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Lavatory
Fire Extinguisher Test Standard (LAVEX)
The requirement
for an automatic fire extinguisher which discharges into a lavatory
trash container was proposed in FAA Notice 84-5 as a consequence
of two incidents. The first involved an aircraft cabin fire (Air
Canada, Cincinnati 1983) in which 23 people perished. The second
occurred at Tampa International Airport in Florida on June 25,
1983 that resulted in evacuation of the aircraft with no injuries
or loss of life. Following these accidents, an inspection survey
of the U.S. carrier fleet by the FAA revealed that the fire containment
capabilities of trash containers may be compromised by the wear
and tear typical of service. Considering the seriousness of in-flight
cabin fires, enhanced fire protection was considered necessary.
As a result, rulemaking was implemented on April 29, 1987, that
required each lavatory trash container be equipped with a built-in
automatic fire extinguisher which discharges automatically into
the container upon the occurrence of a fire.
Currently, all aircraft
lavatory disposal receptacle fire extinguishers use Halon 1301
as the fire extinguishing agent. To establish that a replacement
agent provides an equivalent level of safety to that of Halon
1301, the performance is measured against a standard test method.
The FAA established the International Halon Replacement Working
Group to address the development of performance standards for
aircraft fire extinguishing systems employing halons. A specific
Task Group was formed to develop a minimum performance standard
for the lavatory trash receptacle fire extinguishing system.
The minimum performance standard development process started
with the test article, shown in figure 1, based on input from
the Boeing Commercial Airplane Group. The test article is considered
to be representative of the largest trash receptacle in current
service. Ventilation is provided at both the top and bottom of
the test article to allow sufficient circulation of air for combustion
to start and sustain until the lavatory extinguisher (Lavex)
discharges. The ventilation holes were provided with damper flaps
that can be closed upon discharge initiation to minimize leakage
of the agent from the bottom of the test article.
Based on numerous
initial tests, crumpled paper hand towels was established as
the most appropriate fire load. A pair of nichrome coils located
close to the bottom of the trash receptacle comprises the ignition
source. The intention is to simulate a glowing cigarette buried
in the trash, resulting in deep-seated, smoldering combustion.
In order to cover the range of aircraft operational conditions,
a minimum test temperature was established to ensure proper functioning
of the Lavex in cold climates, which can result when an aircraft
is parked for extended periods. Several other requirements were
implemented into the minimum performance standard in order to
obtain a repeatable test condition. These include: standardization
of the ignition source temperature, towel specification, a minimum
number of required successful tests for acceptance, and tolerances
on the actual "crumpling" tightness of the paper towels.
The minimum performance standard development chronology is documented
in FAA Report, "Development of a Minimum Performance
Standard for Lavatory Trash Receptacle Automatic Fire Extinguishers,
DOT/FAA/AR-96/122", dated February 1997. You may view
this report from the Reports page
of this website. The aforementioned test standard may be used
in certification testing of alternative agents to halon for lavatory
trash receptacles. Policy Letter TAD-97-003, March 31, 1997 generated
by the FAA Transport Airplane Directorate, was circulated to
the various Aircraft Certification Offices to serve notice that
this new standard is now in place.
Lavex
Minimum Performance Standard
For
Further Information please contact :
Tim
Marker, AAR-422, (609) 485-6469, or e-mail at Tim_Marker@admin.tc.faa.gov
LAST UPDATED
7/26/99
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