Radiative forcing:

net change in irradiance (in watts per meter squared, Wm^-2) at the tropopause after allowing for stratospheric temperatures to readjust to equilibrium.

Radical:

or free radical; an atom or molecule that has one unpaired electron.

RDT&E:

research, deployment, test, and evaluation.

Retrofit:

installation of new or updated systems in existing platforms.

SNAP:

Significant New Alternatives Program.

Stratosphere:

that region of the atmosphere lying above the tropopause in which, in contrast to adjoining regions, temperature does not increase with increasing height. The stratosphere extends from the tropopause to a height of about 50 km, where the temperature reaches a maximum.

Streaming agent:

a fire suppression agent (typically liquid) applied in a stream, often from hand-held extinguishers, directly on an unobstructed fire.

Teraflop:

1 million million (10¹²) floating point operations per second.

TFA:

trifluoroacetic acid (CF₃COOH).

Thermosphere:

the atmospheric shell extending from the top of the mesosphere to outer space. It is a region of more or less steadily increasing temperature with increasing altitude, starting at about 80 to 95 km.

Total flooding agent:

an easily dispersed fire suppression agent (typically gaseous) for use in obstructed spaces.

Tropodegradable:

tending to degrade, or break down into constituent elements, in the lower atmosphere (troposphere). Tropodegradable compounds emitted at the surface are not likely to be transported to the stratosphere.

Tropopause:

the atmospheric boundary between the troposphere and the stratosphere, defined as the level at which the decrease in temperature with height becomes 2°C/km or less, over at least 2 km.

Troposphere:

the lowest layer of the atmosphere below the tropopause extending from Earth's surface to about 8 km at the poles and 16 km at the equator.

Ullage:

space above fuel inside a partially filled fuel tank.

Ultraviolet (UV) radiation:

electromagnetic radiation lying beyond the violet end of the visible spectrum with wavelength less than 400 nm.

UNEP:

United Nations Environment Programme.

UV-B radiation:

electromagnetic radiation with wavelength in the range of 280 to 320 nm, which affects plants and animals.

V-22:

"Osprey"; a vertical takeoff and landing tilt-rotor aircraft currently under development.

Volume mixing ratio:

the ratio of the number of molecules of a species in air to the total number of gas molecules in a sample.

Water mist systems:

fire suppression systems that dispense water in the form of finely aerosolized droplets. The fine water mist behaves, in some instances, like a gaseous agent and is able to be dispersed effectively in obstructed spaces.

Window region:

a region in the infrared portion of the electromagnetic spectrum with wavelengths in the range of 8 to 12 µm. The atmosphere is relatively transparent to radiation in this spectral region.

WMO:

World Meteorological Organization.

FRONT MATTER (R1-R12)

EXECUTIVE SUMMARY (1-2)

INTRODUCTION (3-5)

ASSESSMENT OF RESEARCH ON ALTERNATIVES FOR HALON (6-21)

ATMOSPHERIC CHEMISTRY AND EVALUATION OF ENVIRONMENTAL EFFECTS OF FIRE SUPPRESSANTS (22-44)

NAVY-SPECIFIC ISSUES (45-62)

APPENDIX A: HALON USE BY THE NAVY (63-74)

APPENDIX B: REGULATION OF HALON AND HALON REPLACEMENTS (75-79)

APPENDIX C: STABILITY AND MATERIALS COMPATIBILITY OF CANDIDATE REPLACEMENTS FOR HALON (80-84)

APPENDIX D: WATER MIST FIRE SUPPRESSION TECHNOLOGY (85-95)

GLOSSARY (96-98)