Fire Hydrants, or hydrant outlets, are installed within the building to enable firefighters to connect their hoses to a water supply to fight fires. Fire hydrants may be of the dry type which are empty in normal situations, but are charged with water supplied through fire brigade’s pumping appliance to the inlet at ground level in the building perimeter during emergency. Alternatively, they may be kept full of water and supplied from tanks and pumps in the building. Normally, the wet fire hydrants are also coupled with fire service inlets. These are located at the perimeter of the building to enable water from the external source to be fed into the building via the fire brigade’s pumping alliance. Building height generally determines which type is used.