.

5.2.1 Methanol bunkering stations are not to be used for any other purpose than bunkering methanol fuel.

5.2.2 Bunkering stations on open deck shall be located in a naturally well-ventilated area and protected from possible mechanical damage.

5.2.3 Bunkering stations shall be physically separated or structurally shielded from accommodation, service areas and control stations.

5.2.4 Bunkering stations shall not be adjacent to, above or below:

1. accommodation spaces;

2. service spaces;

3. control stations.

5.3.1 Fuel storage tanks can be integral tanks or independent tanks, see Ch 1, 1.3 Definitions.

5.3.2 Fuel storage tanks shall not be located within the accommodation area or high fire risk spaces such as machinery spaces of category A.

5.3.3 No part of the outer extent of fuel storage tanks shall be less than 800mm inboard from the ship shell side or from the boundary of any adjacent space, except as otherwise allowed by Ch 1, 5.3 Fuel storage tanks 5.3.6.

5.3.4 Fuel storage tanks shall be protected against the effects of fire and heat when adjacent compartments are high fire risk/fire load spaces and the design details shall be considered in the risk-based studies.

5.3.5 Spaces forward of the collision bulkhead (forepeak) and/or, aft of the aftermost bulkhead (aft peak) shall not be arranged as fuel storage tanks.

5.3.6 Integral fuel storage tanks shall be surrounded by a cofferdam where not bounded by bottom shell plating or fuel pump rooms.

5.3.7 Where cofferdams surrounding integral fuel storage tanks are water filled, they shall be specially considered in the risk-based studies, see Ch 1, 3.1 Purpose 3.1.1.(c).

5.3.8 Independent fuel storage tanks:

1. on open deck shall be located in a naturally well-ventilated area;

2. may be located in enclosed or semi-enclosed fuel storage hold spaces.

5.3.9 Independent fuel storage tanks on open deck shall be surrounded by coamings and shall be provided with means for safely draining accidental spills, see Ch 1, 7.3 Drainage arrangements.

5.3.10 "Independent fuel storage tanks and hold spaces shall not be adjacent to, or below accommodation spaces, service spaces or control stations, where practicable."

5.4.1 All equipment containing fuel that is provided for supply to consumers shall be located in a dedicated space (e.g. a pump room) and these spaces shall be:

1. considered hazardous;

2. gastight and liquid-tight;

3. provided with approved piping and cabling penetrations;

4. located outside of the machinery space.

5.4.2 The fuel supply system and equipment shall not be adjacent to accommodation spaces, service spaces or control stations, where practicable.

5.5.1 Consumers and the associated supply piping shall be arranged so that the machinery spaces in which they are located are non-hazardous, see Ch 1, 6 System design .

5.6.1 Direct access from a non-hazardous space to a hazardous space is not permitted. Where access from a non-hazardous space to a hazardous space is required for operational reasons, an air-lock shall be provided.

5.6.2 Air-locks shall be:

1. of simple geometric form;

2. provided with clear passage;

3. comprise of two self-closing gastight steel doors.

5.6.3 Air-lock doors shall be:

1. spaced at least 1,5 m but no more than 2,5 m apart;

2. provided without any hold-back arrangements;

3. capable of maintaining the differential pressure, see Ch 1, 5.6 Access 5.6.4.

5.6.4 The air-lock space shall be maintained with a differential pressure and shall ensure that no fuel can be released to non-hazardous spaces in the event of a fuel release into the hazardous space.

5.6.5 The air-lock space shall be mechanically ventilated from a non-hazardous area.

5.6.6 The air-lock doors shall be monitored, see Ch 1, 8.2 Control, alarm and safety functions 8.2.13.

5.6.7 Mechanical ventilation to the air-lock shall be monitored, see Ch 1, 8.2 Control, alarm and safety functions 8.2.14.

5.6.8 The air-lock space shall be monitored for flammable vapour, see Ch 1, 8.4 Methanol vapour detection 8.4.1.(c).

5.6.9 Electrical equipment that is not of the certified safe type and is located in non-hazardous spaces protected by air-locks shall be de-energised in case of loss of overpressure in the space.

5.6.10 Essential equipment required for safety shall not be de-energised upon loss of overpressure in the space and shall be of a certified safe type. This may include lighting, fire detection, public address, general alarms systems.

5.6.11 Electrical equipment which is not of the certified safe type for propulsion, power generation, manoeuvring, anchoring and mooring equipment as well as the emergency fire pumps shall not be located in spaces to be protected by air-locks.

5.6.12 Fuel storage tanks and surrounding cofferdams shall have suitable access from open deck for cleaning, maintenance, inspection and purging of fuel, except as given in Ch 1, 5.3 Fuel storage tanks 5.3.8 and Ch 1, 5.3 Fuel storage tanks 5.3.9.

5.6.13 The pump room shall have an independent access direct from open deck. An air-lock shall be provided where this is not practicable.

5.6.14 For fuel storage tanks and cofferdams without direct access from open deck, the arrangements shall be such to ensure that, these spaces are free from flammable and toxic vapour or other gases that represent a hazard to the crew before any access hatch is opened.

5.6.15 For fuel storage tanks or cofferdams without direct access from open deck, the entry space shall comply with the following:

1. The entry space shall be well ventilated;

2. The entry space shall have sufficient open area around the fuel storage tank hatch for efficient evacuation and rescue operation.

5.6.16 Direct access to fuel storage tanks or cofferdams from accommodation spaces, service spaces, control stations and machinery spaces of category A will not be accepted. Access from cargo spaces may be accepted, dependent upon the types of cargo intended to be carried, and if the area is capable of being cleared of cargo and cargo operations suspended.

5.6.17 The area around independent fuel storage tanks shall be sufficient to carry out maintenance, inspections, evacuation and rescue operations.

5.6.18 Horizontal hatches or openings to or within fuel storage tanks or cofferdams shall have a minimum clear opening of 600 X 600 mm that also facilitates the hoisting of an injured person from the bottom of the tank/cofferdam.

5.6.19 For access through vertical openings providing main passage through the length and breadth within fuel storage tanks and cofferdams, the minimum clear opening shall not be less than 600 X 800 mm at a height of not more than 600 mm from bottom plating unless gratings or footholds are provided. Smaller openings may be accepted provided evacuation of an injured person can be demonstrated.

5.6.20 Maintenance hatches or removable panels providing access to enclosed spaces considered as hazardous, such as cofferdams, shall be provided with suitable seals to prevent the passage of fuel vapour when closed. The sealing arrangements on hatches and panels shall be capable of being tested for gas-tightness following maintenance.

5.6.21 Access hatch seals shall be secured in place.

5.7.1 Ventilation and pressurisation shall comply with the requirements of IEC 60092-502: Electrical installations in ships – Part 502: Tankers – Special features, the Rules for Ships, Pt 6, Ch 2, 14 Electrical equipment for use in explosive gas atmospheres or in the presence of combustible dusts and these Rules.

5.7.2 Ventilation arrangements shall be such that the required ventilation capacity can be maintained under all foreseeable operating conditions, including single failure in equipment or control system.

5.7.3 All enclosed hazardous areas, except for cofferdams (see Ch 1, 6.4 Cofferdams ), shall be provided with fixed mechanical ventilation of negative pressure that has a capacity of at least 30 air changes per hour under all foreseeable operating conditions, including a single failure in equipment or control system. The arrangements shall be such that there will be no regions of stagnant air within the ventilated space.

5.7.4 Air supplied for ventilation shall be in addition to the air supplied for combustion in consumers.

5.7.5 "Ventilation exhausts shall discharge to atmosphere at least 3 m from the nearest air intakes or open decks that are accessible to personnel, or openings to accommodation and enclosed working spaces, and from any possible source of ignition, to ensure that any such opening, air intake or source of ignition lies outside the hazardous area associated with the ventilation exhaust, as identified by Ch 1, 3.5 Hazardous areas classification study.

5.7.6 Fans located in hazardous areas or in ventilation ducts serving hazardous areas shall be of the non-sparking type, in accordance with Pt 5, Ch 15, 1.9 Non-sparking fans for hazardous areas of the Rules for Ships.

5.7.7 ‘Fail-safe’ automatic closing fire dampers of an approved type shall be fitted in all ventilation trunks serving hazardous areas. The characteristics of the ‘fail-safe’ operation shall be evaluated, not only on the basis of the function of the fire damper, but also the availability of the machinery and systems within the space that it serves.

5.8.1 In order to facilitate the selection of appropriate electrical apparatus, mechanical equipment and the design of the electrical and mechanical installations, hazardous areas shall be identified and classified into zones 0, 1 and 2.

5.8.2 The hazardous areas identified in Ch 1, 5.8 Hazardous areas 5.8.4 andCh 1, 5.8 Hazardous areas 5.8.5 are only valid for the following assumptions. If (a) or (b) are not met, hazardous areas shall be determined in accordance with Ch 1, 3.5 Hazardous areas classification study:

1. ventilation is supplied at least 30 air changes per hour;

2. fuel supply pressure does not exceed 10 bar.

5.8.3 Hazardous areas of zone 0 include, but are not limited to:

1. the interior of fuel tanks;

2. the interior of pipework for pressure-relief and venting systems for fuel tanks;

3. the interior of pipes and equipment containing fuel.

5.8.4 Hazardous areas of zone 1 include, but are not limited to:

1. cofferdams;

2. enclosed or semi-enclosed bunker stations;

3. enclosures or compartments containing fuel valves;

4. areas on open deck or semi-enclosed spaces on deck, within 3 m of ventilation outlets of spaces identified in (a), (b) and (c);

5. areas on open deck or semi-enclosed spaces on deck, within the vicinity of any fuel storage tank outlet intended for the passage of large volumes of fuel (e.g. fuel containment pressure relief valves). This hazardous area is defined as a vertical cylinder of unlimited height and 6 m radius centred upon the centre of the outlet and within a hemisphere of 6 m radius below the outlet;

6. areas on open deck, or semi-enclosed spaces on deck, within 3 m of;

   1. any fuel storage tank outlet,

   2. any vapour outlet,

   3. bunker manifold valve,

   4. other fuel valve,

   5. fuel pipe flange,

   6. fuel pump-room ventilation outlets,

   7. tank openings for pressure release provided to permit the flow of small volumes of vapour mixtures caused by thermal variation;

7. areas on open deck or semi-enclosed spaces on deck, within 1,5 m of compressor and pump room entrances, pump and compressor rooms, and bunker stations;

8. areas on open deck or semi-enclosed spaces on deck, within 1,5 m of ventilation inlets and other openings into zone 1 spaces;

9. areas on open deck within spillage coamings surrounding methanol bunker manifold valves and 3 m beyond these, up to a height of 2,4 m above the deck;

10. areas within 2,4 m of the outer surface of a fuel containment system where such surface is exposed to the weather.

5.8.5 Hazardous areas of zone 2 include, but are not limited to:

1. areas within 1,5 m of surrounding open or semi-enclosed spaces of zone 1, other than those mentioned inCh 1, 5.8 Hazardous areas 5.8.5.(b), Ch 1, 5.8 Hazardous areas 5.8.5.(c) and Ch 1, 5.8 Hazardous areas 5.8.5.(d);

2. areas 4 m beyond the cylinder and 4 m beyond the sphere defined in Ch 1, 5.8 Hazardous areas 5.8.4.(e);

3. areas 3 m beyond the areas in Ch 1, 5.8 Hazardous areas 5.8.4.(h) up to a height of 2,4 m above the deck;

4. air-locks protecting a non-hazardous area from a zone 1 area.