14B.2.13 Ventilation systems

  14B.2.13.1 Ventilation ducts should be of non-combustible material. Short ducts, however, not generally exceeding 2m in length and with a cross-section not exceeding 0.02m² need not be non-combustible, subject to the following conditions:

• .1 they should be of a suitable material having regard to the risk of fire;

• .2 they should be used only at the end of the ventilation device; and

• .3 they should not be situated less than 600mm, measured along the duct, from an opening in an "A" or "B" class division including continuous "B" class ceilings.

  14B.2.13.2 Where ventilation ducts with a free cross-sectional area exceeding 0.02m² pass through class "A" bulkheads or decks, the opening should be lined with a steel sheet sleeve unless the ducts passing through the bulkheads or decks are of steel in the vicinity of passage through the deck or bulkhead and the ducts and sleeves should comply in this part with the following:

• .1 Sleeves should have a thickness of at least 3mm and a length of at least 900mm. When passing through bulkheads, this length should be divided preferably into 450mm on each side of the bulkhead. The ducts, or sleeves lining such ducts, should be provided with fire insulation. The insulation should have at least the same fire integrity as the bulkhead or deck through which the duct passes.

• .2 Ducts with a free cross-sectional area exceeding 0.075m² should be fitted with fire dampers in addition to the requirements of .1 above. The fire damper should operate automatically but should also be capable of being closed manually from both sides of the bulkhead or deck. The damper should be provided with an indicator which shows whether the damper is open or closed.

  Fire dampers are not required, however, where ducts pass through spaces surrounded by "A" class divisions, without serving those spaces, provided those ducts have the same fire integrity as the divisions which they pierce.

  14B.2.13.3 Ducts provided for the ventilation of a machinery space of category A, galleys lies, spaces containing vehicles or craft with fuel in their tanks or lockers storing such fuel, should not pass through accommodation spaces, service spaces or control stations unless they comply with the conditions specified in .1 to .4 or .5 and .6 below:

• .1 are constructed of steel having a thickness of at least 3mm and 5mm for duct widths or diameters of up to and including 300mm and 760mm and over respectively and, in the case of ducts with widths or diameters between 300mm and 760mm, thickness should be obtained by interpolation;

• .2 they are suitably supported and stiffened;

• .3 they are fitted with automatic fire dampers close to the boundaries penetrated; and

• .4 they are insulated to "A-60" standard from a machinery space or galley to a point at least 5m beyond each fire damper;

  or

• .5 they are constructed of steel in accordance with .1 and .2 above; and

• .6 they are insulated to "A-60" standard throughout accommodation spaces, service spaces or control stations; except that penetrations of main zone divisions should also comply with the requirements of 14B.2.13.8.

  14B.2.13.4 Ducts provided for ventilation to accommodation spaces, service spaces or control stations, should not pass through a machinery space of category A, galley, spaces containing vehicles or craft with fuel in their tanks or lockers storing such fuel, unless they comply with the conditions specified in .1 to .3 or .4 and .5 below:

• .1 where they pass through a machinery space of category A or galley, ducts are constructed of steel in accordance with 14B.2.13.3.1 & .2;

• .2 automatic fire dampers are fitted close to the boundaries penetrated; and

• .3 the integrity of the machinery space or galley boundaries is maintained at penetrations or;

• .4 where they pass through a machinery space of category A or galley, ducts are constructed of steel in accordance with 14B.2.13.3.1 & .2; and

• .5 within a machinery space of category A or galley, ducts are insulated to “A-60” standard; except that penetrations of main zone divisions should also comply with the requirements of 14B.2.13.8.

  14B.2.13.5 Ventilation ducts with a free cross-sectional area exceeding 0.02m² passing through "B" class bulkheads should be lined with steel sheet sleeves of 900mm in length divided preferably into 450mm on each side of the bulkheads, unless the duct is of steel for this length.

  14B.2.13.6 For a control station outside machinery spaces and other normally manned control stations, practical measures should be taken to ensure that ventilation, visibility and freedom from smoke are maintained so that, in the event of fire, the machinery and equipment contained in the control station may be supervised and continue to function effectively. Alternative and separate means of air supply should be provided; air inlets of the two sources of supply should be so disposed that the risk of both inlets drawing in smoke simultaneously is minimized. These requirements need not apply to control stations situated on, and opening on to, an open deck, or where local closing arrangements would be equally effective.

  14B.2.13.7 Exhaust duct(s) from a galley range should be constructed of "A" class divisions where passing through accommodation spaces and/or spaces containing combustible materials. In addition to the requirements of 14B.2.13.3 an exhaust duct should be fitted with:

• .1 a grease trap readily removable for cleaning;

• .2 a fire damper located in the lower end of the duct and in addition, a fire damper in the upper end of the duct (if required for the extinguishing medium);

• .3 arrangements for shutting off the exhaust fans;

• .4 fixed means for extinguishing a fire within the duct;

• .5 local controls to activate extinguishing system; stop the fans and close the fire dampers should be grouped in one position immediately outside the main entrance to the galley.

  14B.2.13.8 When it is necessary for a ventilation duct to pass through a main vertical zone division, a fail-safe automatic closing fire damper should be fitted adjacent to the division. The damper should also be capable of being manually closed from each side of the division. The operating position should be readily accessible and be marked in red light-reflecting colour. The duct between the division and the damper should be of steel or other equivalent material and, if necessary, insulated to comply with the requirements of SOLAS regulation II-2/9.3.1. The damper should be fitted on at least one side of the division with a visible indicator showing whether the damper is in the open position.

  14B.2.13.9 Inlets and outlets of ventilation systems should be capable of being closed from outside the space being ventilated.

  14B.2.13.10 Power ventilation of accommodation spaces, service spaces, control stations and machinery spaces should be capable of being stopped from an easily accessible position outside the space being served. This position should not be readily cut off in the event of a fire in the spaces served. The means provided for stopping the power ventilation of a machinery space should be entirely separate from the means provided for stopping ventilation of other spaces.

  14B.2.13.11 Where public spaces span three or more open decks and contain combustibles such as furniture and other enclosed spaces, the space is to be equipped with a smoke extraction system. The smoke extraction system is to be activated by the smoke detection system required by 14B.2.14 and is to be capable of manual control. The fans are to be capable of exhausting the entire volume within the space in not more than 10 min.

  14B.2.13.12 Store-rooms containing highly flammable products are to be provided with ventilation arrangements that are separate from other ventilation systems. Ventilation is to be arranged to prevent the build up of flammable vapours at high and low levels. The inlets and outlets of ventilators are to be positioned so that they do not draw from or vent into an area which would cause undue hazard, and are to be fitted with spark arresters.

  14B.2.13.13 Ventilation systems serving Category 'A' machinery spaces are to be independent of systems serving other spaces.

  14B.2.13.14 All enclosed spaces containing free standing fuel tanks are to be ventilated independently of systems serving other spaces.

  14B.2.13.15 Ventilation is to be provided to prevent the accumulation of dangerous concentrations of flammable gas which may be emitted from batteries.

  14B.2.13.16 Ventilation openings may be fitted in and under the lower parts of cabin and public space doors in corridor bulkheads. The total net area of any such openings is not to exceed 0.05 m².

  14B.2.13.17 For spaces containing vehicles or craft with fuel in their tanks or lockers storing such fuels, see 14.1.5. For additional requirements for the ventilation of domestic gaseous fuel, see 14A.5.

  14B.2.13.18 Ducts provided for exhaust ventilation from tumble driers are to be fitted with suitable located cleaning and inspection openings.

  14B.2.13.19 All fire dampers should comply with IMO Resolution A.754(18) pt A11 as referenced in IMO FTP Code, Annex 1, Part 3.