Mechanical Ventilation in the Cargo Area
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquid Chemicals in Bulk, July 2022 - The Rules and Regulations for the Construction and Classification of Liquid Chemicals in Bulk - Mechanical Ventilation in the Cargo Area

Mechanical Ventilation in the Cargo Area

Parent topic: The Rules and Regulations for the Construction and Classification of Liquid Chemicals in Bulk

Scope

For ships to which the Code applies, the requirements of this chapter replace the requirements of SOLAS Regulation 4 - Probability of ignition.

However, for products addressed under Ch 1, 11.1 Application 11.1.2and Ch 1, 11.1 Application 11.1.3, except acids and products for which Ch 1, 15.17 Increased ventilation requirements applies, SOLAS Regulation 4 - Probability of ignition may apply in lieu of the provisions of this chapter.

12.1 Spaces normally entered during cargo-handling operations

12.1.1 Cargo pump-rooms and other enclosed spaces which contain cargo-handling equipment and similar spaces in which work is performed on the cargo shall be fitted with mechanical ventilation systems, capable of being controlled from outside such spaces.

12.1.2 Provision shall be made to ventilate such spaces prior to entering the compartment and operating the equipment and a warning notice requiring the use of such ventilation shall be placed outside the compartment.

12.1.3 Mechanical ventilation inlets and outlets shall be arranged to ensure sufficient air movement through the space to avoid the accumulation of toxic or flammable vapours or both (taking into account their vapour densities) and to ensure sufficient oxygen to provide a safe working environment, but in no case shall the ventilation system have a capacity of less than 30 changes of air per hour, based upon the total volume of the space. For certain products, increased ventilation rates for cargo pump-rooms are prescribed in Ch 1, 15.17 Increased ventilation requirements.

12.1.4 Ventilation systems shall be permanent and shall normally be of the extraction type. Extraction from above and below the floor plates shall be possible. In rooms housing motors driving cargo pumps, the ventilation shall be of the positive-pressure type.

12.1.5 Ventilation exhaust ducts from spaces within the cargo area shall discharge upwards in locations at least 10 m in the horizontal direction from ventilation intakes and openings to accommodation, service and machinery spaces and control stations and other spaces outside the cargo area.

12.1.6 Ventilation intakes shall be so arranged as to minimize the possibility of recycling hazardous vapours from any ventilation discharge opening.

12.1.7 Ventilation ducts shall not be led through accommodation, service and machinery spaces or other similar spaces.

12.1.8 Electric motors driving fans shall be placed outside the ventilation ducts if the carriage of flammable products is intended. Ventilation fans and fan ducts, in way of fans only, for hazardous locations referred to in chapter 10 shall be of non-sparking construction, defined as:

  1. impellers or housing of non-metallic construction, due regard being paid to the elimination of static electricity;

  2. impellers and housing of non-ferrous materials;

  3. impellers and housing of austenitic stainless steel; and

  4. ferrous impellers and housing with not less than 13 mm design tip clearance.

Any combination of an aluminium or a magnesium alloy fixed or rotating component and a ferrous fixed or rotating component, regardless of tip clearance, is considered a sparking hazard and shall not be used in these places.

12.1.9 Sufficient spare parts shall be carried for each type of fan on board required by this chapter.

12.1.10 Protection screens of not more than 13 mm square mesh shall be fitted in outside openings of ventilation ducts.

12.2 Pump-rooms and other enclosed spaces normally entered

12.2.1 Pump-rooms and other enclosed spaces normally entered which are not covered by Ch 1, 12.1 Spaces normally entered during cargo-handling operations 12.1.1 shall be fitted with mechanical ventilation systems, capable of being controlled from outside such spaces and complying with the requirements of Ch 1, 12.1 Spaces normally entered during cargo-handling operations 12.1.3, except that the capacity shall not be less than 20 changes of air per hour, based upon the total volume of the space. Provision shall be made to ventilate such spaces prior to personnel entering.

12.3 Spaces not normally entered

12.3.1 Double bottoms, cofferdams, duct keels, pipe tunnels, hold spaces and other spaces where cargo may accumulate shall be capable of being ventilated to ensure a safe environment when entry into the spaces is necessary. Where a permanent ventilation system is not provided for such spaces, approved means of portable mechanical ventilation shall be provided. Where necessary, owing to the arrangement of spaces, for instance hold spaces, essential ducting for ventilation shall be permanently installed. For permanent installations the capacity of eight air changes per hour shall be provided and for portable systems the capacity of 16 air changes per hour. Fans or blowers shall be clear of personnel access openings, and shall comply with Ch 1, 12.1 Spaces normally entered during cargo-handling operations 12.1.8.

LR 12.3(a) Particulars of the type and number of portable fans, their arrangement and means of attachment are to be submitted for consideration in relation to the internal and external arrangement of the space concerned.

LR 12.3(b) Increased ventilation will be required for spaces which contain gas-freeing systems, unless these systems are totally enclosed.

LR 12.3(c) Ventilation systems are to be capable of use prior to entry and during occupation.

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