Section 12 Mechanical Ventilation in the Cargo Area

The requirements of this Section are to be substituted for SOLAS regulation II-2/4.5.2.6 and 4.5.4. 1201. Spaces required to be entered during normal cargo handling operations

1. Electric motor rooms, cargo handling system rooms, other enclosed spaces which contain cargo han- dling equipment and similar spaces in which cargo handling operations are performed are to be fit- ted with mechanical ventilation systems capable of being controlled from outside such spaces. Provision is to 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 are to be placed outside the compartment.

2. Mechanical ventilation inlets and outlets are to be arranged to ensure sufficient air movement through the space to avoid the accumulation of flammable or toxic vapours and to ensure a safe working environment, but in no case the ventilation system is to have a capacity of less than 30 changes of air per hour based upon the total volume of the space. As an exception, gas-safe cargo control rooms may have eight changes of air per hour.

3. Ventilation systems are to be fixed and, if of the negative pressure type, permit extraction from ei- ther the upper or the lower parts of the spaces, or from both the upper and the lower parts, de- pending on the density of the vapours.

4. In rooms housing electric motors driving cargo handling system, spaces except machinery spaces containing inert gas generators, cargo control rooms if considered as gas-safe spaces and other gas- safe spaces within the cargo area, the ventilation are to be of the positive pressure type.

5. In cargo handling system rooms and in cargo control rooms if considered gas-dangerous, the ven- tilation are to be of the negative pressure type.

6. Ventilation exhaust ducts from gas-dangerous spaces are to discharge upwards in locations at least 10 m in the horizontal direction from ventilation intakes and openings to accommodation spaces, service spaces and control stations and other gas-safe spaces.

7. Ventilation intakes are to be so arranged as to minimize the possibility of recycling hazardous car- go gases from any ventilation discharge opening.

8. Ventilation ducts from gas-dangerous spaces are not to be led through accommodation, service and machinery spaces or control stations, except as allowed in Sec 15.

9. Fans serving hazardous spaces

(1) Electric motors driving fans are to be placed outside the ventilation ducts.

(2) Ventilation fans are not to produce a source of gas ignition in either the ventilated space or the ventilation system associated with the space.

(3) Ventilation fans and fan ducts, in way of fans only, for gas-dangerous spaces are to be of non sparking construction defined as:

(A) impellers or housing of nonmetallic construction, due regard being paid to the elimination of

static electricity;

(B) impellers and housing of nonferrous materials;

(C) impellers and housing of austenitic stainless steel; or

(D) ferrous impellers and housing with not less than 13 mm design tip clearance.

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

(4) The air gap between the impeller and the casing is to be not less than 10 % of the shaft diam- eter in way of the impeller bearing and not less than 2 mm. It need not be more than 13 mm.

10. Spare parts are to be carried for each type of fan on board referred to in this Section.

11. Protection screens of not more than 13 mm square mesh are to be fitted in outside openings of ventilation ducts.

12. The shafting penetration of motors driving fans through bulkheads and decks of dangerous spaces or through ventilation ducts is to be fitted with a gas-tight sealing device, of the oil seal type or

equivalent, deemed suitable by the Society.

1202. Spaces not normally entered

Hold spaces, void spaces, cofferdams, spaces containing cargo piping and other spaces where cargo vapours may accumulate, are to 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 are to be provided. Where necessary ow- ing to the arrangement of spaces, such as hold spaces, essential ducting for such ventilation is to be permanently installed. Fans or blowers are to be clear of personnel access openings, and are to comply with 1201. 9.

The ventilation system for spaces not normally entered shall have a capacity of not less than eight 8 changes per hour based on the total volume of the space.