High speed water mist helps minimise damage from fire

Paul Boughton

Stefan Gordin outlines the advantages of using high pressure water mist as a safe and efficient means of fire protection in a wide variety of both offshore and onshore operations.

T he use of high pressure water mist is not restricted to machinery spaces. As water mist attacks two of the three elements of the so-called ‘fire triangle’, ie the heat and oxygen, it is efficient on virtually any fire.

And when the HI-FOG high pressure water mist sprinkler system was installed on M/S Frans Suell in 1991, a new era in fire fighting started. In less than a decade, high pressure water mist established its position as a safe and efficient means for fire protection. In some market segments, such as the very safe-minded passenger cruise vessel market, it has become the system of choice of all major operators.

In machinery spaces, offshore as well as onshore, the major benefit of water mist is that it is harmless to people. This means that the system can be activated the second a fire is detected. People inside the space will escape unharmed. In case the alarm turns out be false, the system is simply shut off and the operation can continue without interruption. This possibility for immediate activation means that the fire damages are kept at a minimum.

A good high pressure water mist system is not only efficient in extinguishing machinery spaces fire. Due to its cooling effect, it will provide fast cooling of the space after the fire has been extinguished, thus preventing reignition.

Furthermore, it will not be depleted upon activation, but is always ready for the next activation. Finally, as fresh water used, there is no laborious clean-up to be done, neither is there any corrosion problems caused by the extinguishing media. The last item alone will prevent any hesitation from the staff to activate the system immediately.

Water mist can be used in machinery spaces as an integrated system to provide both total flooding protection, in lieu of, for example, CO2 and foam, and local application, which has to be water based and nowadays is mandatory in the marine market. Combining the two means considerable savings in material and installation costs.

This year has seen the development of the third generation total flooding systems, such as Marioff’s HI-FOG MT4. Better understanding of the extinguishing process and extensive R&D have resulted in simpler and less power consuming systems. Before being applied, such system have to pass rigorous fire and component tests, defined by IMO, FM, VdS or other authorities.

A special application related to the machinery of a ship, platform or industrial plant is the gas turbine enclosure. Special high pressure water mist systems have been developed to minimise the thermal chock on the high-tolerance rotor blades, caused by the water hitting the turbine mantle.

Stefan Gordin is with Marioff Corporation Oy, Vantaa, Finland. http://www.hi-fog.com

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