Aerojet-NAWC

A GenCorp Company

Advanced Propellant/Additive Dev

for 

Fire Suppressing Systems

Stephen Fallis and Russell Reed

Research Department, Naval Air Warfare Cente

Division, China Lake, CA 

Paul Wierenga, Gary F. Holland

Aerojet-Redmond Rocket Center

Redmond, WA

Halon Options Technical Working Confere

May 2003
Aerojet-NAWC HOTWC 2003 

Outline of Presentation

• Introduction

– Program Background Information– Fire Suppression and GG’s

• Propellant Development

– Cooler, High Nitrogen Compositions

• Effectiveness Testing 

– SPFEs (Solid Propellant Fire Extinguishers)– HFEs (Hybrid Fire Extinguishers)

• Summary• Acknowledgements
Aerojet-NAWC HOTWC 2003 

But First...

GF Holland

PH Wierenga

Olin Aerospace

Rocket Research
Aerojet-NAWC HOTWC 2003 

Fire Suppression Mechanist

FE = Xdil + Xcool + Xchem + 

•Xdil ~ dilution effects: [O2] ≈ 12-13

•Xcool ~ cooling effects: Cp ≈ 40-50 ca

•Xchem ~ chemical effects: radical trap

•Xflow ~ flow rate effects: dec τres in fl
Aerojet-NAWC HOTWC 2003 

Solid Propellant

Fire Suppression System

Current State of the Art:

– Size competitive w/ Halon-1301 (volume, mass)– Effective, clean, fast acting– Environmentally rugged and reliable– Low human hazard: CO2, N2, H2O

– Environmentally friendly, SNAPapproved– Temperature compensating designs– All based on commercial automotive 

airbag technology

Next Ge

Obje

• Improve effect

– Increased 

• Cooler bu• Hybrid co

– Increased – Added che

Oppo

– 2-5x reduc
Aerojet-NAWC HOTWC 2003 

Program Background Informa

Propellant Development

• Phase I

– Developmental Compositions, High-N Compound– Chemically Active Formulations: vary agent

• Phase II

– BTATZ Scale-up– Chemical additives incorporated into SPFE, HFE

• Phase III

– BTATZ Formulations: Ballistic Testing– Chemically Active Formulations: vary [agent]
Aerojet-NAWC HOTWC 2003 

High-Nitrogen Fuels Used 

CL/PAC Propellant Developm

N NN N

NH

N

N

N

HNN

N

N

HN

N N

NN N

N

NH

NN

N

NH

N

N

N

N

N

N

HN

N

N

N

N

N

N

N

N

NHNH2

H2NHN NHNH2

NH2

H2N NH2

NH2

H2N NH2

NO3

N

NN

HN

NH2

+

+

2-

2

-

+

-

GuanidiniumBitetrazole(GBT)

BisguanidiniumAzotetrazole(GAZT)

TriaminoguanidiumNitrate(TAGN)

Bitetrazole(BT)

Bis(aminotetrazolyl)tetrazine

(BTATZ)

5-Aminotetrazole(5AT)
Aerojet-NAWC HOTWC 2003 

Effect of Combustion Temperature o

• Trends

– BR not predictable by Tc alone

– Falloff in BR follows Arrheniustype activated process

• ln(BR)= f(1/Tc)

• Slopes vary

• Predictive tool?

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

0.0003 0.0004 

ln(BR

1000,

) (in/s)
Aerojet-NAWC HOTWC 2003 

Control of Exhaust Temperatu

• Propellant modifications

– Vary F, O

• F+O –––> CO2, N2, H2O

– Incorporate coolant– Calculate Tc (combustion)

– Tmeas ~ 200–600 °C

• Hybrid combinations

– Tmeas ~ 50 100 °C

0

500

10001500200025003000

0 10 

Tc, °K

N NN N

NH

N

N

N

NH

HN

N

N

N

HN

N

NN

HN

NH2

Bis(aminotetrazolyl)tetrazine

(BTATZ)

5-Aminotetrazole(5AT)
Aerojet-NAWC HOTWC 2003 

Developmental Propellants

High Gas, Cooler Gas

Descriptors Tc, ¡C Gas, mol/100g theoretica

density, g/cc 

BTSN-00 2501 2.27 2.38 

BTSN-10Ê 2289 2.12 2.43 

BTSN-20 2032 2.00 2.49 BTSN-30 1621 1.89 2.55 BTSN-40 1537 1.79 2.61 BTSN-50 1071 1.54 2.67 
Aerojet-NAWC HOTWC 2003 

Propellant Combustion
Aerojet-NAWC HOTWC 2003 

Aerojet Fire Test Fixture
Aerojet-NAWC HOTWC 2003 

Test Fixture Parameters

• ~700 kW Flame Intensity

– Flame temperature = ~1000 K (1300 °F)– Air flow rate = 450 g/s (1 lbm/s)

– Fuel flow rate = 15 g/s (0.033 lbm/s)

– Air:fuel ratio = 31 – Equivalence ratio = 0.5

• 24 ft3 Total Volume (16 ft3 fire zone)

– Residence time = ~1 s (through fire zone)

• 100-200 ms Discharge Time for SPFEs and HFE

mair m

& / &
Aerojet-NAWC HOTWC 2003 

Aerojet SPFE Active Agent Tes
Aerojet-NAWC HOTWC 2003 

Test Videos: Active Agent Ass

Fe2O3/FeCp2 KI/K
Aerojet-NAWC HOTWC 2003 

Summary of FTF Data

50% split 50% split

Neat

agent

Agent

mass, g

Test

No.

Result Neat

agent

Agent

mass, g

KI 20 027-06 fire not out Fe2O3 40 0

40 027-07 fire not out 80 0

40 027-05 fire out

60 027-04 fire out

KBr 40 032-02 fire not out Ferrocene 40 

60 032-03 fire not out 80 0

60 032-01 fire not out

K2CO3 20 035-03 fire not out Fe Oxalate 40 

40 035-02r fire out

60 035-01 fire out PBPE 60 
Aerojet-NAWC HOTWC 2003 

SPFE’s

• Advantage

– Rapid di– No stora– T-compe

• Application

– Ballistic 

protectio

– Land veh

compart

– Electron
Aerojet-NAWC HOTWC 2003 

Hybrid Fire Extinguishers

• Advantage

– Tailora– Fits int

envelo

– Low/No – T-comp

• Applicatio

– Armore

compar

– Aircraft – Automo

fire/exp
Aerojet-NAWC HOTWC 2003 

SPFE, HFE Testing

Discha

active a

Fire Test, active agent
Aerojet-NAWC HOTWC 2003 

3304/FM200 HFE Fire Out Sequen

HFE Function: T= 0 msec T= 33 msec 

T= 99 msec T= 132 msec 
Aerojet-NAWC HOTWC 2003 

Performance Summary

0

50

100150200250300350400

Mass of Initial Agent (g)

FS01-40

SPFE

PAC-3304

SPFE

GD-05

SPFE

GD-06

SPFE

FS01-40/

HFC-227ea

 HFE

FS0

Nove

 H

SPFE

Baseline

HFE

Baseline

Series: 10:1 – 6:1

Vary Texh(+1 ft) ~ 50–65 °C
Aerojet-NAWC HOTWC 2003 

Conclusions

• BTATZ-based formulations provide excellent 

burning FS compositions

• Increasing the amount of active additive lead

SPFE and HFE performance.

– Catalysis not yet saturated

• HFE’s effective for low vapor pressure fluids

– Higher-boiling fluorocarbons– Water-based systems
Aerojet-NAWC HOTWC 2003 

Acknowledgements

• Suppression and Ballistics Testing: 

– At China Lake: Dr. T. P. Parr, R. Stalnaker, J. Hitner, P

– At Aerojet/GD: Gary Gregg, Jennifer McCormick, Chu

Paxton, Ray Nikko

• Funding

– SERDP’s Next Generation Fire Suppression Technolo– Naval Air Combat Survivability Program