Fire Pumps and Water Sources For Private Fire Protection
Industrial Fire Safety
In many facilities, the lack of adequate municipal water supplies for automatic sprinkler systems and fire hose lines makes private or secondary water s supplies a must. A vital part of any improved distribution system is an automatic fire pump connected to either a municipal water system or water in storage on the site.
Fire pumps must be UL-listed and or FM-approved, as they perform a special function in fire protection and must be of proven capability. The positive suction horizontal split-case centrifugal pump takes suction from a water source under pressure, such as a suction tank. The negative suction horizontal split-case centrifugal pump takes water from a source such as a pond. This unit is also usable under positive suction with proper attachments.
Vertical shaft turbine pumps are used when taking suction from a source below ground level and when the installation of any other pump below the minimum water level would be difficult, such as in a tested, reliable, deep well. The turbine pump’s rotating impellers are deep in the well, suspended from the pump head by a column or eduction pipe which supports the shaft and bearings. When being drafted, water is pushed to the surface rather than pulled.
Range of sizes: Fire pump sizes range from 250 to 2500 gpm or more. Net pressures of from 40 to 100 psi or more can be obtained, according to the need.
Although not a fire pump, a jockey or makup pump is usually required to maintain pressure on lines at a high level and control actual fire pump use for minor water makeup. The estimate of usual gallons-per-minute rating is in the 20 to 60-gpm range with a pressure of 100 psi to maintain system pressure.
Special fire service pumps are sometimes used where the water supply is limited and drafting water in excess of the maximum delivery of the pump would be likely to reduce the supply pressure to a lower than usual level. These pumps range from 200 to 450 gpm and from 40 to 100 psi. They should be used only where conditions do not justify the installation of a standard fire pump.
Drivers for the fire pump can be diesel, gasoline or LPG internal combustion engines, steam-operated turbines or electric motors. The final choice of driver, of course, must be based upon the plant location, pump location, and sources of electricity and steam.
Volume, reliability of source: Water supplies for any pump must be from adequate volume sources (dictated by the fire-loading demand placed on automatic sprinkler systems) and be reliable at all times of the year. These sources can be ponds, lakes, canals, steel tanks, impregnated fabric storage basins and deep wells, to name the most acceptable.
The basic information on types of fire pumps is only one part of the whole story and articles on fire pump installations and maintenance will follow.
For full specifications for fire pumps, look at NFPA No. 20, “Standard for the Installation of Centrifugal Fire Pumps,” and consult your insurance carrier, rating organization or the authority having jurisdiction.
In conclusion, fire pumps are becoming more and more the usual in industrial fire protection, rather than the exception, as municipal water supplies continue to fail to keep pace with industrial construction. Industry contributes to the problem by failing to seek qualified fire protection engineering assistance in planning.
Therefore, we recommend that you survey your property and install automatic fire pumps and water supplies required to protect your assets. Automatic sprinkler systems are excellent large loss deterrents, but without proper backup of volume and water pressure, they can fail.