NFPA13R - Residential/Commercial Fire Pumps

NFPA-13R is the code section concerning residential buildings up to 4 stories in height. Buildings falling under this heading would include apartment complexes, mixed occupancy business/residential buildings, assisted living centers, etc. 13R regulations refer back to NFPA 20 codes which apply to any stationary pump system. As such, it occupies a sort of grey area between residential and commercial requirements.

Since 13R systems are intended for buildings up to 4 stories the pressure portion of the design condition can be in the lower range of a pump's capabilities. One of the ways pressure is measured is in head feet, literally the amount of force required to drive water vertically a certain distance in feet (Head feet/2.31=PSI). Taller buildings require higher pressures from the pump in order to push water up against gravity and the way pumps create higher pressure is by higher horsepower. So, if a system is designed for a shorter building it will require less pressure which in turn means a lower horsepower motor can be used.

The main factor involved with lower horsepower motors is the voltage and amperage on which they can run. Most residential buildings are supplied with 230 volt power which is suitable for lower horsepower motors to run with a reasonable amp draw. If the motor is 30hp or less a relatively inexpensive limited service controller can be used. 30 horsepower will cover most design conditions up to 400GPM at over 90PSI. Applications requiring only 10hp (230 volt single-phase; standard house current) can utilize an even less expensive residential controller. In short, lower horsepower leads to less expense, which is the main difference between 13R compliant systems and their more demanding, higher-powered NFPA-20 counterparts.

Almost every component in the pump system must be listed by either Underwriters Laboratories (UL) or Factory Mutual (FM), though most will carry both listings. The pump and motor are selected to meet certain performance criteria as required by the system design conditions and are tested and certified by their manufacturers before leaving the factory. Various valves are required to isolate the pump from the water supply (suction side), the sprinkler system from the pump (discharge side), to allow for regular testing of the whole system, for temperature or pressure regulation, etc. All of the fittings and pipe sections are selected to withstand system pressure and sized to allow proper flow.

Several different piping configurations are commonly employed to provide for fail-safe pump operation and required system testing. City by-pass loops and FDCs act as back-ups in case of system failure for any number of reasons. For system testing, test headers and flow meters can be utilized either individually or together on the same system, each one serving to verify the results of the other. A pump system may be required to have any or all of these configurations depending on local authorities or codes, how the system is to be installed, or what kind of structure the system will be protecting.

Our turnkey ULR Packaged Systems are designed and built in complete compliance with NFPA-20. Standard package flow rates range from 50 to 750 GPM with system pressures of up to 160 PSI. Higher flow systems (up to 1500 GPM) are available as well, but not cataloged. We can also offer water storage tanks custom sized to your specific application. Our ULR packaged fire pump systems have been installed all over North America, coast to coast and sea to gulf, with an unmatched service record.

Talco Fire Systems 2016©