Water Spray Systems

General

Fires on Hydrocarbon are more frequent due to the volatility of the hydrocarbon and its property to not dissolve with water and lighter than water the fire extinguishing of hydrocarbon fire with water is not possible. In case of fire on Hydrocarbon if the water is sprayed, due to the light weight of the hydrocarbon it will float on the water and reignite them to fire and due to the speed of water the fire will travel from one place to other place. However for these plant water spray system can be provided as exposure protection. That means if any plant is under fire the plants nearby shall be kept cool with the water spray system, while plant under fire shall be applied foam.

Hence in this case where plant is using hydrocarbon the exposure should be protected with water spray system designed as per NFPA 15.

Water shall be applied at a minimum density of 10.2 lpm/m2 of the exposed area of the plant.

A minimum pressure of 1.4 bars shall be achieved at the hydraulically remotes sprayer. However, pressure at the hydraulically favorable sprayer shall not exceed 3.5 bars.

The sprayers shall be installed in rows at the ceiling level above the centre of plant floor and spaced at not more than 3M.

Quartzoid Bulb Sprinklers (Q. B. S.) Detection is used to for detection of fire which will be connected to deluge valve for auto operation of the system. Q B Sprinklers shall be of 68 Deg. Or 79 Deg. C depending upon the ambient temperature of the location of the plant.

For automatic operation of the system the deluge valve shall be provided with pressure switches and annunciation panel.

In case of fire the Quartzoid Bulb sprinkler shall burst due to heat which allow water in the detection pipe to drain out and in process allow the Deluge valve to open fully. As soon as the Deluge valve opens the water shall flow through the piping to flow water to all water spray nozzles mounted on the ceiling of the plant. The water shall be sprayed in solid conical spray pattern to cover entire area of the plant floor so that the equipment installed shall be kept cool to avoid heat radiation and further ignition of fire.

The fire shall be control with the help of the water spray system.

The indication of operation of the system shall be available on the control panel with Alarming Siren.

Advantages of M.V. Water Spray System

• Entire area is flooded with foam, hence very useful for fire fighting in hazardous area, plant, storage tanks, etc. where manual approach is difficult.
• Very quick in response.
• The fire losses is kept low as the area under fire get foam blanket and also cooling due to water contain and so chances of spreading fire is negligible.