The catastrophic consequences of fires on board Ro-Ro ships in the last decade, particularly on-board the “Norman Atlantic” in December 2013 and the “Sorrento” in April 2015, have pushed this issue into the limelight. They have encouraged studies from internationally acclaimed bodies such as the International Union of Marine Insurers (IUMI) and DNV GL. These studies confirm that the risk of fire is twice as great on Ro-Ro boats than on many other cargo and passenger vessels. Fire remains the number one cause for port state control detaining ships. Consequently, the maintenance and proper understanding of a vessel’s fixed fire extinguishing (FFE) systems is critical. These boats, as with any vessel at sea, must act as their own fire-rescue system and be able to tackle on-ship fires in a safe, efficient and self-contained manner. As such, proper understanding and maintenance of FFE are of crucial importance, not just for cargo security and reduced insurance claims, but most fundamentally to protect human life through safe-ship practice.
The FFE systems on-board Ro-Ro vessels typically include CO2 gas cylinders for fire suppression. These large gas cylinders are stored under pressure, and consequently are subject to risk of leakage or accidental discharge; any small change in pressure of a gas cylinder can result in pressure falling below the point at which fire suppression would be effective. Currently, to ensure the effectiveness of these systems and abide by legal requirements, periodic inspections are conducted annually or biennially by an Accredited Service Agent i.e. an external Marine Servicing Company. However, the IMO SOLAS FSS Code also requires inspection of cylinders in between these periodical tests by the vessel’s own onboard crew.
Typical methods for on-ship regular cylinder inspection primarily consists of trained professionals weighing the chosen cylinder, to assess if there has been weight loss due to gas leakage. However, although this method is widely used, it is ultimately unsafe practice, requiring constant handling of tanks in a delicate, high-pressure state, usually at 720psi or approx.50 bar. To tackle this issue, technological advances have been made to create portable ultrasonic liquid level indicators which serve as liquid gaseous inspection equipment. Coltraco Ultrasonics is one such company providing safe, simple, non-invasive monitoring equipment that facilitates regular inspection of FFE gaseous systems. Through use of Ultrasonic Technology, these products are able to accurately and quickly assess the liquid level of CO2 or clean agent (commonly FM-200® or NOVEC™ 1230) suppression systems, in order to identify leakage or accidental discharge.