Physical Scaling of Fire Suppression by Water Mist

Author(s):  
G. Su ◽  
J. G. Quintiere ◽  
N. Schultz

Abstract The objective of the project is to develop water mist extinguishments design by scaling. The report describes the requirement and criteria of scaling fire, scale model, and the results of suppression for a developing water mist system design. The Maritime Safety Committee Draft Circular, MSC 914 is used as a basis test to evaluate a water mist design. A series of three full-scale tests related to MSC 914 were performed: fire only, fire with steel trailers, and fire with steel trailers and combustible commodities. A simulation was accordingly studied. Then, a scaled water mist design was tested in the scale model to find the characteristics needed for suppression in terms of pressure, water flow rate, droplet size, and the spray momentum. Based on these characteristics, a candidate nozzle will be selected for the full-scale MSC 914 test. The results so far show that the water mist system can effectively suppress the fire in scaled MSC 914 model. The full-scale MSC 914 is scheduled for September 2001. Therefore, the final answer is still pending until then. Scaling results are confirmed for temperatures, heat flux and flow for the MSC 914 fire without water add in.

2019 ◽  
Vol 56 (3) ◽  
pp. 1315-1352 ◽  
Author(s):  
Roberto Bellas ◽  
Miguel A. Gómez ◽  
Arturo González-Gil ◽  
Jacobo Porteiro ◽  
José L. Míguez

2016 ◽  
Vol 8 (1) ◽  
pp. 213-224
Author(s):  
Norbert Tuśnio ◽  
Paweł Wolny

An example of modern water mist extinguishing technology is presented in the article. Water mist systems are firefighting systems which uses very fine water sprays. The smallest water droplets allow a water mist to control, suppress or extinguish fires by cooling both the flame and hot gases by evaporation, displacing oxygen by evaporation and reducing radiant heat through the small droplets themselves. The effectiveness of water mist systems in fire suppression depends on its spray characteristics, which include the droplet size and distribution, flux density and spray dynamics, phase of fire development, fire size and the ventilation conditions. The COBRA (known as PyroLance in USA) systems presented use of a cutting extinguisher is a fire extinguishing technique that combines abrasive waterjet cutting with water spray extinguishing, through a single handpiece or nozzle. The firefighter approaches the fire from outside the main fire area, then uses the cutting action to drill a small hole through a barrier such as a door, wall, roof or floor. Switching to a water spray then allows the fire to be fought, as with a conventional fog nozzle. An analysis of the benefits of using high-pressure water mist in conjunction with new firefighting tactics is described. State Fire Service should aim to minimize water consumption and thus reduce the post-fire losses, take care of environmental protection and improve safety conditions for firefighters.


2012 ◽  
Vol 30 (2) ◽  
pp. 138-157 ◽  
Author(s):  
Na Meng ◽  
Longhua Hu ◽  
Shuai Liu ◽  
Long Wu ◽  
Longfei Chen ◽  
...  

2018 ◽  
Vol 67 ◽  
pp. 04039
Author(s):  
Kuswantoro ◽  
Y.S. Nugroho

This study aims to investigate the effectiveness of water mist on suppressing a shielded fire. Full-scale experiments are carried out in a partition room of (lxwxh) 2x2x2.5 m size. Five water mist nozzle which consist of two type nozzle was used, high flow (fogjet) nozzle installed at top center of the room and fine spray nozzle installed at each side of room at high 1.5 m from ground. The pressure of water mist system was maintained at 20 bar which correspond to 2.6 lpm of water flow rate. Wood crib of 6.5 x 6.5 x 6 cm size was used as the fuel source. The obstruction used as a fuel shield has table like form with 40 x 40 cm cover area and 0.5 m height. The location of fuel source and fuel shield was varied (1) fuel source and shield at centre of room, (2) fuel source at one side of shield and the shield at centre of room, (3) fuel source and shield at corner of room, and (4)) fuel source at one side of shield and the shield at corner of room. Numerical simulation using FDS 6.5.3 was also performed to validate the use of FDS and get better understanding of the phenomena. The results showed that water mist was able to extinguish the fire around 20 s, 16 s, 30 s, and 24 s for scenario 1, 2, 3 and 4 respectively. It is also observe that the mist distribution around the shield and cover area of the shield play a role on the capacity and time needed of water mist to extinguish the fire.


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