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Oxygen occupies 21% place in the air, by volume. Continuous combustion requires more than 15% of oxygen concentration by volume. When Fire Shield HFC 227 ea ( FM 200 ) systems actuates to put out a fire, it suppresses fire by a combination of chemical & phisical mechanisim without effecting the available oxygen for evacuation as the oxygen concentration in the extinguishing sector changes only to about 17% from 21% due to initial combustion before the system actuates.
The faster extinguishing effect of Fire Shield HFC 227 ea as compared with conventional FM200 systems is achieved solely by means of the High Pressure Technology. By HPT, we understand a minimum operation pressure, at the nozzle of 10 bar as well as an HFC 227ea storage pressure of 42 bar together.
Criteria for extinguishing fire in less than 30 seconds.
The results of numerous extinguishing tests in our laboratories have shown, that as a rule, a fire can be completely extinguished in less than 30 seconds after the system has been actuated, only when all three of these criteria are completely fulfilled.
HFC 227ea is rapidly released in liquid form to the nozzles in the extinguishing sector, where it is atomized. required energy must be supplied to the droplets for vaporization. As the graphic shows, the ambient air is drawn into the HFC 227ea droplets / nitrogen jet providing the necessary energy for vaporization.
The life of an HFC 227ea droplet expressed, as the distance travelled in metres, as a function of the operating pressure at the nozzle, as per thermodynamic calculations.
|Operating pressure at the nozzle ( bar )||Distance travelled by droplet ( m )|
It clearly shows that only at a minimum operating pressure of 10 bars is an HFC227ea droplet completely vaporized before it can collide with any object in the extinguishing begins at the latest, when all the liquid HFC 227ea has entered the extinguishing sector, i.e. before the end of 10 seconds flooding - time.
The Room nozzles sprays the jet at an optimal angle of 500 to the nozzle axis, whereas for Void nozzles the jet angle is 900. All the nozzles are so arranged to overlap the jet angles of each other, which increases the homogenization in the extinguishing sector, providing you an added advantage of flooding rooms upto a height of 5 metres over conventional low pressure systems which are usually limited to room heights of less than 4 m.
Solubility of Nitrogen
While nitrogen in the cylinder head, via the HFC 227ea liquid surface, serves to fill the pipe network with liquid HFC 227ea initiating atomization at the nozzle, the dissolved Nitrogen in the HFC 227ea is very crucial, since it sustains the flooding of HFC 227ea in the extinguising sector.
|Storage pressure ( bar )||Solubility of nitrozen ( g/kg HFC 227ea)|
In liquid FM200, Nitrogen is highly soluble. It is comparable with that of N2 in the blood of a diver which increases with the increasing pressure. As a result Fire Shield HFC 227ea systems, gurantees almost twice as much nitrogen propellet for each stored kilogram of HFC 227ea, if one takes into account the fact that under high pressure, more Nitrogen can be stored in the space available in the cylinder head, with which even with larger and more complex application, the maximum filling factors can be realixed in compaison to conventional systems. Finally, the increased impetus of jet and a special nozzle design and arrangement by Fire Shield HFC 227ea systems provides Rapid release, Total vaporization & Perfect homogenization of HFC 227ea upon entering the extinguishing sector, which results in extinguishing the fire within 30 seconds.
|Storage pressure||42 bar ( 200 C)|
|Temperature range||-200 C - 500 C|
|Maximum room height||5m|
|Filling factor||0.45 - 1.15|
|Flooding tme||< 10 s|
|Extinguishing time||< 30 s|