Changes to NFPA 13: Tying the Need to Research to Changes in the Standard
By Carl Anderson, P. E . | Fire Protection Engineering
NFPA 13, Standard for the Installation of Sprinkler Systems,1 provides fire protection and fire service industry professionals with design criteria needed to address fire control or fire suppression for a wide range of occupancy hazards and combustible commodities.
Since the late 1800's, when first published as the Rules and Regulations of the National Board of Fire Underwriters for Sprinkler Equipment, Automatic and Open Systems, fire sprinkler system design has evolved considerably. Simple pipe schedule systems have given way to hydraulically calculated systems and an often complicated array of design criteria for sprinkler protection in storage occupancies.
But how does NFPA 13 keep pace with the rapidly changing challenges presented by today’s built environment?
NFPA publishes an updated edition of NFPA 13 on a three-year cycle. With hundreds of proposed changes in each cycle, the challenge of maintaining and updating a consensus standard may seem insurmountable. NFPA tackles the review of all of these proposals through their proven consensus process, utilizing expertise from a broad cross section of the fire protection industry with volunteers serving on five technical committees.
This article is not intended to provide a laundry list of changes but will focus only on a small sample of recent and proposed changes to NFPA 13 sprinkler design and installation criteria, and the process that moves an identified need to a proposal, and eventually to a change in the standard.
In regards to storage, NFPA 13 has not always specifically addressed sprinkler design for high piled combustible storage. In 1971, NFPA 231C, Standard for Rack Storage of Materials,2 was first adopted and included design curves for protecting storage of various commodities based on small-scale and full-scale fire testing. At this time, fire testing of plastics and other high-heat-release-rate commodities was beyond the scope of the standard. Since then, plastics have become far more commonplace in society and, therefore, in the warehousing industry. Over time, protection criteria has been added and modified. The information in NFPA 231C was moved into NFPA 13 in 1999, and protection criteria for storage occupancies has continued to improve over time.
From a relatively simple set of design curves in 1971, storage requirements in the 2013 edition have grown to include 10 chapters (Chapters 12 through 21) that are dedicated to storage. Protection options include Control Mode Density/Area (CMDA) sprinklers, Control Mode Specific Application (CMSA) sprinklers, and Early Suppression Fast Response (ESFR) sprinklers that have various temperature ratings and K factors ranging from 5.6 to 25.2.
ROLE OF THE TECHNICAL COMITTEE
Technical committees play a key role in the NFPA standards development process. Technical committees are made up of volunteers from various groups that have an interest in the various standards. Insurers, engineers, fire service enforcers, industry professionals, and manufacturers typically have representation on the committees.
CHAPTERS DEDICATED TO STORAGE IN NFPA 13, 2013 EDITION
Chapter 12 – General Requirement for Storage
Chapter 13 – Miscellaneous Storage
Chapter 14 – Protection for Palletized, Solid-Piled, Bin Box, Shelf, or Back-to-Back
Shelf Storage of Class I Through Class IV Commodities
Chapter 15 – Protection for Palletized, Solid-Piled, Bin Box, Shelf, or Back-to-Back
Shelf Storage of Plastic and Rubber Commodities
Chapter 16 – Protection of Rack Storage of Class I Through Class IV Commodities
Chapter 17 – Protection of Rack Storage of Plastic and Rubber Commodities
Chapter 18 – Protection of Rubber Tire Storage
Chapter 19 – Protection of Roll Paper
Chapter 20 – Special Designs of Storage Protection
Chapter 21 – Alternative Sprinkler System Designs for Chapters 12 Through 20
For NFPA 13, there are five technical committees:
Hanging and Bracing for Water-Based Fire Protection Systems
Private Water Supply Piping Systems
Residential Sprinkler Systems
Sprinkler System Discharge Criteria
Sprinkler System Installation Criteria
Because changes proposed to the standard may span more than one technical committee’s area of responsibility, NFPA 13 has a sixth committee, the Technical Correlating Committee on Automatic Sprinkler Systems, which has overall responsibility for the standard.
In 1982 the Fire Protection Research Foundation (FPRF) was founded to address a growing need for research to support NFPA’s growing body of standards. FPRF’s mission is to plan, manage, and communicate research in support of the association. Through FPRF’s efforts, many proposed changes to NFPA 13 and other standards can be based on solid research, and technical committees can confidently vote to include changes to the standards as they progress through their change cycles. Information on the FPRF mission and results of many past and ongoing projects is available at www.nfpa.org/research/fire-protection-research-foundation.
RECENT AND UPCOMING CHANGES
New in the 2013 edition is guidance on sprinkler protection design when High Volume Low Speed (HVLS) fans are installed. These large fans have become more popular and can have a significant impact on successful sprinkler operation and water discharge. Based on tests described in the FPRF reports, HVLS Fans and Sprinkler Operation Phase 1 Research Program – Final Report (2009) and High Volume/Low Speed Fan and Sprinkler Operation – Ph. 2 Final Report (2011),5 it was found that successful results were obtained when the HVLS fan was shut down upon activation of the first sprinkler followed by a 90-second delay. Accordingly, the technical committee was able to include the criteria now found in section 12.1.4 of the standard that includes:
The maximum fan diameter to be 24 ft. (7.3 m).
The HVLS fan shall be centered approximately between four adjacent sprinklers.
The vertical clearance from the HVLS fan to sprinkler deflector shall be a minimum of 3 ft.
All HVLS fans shall be interlocked to shut down immediately upon receiving a waterfowl signal from the alarm system in accordance with the requirements of NFPA 72.
Many of NFPA 13’s recent technical content changes have been in the area of protection of storage occupancies. Increases in building height and the height of storage racks along with the introduction of increasing amounts of plastics have resulted in far more challenging fire scenarios. These challenges are more difficult to properly, efficiently, and effectively protect with fire sprinklers. Furthermore, they are more difficult for responding fire fighters to contain if there are no sprinklers or if the installed sprinkler system isn’t up to the challenge presented by the fuel load.
To properly select design criteria from NFPA 13 for a storage occupancy, the engineer must first understand the commodity being stored. Chapter 5 provides general guidelines on commodity types with an expanded list found in Appendix A. Proposed for the 2016 edition is an expanded explanation of how to account for packaging materials. Additionally, a new figure will be provided to assist with categorizing commodities that contain a percentage of Group A plastics. It will include an expanded tabular listing of commodities categorized based fire test results. A similar table is currently in FM Global Data Sheet 8-1.
Currently several commodities/arrangements are outside the scope of NFPA 13. For example, Table A.5.6 notes that boats stored on racks and large container storage of household goods are commodities not addressed by the classifications in Chapter 5. At the same time, if a designer is looking for protection criteria in Chapter 17 for the rack storage of exposed expanded Group A plastics, it will be difficult to identify a design solution. Obviously, this leaves the engineer in a bind.
Although these known gaps in protection criteria exist, valid technical data is needed to demonstrate that proposed changes are rooted in science and likely to provide an effective design solution in order for the technical committee to recommend adding criteria to the standard.
Proposed changes to the next edition begin to address one of these gaps: the exposed expanded plastics issue. The FPRF has released a report on exposed expanded plastics.3,4 The findings in this report were used as supporting technical data behind a proposal to add design criteria for exposed expanded plastics to the 2016 edition of NFPA 13. The Technical Committee on Sprinkler System Discharge Criteria has evaluated the data and voted to include the criteria. Should these changes be approved by vote at the next NFPA annual meeting, they will have successfully navigated the consensus process and will be published in the 2016 edition.
FPRF’s five-year plan includes a goal to assess factors impacting the effectiveness of fire protection systems. Taking its lead from FPRF’s plan, the FPRF Automatic Sprinkler Fire Protection Research Council works to identify areas where NFPA 13 lacks guidance or needs more information. With needs identified, the Council can help direct potential research topics. As funding becomes available and research is completed, technical challenges will be met and future changes to NFPA 13 will take shape. With continued study, topics such as sloped ceilings in storage occupancies, indoor rack storage of boats, and household goods ‘pod’ storage will be more comprehensively addressed. For example, a 2008 FPRF project, Marina and Boatyard Indoor Rack Storage Sprinkler Protection Literature and Data Review, began the process of identifying and defining the hazard. If further research and test data is developed and presented to the technical committee, NFPA 13 may include design criteria for this storage situation.
As the challenge of protecting lives and property against damaging fire grows, the practice of fire protection engineering and the efforts of organizations such as the NFPA Fire Protection Research Foundation along with fire protection industry professionals who support research and standardization will need to keep pace.
Carl Anderson is with The Fire Protection International Consortium, Inc.
NFPA 13, Standard for the Installation of Sprinkler Systems, National Fire Protection Association, Quincy, MA, 2013.
NFPA 231C, Standard for Rack Storage of Materials, National Fire Protection Association, Quincy, MA, 1971.
2014 Proceeding, Global Research Update, High Challenge Storage Protection, Protection Strategies for High Hazard Plastic Storage Contents, Steven Colin, Code Consultants, Inc., USA Tom Petersen, IKEA, Sweden.
Protection of Rack Stored Exposed Expanded Group A Plastics with ESFR Sprinklers and Vertical Barriers - Test 8 (2014) NFPA FPRF.
HVLS Fans and Sprinkler Operation Phase 1 Research Program Ð Final Report (2009) and High Volume/Low Speed Fan and Sprinkler Operation Ð Ph. 2 Final Report (2011).