Ventilation of dry cargo vessels

9.1.0.12 Ventilation

9.1.0.12.1 It must be possible to ventilate each hold by means of two mutually independent extraction ventilators having a capacity of not less than five changes of air per hour based on the volume of the empty hold. The extraction ducts shall be positioned at the extreme ends of the hold and extend down to not more than 50 mm above the bottom. The extraction of gases and vapours through the duct shall also be ensured for carriage in bulk.

If the extraction ducts are movable they shall be suitable for the ventilator assembly and capable of being firmly fixed. Protection shall be ensured against bad weather and spray. The air intake shall be ensured during ventilation.

9.1.0.12.2 The ventilation system of a hold shall be arranged so that dangerous gases cannot penetrate into the accommodation, wheelhouse or engine rooms.

9.1.0.12.3 

(a) Ventilation shall be provided for the accommodation, wheelhouse and for service spaces;

(b) The ventilation system in such spaces shall meet the following requirements:
(i) The air intakes of the ventilation system shall be located as far away as possible, and not less than 6.00 m from the protected area and not less than 2.00 m above the deck;
(ii) Overpressure of at least 0.1 kPa (0.001 bar) may be maintained in the premises;
(iii) A breakdown alarm is integrated;
(iv) The ventilation system, including the breakdown alarm, shall be at least of the "limited explosion risk" type;
(v) A gas detection system conforming to conditions 1. to 4. below is connected to the ventilation system: 
  1. It is appropriate at least for use in zone 1, explosion group IIC and temperature class T6;
  2. It is equipped with sensors:
    - On the suction inlets of the ventilation systems; and
    - Directly below the top edge of the sill of the entrance doors;
  3. Its t90-time is lower than or equal to 4 s;
  4. Measurement shall be continuous;
(vi) In the service spaces, the ventilation system is linked to the emergency lighting, which shall be at least of the "limited explosion risk" type;
This emergency lighting is not necessary if the lighting installations in the service spaces are of at least the "limited explosion risk" type;
(vii) The suction of the ventilation system and installations and equipment that do not meet the requirements of 9.1.0.51 and 9.1.0.52.1 shall be shut down when a concentration equal to 20 % of the LEL of n-Hexane is reached;
The switching-off shall be indicated in the accommodation and wheelhouse by visual and audible signals;
(viii) In the event of failure of the ventilation system or of the gas detection installations in the accommodation, installations and equipment in the accommodation that do not comply with the requirements of 9.1.0.51 and 9.1.0.52.1 shall be switched off;
The switching-off shall be indicated in the accommodation, the wheelhouse and on the deck by visual and audible signals;
(ix) In the event of failure of the ventilation system or of the gas detection installations in the wheelhouse or the service spaces, installations and equipment in those spaces that do not comply with the requirements of 9.1.0.51 and 9.1.0.52.1 shall be switched off;
The switching-off shall be indicated in the wheelhouse and on the deck by visual and audible signals. The alarm must be relayed to the accommodation automatically if it has not been switched off;
(x) Any switching-off shall take place immediately and automatically and, if necessary, shall switch on the emergency lighting;
The automatic switch-off device is set so that no automatic switching-off may occur while the vessel is under way;

(c) If there is no ventilation system or the ventilation system of a space does not comply with all the requirements set out in (b) above, any installations or equipment present in that space that may, if switched on, give rise to surface temperatures higher than those mentioned in 9.1.0.51 or that do not meet the requirements set out in 9.1.0.52.1 must be capable of being switched off.

9.1.0.12.4 Notice boards shall be fitted at the ventilation inlets indicating the conditions under which they shall be closed. All ventilation inlets of accommodation, wheelhouse and service spaces leading into the open air outside of the protected area shall be located not less than 2.00 m from the protected area.

All ventilation inlets shall be fitted with fixed devices according to 9.1.0.40.2.2 (c) enabling them to be closed rapidly. It shall be clear whether they are open or closed.

9.1.0.12.5 Ventilators including their motors used within the protected area and motors for hold ventilators which are arranged in the air flow shall fulfil at least the requirements for use in zone 1. They shall meet at least the requirements for temperature class T4 and explosion group II B.

9.1.0.12.6 The requirements of 9.1.0.12.3 (b) or (c) must be met only if the vessel is located within or in the immediate vicinity of a shoreside assigned zone.