One factor mitigating against the adoption of new fuels for ship propulsion is safety onboard. Existing fire safety measures may not cope
A new fire safety study by global survival technology solutions provider Survitec reveals that existing fire-fighting methods used to extinguish machinery space spray and pool fires on conventionally fuelled vessels are inadequate when dealing with methanol-based fires. Survitec carried out extensive comparative fire tests on dual-fuel marine engines using diesel and methanol, amid growing interest in methanol as an alternative marine fuel.
“Our tests confirm that traditional water mist fire suppression mechanisms do not perform as expected on methanol pool fires and methanol spray fires. A completely different approach is required if these ships are to remain safe,” says Michal Sadzynski, product manager, Water Mist Systems, at Survitec.
Methanol (CH3OH) burns in a completely different way than hydrocarbon fuels and has a much lower flashpoint – 12°C (54°F). However, while there are established fire safety regulations and testing standards for diesel, clear test protocols for alcohol-based fuels such as methanol and ethanol have yet to be developed.
“We believe this is a high-risk situation that needs immediate action,” Sadzynski stresses. “Methanol fires are far more aggressive than fires involving traditional hydrocarbon fuels. Methanol fires have different physicochemical properties and so they cannot be extinguished as easily or with the same approach.”
TAKE ANOTHER LOOK
The Survitec tests found that while water mist systems are highly effective in absorbing heat and displacing oxygen on diesel fires, they do not produce the same results on methanol fires. “We had to completely rethink nozzle placement, spacing and other factors to make water mist suppression effective on methanol. For instance, the range for nozzle installation height is much lower than that needed to put out a diesel fire,” Sadzynski says.
This indicates that if existing vessels are retrofitted to run on methanol, their fixed fire-fighting arrangement would need to be completely overhauled and redesigned. For bilge areas, statutory rules formulated in IMO MSC.1/Circ.1621 establish a requirement for an approved alcohol-resistant foam system for ships running on methanol. For the first time, a fixed, low-expansion foam system is mandatory under the rules when it comes to protecting machinery space bilges.
“Our tests demonstrate that standard discharge devices do not properly extinguish methanol pool fires in the confined bilge space. It is crucial to deliver properly expanded foam on the methanol pool fire and this is not an easy task within such a narrow space where throw length is limited,” explains Maciej Niescioruk, product manager, Foam Systems, at Survitec.
“MSC.1/Circ.1621 provides us with a starting guideline but it is very general and therefore open to interpretation. Moreover, methanol compliance for Local Application Firefighting (LAFF) systems is not yet covered. As an industry, we need to come together and develop comprehensive and robust fire test standards and safety rules tailored to methanol’s unique properties,” Niescioruk adds.
Orders for methanol-fuelled newbuilds increased by 9 per cent in the last 12 months, faster than those for LNG-fuelled ships. Analysts suggest the methanol-fuelled fleet will account for 20m gt by 2028. “We are seeing a significant uptake in orders for methanol-fuelled vessels, with 2023 being the breakout year for this alternative marine fuel. With more methanol-powered ships being built every year, the industry must act now to prevent dangerous gaps in fire safety,” says Niescioruk.
“We encourage all stakeholders to come together to address methanol’s unique fire risks and create clear standards, new testing protocols and updated safety rules for methanol.”
source: https://hcblive.com/putting-out-fires-with-alcohol/
