Thermodynamic Properties of Alternative Agents.
Thermodynamic Properties of Alternative Agents.
(977 K)
Yang, J. C.; Breuel, B. D.
NIST SP 861; April 1994.
Evaluation of Alternative In-Flight Fire Suppressants
for Full-Scale Testing in Simulated Aircraft Engine
Nacelles and Dry Bays. Section 2, Grosshandler, W. L.;
Gann, R. G.; Pitts, W. M., Editor(s)(s), 13-35 pp, 1994.
Available from:
Government Printing Office
Order number: SN003-003-03268-9
Keywords:
halons; thermodynamic properties; halon 1301;
solubility; fire extinguishing agents
Abstract:
Depending upon their applications, current halon 1301
(CF3Br) bottles are normally filled to about half of the
bottle volume, and the bottle is then pressurized with
nitrogen to 4.1 MPa (600 psig) at room temperature. The
purpose of using the pressurization gas is to expedite
the discharge of the agent and to increase the
penetration distance of the agent during discharge.
However, this driving force, i.e., the total pressure in
the bottle, will vary depending on the ambient
temperature because the vapor pressure of the agent and
the solubility of the pressurization gas in the liquid
agent vary with temperature. The current military
specification (MIL-C-22284A) for halon 1301 containers
stipulates that the container should have a proof
pressure of 9.62 MPa (1400 psig), a burst pressure of
12.37 MPa (1800 psig), and a frangible disc that will
rupture at a pressure between 8.59 MPa (1250 psig) and
9.62 MPa (1400 psig) at 70 deg C. In order to explore
the possibility of using existing halon 1301 bottles for
"drop-in" replacement agents or to provide safety
guidelines on bottle design for the alternative agents,
two important tasks are to determine (1) the solubility
of the pressurization gas in the liquid agent and (2)
the final pressure of the vessel when exposed to
different ambient temperatures.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899