Water Mist High Pressure
High Pressure Water Mist systems are those with operating pressures of 34.5 bar (500 psi) or greater. Water supply pressure can be provided by a high pressure pump (120 bar) connected to a tank or continuous water supply or by high pressure nitrogen cylinders (200 bar) driving a number of separate water containers. Mean droplet sizes of these systems are approximately 100-200µ (micron) in diameter and are ideally suited to most applications including Class A hazards.
This means that High Pressure Water Mist systems can be used either in an open head configuration (deluge), or in a closed head configuration within an assumed area of operation (protection). In many cases, these systems are able to substitute for sprinkler systems providing equivalent protection with a fraction of the water usage.
A unique permutation of this technology is a Water Mist system specifically designed to extinguish fires in commercial kitchen environments, doing away with conventional wet chemical systems and the potential messy clean-up process. The system complies with AS 4587 and is LPCB approved for specific kitchen exhaust hood applications.
Water Mist Intermediate Pressure
Intermediate Pressure Water Mist systems are those with operating pressures greater than 12.1 bar (175 psi) but less than 34.5 bar (500 psi). The most common examples of these systems are self-contained, skidded units that have water stored at atmospheric pressure and high pressure nitrogen cylinders to provide the propellant to discharge the water. Mean droplet sizes for these systems tend to be larger than that for high pressure systems and since they have a limited water supply are usually limited to certain size risk volumes up to 1000 cubic metres.
Typical uses of Intermediate Pressure Water Mist systems include turbine enclosures, machinery spaces, hydraulic pump rooms etc. These extremely economic systems have been found to be very popular due to the self-contained skid arrangement incorporating a single connection point for water outlet and actuation as well as the ability for the releasing and control panel to be mounted directly on the skid.
Water Mist Low Pressure
Low Pressure Water Mist systems are those where the distribution piping is exposed to pressures of 12.1 bar (175 psi) or less. Very similar to ‘low flow’ sprinkler systems where the flow rates and mean droplet size are generally higher than that for high pressure or intermediate pressure Water Mist systems.
These systems are usually installed together with conventional sprinkler alarm valve equipment and are quite economical, however the applications are somewhat limited as the extinguishment efficacy is lower than that of High and Intermediate Pressure Water Mist systems.
Deluge Water Mist Systems; the IFI Deluge-Tech RC150A Nozzle has a rotor that improves water droplet momentum and distribution, making it a more effective suppression nozzle than conventional deluge nozzles with deflector plates. The water is simultaneously directed at a wide angle, providing a protective water curtain, as well as forward which allows for greater reach. The nozzle is used in applications where deluge water spray systems are installed for special hazards protection. The IFI nozzle produces superior protection with a minimum water pressure of 50 psi to a maximum pressure of 175 psi. The nozzle may be oriented in any direction necessary to protect the hazard.