Revolutionary high pressure water mist system

Eusebi Impianti srl, European leaders in the design and manufacture of fire fighting equipment, have devised a new EI - FOG Water Mist system, a revolutionary high pressure water mist system. This system operates at a pressure of between 100 and 120 bar, and is fitted with special distributor nozzles which sprinkle water in tiny droplets at the aforementioned pressure. These droplets are less than 100 m in size (in accordance with the applicable regulations in force), and have been proven to be highly effective in fighting fires.

The spraying of microdrops of water has a total extinguishing action on the fire itself, extremely quickly, thanks to the combination of three main features:
• cooling action: the water particles, as a consequence of their size, are subject to rapid evaporation, with the consequent removal of a large quantity of thermal energy;
• inerting action: the water vapour, generated by the water evaporation due to the high temperatures associated with fire and the ensuing smoke, behaves just like an inert gas and, since it occupies a volume that is a hundred times greater than that of the extinguishing water, it helps to control and suppress the fire;
• shielding action: the particles of water sprayed are capable of absorbing the radiant energy released by the fire, and so they significantly reduce the probability of the materials situated in the vicinity of the flames reaching their ignition temperature, contributing to the fire although not being directly burnt by the flame itself.

The EI-FOG water mist sprinkler fire extinguishing system was tested and certified in the SP laboratory in Sweden. In this laboratory, Eusebi Impianti engineers, together with their colleagues from the SP laboratory, carried out various types of test, and also placed the system in the most particular and problematic situations, with great results every time.

The EI FOG system offered by Eusebi Impianti srl complies with the NFPA 750/96 fire protection standards and to IMO 913 and A800. Not only is the system classified as class 1 (minimum diameter of the water droplets sprayed less than 100 microns) but it has also been acknowledged as being suitable, in accordance with the above standards, for use in extinguishing both Class A fires (solid combustibles such as paper, wood, etc.) and class B fires (liquid combustible such as petrol, oils, etc.).

The nozzles used are designed for use in the particular conditions which the fire extinguishing system will be under in the event of fire; the choice of nozzle especially depends on the type of fire load and on the dimensions of the room on the plan and on its height.
Based on these parameters, the following can be determined: the spraying angle, the nozzle flow rate and the number of distribution openings. The characteristics of the sprinkler head are indicated with a special code which is stamped on the nozzle itself.

The nozzles are closed and feature a fuse bulb. They are activated as soon as the heat-sensitive bulb breaks, on reaching the relative calibration temperature set at 57°C.

DESCRIPTION OF THE SYSTEM’S COMPONENTS

Pumping module

The pressure system consists of at least one high-pressure pump (up to 6, depending on the capacity required by the protected area which has been defined as the project area) fitted on a skid.
The water is transported from the pump by means of a check valve in the manifold at the top of the pumping system.
A pressure regulation valve, which regulates the excess water by carrying it back to the back-up tank, is fitted to this manifold.
The pressure system manifold is equipped with all the necessary pipe fittings, pressure gauge switches, accumulators and security valves.
When the whole system is at rest, the water is present in the entire network with intact discharge nozzles. A possible fire can cause the bulb of the discharge nozzle to break and the decrease in the system’s pressure will be signalled immediately by the low pressure switch, which allows the jockey pump to start.

Back-up tank

The pressure system is connected to a back-up tank which is built with AISI 304 stainless steel plates and section bars. This is fed by the internal pipeline network.
The level of the water in the tank (minimum storage capacity and too full) is kept under control both by an electrical indicator fitted onto the top of the tank, and by a transparent level indicator fitted on one of its sides.
For example, if the water level is at a minimum, the electrical level indicator signals the anomaly to the Control and Command Centre (which then fills the tank up by opening a solenoid valve that is fitted on the tank itself), while the transparent indicator views the on-site situation. In addition to this, a filter, 2 solenoid valves (one of them as a spare), a ball valve for sectioning, a drain, a vent, an opening for maintenance, an entrance for the system test and an entrance for system overpressure.

Back-up system

The system’s propulsion can be either by means of pumps or only nitrogen and water cylinders: therefore, the system can have the pumps to supplement it, or it can itself be the only means of propulsion, thereby allowing any expenses related to the pump propulsion to be eliminated. In the event of a fire or a malfunction of the main extinguishing system, the back-up system will be activated.

The back-up system is made up of the following main pieces of equipment:
• N2 cylinders
• H2O cylinders

The N2 pressurises the water contained in the cylinders, causing it to flow out and be discharged through the nozzles.
As soon as the nominal rated voltage has been re-established, the solenoids de-energise and return to the closed position.
Once the main system’s malfunction has been repaired, the main pump restarts automatically.

Example of typical scaling for normal residential areas and deposits/warehouses