Suppression Effectiveness Screening for Impulsively Discharged Agents.
Suppression Effectiveness Screening for Impulsively
Grosshandler, W. L.; Hamins, A.; Charagundla, S. R.;
Halon Options Technical Working Conference.
Proceedings. HOTWC 2000. Sponsored by: University of
New Mexico, Fire Suppression Systems Assoc., Fire and
Safety Group, Great Lakes Chemical Corp., Halon
Alternative Research Corp., Hughes Associates, Inc.,
Kidde Fenwal, Inc., Kidde International, Modular
Protection, Inc., Next Generation Fire Suppression
Technology Program, Sandia National Laboratories, Summit
Environmental Corp., Inc. and 3M Specialty Materials.
May 2-4, 2000, Albuquerque, NM, 15-25 pp, 2000.
Available from:For more information contact: Center for Global
Environmental Technologies, New Mexico Engineering
Research Institute, University of New Mexico, 901
University Blvd., SE, Albuquerque, NM 87106-4339 USA.
Fax: 505-272-7203. WEB:
halon alternatives; fire suppression; aircraft safety;
solid propellants; test methods; experiments; injection;
halon 1301; halons
Agent suppression effectiveness is typically measured by
experiments in quasi-laminar diffusion flames
established in a cup burner or counter-flow burner.
Those experiments are conducted by increasing the agent
flow slowly until a critical mole fraction is achieved
in the oxidizer and flame extinction is observed. In
practice, however, agents designed to replace CF3Br are
discharged rapidly, not quasi-statically. Solid
propellant gas generators (SPGG), for example, typically
discharge in 10 ms to 500 ms. A robust and repeatable
means to evaluate the effectiveness of different
formulations and burning rates is required, something
that is impossible with conventional screening devices.
Hirst, Dyer, and coworkers developed a wind tunnel to
explore the impact of step height, air flow, pressure,
and agent mass requirements on the suppression of a pool
fire and concluded that liquid pool fires established
behind an obstacle are highly challenging to extinguish.
Hamins et al. developed a phenomenological model to
characterize the stability of baffle stabilized fires.
Takahashi et al. examined the character of methane/air
flames for varying air velocity and baffle step height,
and measured the amount of Halon 1301 required to
suppress the flames as a function of the flow parameters
and injection interval. The transient-agent
recirculating-pool-fire (TARPF) suppression facility was
designed to screen the performance of agents that are
applied suddenly and for a short duration. The TARPF
facility, originally described at the 1999 Halon Options
Technical Working Conference, consists of a horizontal
wind tunnel designed to simulate challenging fire
situations and to control precisely the air flow, amount
of agent, discharge rate, and discharge duration. Air is
metered through a sonic orifice to overcome the
unintended disruption that occurred in some previous
studies during the agent discharge period. The influence
of common geometric complexities (baffles, a
backward-facing step, and a cavity) on flow field
dynamics and flame stability and a relationship between
the mass of agent necessary for suppression and the
agent injection duration are described in a paper by
Grosshandler et al. Direct numerical simulation of flame
suppression is used in that paper to help explain the
observations. The capability to test solid-propellant
gas generators has been added to the TARPF. For the
first time, both compressed and solid-propellant
generated gases can be compared side by side. It is now
possible to discriminate among formulations, particle
loadings, and burning rates for various SPGG designs.
The SPGG injection system and measurement method are
described in this paper, and the results from
experiments with a commercial air-bag gas generator are