Section 2 Coal storage, handling, ash collection and disposal arrangements

2.1.1 The arrangements for coal bunkers, including hatchways, ventilation, monitoring and their design characteristics regarding intact and damaged stability are to comply with the requirements detailed in Pt 7, Ch 7, 4 Ship structure and Pt 7, Ch 7, 7 Fire protection and extinction, as applicable.

2.1.2 Coal is to be stored in not less than two bunkers. Vessels on restricted routes having a voyage time less than the capacity of the daily service hoppers, or where the boiler has the alternative means of firing, or where alternative means of propulsion are fitted, may be provided with only one bunker.

2.1.3 The clearance spaces between the boilers, other heated surfaces and the coal bunkers are to be adequate for the free circulation of air necessary to avoid transmission of heat to the coal.

2.1.4 A daily service storage hopper is to be provided for each coal-fired boiler.

2.1.5 Coal bunkers and daily service storage hoppers are to be designed to avoid dead spots and areas where coal can accumulate and impede the normal flow or can provide the conditions to promote spontaneous combustion.

2.1.6 Bunker and daily service storage hopper outlet gravity-fed discharges are to be provided with shut-off devices. Stopping the transfer device will be acceptable in lieu where a bunker delivers to transfer arrangements and stopping the transfer device effectively prevents flow from the bunker, see Pt 7, Ch 7, 2.2 Coal handling 2.2.4.

2.1.7 Shut-off devices on the coal bunker and daily service storage hopper outlets are to be capable of being operated locally and also from an accessible position outside the compartment in which they are situated.

2.1.8 The arrangements for loading coal into bunkers or during transfer into daily service storage hoppers should, in general, avoid the tendency of the coal to segregate. For this purpose multiple loading points should be used if necessary.

2.2.1 Each daily service storage hopper is to be provided with a separate system for transferring coal from the bunker(s). In the case of a single boiler installation, more than one transfer system from the bunker(s) to the daily service storage hopper are to be provided, unless alternative means of firing the boiler is available.

2.2.2 Adequate access facilities are to be provided in the coal feeder systems to permit maintenance and removal of blockages.

2.2.3 Where coal screens or crushers are necessary for the efficient operation of the coal burning equipment, they are to be provided in each boiler coal feed arrangement.

2.2.4 The coal handling plant is to be capable of being stopped locally and from an accessible position outside the compartment in which it is situated, see Pt 7, Ch 7, 2.1 Coal storage 2.1.6.

2.2.5 The use of milling systems for the production of pulverised fuel will be specially considered.

2.3.1 Each coal fired boiler is to be provided with a bottom ash and fly ash collecting and disposal arrangement.

2.3.2 Where both bottom ash and fly ash collecting and disposal arrangements are operated by either pneumatic or water systems, then these may be made common.

2.3.3 Two independent means of supplying the operating medium for ash collection and disposal systems are to be provided.

2.3.4 Heated ash storage and transfer systems are to be efficiently lagged to minimise risk of fire and to prevent damage by heat.

2.3.5 Where wet ash water transfer systems are used, consideration is to be given to the effects of corrosion and erosion on the collection, transfer and storage equipment.

2.3.6 Ash transfer systems employing water separation arrangements are to be such that water will drain naturally back to the de-watering bins or into a collection tank. Such drainage facilities should not, in general, be led direct to bilge wells.

2.3.7 Where a dry ash collection system is proposed, the arrangement of conveyors, pipes and chutes should avoid condensation due to excessive cooling to prevent solidification of the ash.

2.3.8 Adequate ash storage capacity, with access facilities to permit maintenance and removal of blockages, is to be provided for systems using boilers which have no alternative means of firing. Certain National Authorities or local Administrations prohibit the direct discharge of ash overboard.