Connecting the Dots: The Top 10 Impacts of the Fire Protection Research Foundation on the Suppression World

While the first sprinkler systems in the early 1800s consisted of pipes with pierced with holes, the advancement in research and technology has catalyzed the evolution of sprinkler systems to be an effective tool in the life safety and property protection. Although the concept of applying the wet stuff to the hot stuff still applies, the capabilities of sprinklers has significantly improved over the years from a series of pipes pierced with holes to sprinklers that can suppress high-challenge fire scenarios in warehouses.

The Fire Protection Research Foundation (FPRF), NFPA’s research affiliate, has completed over 80 suppression related projects in its 40 year-history. Here are the top 10 impacts the Foundation has made in the fire suppression world that you need to know about. After you read this list, please tell us what you think the future research projects should be!

1. Retrofit Sprinkler Systems (1983)
In 1983, the first Fire Protection Research Foundation project was published in response to several deadly hotel fires in the early 1980s, including the MGM Grand Hotel fire in Las Vegas, NV and the fire at the Stouffer Inn located in White Plains, NY, which led to 85 and 26 fatalities, respectively. The objective of the FPRF project titled: “Field test of a retrofit sprinkler system” was to conduct a series of fire tests based on realistic expected hotel fire scenarios, evaluate the effectiveness of a retrofit sprinkler system to control a fire scenario, and evaluate the survivability in a hotel environment protected by a retrofit sprinkler system.

Impact: This research aided in achieving wide acceptance of plastic piping for hotel fire sprinkler retrofits.

2. Halon (1983 – 2001)
Halogenated hydrocarbon (Halon for short) was used to extinguish fires by disrupting the chemical chain reaction of a fire. However, Halons are an ozone-depleting substance and have been banned from production in the United States in the early 1990s. FPRF completed four projects about Halon. First, in 1983 the report titled: “Halon 1301 Discharge Testing: A Technical Analysis” aimed to analyze the technical issues and alternatives to Halon 1301 total flooding system discharge tests, which were used to evaluate installed systems. Although not required by NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems, (1987 ed.), language provided in the annex describes the validity of conducting a full discharge test to confirm the system is performing as it was designed. The report concluded that while eliminating the Halon 1301 full discharge testing appears inappropriate, alternative strategies to address the performance objectives are within reach.

This brings us to the next published FPRF report titled: “Enclosure Integrity Procedure for Halon 1301 Total Flooding Fire Suppression Systems,” which addressed one of the six identified future research ideas proposed in the previously published report. This project provided fire safety professionals with documented guidelines and techniques to effectively measure Halon 1301 leakage from enclosures using fan pressurization tests and correlate enclosure integrity with halon 1301 discharge tests as well as recommend techniques for correcting leakage problems.

To summarize all the information relevant to Halon, the report titled: “Best and Essential Halon Use: A Methodology” was published by FRPF to outline a method to evaluate alternative fire protection measures for hazards where fixed halon fire protection systems and manually applied fire equipment employing halons have been the agents of choice.

The “Handbook on Standards & Codes of Practice to Eliminate Dependency on Halons” was published by FPRF in 2001 to encourage developing countries in the design and establishment of standards and codes of good practice in the halon sector.

Impact: This research aided in the NFPA Technical Committee on Gaseous Fire Extinguishing Systems, revising the 1992 edition of NFPA 12A to address the decommissioning and removal of systems, as well as revising provisions to be more concise and provide separate advisory text to make the standard more useable, enforceable and adoptable. The research reports and handbook also provided the fire protection industry the much-needed guidance for the use, recycling, and banking of Halon.

3. Fire Protection of Various Shelving Types & Arrangements (2006-2008)
In 2006, FPRF published a report titled: “Evaluation of Sprinkler Performance in Protecting Gondola Type Shelf Storage”, which studied automatic sprinkler protection of Class A commodities on solid gondola shelving. Full scale fire tests were performed and results were provided to the NFPA 13, Standard for the Installation of Sprinkler Systems Discharge Committee, which decided to revise existing definitions and develop new definitions of different shelf storage arrangements to clarify the different concepts between shelf storage and shelving on racks.

To provide the NFPA 13 technical committee with information and knowledge on design criteria for compact mobile storage, FPRF published three reports all within two years’ time.

Impact: The reports titled “Sprinkler Design Criteria for the Protection of Compact Mobile Shelving Systems, “Fire Performance Evaluation of Nominal K-5.6 Ceiling Sprinklers of Protecting 8-FT High Storage of Paper Files in Compact Mobile Shelving Under a 10-Ft. Ceiling

4. Early Suppression Fast Response (ESFR) Sprinklers (1980 – 2020)
Sprinkler designers often use Early Suppression Fast Response (ESFR) sprinklers when protecting high challenge storage arrangements in warehouses. ESFR sprinklers distinguish themselves from the standard sprinklers in three ways: (1) they are designed to activate quickly to achieve full suppression of a fire; (2) they create large water droplets that resist evaporation on their way to the seat of a fire; and (3) they release an immense amount of water to aid in suppression. Since their origin in the 1980s, ESFR sprinklers are viewed as one of the greatest game changers in the sprinkler industry and it should be no surprise that a plethora of research has been conducted over the years to analyze enhance the performance of this sprinkler technology.

Beginning in the mid-1980s, FPRF kicked off a variety of projects including large-scale fire tests, a series of warehouse retrofit tests, and performance tests, all of which contributed to several significant changes in NFPA 13 for high-challenge storage fires.

More recently, in 2014 FPRF published reports on the “Protection of Rack Stored Exposed Expanded Group A Plastics with ESFR Sprinklers and Vertical Barriers” which contributed to provisions in NFPA 13 for sprinkler protection criteria for rack storage of exposed expanded Group A plastic commodities for ceiling only protection.

Obstructions and ESFR sprinklers do not mix. Obstructions such as beams, columns, ductwork, and lighting could be detrimental in the performance of ESFR sprinklers. NFPA 13 provides minimum distances between continuous and noncontinuous obstructions and ESFR sprinklers. There is a joke in the industry that that states: “the building should be designed around the ESFR sprinklers to reach code compliance”. However, FPRF kicked off a six-year project titled: “Obstructions and Early Suppression Fast Response Sprinklers,” which included four different phases with the end-goal of developing a tool that can be used to provide reliable analysis of the impact of obstructions on ESFR sprinklers based on existing data, and to develop technical basis to the NFPA 13 technical committee for new requirements and guidelines.

Impact: The 2022 edition of NFPA 13 has improved installation restrictions and now allows ESFR sprinklers to be located closer to obstructions. There is also a new provision in Chapter 14 to address isolated and continuous obstructions below ESFR sprinklers. These modifications to the latest edition of the standard reduces the challenges designers currently face by maintaining appropriate sprinkler spacing while offering new approaches to common obstructions. The tool from this research report is utilized by industry experts.

5. Single Point vs. Tradition Density-Area Curves (2006)
It wasn’t until the 2022 edition of NFPA 13, that single point density design became an option for new systems, moving away from the use of the density/area curves developed in the 1970s. While discussions on this topic at NFPA 13 committee meetings can be traced back to the early 2000s, the subject of single point density has been widely considered as sprinkler technology, specifically sprinkler k-factor sizes available continue to increase over time. FPRF published a report titled: “Single Point Sprinkler Design Criteria vs. Traditional Density-Area Curves” in 2007 which reviewed the background and basis for the density-area curve of the 2006 edition of NFPA 13 and identified future testing to be conducted for Class III and IV commodities using large k-factors.

6. Antifreeze Solutions (2010-2012)
FPRF published four reports about antifreeze solutions between 2010 and 2012. NFPA 13 has included language on the use of antifreeze solutions in fire sprinkler systems since the 1940 edition. However, after a tragic incident in 2009 that resulted in a fatality, it was found that some antifreeze solutions under certain conditions were identified to ignite when discharged.  “Antifreeze Solutions in Home Fire Sprinkler Systems” and the “Antifreeze Solutions in Home Fire Sprinkler Systems - Phase II Research Interim Report” were published by FPRF in 2010 and consisted of a literature review, preliminary testing and a long-term research plan to further evaluate propylene glycol and glycerin antifreeze solutions at various concentrations and operating conditions. The results of this study concluded that antifreeze solutions of propylene glycol exceeding 40% and glycerin exceeding 50% by volume are not appropriate for use in home fire sprinkler systems.

Impact: This information and knowledge provided vital information to the fire protection and life safety community and resulted in Tentative Interim Amendments (TIAs) on the 2010 editions of NFPA 13, NFPA 13R, Standard for the Installation of Sprinkler systems in Low-Rise Residential Occupancies,  and NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes,  to prohibit the use of antifreeze in new residential sprinkler systems until further information is available.

Per the request of the NFPA Standards Council, the Foundation completed additional research to expand the antifreeze research from residential sprinklers to include spray (commercial sprinklers) in the “Antifreeze Solutions Supplied through Spray Sprinklers Interim Report” and “Antifreeze Solutions Supplied through Spray Sprinklers – Final Report,”  which were published in 2012. These reports concluded that limitations should be considered on the use of 50% glycerin or 40% propylene glycol antifreeze solutions in non-residential sprinkler systems.

The 2013 edition of NFPA 13 included several modifications pertaining to freeze protection and the use of antifreeze in new NFPA 13 sprinkler systems was prohibited unless the solution was listed, and the listing indicated the inability for the solution to ignite. These reports allowed the industry to get on the same page for safety and freeze protection for sprinkler systems.

7. Cloud Ceilings (2014)
Cloud ceilings are ceiling panels that sit beneath the structural ceiling of a room or space and are increasingly common in commercial and industrial buildings. Some panels are discrete with large spaces in between while others provide continuous coverage with small gaps at the perimeter wall. Cloud ceilings could be used for a variety of reasons, including aesthetics or for sound purposes.  Figuring out if sprinklers were required at both the structural ceiling and cloud ceiling panels left designers, enforcers and building owners frustrated. However, in the 2016 edition of the standard, NFPA 13 recognized and defined the term “cloud ceilings”, reflecting information and knowledge from an FPRF published in 2014 titled “Sprinkler Protection for Cloud Ceilings.” This two-phase project focused on how cloud ceiling panels impact sprinkler actuation thresholds to provide technical basis for sprinkler installation requirements. Phase 1 of the study investigated the effectiveness of sprinklers on large area clouds and Phase 2 of the project focused on developing guidance for sprinkler installation requirements for small area clouds. The information collected from this allowed the project team to develop guidance for sprinkler installation requirements by determining the maximum gap size between the wall and cloud edge at which ceiling sprinklers are not effective.

Impact: Based on the “Sprinkler Protection for Cloud Ceilings” report, a new section on sprinkler design for cloud ceilings was added to the 2016 edition of NFPA 13. The design scheme allows sprinklers to be omitted above cloud ceilings when the gap between clouds (or clouds and walls) meets a maximum allowable dimension based on the floor-to cloud ceiling height. Providing this information for designers, enforcers and building owners allows the fire protection and life safety community to have a common understanding of the minimum requirements for cloud ceilings.

8Energy Storage Systems (2011 to present)
Between 2011 and 2016, the Foundation facilitated and managed multiple research projects and workshops on energy storage systems. For example, lithium-ion batteries, which are deployed in a wide range of energy storage applications, were analyzed in a series of projects.  In 2011, the I report outlined the hazard assessment of Li-ion batteries and found that throughout their lifecycle, lithium-ion batteries are located in warehouse settings. Gaps were also identified in research-based sprinkler protection guidance for storage of Li-ion batteries. Phase II of the project characterized the flammability of lithium-ion batteries to provide a basis for the fire protection guidelines of common small-format batteries stored in warehouse rack storage configurations. Lastly, Phase III of the project was published in 2016 and includes one of the first large-scale fire tests to determine sprinkler protection guidance for warehouse storage of cartooned li-on batteries.

The Hazard Assessment of Lithium-Ion Battery Energy Storage Systems published in February of 2016 developed a hazard assessment of the usage of lithium-ion batteries in Energy Storage Systems (ESS).  To allow for the development of safe installation requirements and appropriate emergency response tactics, this research study included a full-scale fire testing of 100-kilowatt hour (kWh) li-ion battery ESS designed by Tesla for use in commercial applications.

The Workshop on Energy Storage Systems and the Built Environment hosted in November of 2015 at FDNY’s Randall’s Island in New York City utilized the New York City experience with energy storage systems in the built environment as a case study and developed a workshop report to help the NYC Building Department and FDNY in evaluating applications for the installation of energy storage systems, and inform firefighting practices. Gaps in regulation identified in this workshop held by the US Department of Energy and FPRF led an individual on behalf of the California Energy Storage Alliance to submit a project request to the NFPA Standards Council on Energy Storage Systems. The technical committee on Energy Storage Systems was appointed and began working on the development of the draft standard which was released to the public in 2017. Several meetings addressed the feedback from the public and within two years, the first edition of NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, became approved in 2019. 

The Sprinkler Protection Guidance for Lithium-Ion Based Energy Storage Systems[WJ1]  published in 2019 provides sprinkler protection guidance for grid-connected lithium-ion battery based ESS for commercial occupancies and highlights the concerns of separation distance and propagation potential.

Impact: The Workshop on Energy Storage Systems and the Built Environment facilitated industry discussions, which led to the new project request to the NFPA Standards Council on a document to address energy storage systems. The continued published research has significantly helped the industry as a whole and provided the Technical Committee responsible for the development of NFPA 855 with information and knowledge to make informed decisions. 

In addition, the Energy Storage Research Consortium was formed to bring industry stakeholders together to provide guidance on how to handle and manage hazards posed by Lithium-ion batteries and other ES applications.

In addition, the current project titled: “Landscape of Battery Energy Storage System hazards & Mitigation Strategies” is working to establish an understanding of the landscape of lithium ion battery-based energy storage system deployments, their hazards and consequences, and the factors that should be considered for a comprehensive protection an hazard mitigation strategy. Additionally, the project aims to identify and prioritize the existing knowledge gaps to develop a future research plan.

9. Inspection, Testing & Maintenance (2018)
Many NFPA Codes and standards specify the minimum requirements for periodic inspection, testing and maintenance (ITM) for fire protection systems such as NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, and NFPA 72, National Fire Alarm and Signaling Code. These requirements are often historical provisions that are not based on ITM data or on observed deficiencies. The FPRF report titled: “Applying Reliability Based Decision Making on ITM Frequency” published in July of 2018 provided recommendations to set up and maintain ITM of fire protection systems data exchange based on the connectivity annex in the 2017 edition of NFPA 25 and the database format in the Connectively Annex of the 2019 edition of NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection.

Impact: To extrapolate historical data for a performance-based approach, the NFPA 25 technical committee recognized that performance data needs to be collected and collated more systematically. Therefore, in the 2017 edition of NFPA 25, a new Annex F was added to provide uniform electronic reporting of performance data.  The 2016 edition of NFPA 20 also added a new Annex C, Fire Pump Controller Connectivity, which provides for uniform reporting of fire pump performance.

10. Protection Under Sloped Ceilings (2010-2013)
The “Analysis of the Performance of Residential Sprinkler Systems with Sloped or Sloped and Beamed Ceilings” reported published by FPRF in 2010 investigated the design criteria for the installation of residential sprinklers on sloped ceiling with and without beams.

This research aided in achieving wide acceptance of plastic piping for hotel fire sprinkler retrofits. The reports titled “, “ and “ contributed to providing the NFPA 13 technical committee with the data to develop protection criteria for compact shelving of commodities consisting of paper files, magazines, books, and similar documents in folders and miscellaneous supplies with no more than 5 percent plastics up to 8 ft high for the 2010 edition of the standard. Additionally, “Back-to-Back Shelf Storage” was introduced to clarify requirements for the protection of shelf storage.   The Workshop on Energy Storage Systems and the Built Environment facilitated industry discussions, which led to the new project request to the NFPA Standards Council on a document to address energy storage systems. The continued published research has significantly helped the industry as a whole and provided the Technical Committee responsible for the development of NFPA 855 with information and knowledge to make informed decisions.

Impact: In the 2013 edition of NFPA 13R, Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies, new language addressed the number of sprinklers to be calculated for certain sloped and beamed ceiling configurations.

The “Protection of Storage Under Sloped Ceilings Phase III: Large Scale Testing Summary and Guidance”, published in September of 2020, was a four-year project that consisted of three phases to develop the technical basis for the NFPA 13 technical committee for new requirements and guidance for the protection of storage under ceilings with slopes steeper than 2/12 (16.7 percent).  The first phase reviewed current storage configuration and numerical simulations of the effects of ceiling slope on suppression performance using computational fluid dynamics (CFD). Phase II of the project consisted of laboratory characterization of sprinkler sprays and numerical modeling that extended the work completed in Phase I. The analysis of the results from Phases I and II guided the development of the large-scale fire suppression test matrix in Phase III which was designed to address suppression performance effects from variations in ceiling slope, purlin and girder arrangements, and sprinkler deflector orientation.

Impact: The 2022 edition includes several revisions for sprinkler system criteria for low-piled rack storage using in-rack sprinklers and miscellaneous storage with ceiling sprinkler design in combination with in-rack sprinklers that have ceilings with slopes greater than 2 in 12.

Where do we go from here? You tell us!

With over 80 published Fire Protection Research Foundation reports related to fire suppression in the last 40 years, what future research needs to be done? Please submit a project idea on our website and contact us with any questions at

Here are a few of the suppression-related ideas we have received:

  • Update Fire Tests to include Modern Cardboard: Cardboard is no longer being manufactured the same way and fire tests need to include the cardboard being utilized today which contains more was and recycle material which shed water from the sprinkler discharge rather than absorbing it. New criteria is needed to determine how to protect commodities stored in modern cardboard.
  • Assess the Need of Sprinklers in Elevator Pits: The requirement to install sidewall sprinklers in elevator hoist ways that contain combustible hydraulic fluid has been an ongoing contentious topic.
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Jacqueline R. Wilmot, P.E.
Research Project Manager, Fire Protection Research Foundation, the research affiliate of NFPA

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