Section 3 CA zones and adjacent spaces

3.1.1 The CA zones are to be made air-tight in accordance with the requirements in Pt 7, Ch 1, 9.3 Air-tightness of CA zones. Particular attention is to be paid to sealing of hatches, plugs and access doors in each CA zone. Double seals are to be fitted to each opening.

3.1.2 Openings for pipes, ducts, cables, sensors, sampling lines and other fittings passing through the decks and bulkheads are to be suitably sealed and made air-tight.

3.1.3 The liquid sealed traps from bilges and drains from the cooler trays are to be deep enough to withstand, when filled with liquid which will not evaporate or freeze, the design pressure in each CA zone when taking account of the ship's motion.

3.1.4 Air refreshing inlets and outlets are to be provided with isolating arrangements.

3.2.1 Means are to be provided to protect CA zones against the effect of overpressure or vacuum.

3.2.2 At least two P/V valves are to be fitted in each CA zone. They are to be set for the design conditions of the CA zone.

3.2.3 Consideration will be given to the use of a single valve in combination with other suitable means of overpressure or vacuum protection.

3.2.4 The proposed P/V valves for each zone are to be of adequate size to release any excess pressure and to relieve the vacuum at maximum cooling rate.

3.2.5 P/V valve discharges are to be located at least 2 m above deck and 10 m away from any ventilation inlets. Discharge piping is to be arranged to preclude ingress of water, dirt or debris which may cause the equipment to malfunction.

3.2.6 Pressure sensors are to be installed in locations necessary to monitor pressure of all CA zones. Pressure sensors are to be installed away from fans, air inlets and outlets.

3.3.1 The arrangements for gas freeing of CA zones are to be capable of purging all parts of the zone to ensure a safe atmosphere.

3.3.2 Cargo air cooling fans and the air refreshing arrangements may be used for gas freeing operations.

3.3.3 Gas freeing outlets are to be led to a safe place in the atmosphere 2 m above the deck, away from accommodation spaces and intakes of the fans for accommodation.

3.4.1 Deckhouses and other adjacent spaces which require to be entered regularly are to be fitted with a positive pressure type mechanical ventilation system with a capacity of at least 10 air changes per hour capable of being controlled from outside these spaces.

3.4.2 Adjacent spaces not normally entered are to be provided with a mechanical ventilation system which can be permanent or portable to gas free the space prior to entry.

3.4.3 Ventilation inlets are to be arranged so as to minimise recycling any gas and are to be at least 10 m in the horizontal direction away from the ventilation outlets.