Hydrant System

Fire hydrant installation consists of a system of pipe work connected directly to the water supply main to provide water to each and every hydrant outlet and is intended to provide water for the firemen to fight a fire. The water is discharged into the fire engine form which it is then pumped and sprayed over fire. Where the water supply is not reliable or inadequate, hydrant pumps should be provided to pressurize the fire mains.

A typical hydrant installation fed directly from water main and pressurized by fire pumps is shown as below :

The Fire Pump Station comprises of the Jockey Pump, Electric Driven Pump and Stand-by Diesel driven Pump. The pump operation is automatic through pressure switch contacts based on header Pressure in the hydrant network. The delivery of the jockey pump and main pump is connected to the common delivery header.

The Fire Hydrant Line is always kept pressurized with water. In the event of any minor pressure drop in the system, the pressure reaches the preset pressure setting for Jockey pump, the Jockey pump will start automatically to compensate the pressure differential. In the event of opening one or more hydrant valve for fighting fire the Jockey pump will not be able to make up this water loss resulting in further pressure drop. When the falling pressure reaches the Preset pressure for main pump, the main pump will start automatically. In case of electric supply failure, stand by diesel engine driven pump will come into operation.

A fire-fighter connects a fire hose to the fire hydrant and releases a valve to get water from the water main. Most fire hydrants are designed to allow not less than 250 gallons (950 litres) of water to flow through the hydrant per minute.