To efficiently absorb heat, droplet size and spray pattern are essential. The surface of the water droplet absorbs and cools the heat radiation from the fire gases.
Many small droplets create a larger effective spray area per litre of water. Therefore, getting as large an effective surface area as possible is vital.
Depending on pressure and flow, the droplet size from a spray nozzle varies. For example, a conventional system has low pressure and a high water flow, which generates a good throw length but larger droplets than a system with high pressure and low water flow.
Cobra uses a pressure of 300 bar and a flow rate of 60 l/min, which results in many small droplets in a fine water mist, giving a large effective surface area. With its long throw length, Cobra can quickly cool the fire gases and reduce the temperature in the fire compartment.
A metaphorical explanation
The metaphor of a football pitch can be used to describe this fact in a more understandable and tangible way. In this example, the same amount of water is used in all illustrations.
A given volume of water introduced at 8 bar will cover half a football goal.
The same amount of water introduced at 40 bar will cover half the penalty field.
The same given amount of water introduced by a Cobra at 260 bar will cover the whole football pitch field.
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