Section 10 Ballast water treatment room location and boundaries

10.1.1 The structural requirements are to comply with the relevant LR Rules and statutory requirements as applicable and separately approved. Consideration is to be given to BWTS space boundaries, fire integrity, hull penetrations and chemical storage tank constructions, if fitted.

10.2.1 BWTS using chemical substances

1. For BWTS storing, introducing or generating chemicals, the BWTR and chemical substance storage rooms are not to be located in the accommodation area. Any ventilation exhaust or other openings from these rooms is to be located not less than 3 m from entrances, air inlets and openings to accommodation spaces.

   This requirement need not apply in a case where the BWTS is located in the engine room.

10.2.2 Ozone-based BWTS

1. Ozone-based BWTS – i.e. category 7a and 7b as per Table 25.1.1 Categorisation of BWTS technologies – are to be located in a dedicated compartment, separated from any other space by gastight boundaries. Access to the BWTR from any other enclosed space shall be through airlock only, except if the only access to that space is from the open deck.
   Access to the ozone-based BWTR may only be provided through the engine room if:

   • Access from the engine room to the BWTR is through an airlock; and
   • An alarm repeater is provided in the BWTR, which will repeat any alarm activated in the engine room.
2. A sign shall be affixed to the door providing personnel with a warning that ozone may be present and with the necessary instructions to be followed before entering the room.

10.3.1 Ventilation arrangement

1. The ventilation systems for BWTR containing BWTS of the following types is to be independent of the ventilation systems serving any other spaces:
   • BWTS storing, introducing or generating chemical substances;
   • De-oxygenation, including pasteurisation and de-oxygenation (category and category 8 as per Table 25.1.1 Categorisation of BWTS technologies);
   • Electrolysis;
   • Ozone injection.
2. The ventilation exhaust for BWTR containing a nitrogen generator is to be located in the lower part of the room in order to efficiently evacuate dangerous gases – as defined in Pt 5, Ch 25, 1.2 Definitions – heavier than air.
3. The ventilation exhaust for BWTR containing electrolysis systems is to be located so as to be able to efficiently evacuate dangerous gases – as defined in Pt 5, Ch 25, 1.2 Definitions – that could be generated during the electrolysis process. Due regard is to be paid to the expected quantity and density of such gases when designing the ventilation exhaust.
4. The following requirements apply to ventilation ducts serving BWTR for ozone-based BWTS:
   • The part of the ducts located outside of the BWTR are to be made of steel having a thickness of at least 3 mm for ducts with a free cross-sectional area of less than 0,075 m², at least 4 mm for ducts with a free cross-sectional area of between 0,075 m² and 0,45 m², and at least 5 mm for ducts with a free cross-sectional area of over 0,45 m²;
   • The ducts are to be suitably supported and stiffened; and
   • The outside openings of the ducts are to be fitted with protective screens of not more than 13 mm square mesh.
5. The ventilation system for BWTR containing ozone-based BWTS or the ventilation system for hydrogen de-gas arrangement as required by Pt 5, Ch 25, 11.3 Special requirements for BWTS generating dangerous gas or dealing with dangerous liquids (categories 2, 3a, 3b, 3c, 4, 5, 6, 7a, 7b and 8) 11.3.1.(e) is to be interlocked with the BWTS such that:
   • In case of loss of ventilation (primary and secondary), a visual and audible alarm is to be triggered both inside and outside the BWTR and at a place where a responsible member of the crew is on duty. If the ventilation is not restored after a pre-set time, the BWTS is then automatically shut down. Any need for cooldown necessary for safe shutdown is to be considered in the shutdown sequence.
   • It is not to be possible to start the BWTS without the ventilation running.

For ventilation systems serving BWTR and containing or conveying a dangerous gas, the relevant requirements in Pt 5, Ch 25, 11.3 Special requirements for BWTS generating dangerous gas or dealing with dangerous liquids (categories 2, 3a, 3b, 3c, 4, 5, 6, 7a, 7b and 8) are to be satisfied.