Fixed foam system is provided to suppress fire in absolute alcohol storage tanks and spill fire in dyke areas of storage tanks. The water required for foam system shall be taken from a branch of the hydrant main. Foam protection system shall be automatic in operation to extinguish fire inside tank and manual operated type for dyke area. The foam application rate to extinguish the fire is 5.0 LPM/ Sq M and minimum discharge time is 65min. The automatic foam system shall be actuated by receiving the signal from probe type heat detectors. The automatic foam system shall be actuated by receiving the signal from probe type heat detectors (Each tank shall be installed with 2 Nos min).
Automatic foam system comprises of Solenoid operated deluge valve, isolation gate valves, and strainer, and inline inductor, foam making chamber, GI piping and probe type heat detectors. The water for the foam system shall be tapped from the nearby hydrant underground piping network. Deluge valve is the system control valve located at safe location. An isolation gate valve and a ‘Y’ type strainer will be provided on the upstream line of deluge valve.
Pipeline up to the upstream flange of deluge valve will be filled with pressurized water. Inline inductor will be fixed in downstream of the deluge valve with a foam solution inlet. Foam maker cum foam pourer is fixed on the tank. GI pipe will be connecting between Deluge valve outlet and foam making chamber via inline inductor. Probe type heat detector shall be mounted on the roof of tank.
During ‘fire’ condition, the probe type heat detector mounted on the roof of the tank detects the temperature inside the tank. Once the temperature of the tank reaches 58 Deg. C (136.4 Dec.F) it will send an electrical signal to deluge valve control panel. In turn the deluge valve control panel will operate the respective tank foam system by actuating solenoid valve mounted on deluge valve and open the foam solution line. The pressurized water will pass through the inline inductor where foam solution will be added in appropriate ratio. The foam solution mix will be converted into foam at foam making chamber and discharges into the tank. The foam discharged into the tank will form a blanket over the liquids stored on the tank and extinguishes fire by cooling and cutting oxygen supply to the source of fire. Foam solution should be stored in the bladder tank and further distribution to the inline inductor. All pipes shall be supported with superstructure and minimum head room clearance of 2.5m from the finish floor level inside the storage section dyke area.