ISSUE 13 // FEBRUARY 2025 BRITANNIA LOSS PREVENTION MANY CARGO CLAIMS RESULT FROM MOISTURE DAMAGE, OCCURRING DUE TO THE DEVELOPMENT OF CONDENSATION (“SWEAT”). ESSENTIAL GUIDE TO UNDERSTANDING CARGO VENTILATION Proper ventilation is instrumental in preventing the deterioration of cargo, by removing excessive moisture and minimising the formation of sweat. Ventilation is also required for some cargoes to disperse hazardous gases emitted by the cargo, such as carbon dioxide, carbon monoxide and methane. OUR PARTNER FOR THIS ISSUE Triglav Maritime provides bespoke, comprehensive consultancy services focusing on risk management, loss prevention, as well as marine vetting and assurance matters. The founder, Capt. Ostrowicki has 34 years of combined command and shore-based experience. He has sailed on bulk carriers, general cargo and container ships. His shore-based experience includes ship operations and marine vetting of dry cargo ships, tankers and gas carriers, as an operations manager, marine vetting director and loss prevention manager. Capt. Ostrowicki provides expert advice on risk management and safety management processes. In addition to marine incident and claim investigations, he performs management reviews, ISM and TMSA audits and in-depth risk assessments through data analysis. He has also authored several publications. FOR SOLID BULK CARGOES, THE REQUIREMENTS OF THE INTERNATIONAL MARITIME SOLID BULK CARGOES CODE (IMSBC CODE) APPLY. In addition to specific cargo schedules, the general requirements of IMSBC Section 3 regarding ventilation relate to: Attention which should be paid to cargoes depleting oxygen and emitting toxic gases Preventing formation of explosive or flammable atmosphere in cargo holds Prevention of ventilation (other than surface ventilation) in cargoes which may spontaneously heat Protection of personnel from hazardous gases, vapours or dust. Cargo ships are provided with natural, or mechanical ventilation systems. It is essential that the ship’s master and officers have thorough understanding of the design and operation of the ventilation system to use it correctly and to full capacity. In a natural ventilation system, the circulation of air is achieved without mechanical power, by pressure differential resulting from relative wind, or by thermal differential between the ambient air and the air inside the cargo hold. A typical mechanical ventilation system is open circuit, where supply fans draw the ambient air into the cargo hold which, after passing through the headspace over cargo, exits the cargo hold through exhaust vent openings. There are also other designs and arrangements to remove excessive moisture from within cargo holds. Such arrangements may involve the use of dehumidifiers (a fixed installation or portable devices). They are typically used where open circuit ventilation is impossible, or insufficient to prevent cargo damage – for example, on ships carrying steel cargoes loaded in winter for discharge in warm conditions. PRINCIPAL TERMS RELATED TO HUMIDITY WATER VAPOUR, AS THE GASEOUS STATE OF WATER, IS GENERALLY INVISIBLE IN THE AIR. Relative humidity (RH) expressed in %, is the amount of water vapour present in the air, compared with the maximum humidity the air can hold. When RH reaches 100%, the air is saturated with water vapour. Warm air can hold more water vapour than cold air. If the air cools down, its RH will eventually increase to 100% and condensation (“dew”) will form on the surround