For centuries, water has been used to fight fires. In 1806, the first patent was filed in London describing a perforated pipe concept for a fire protection system. This was followed in 1860 by the first sprinkler patent. Later, more advanced sprinkler heads were developed, including bulbs. The common feature of this development was the use of water as a fire fighting medium for cooling the fire.
The intelligent use of water….High-pressure water mist
For a fire to survive, it relies on the presence of the three elements of the ‘fire triangle’: oxygen, heat and combustible material. The removal of any one of these elements will extinguish a fire. A high-pressure water mist system goes further. It attacks two elements of the fire triangle: oxygen and heat.
The very small droplets in a high-pressure water mist system quickly absorb so much energy that the droplets evaporate and transform from water to steam, because of the high surface area relative to the small mass of water. This means that each droplet will expand more than 1,700 times, when getting close to the combustible material, whereby oxygen and combustible gasses will be displaced from the fire, meaning that the combusting process will increasingly lack oxygen.
To fight a fire, a traditional sprinkler system spreads water droplets over a given area, which absorb heat to cool the room. Due to their large size and relatively small surface, the main part of the droplets will not absorb enough energy to evaporate, and they quickly fall to the floor as water. The result is a limited cooling effect.
By contrast, high-pressure water mist consists of very small droplets, which fall more slowly. Water mist droplets have a large surface area relative to their mass and, during their slow descent towards the floor, they absorb much more energy. A great amount of the water will follow the saturation line and evaporate, meaning that water mist absorbs much more energy from the surroundings and thus the fire.
That’s why high-pressure water mist cools more efficiently per litre of water: up to seven times better than can be obtained with one litre of water used in a traditional sprinkler system.
The uniqueness of water mist is that it combines the suppression effect of gas and traditional sprinkler systems. As well as removing the oxygen like a gas system, it simultaneously cools the fire like a traditional sprinkler.The cooling effect additionally lowers the risk of re-ignition.
The System Design
The G Fire water mist system is a unique fire fighting system. By forcing water at a high pressure through nozzles, an extremely fine mist is created.
Water is supplied via a pump unit. For every ship type, the G Fire pump unit can supply all water mist applications. This is beneficial because you only need one unit for all applications, and it is easy to add more sections and applications, if needed. In addition, servicing of only one unit is easier and less costly.
G Fire water mist system for accommodation areas
On stand-by, the system maintains a pipe pressure of approx. 12 bars. When the temperature exceeds a given level – for example, 57 °C – the heat-sensitive glass bulbs mounted in the nozzle heads melt. At this point, the high-pressure pump is automatically activated and water is forced through micro-nozzles at very high pressure (100 bar) to create a fine mist. Importantly, only those nozzles with melted bulbs are actually activated. This means that only the heat-affected area will be sprayed.
G Fire water mist system for engine rooms
On stand-by, the system has dry piping. The local protection system will activate automatically when sensors have detected heat, smoke or a flame, depending on type and application. The nozzles are dimensioned in sections and all nozzles in the activated zone will be released. The total flooding system is dimensioned with one section per fire zone and is activated manually either from the valve operation panel (VOP) in the engine control room or the mimic panel on the bridge.
G Fire water mist system in operation
G Fire Water Mist System in operation. During operation, the high pressure pump draws water from the non pressurized stainless steel buffer tank and forces it through a non-return valve to a high-pressure manifold. From here, it is distributed to the relevant section(s) via the main valve. A pressure relief valve controls the pump pressure and has the ability to return the full pump capacity to the buffer tank.
The benefits of G Fire water mist system
Quick fire fighting
Reduced down time
No need for extra installations
Pioneers of high-pressure Water mist technology
As one of the acknowledged pioneers of high-pressure water mist technology, G Fire Solutions is a leading force in the market. G Fire Solutions is the only water mist supplier with direct access to its own development and production of all three key components needed for a top quality, cost-effective, high-pressure water mist system: nozzles, pumps and valves. All our products are made of first class materials to a comprehensively tested design. G Fire Solutions’s fire fighting systems are recognised by all leading classification societies and national maritime authorities. G Fire Solutions HSE&Q system is in accordance with DS/EN ISO 9001:2008, DS/EN 14001:2004, and DS/OHSAS 18001:2008 and is certified by DNV.