Top Ten Changes to NFPA 13 - 2010 Edition

Issue 33: Emerging Trends in Fire Pump

By Gayle Pennel

With the advent of taller high rise buildings, and concern that some of the current design practices do not provide the high level of reliability needed, NFPA 201 developed specific requirements for fire pumps installed in high rise buildings in the 2010 edition.

High rise buildings that are beyond the pumping capacity of the fire department must be self-contained and the occupants may need to be protected in place. This makes the reliability of fire protection systems critical.

In general, the new fire pump requirements in the 2010 edition of NFPA 20 are intended to maintain the availability of the required fire protection water flow even with a single failure of any component for buildings where there are stories that are beyond the pumping capacity of the fire department. These requirements include:

  1. Auxiliary power for electric motor driven fire pumps is required whenever the fire pump serves any floors that are beyond the pumping capacity of the fire department.
  2. Access to fire pump rooms is required directly through an exterior door or through a two hour rated enclosed passageway connected to an exterior door or an enclosed stairway.
  3. Water tank(s) supplying fire pump(s) that serve floors beyond the pumping capacity of the fire department:
    1. Must hold the full fire protection water demand.
    2. Must be subdivided and piped so that a minimum of 50% of the total fire protection water demand is available with any one compartment or tank out of service.
    3. Must have a minimum of two automatic fill valves. Each fill valve, when operating independently, is required to refill the system at a rate equal to or greater than the fire protection demand rate.
  4. The water supply/fire pump arrangement must be such that the full fire protection water demand can be met even with the failure of any single component. This requirement can be met with a properly arranged backup fire pump, or possibly from a tank located higher in the building.
A requirement that fire pumps operating in series must be located in the same room was included by the committee responsible for developing NFPA 20, but was later removed by a floor vote at the NFPA Annual Meeting. This requirement is likely to be revisited and included in future editions of NFPA 20.

In the current edition of NFPA 14,2 a change was enacted which allows "master" pressure control valves to supply whole standpipe or sprinkler system zones. Currently, NFPA 14 has a pressure limit of 350 psi (2.4 MPa), which limits the applicability of the "master" pressure control valves. There is a proposal to remove the pressure limit for express risers in the next edition of NFPA 14. Currently, fire pumps that develop approximately 250 psi (1.7 MPa) of net pressure are available. If the proposal passes, this will likely lead to pump manufacturers listing fire pumps rated for higher pressures, so that a single fire pump rated for 500 psi (3.4 MPa) or more could be used to supply multiple standpipe or sprinkler zones.

 

NFPA 20 was also modified to allow variable speed drivers to maintain a pump suction pressure as well as the pump discharge pressure.

Limited service controllers have been a subject of debate for many years. These controllers are limited to 30 horsepower (22 kW), and were originally intended to lower the cost of retrofitting schools. Over the years, additional requirements added to address safety and other concerns have narrowed the distinction and cost differential between limited service and full service controllers. Over the past few code cycles, a proposal to eliminate limited service controllers from NFPA 20 has been rejected by the NFPA 20 committee by a narrower margin each cycle, until it finally passed in the current (2010) cycle. However, limited service controllers were restored the 2010 edition by floor action at the NFPA Annual Meeting. This issue will most likely be considered again in the 2013 NFPA 20 cycle.

Gayle Pennel is with Schirmer Engineering Corporation

1 NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, National Fire Protection Association, Quincy, MA, 2010.
2 NFPA 14, Standard for the Installation of Standpipe and Hose Systems, National Fire Protection Association, Quincy, MA, 2007.

 

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