NEXT-GENERATION FIRE SUPPRESSION TECHNOLOGY PROGRAM 

Richard G. Gann 

NGP Technical Program Manager 

and 

Chief, Fire Science Division 

Building and Fire Research Laboratory 

National Institute of Standards and Technology 

Gaithersburg, MD 20899 USA 

ABSTRACT 

The Next-Generation Fire Suppression Technology Program (NGP), now in its second year, has 

as its goal the development by 2004 of alternative fire fighting technologies to Halon 1301 that 

can be economically implemented in aircraft, ships, land combat vehicles, and critical mission 

support facilities. This paper describes the first projects and their early results. 

BACKGROUND 

In FY1997, the Department of Defense (DoD) initiated the NGP, an %year, $46M research 

program to develop new fire suppression technologies for the replacement of Halon 1301 in 

weapon systems. Halon 1301 (CF3Br) has long been the choice for fire extinguishment in most 

weapon systems and mission-critical facilities. However, due to its high ozone-depletion 

potential, Halon 1301 was banned from production as of 1 January 1994, under the Copenhagen 

Amendments to the Montreal Protocol on Substances that Deplete the Ozone Layer. 

The NGP is a logical extension of the on-going DoD activities under the Technology 

Development Plan (TDP) for Alternatives to Ozone-Depleting Substances for Weapon System 

Use. TDP efforts had identified viable, near-term halon alternatives for a wide variety of weapon 

system applications. These alternatives typically require weights and volumes that are double or 

triple those of Halon 1301 for equivalent effectiveness. While they can be readily accommodated 

in new system designs, they pose a significant problem to existing weapon systems because of 

form, fit, and function constraints. Given the current extensions of in-service lives of fielded 

weapon systems, this problem could ultimately require DoD program managers to expend large 

amounts of funding and time for fire suppression system redesign and reconfiguration. 

The goal of the NGP is to develop and demonstrate, by 2004, retrofitable, economically feasible, 

environmentally acceptable and user-safe processes, techniques, and fluids that meet the 

operational requirements currently satisfied by Halon 1301 systems in aircraft, ships, land 

combat vehicles, and critical mission support facilities. The results are to be specifically 

applicable to fielded weapons systems. If successful, the NGP could eliminate DoD dependence 

on a substance no longer in national production, minimize any readiness impacts that could result 

if Halon 1301 use restrictions were imposed in the future, and achieve these at greatly reduced 

cost. The potential fire locations for which alternatives to Halon 1301 are sought include aircraft 

engine nacelles, dry bays, cargo bays, and fuel tanks; ground vehicle crew compartments; and 

shipboard machinery spaces and storage compartments (Figure 1). These locations vary in size, 

shape, and occupancy; the fuels are solids, vapors, and liquids (pools and sprays); and the 

Halon Options Technical Wolking Conference 12-14 May 1998 23 
I 

24 Halon ODliansTechnical Workinq Conlerence 12-14 May 1998 
suppression times range from about 0.01 to 100 sec. The hazards to be avoided include harm to 

people, thermal damage, post-fire corrosion, loss of visibility, and overpressure. Successful 

candidates must thus do well in the following: fire suppression efficiency and reignition 

quenching, ODP, GWP, atmospheric lifetime, suppressant residue level, electrical conductivity, 

metals non-corrosivity and polymeric materials compatibility, long-term storage stability, low 

toxicity of the chemical and its combustion and decomposition products, speed of dispersion, and 

safety and occupational health requirements. To be cost-effective, the suppressant and 

storage/delivery system must be of light weight and low volume, as well as compatible with the 

host designs of existing platforms. 

Information on the strategy of the NGP can be found at the Defense Research and Engineering 

website: www.dtic.mil/ddre/fire_suppression/. 

CURRENT PROJECTS 

The NGP is now in its second year of operation. Ten projects began in FY97, six of which are 

continuing into FY98. Fifteen additional projects were initiated recently in FY98. While the 

overall effort can be described in different ways, at this early stage of the NGP, it appears most 

informative to use the following structure. The distribution of effort is shown in Figure 2. The 

full progress reports will soon be available at the NGP website: www.dtic.mil/ngp/. 

DATA ON CURRENT FIRES AND SUPPRESSION SYSTEMS 

(1) Development of Model Fires for Fire Suppression Research-PI: Anthony Finnerty, 

Am; Associate Investigators: James Tucker, AFRL and Juan Vitali, ARA, Ronald 

Sheinson, NRL 

Objectives: To characterize the types of fires on which the Military uses Halon 1301 in ground 

vehicles, aircraft, and ships; to tabulate the spatial and operational constraints of current Halon 

1301 systems to serve as guidance for the appropriateness of retrofit fire suppression 

technologies. 

Status: A report is in draft, characterizing Halon 1301 fire suppression systems in representative 

current combat platforms and the type of fires on which these halon systems are used. 

VIABILITY OF NEW FIRE SUPPRESSION TECHNOLOGIES 

(1) Relative Benefit Assessment of Fire Protection System Changes-PI: Dennis 

Weiland, AFRL 

Objectives: To develop a methodology that will quantify a technology by its cost in order to 

determine if it is sufficiently superior to the state of the art to warrant further pursuit; to provide a 

groundwork for a future, more comprehensive model to be used by weapons program managers 

for determining, via life cycle costs, the most appropriate alternative to use to replace Halon 1301 

in their systems; and to use the developed methodology to identify the aspects of fire protection 

Halon Options Technical Working Conference 12-14 May 1998 25 
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26 Halon Oplions Technical Working Canlerenee 12-14 May 1998 
technologies that offer the highest potential payoffs. This knowledge can be fed back into the 

NGP for immediate exploitation. 

Status: New project 

(2) Laser-based Instrumentation for Real-time, In-situ Measurements of Combustible 

Gases, Combustion By-products, and Suppressant Concentrations-PI Kevin 

McNesby, ARL 

Objectives: To develop and demonstrate/validate new laser-based instrumentation for the 

measurement of concentrations of candidate suppressants, oxygen, fuels, and combustion 

byproducts during suppression of flames and explosions; and to measure gas production and 

distribution during suppression of deflagrations in crew and engine compartments of a ground 

vehicle. 

Status: A test rig has been installed in a Bradley fighting vehicle for measurement of HF gas 

using NE-TDL absorption spectroscopy, FT-IR spectroscopy and using a fluoride ion selective 

electrode. In-situ, real-time measurement of HF during suppression of JP-8 fuel fires 

demonstrated the effectiveness of HF scavenging agents when added to fluorocarbon-based 

suppressants. NIR-TDL absorption spectroscopy was also used to measure 02 during 

suppression of fires in the crew compartment. Laser-induced breakdown spectroscopy is being 

developed for detection of both flame suppressants and some combustion products. 

(3) Fast Response Species Characterization During Flame Suppression-PI: George 

Mulholland, NIST 

Objective: To develop new instrumentation for measuring agent concentration during a release 

with a 10 ms time response, fast enough to follow the fastest fires experienced in current 

weapons systems. 

Status: New project. 

SUPPRESSANT SCREENING TESTS 

(1) Dispersed Liquid Agent Fire Suppression Screen-PI: Jiann C. Yang, NIST 

Objective: To develop a bench-scale suppression screen (or multiple screens) for comparing the 

flame extinction performance of dispersed gases and liquids. 

Status: A flow facility and modified, propane-air Tsuji-type burner have been developed for 

routine determination of the flame suppression effectiveness of both gaseous and aerosol 

suppressants. Extinction is defined as when blow-off (an abrupt transition from a stable 

enveloped flame to a wake flame) occurs. The performances of the burner and the flow facility 

have been characterized and calibrated using gaseous suppressants. The performance of several 

prototype droplet generators is currently being evaluated using water droplets. 

Halon Options Technical Working Conference 12-14 May 1998 27 
(2) 

Objectives: To design and construct a well-characterized bench-scale suppression screen for 

measuring the effectiveness of gaseous agents and dispersed fluid mists in suppressing and 

preventing re-ignition of a turbulent, obstructed flame burning either gaseous or condensed fuels; 

to evaluate the impact of transient agent delivery on flame extinguishment; and to screen the 

effects of agents on condensed (solid and liquid) fuel surfaces. 

Status: New project 

(3) 

Suppression System Effectiveness Screening-PI William Grosshandler, NIST 

Toxicological Assessment of Human Health Consequences Associated with 

Inhalation of Halon Replacement Chemicals-PI: Gary Jepson, AFRL 

Objectives: To provide a defensible approach and appropriate tools for decision makers, tasked 

with balancing performance and personnel safety issues; and to evaluate the acute toxicity 

potential of inhaled fire suppressants. 

Status: New project 

(4) Agent Compatibility with People, Materials and the Environment-PIS: Marc 

Nyden, NIST, and Stephanie Skaggs, Universal Technical Services 

Objectives: To identify and document the best available screening methods for the toxicity, 

environ-mental impact, and materials compatibility of new suppressants and their fire 

degradation products; and to identify those screening methods needing further development to 

meet the needs of the NGP. 

Status: A workshop of experts in these fields was held 14-15 November 1997. The unanimous 

agreement was that there are no research areas, other than those already being pursued, that 

required new efforts in FY 1999. A report on the screens to be used is being prepared. 

(5) Environmental Impact of New Chemical Agents for Fire Suppression-PIS: Robert 

Huie, NET, and Andaej Miziolek, ARL 

Objective: To evaluate candidate agents from new chemical families in order to establish their 

environmental impact and behavior during storage. 

Status: New project 

NEW FLAME SUPPRESSION CHEMISTRY 

(1) Mechanisms of Ultra-high Efficiency Chemical Suppressants-PIS: Kevin McNesby, 

ARL and James Fleming, NRL 

Objectives: To determine how chemicals that are as or more efficient than Halon 1301 (CF3Br) 

quench the various flames of military interest; using iron pentacarbonyl as the prototype 

“superagent” fire suppressant, to understand key chemical reactions or processes of combustion 

that are affected by “superagent” suppressants and how these reactions or processes differ from 

28 Halon Options Technical Working Conference 12-14 May 1998 
those important for fire suppression by Halon 1301; to determine minimum properties for a 

“superagent” suppressant; to identify other candidate high-efficiency chemical fire suppression 

agents as candidates for replacing Halon 130 1. 

Status: A comprehensive literature survey has been completed of flame inhibition and flame 

suppression data on “superagents,” chemicals that are at least as effective as Halon 1301. Lowpressure, opposed flow, methanehir diffusion flames, both unperturbed and with the addition of 

CFjBr and Fe(CO), were characterized. The flame character and extinction concentration for 

Fe(C0)s added to the oxidizer side were determined. The capability to measure visible emission, 

infrared, and OH spectra were added. Changes in C2 and CH2 radicals upon addition of Fe(C0)S 

to the oxidizer stream were measured. The size, composition, and infrared reflectance 

spectroscopy of particulates formed during inhibition of low pressure methane/air flames 

inhibited by Fe(C0)s were measured. 

(2) Identification and Proof Testing of New Total Flooding Agents-PI Robert E 

Tapscott, NMERI 

Objectives: To identify and develop performance data for best compounds from among the 

following classes: phosphorous nitrides, silanes, siloxanes, and perhaps fluorinated amines 

and/or ethers; and to determine which types of these chemicals are the best candidates for further 

study. 

Status: This project has been completed. A detailed examination has been performed of the 

ODP, GWP, and toxicity estimates and the development of synthetic procedures for a range of 

silicon and phosphorus compounds, fluorinated amines, and fluorinated ethers. A number of 

these appear to have potentially acceptable fire suppression, toxicity, and environmental 

properties. 

(3) Flame Inhibition by Phosphorus-containing Compounds-PI Elizabeth M. Fisher, 

Cornell University 

Objectives: To identify and evaluate the flame extinction performance and toxicity of highly 

effective, low-ODP and low-GWP phosphorus-containing fire suppressants that could be used as 

total flooding agents. 

Status: A novel method for approaching extinction was devised for low vapor-pressure 

additives. Dimethyl methylphosphonate and trimethyl phosphate were found to be 2-4 times as 

effective as CSBr as a flame suppressant in propanehir diffusion flames. A literature search 

shows that some PCCs likely to have low environmental impact and low toxicity. 

(4) 

Objectives: To identify, synthesize, and test the flame extinguishment capability of 

organobromine compounds with estimated acceptably low toxicity, ODP, and GWP, which could 

be used as flooding agents. 

Status: New project 

Tropodegradable Bromocarbon Extinguishants-PI: J. Douglas Mather, NMERI 

Halon Options Technical Working Conference 12-14 May 1998 29 
(5) 

Objectives: To determine whether there are compounds based on the chemistries of sulfur, 

silicon, boron, etc., that are suitable for fire suppression; and, if so, to identify promising 

candidates for full characterization. 

Status: New project 

(6) 

Objectives: To assess whether or not thermal fire extinguishing agents comparable in efficiency 

to Halon 1301 are feasible; and, if so, to provide a list of the best potential candidates and their 

properties along with recommendations for additional testing. 

Status: New project 

BETTER USE OF WATER 

Main Group Compounds as Extinguishants-PI: J. Douglas Mather, NMERI 

Super-effective Thermal Suppressants-P1: William Pitts, NIST 

(1) Suppression Effectiveness of Aerosols and Particles-PI Ronald Sheinson, NRL 

Objectives: To quantify the effect of aerosol properties on the efficiency of gas-phase flame 

suppression and develop a list of liquids and solids manifesting desirable values of these 

properties. 

Status: A powder delivery system was designed and integrated into a counterflow diffusion 

flame (CFDF) burner assembly. Extinction concentrations for propane/air flames were 

determined for potassium bicarbonate, sodium bicarbonate, and potassium bicarbonate, each 

sized from < 38 mm to > 90 mm. Potassium (vs. sodium) and smaller particle size yielded 

higher efficiency. Particle sizes diminished as particles penetrated the flames. Aerosol 

momentum is also a key factor for suppression effectiveness, especially if the aerosol and air 

velocities differ. 

(2) Droplet Interactions with Hot Surfaces-PI Yudaya Sivathanu, En’Urga, Inc. 

Objectives: To obtain the data and understanding of interactions with burning surfaces required 

to engineer improved heterogeneous agent dispersion systems with enhanced fire-extinction 

capability. 

Status: New project 

(3) Technical Support for the Study of Droplet Interactions with Hot Surfaces-PI: 

Jiann Yang, NIST 

Objectives: To provide fluid property and possibly droplet impact data for the study of the 

dynamics of droplethrface interaction and its effect on burning cessation to be conducted by 

other PI s in the 2b projects. 

Status: New project 

30 Halon Options Technical Working Conference 12-14 May 1998 
(4) Electrically Charged Water Mists for Extinguishing Fires-PI: Charles H. Berman, 

AeroChem Research Laboratory, Titan Corp. 

Objectives: To determine whether charged water droplets are drawn to a fire and are more 

effective at suppressing it. 

Status: The project has been completed. For exposed, 5 and 10 cm diameter, turbulent heptane 

pool fires sitting well above the floor in a ventilated chamber, in the presence of a grounding 

electrode, extinguishment times were significantly reduced by charging the water spray at 5 and 

15 kV. The charging also induced significant spreading of the water spray. 

(5) Development of a Self Atomizing Form of Water-PI: Richard K. Lyon, EER, Inc. 

Objectives: To make mist systems consisting of molecular hydrates and determine whether they 

“explode” downstream, increasing the effectiveness of total flooding; and to assess whether 

flashing of water can be affected by molecular hydrates and the approximate temperature range 

over which this is possible. 

Status: The project has been completed. CO2 hydrate was been found to disperse water 

effectively. However, the self-atomization was ineffective at extinguishing an obstructed flame. 

Upon analysis of the possible causes for the failures, the potential for success was deemed low 

and further research along this line was not recommended. 

NEW AEROSOLS AND POWDER SUPPRESSANTS 

(1) 

Objectives: To assess, and if reasonable develop, the capability for encapsulating in inorganic 

media, toxic but efficient fire suppression agents, enabling safe delivery to the fire, where the 

high temperatures will release the agent efficiently. 

Status: New project 

(2) 

Objectives: To evaluate the potential for using metals, internally complexed in a dendritic 

polymer shell, as Halon 1301 replacements. 

Status: New project 

BETTER SUPPRESSANT DELIVERY 

(1) 

Objectives: To understand how and the extent to which flame stabilization behind bluff bodies 

can reduce the observed effectiveness of a suppressant and guide identification of technologies 

that mitigate this limit to suppression efficiency; and to establish worst cases for extinguishment 

Powder-matrix Systems-PI: Donald Burgess, NIST 

Dendritic Polymers as Fire Suppressants-PI Nora Beck Tan, ARL 

Stabilization of Flames-PI Vincent Belovich, AFRL 

Halon Options Technical Woning Conference 12-14 May 1998 31 
by gaseous, liquid, and solid suppressants and the increases in agent concentrations needed to 

cause flame extinguishment. 

Status: A workshop was held to define practical geometries for consideration. Determination of 

the most effective flame stabilization geometries is now being accomplished by (1) Experiments: 

Preliminary results indicated that more stable flames were produced when the fuel was injected 

into the wake of a flow obstruction, producing a diffusion flame; and (2) Modeling of a variety of 

configurations: -Geometries with a cavity were generally more stable than the cases where a 

flame is stabilized downstream of a single bluff-body. Since both sets of results showed that the 

geometry of a cavity formed between two steps is the most stable, this is a likely candidate for 

the more-detailed testing later in the program. 

(2) Dual Agent Approach to Crew Compartment Explosion Suppression-PI Douglas 

S. Dierdorf, ARA Corp. 

Objectives: To determine the feasibility of a two-shot (powder, followed by water mist) system 

for fire suppression in a combat vehicle crew compartment. 

Status: New project 

(3) 

Objectives: Develop and validate a computer code capable of predicting single- and two-phase 

hydrodynamic behavior of fire suppressant fluids during transport through piping systems: 

pressure losses and flow rates for a variety of fluids; through piping systems with various 

combinations of fittings, over a range of pressure and composition conditions, and for transient 

start and stop of flows, as well as for time-varying pressure heads. 

Status: New project 

NEW WAYS OF GENERATING SUPPRESSANTS 

No Projects Underway 

IMPROVED FIRE INERTION 

No projects underway 

Suppressant Flow Through Piping-PI: John Chen, Lehigh University 

FY1999 AND BEYOND 

Solicitations for proposals for Element 4D (New and More Effective Fire Suppression 

Technologies that are Presently Conceptual) and Element 5E (Enhanced Powder Panels) were 

advertised in January 1998 and closed on 20 March 1998. Decisions on the received proposals 

are in progress. 

The next solicitation for proposals will be advertised in December 1998, with a likely closure 

similar to this year. The announcements will appear in Commerce Business Daily, on the 

SERDP website (http://www.serdp.gov/ngp-federal/ngp.htm), and on the soon-to-be-open NGP 

website (www.dtic.mil/ngp/). 

32 Halon Options Technical Working Conlerenc~ 12-14 May 1998