Water Mist in Large Machinery Spaces

By Ragnar Wighus, Chief Scientist SINTEF NBL
Wednesday, December 18, 2013
Ignition of pool fire in a test of a water mist system according to IMO 1165. Photo: Kristian Hox, SINTEF NBL.

Water mist systems are extensively used as fire protection of machinery spaces onboard passenger ships, and have almost taken over as fire extinguishing systems after IMO standardized such systems. Water mist systems are documented through full scale fire testing of the manufacturers' solutions. In practice it has been shown that in spaces with a ceiling height above approximately 10m it is necessary with more water mist nozzles to extinguish low seated fires. The IMO-method that describes the test procedures requires that all nozzles are mounted at ceiling level, and gives no opportunity to extrapolate results from fire tests to spaces with higher ceiling heights.

Conventional merchant vessels have large machinery spaces with ceiling heights above 10m. Therefore it is still common to install CO2-systems in these ships, since no alternative extinguishing systems are approved for this application area. Until now several manufacturers of water mist systems have documented that it is possible to extinguish fires in machinery spaces with height up to 10m and a volume exceeding 3,000m3. A research project initiated by IWMA (International Water Mist Association) resulted in a change of IMO's regulations. That means that the test results will be valid also for spaces up to twice the tested volume, but there was not given any possibility to increase the ceiling height.

If it can be shown through testing that water mist systems have sufficient ability to fight fires in larger machinery spaces, such systems will challenge and replace CO2-systems. In practice this means that fire extinguishing can start immediately after a fire has been detected. Today the start of extinguishing may be delayed with 10-15 minutes because CO2 represents a toxic hazard to persons in the machinery space. The CO2 cannot be released before people are evacuated from the engine room and all air supply is stopped and all openings are closed. Every minute with a fire in the machinery space increases the damage to equipment and cables; it has been indicated that the damage increases with €12,000 per minute.

Water mist systems can be released immediately after fire detection, and will quickly cool down the machinery space. Most fires will be extinguished after 10-15 minutes. In addition water mist systems have become popular among engineers and crew because they, besides being possible to use without hazard to people, are easy to test regularly. Water mist systems on passenger ships are often tested every week, and are simultaneously used for cleaning the machinery space. The costs connected to refilling the water reservoir are negligible in contrast to replacement of CO2-bottles after release of a CO2-system.

SINTEF NBL is now working to start projects that can open up for use of water mist system in large machinery spaces, and for this purpose we have the possibility to utilize our large test hall. The test hall is over 20m high and has a total volume of approximately 14,000m3.

Maritime Reporter September 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Marine Power

Friendship to Green Ships

Korea and Denmark both have ambitious national plans for a transition to greener and more energy efficient economies.    The Danish-South Korean Green Growth Alliance met for roundtable talks.

EfficienSea2 Rolls out Maritime Cloud

The Danish-led e-navigation project, EfficienSea2, got one step closer to being launched when a core element of the project – Maritime Cloud – was debated by a

Servowatch IPMS Completes FATs for UK Navy

The fully integrated platform management system Servowatch designed and built for three new offshore patrol vessels for the U.K. Royal Navy has completed BAE Systems’ Factory Acceptance Tests (FAT).

Marine Equipment

Using Big Data for Engine Preventive Maintenance

Mitsui O.S.K. Lines, Ltd. announced that it has started a demonstration test of a next-generation condition-based engine monitoring system called “CMAXS e-GICSX”

Servowatch IPMS Completes FATs for UK Navy

The fully integrated platform management system Servowatch designed and built for three new offshore patrol vessels for the U.K. Royal Navy has completed BAE Systems’ Factory Acceptance Tests (FAT).

Yanmar to Display New Common-rail Diesels at METS

Yanmar Marine International (YMI) will show its new range of common-rail fuel injected marine diesel engines rated for leisure marine and workboat applications at METS 2015,

Maritime Safety

Security Advisory: Piracy – Revision of BMP4 High Risk Area

BIMCO says that the co-sponsors of BMP 4 have agreed to a revised definition of the High Risk Area. The High Risk Area is now defined as being bounded by: In

Captain of Ill-fated El Faro was Known as Trusted Mariner

The captain of the ill-fated cargo ship that sank in a hurricane off the Bahamas with no survivors last week was an experienced and highly trusted mariner who had spent a lifetime on the water,

Collision Course with a Hurricane: How Doomed US Ship Met its End

The ill-fated U.S.-flagged El Faro cargo ship sunk by Hurricane Joaquin was sailing at near full speed into the center of the storm before it lost propulsion amid mountainous waves and brutal winds,

Maritime Careers / Shipboard Positions Maritime Contracts Maritime Standards Navigation Pipelines Pod Propulsion Port Authority Salvage Ship Repair Ship Simulators
rss | archive | history | articles | privacy | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.5546 sec (2 req/sec)