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Plumbing Engineer - Columns: October 2012: Fire Protection

NFPA 20 — Changes in the 2013 edition

By Samuel S. Dannaway, PE,
President, S.S. Dannaway Associates, Inc., Honolulu

The next new standard up for us is the 2013 edition of NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection. Here are some of the changes I see as significant. Where paragraph numbers are cited they refer to those in the current 2010 edition of NFPA 20.

• New Definition: In Sight From (or Within Sight From, Within Sight). Fire pump controllers have always been required to be located “within sight” of their associated fire pump motor or engine. This is now defined (as extracted from the NEC) to be “visible and not more that 15 meters (50 feet) from (one another).” An annex note indicates that the controller may be located in a separate room, provided glazing is provided to meet the “visible” portion of the requirement.

• Water Flow Testing. Paragraph 4.6.1 requires that the water supply to fire pumps be reliable. A new paragraph 4.6.1.2 is added to match a similar provision in NFPA 13 that requires water flow tests used for the design of the fire pump system to be performed within 12 months of submission of the working plans (shop drawings). The requirement may be modified by the AHJ where the 12-month requirement cannot be met. I understand this situation is common in Frostbite Falls.

In paragraph 4.6.5.2, the 2010 edition technically permitted the water supply to provide less than 100 percent of the rated flow of the fire pump as long as it could still meet the demand for which the fire pump system was designed. The change to this provision requires that the water supply must be capable of providing at least 100 percent of rated capacity.

• Anti-Vortex Plate. In paragraph 4.14.10, the term “vortex plate” has been changed to the more correct “anti-vortex plate.” Illustrations have been added to the annex to provide examples of anti-vortex plate design.

• Backflow Prevention Assembly (BPA). An annex note has been added to paragraph 4.15.7 to point to A.4.15.6, which identifies conditions where the system side of the BPA can be used as the required discharge control valve.

• Suction Pipe and Fittings. The prohibition against valves other than OS&Y valves within 50 feet of the pump suction flange has been clarified. The prohibition applies to other control valves (such as butterfly valves) and not valves otherwise permitted (such as backflow prevention devices).

• Seismic Protection. Where earthquake protection is required, a specific provision has been added to require that pipe and fitting comply with the requirements of NFPA 13.

• Meters and Testing Devices. Where a flow meter is provided and arranged to flow around the pump or back to a tank, it must also be arranged so that flows through the meter can be routed through the hose test header. The diagrams in the annex have been revised to also show this arrangement.

• Fire Pumps for Very Tall Buildings. Significant new provisions have been added to Chapter 5 Fire Pumps for High Rise Buildings for “Very.” Though not specifically defined in the code text, a new annex note identifies very tall buildings as those that have levels in which fire department apparatus cannot pump into fire department connections and achieve pressures of 100 psi at topmost hose valve outlets. The annex note goes on to say that this limit is normally reached for buildings in the range of 200 to 350 feet tall and above, depending on the water supply and the fire department capability.

The new Section 5.7 Very Tall Buildings contains the following: The provisions for water tanks have been moved into this section. Additional provisions have been added addressing refill of elevated water tanks. The fire pump backup provisions have been moved into this section and expanded to require either a complete independent fire pump system or another means acceptable to the AHJ.

• Electrical Equipment Clearance. Under Section 4.12 Equipment Protection material has been added to address space requirements in fire pump rooms. The new provisions are as follows:

“4.12.1.1.6 The pump room or pump house shall be sized to fit all of the components necessary for the operation of the fire pump and to accommodate the following:

(a) Clearance between components for installation and maintenance
(b) Clearance between a component and the wall for installation and maintenance
(c) Clearance between energized electrical equipment and other equipment in accordance with NFPA 70
(d) Orientation of the pump to the suction piping to allow compliance with4.14.6.3”
(I wonder whether this will help us to get architects to give us enough room to design our fire pump systems.)

• Power Supply Reliability. There will be new provisions to quantify when a primary power source is reliable. The lack of a quantitative definition of reliability has been a problem for us when we contend that an electric motor-driven pump may need a secondary power supply. This new requirement may give us what we need. Introducing the acronyms SAIDI and SAIFI:

“9.3.1.1 For a primary power source to be considered reliable, it shall have a System Average Interruption Duration Index (SAIDI) weighted average rating with Major Events included of 200 or greater unless the AHJ requires a higher rating.


9.3.1.2 For a primary power source to be considered reliable, it shall have a System Average Interruption Frequency Index (SAIFI) weighted average rating with Major Events included of 1.2 or greater unless the AHJ requires a higher rating.”

In your designs you should not allow electric motor-driven fire pump systems to have only one primary source of power unless the SAIDI and SAIFI ratings are known and meet these requirements.

• Alternate Power Sources. Regardless of the reliability of the primary power, an alternate power source is required for any fire pump serving a facility with overnight residents or which is classified as an IBC 2009 occupancy category IV. (What happened to NFPA 5000?)

• Limited Service Controllers. The NFPA 20 Technical Committee reversed a vote during the Report on Proposals which deleted the section on limited service controllers, reinstating the section but requiring that they be provided with locked rotor overcurrent protection. Some argue that this is a more subtle way of eliminating LSCs without eliminating them from the code. This appears to be a big win for manufacturers of fire pump controllers.

• Dikes for Fuel Tanks. A useful exception has been added to the requirement for fuel tanks for diesel engine drives to make it absolutely clear that monitored double wall tanks need not be provided with additional containment.

• Low Oil Pressure and High Engine Temperatures. Requirements have been added to signal the controller when a critically low oil pressure or critically high engine temperature have been reached.

• Full Load Current Test. During acceptance, a one hour “full load (150 percent rated flow) current test” shall be performed. (Hope you have somewhere to put the water.) This, in effect, will force all fire pumps, with no tank to dump water back to, to have an around the pump means of flow testing and a flow meter. Buy stock in meter manufacturers.

• Water Mist Positive Displacement Pumping Units (WMPDPU). There are several new provisions including:

1) A new definition
2) Requirements regarding shop curves for these systems
3) Acceptance test requirements for units with variable speed drivers to meet performance curves for both the variable speed condition and non-variable speed conditions
4) Provisions for use of WMPDPU for pressure maintenance.
5) A new section in Chapter 8 Positive Displacement Pumps applicable to WMPDPU.
6) Acceptance test provisions

• Fire Pump Test Form. The “Centrifugal Fire Pump Acceptance Test Form” has been improved and updated.
Two significant new items passed by the committee were rejected by the membership in floor actions at the NFPA Technical Meeting in June 2012 and thus will not appear in the next edition.

• Location of Pumps in Series. This would have required all pumps in series to be located in the same room. This was done to improve the reliability of the system. Additional provisions allowing for an exception to this requirement were also to be included.

• Fuel Quality Maintenance. This would have required “listed active fuel maintenance systems” on the fuel systems of all liquid fuel driven engines.

Samuel S. Dannaway, PE, is a registered fire protection engineer and mechanical engineer with bachelor’s and master’s degrees from the University of Maryland Department of Fire Protection Engineering. He is past president and a Fellow of the Society of Fire Protection Engineers. He is president of S. S. Dannaway Associates Inc., a 15-person fire protection engineering firm with offices in Honolulu and Guam. He can be reached via email at SDannaway@ssdafire.com.

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