[Federal Register Volume 60, Number 70 (Wednesday, April 12, 1995)]
[Proposed Rules]
[Pages 18566-18574]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-9025]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. 92-66; Notice 3]
RIN 2127-AF36
Federal Motor Vehicle Safety Standards; Fuel System Integrity
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Advance notice of proposed rulemaking (ANPRM).
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SUMMARY: This notice announces the agency's plans to consider upgrading
Federal Motor Vehicle Safety Standard (FMVSS) No. 301, Fuel System
Integrity, by making the current crash requirements more stringent and
by broadening the standard's focus to include mitigation concepts
related to fuel system components and environmental and aging tests
related to components. This notice requests comments on the agency's
plans to explore a three-phase approach to upgrading the standard. The
notice also requests data, methods, and strategies, which may assist in
the agency's regulatory decisions in defining specific requirements and
test procedures for upgrading the standard.
DATES: Comments must be received on or before June 12, 1995.
ADDRESSES: Comments should refer to the docket and notice numbers above
and be submitted to: Docket Section, National Highway Traffic Safety
Administration, 400 Seventh Street SW., Washington, D.C. 20590. Docket
hours are 9:30 a.m. to 4 p.m., Monday through Friday.
FOR FURTHER INFORMATION CONTACT: Dr. William J.J. Liu, Office of
Vehicle Safety Standards, National Highway Traffic Safety
Administration, 400 Seventh Street SW., Washington, D.C. 20590.
Telephone: (202) 366-2264. [[Page 18567]]
SUPPLEMENTARY INFORMATION:
Introduction
The National Highway Traffic Safety Administration (NHTSA) is
announcing its plans to consider upgrading Federal Motor Vehicle Safety
Standard (FMVSS) No. 301, Fuel System Integrity. The purpose of this
rulemaking is to further reduce fatalities and injuries from fires
resulting from motor vehicle crashes. Specifically, the agency is
considering whether to make more stringent the current crash
requirements applicable to vehicles with a gross vehicle weight rating
(GVWR) of 10,000 pounds (4,536 kg) or less. It is considering also
whether to broaden the standard's focus to include ways to prevent or
decrease the severity of vehicle fires by exploring regulations related
to fuel system components and tests of the resistance of components to
environmental and aging factors.
Today's notice outlines NHTSA's plans to explore a three-phase
approach to upgrading the standard. In Phase One, the agency would
evaluate performance criteria for components to ensure that the flow of
fuel from the tank is stopped in a crash. Phase Two would involve
defining upgraded crash test performance for frontal, side, and rear
impacts (e.g., higher test speeds, additional impact barriers, etc.).
During Phase Three, NHTSA would address the effect of environmental and
aging factors such as corrosion and vibration on components in the fuel
system.
Today's notice also summarizes issues related to vehicle fires and
discusses the agency's recent work in this area. The agency is seeking
public comment on the merits of the agency's rulemaking efforts to
explore alternative ways to upgrade the present standard. Today's
notice also supplements a previous notice published on December 14,
1992, in which the agency requested comments about making FMVSS No. 301
more stringent (57 FR 59041, Docket 92-66, Notice 1).
On December 2, 1994, Secretary of Transportation Federico Pena
announced a settlement of an investigation by NHTSA of an alleged
safety defect in certain General Motors (GM) pickup trucks with fuel
tanks mounted outside the frame rails. Under that settlement, GM will
contribute over $51.3 million for a variety of safety initiatives.
Among other things, the settlement will fund research on ways to reduce
the occurrence and effects of post-crash fires. All relevant results of
this research will be placed in the public docket for this rulemaking.
The Fire Problem
While vehicle fires are relatively rare events (occurring in only
one percent of towed vehicles in crashes), they tend to be severe in
terms of casualties. The agency's General Estimates System (GES)
reports that, in 1992, approximately 21,000 passenger cars, light
trucks, and multipurpose vehicles had a fire related to a crash. Based
on an analysis of the agency's Fatal Accident Reporting System (FARS),
four to five percent of occupant fatalities occur in crashes involving
fire (the fatality being due to burns and/or impact injuries). Overall,
the fire itself is deemed to be the most harmful event in the vehicle
for about one-third of these fatalities.
An analysis of 1979-1986 National Accident Sampling System (NASS)
data (Reference: ``Fires and Burns in Towed Light Passenger Vehicles,''
Docket No. 92-66-N01-001) shows that about 29,000 occupants per year
were exposed to fire in towed light passenger vehicles (cars, light
trucks, and multipurpose vehicles), of whom three percent received
second or third degree burns over at least six percent of the body. The
Abbreviated Injury Scale (AIS) defines these burns as moderate and more
severe (AIS 2 and greater). Half of those with moderate and more severe
burns had second or third degree burns over more than ninety percent of
the body; these maximum-severity (AIS 6) burns are always fatal. These
estimates are based on all 47 occupants with moderate and more severe
burns received in vehicle fires that were investigated as part of the
NASS during the eight years from 1979 to 1986.
NASS investigated vehicle fires that involved another 44 occupants
with moderate and more severe burns between 1988 and 1990. The eleven
years of NASS data suggest that each year 280 surviving occupants and
725 fatally-injured occupants received moderate or more severe burns
(AIS 2 or greater). These injuries and fatalities may have been caused
by burns or impacts.
NASS 1988 to 1990 data also indicate that potential escape from the
fire was made more difficult for most occupants (87 percent) with
moderate or more serious burns because they (1) were sitting next to a
door that was jammed shut by crash forces, (2) did not have a door at
their position, or (3) had a part of their body physically restrained
by deformed vehicle structure.
Federal Motor Vehicle Safety Standard No. 301
FMVSS No. 301, Fuel System Integrity, first became effective for
passenger cars in 1968. The requirements in the current standard apply
to all vehicles with a Gross Vehicle Weight Rating (GVWR) of 10,000
pounds (4,536 kg) or less since September 1, 1977, and to school buses
that have a GVWR greater than 10,000 pounds (4,536 kg) GVWR since April
1, 1977. FMVSS No. 301 only applies to vehicles that use fuel with a
boiling point above 32 degrees Fahrenheit (0 degree Celsius).
FMVSS No. 301 limits the amount of fuel spillage from fuel systems
of vehicles tested under the procedures specified in the standard
during and after specified front, rear, and lateral barrier impact
tests. The standard limits fuel spillage due to these required impact
tests to 1 ounce (28.4 grams) by weight during the time from the start
of the impact until motion of the vehicle has stopped and to a total of
5 ounces (142 grams) by weight in the 5-minute period after the stop.
For the subsequent 25-minute period, fuel spillage during any 1-minute
interval is limited to 1 ounce (28.4 grams) by weight. Similar fuel
spillage limits are required for the standard's static rollover test
procedure, which is conducted after the front, rear and lateral impact
tests.
The required impact tests for all vehicles that have a GVWR of
10,000 pounds (4,536 kg) or less are: a 30 mph (48.3 kmph) frontal
fixed rigid barrier impact with the barrier face perpendicular to the
line of travel of the vehicle or at any angle up to 30 degrees from the
perpendicular; a 30 mph (48.3 kmph) rear moving flat rigid barrier
impact with the barrier face perpendicular to the longitudinal axis of
the vehicle; and a 20 mph (32.2 kmph) lateral moving flat rigid barrier
impact in a direction perpendicular to the longitudinal axis of the
vehicle (i.e., with the barrier face parallel to the longitudinal axis
of the vehicle). The weight of the moving barrier is 4,000 pounds
(1,814 kg). A rollover test is conducted following the barrier impacts.
The required impact test for large school buses that have a GVWR
greater than 10,000 pounds (4,536 kg) is a 30 mph (48.3 kmph) moving
contoured rigid barrier impact at any point and angle. The weight of
the barrier is 4,000 pounds (1,814 kg). The static rollover test is not
required for large school buses.
The standard does not apply to large non-school buses or other
vehicles that [[Page 18568]] have a GVWR greater than 10,000 pounds
(4,536 kg).
December 14, 1992 Notice
On December 14, 1992, NHTSA published a Request for Comments notice
in the Federal Register (57 FR 59041, Docket No. 92-66, Notice 1)
stating that the agency ``is considering initiating rulemaking to
upgrade the protection currently provided by'' FMVSS No. 301. The
notice also requested answers to specific questions related to test
impact speeds, impact barriers, effect of vehicle aging on the
likelihood of fire, contribution of occupant entrapment to the
likelihood of fire-related injuries, etc.
NHTSA received 35 public comments by October 1994 including
comments from most of the major vehicle manufacturers, the American
Automobile Manufacturers Association (AAMA), Advocates for Highway and
Auto Safety (Advocates), the Center for Auto Safety (CAS), and the
Insurance Institute for Highway Safety (IIHS). Commenters raised issues
regarding the safety need, the adequacy of the current test procedures,
the availability and necessity of developing new test procedures, and
the existence and feasibility of countermeasures. Many commenters
stressed the need for further detailed investigation of real-world
crash data to determine the causes of vehicle fires and fire-related
occupant fatalities and injuries. In addition to support for the test
procedures currently used in FMVSS No. 301, commenters suggested
several alternatives, including substituting the dynamic side-impact
test procedures of FMVSS No. 214 for those currently specified in FMVSS
No. 301, adding frontal offset crash conditions, and developing new
barriers that might be more representative of real-world crash
conditions.
The agency has initiated work related to several fire safety issues
that need to be considered to define mitigation concepts to reduce
fatalities and injuries. Due to resource considerations, not all the
safety issues discussed in the previous notice are included in this
notice. The issues discussed in this ANPRM include crash conditions,
origin of fires, and vehicle age.
Agency Efforts Related to Fuel System Integrity
NHTSA has undertaken the following activities to more-fully
understand motor vehicle fires. These include comparing fuel system
safety requirements in this country with those in other countries,
conducting extensive test crashes related to fuel system integrity, and
analyzing data of real-world crashes.
Comparison of U.S. and Foreign Fuel System Safety Requirements
FMVSS No. 301's requirements have been compared to the following
foreign fuel system integrity standards: (1) The Canadian CMVSS No.
301, Fuel System Integrity (Gasoline, Diesel); (2) the Economic
Commission for Europe (ECE) Regulation No. 34, Uniform Provisions
Concerning the Approval of Vehicles with Regard to the Prevention of
Fire Risks (01 Series, Amendment 1, January 29, 1979) (Thirteen
European countries have agreed to adopt ECE Reg. No. 34, including
Germany, France, Italy, Netherlands, Sweden, Belgium, Czechoslovakia,
United Kingdom, Luxembourg, Norway, Finland, Denmark, and Romania); and
(3) the Japanese Standard, Technical Standard for Fuel Leakage in
Collision etc. (Amended on August 1, 1989).
The Canadian CMVSS No. 301 has requirements identical to those of
the U.S. FMVSS No. 301.
In terms of application to vehicles: FMVSS No. 301 applies to all
vehicles 10,000 pounds (4,536 kg) or less GVWR and school buses over
10,000 pounds (4,536 kg) GVWR. ECE Reg. No. 34 only applies to
passenger cars, and the Japanese standard applies to passenger cars and
multipurpose passenger vehicles 5,600 pounds (2,540 kg) or less.
In terms of required impact tests: As described above, FMVSS No.
301 requires frontal, rear and side impact tests at 30, 30, and 20 mph
(48.3, 48.3 and 32.2 kmph), respectively, plus a static rollover test,
for vehicles 10,000 pounds (4,536 kg) or less GVWR. FMVSS No. 301 also
requires a 30 mph (48.3 kmph) impact test for school buses over 10,000
pounds (4,536 kg) GVWR.
The ECE Reg. No. 34 requires a 48.3 to 53.1 kmph frontal fixed
barrier impact test and a 35 to 38 kmph rear moving flat barrier impact
test. The flat rigid barrier weighs 1,100+20 kg. A pendulum can be used
as the impactor. ECE Reg. No. 34 does not require a rollover test. The
standard requires a hydraulic internal-pressure test for all fuel tanks
and special tests (impact resistance, mechanical strength, and fire
resistance) for plastic fuel tanks.
The Japanese standard requires a 50+2 kmph frontal fixed barrier
impact test and a 35 to 38 kmph rear moving flat barrier impact test.
The flat rigid barrier weighs 1,100+20 kg. A pendulum can be used as
the impactor.
In terms of test performance requirements: all three standards
limit fuel spillage. As in FMVSS No. 301, the ECE Reg. No. 34 and the
Japanese standard, in general, also limit fuel spillage to about 1
ounce/min (28.4 grams/min). The Japanese standard lists the ECE Reg.
No. 34 and FMVSS No. 301 as examples of equivalent standards.
In summary, FMVSS No. 301 applies to more vehicle classes and to
higher vehicle weights than the ECE Reg. No. 34 or the Japanese
standard. FMVSS No. 301 requires testing in all crash modes (frontal,
side, rear, and rollover). ECE Reg. No. 34 and the Japanese standard
require only frontal and rear impact tests. FMVSS No. 301 uses a much
heavier moving barrier for impact tests than the ECE and Japanese
standards (1,814 kg vs. 1,100 kg). However, FMVSS No. 301 does not
require a hydraulic pressure test for fuel tanks, a battery retention
requirement, or additional tests for plastic fuel tanks; ECE Reg. No.
34 does. In addition, the ECE Reg. No. 34 requires that ``no fire
maintained by the fuel shall occur'' and no failure of the battery
securing device due to the impact. Since ECE Reg. No. 34 also requires
filling the impacted vehicle's fuel tank ``either with fuel or with a
non-inflammable liquid,'' the no-fire requirement is actually
interpreted from the observed fuel leakage. It is the agency's
understanding that in practice, when the ECE Reg. No. 34 tests are
conducted, the fuel tank is filled with non-inflammable liquid.
Safety Issues Related to Vehicle Fires
A. Crash Conditions
The crash conditions discussed in this section refer to real-world
crash conditions that result in vehicle fires and their implications
for compliance test conditions and performance requirements for the
current FMVSS No. 301. To further refine the relationship between real-
world and laboratory crash conditions, this notice has examined certain
engineering parameters such as impact speeds, impact locations, objects
struck, and damage patterns.
Laboratory Crash Test Results
Between 1968 and 1994, the agency has conducted 563 FMVSS No. 301
compliance tests in the frontal impact mode: 14 failures resulted (3%),
the last occurring in 1992. Effective September 1, 1976, the standard
was amended by requiring rear impact tests for all vehicles and side-
impact tests for passenger cars only. Side-impact testing was extended
to all vehicles and became effective on September 1, 1977. For model
years 1977 through 1994, 331 rear impact and 25 side-impact compliance
tests have been conducted; 26 rear impact failures (8%) and 1 side
[[Page 18569]] impact failure (4%) resulted. In computing these failure
rates, the rollover test is considered a part of the frontal, rear, or
side impact test.
The agency conducted a research test program on FMVSS No. 214, Side
Impact Protection, for light trucks. Since December 1988, 24 crash
tests have been conducted, 2 tests produced fuel leakage at a rate
higher than FMVSS No. 301 requirements. Both tests used the FMVSS No.
214 test protocol.
Between 1979 and 1986, 12 out of 201 (6%) frontal New Car
Assessment Program (NCAP) tests indicated leakage at a rate above the
fuel spillage requirements of FMVSS No. 301 at 35 mph (56.3 kmph). In
addition, during the same period, NCAP conducted 53 FMVSS No. 301 rear
impact tests at 35 mph (56.3 kmph), and 6 (11%) leaked at a rate above
the fuel spillage requirements of the standard. Rollover tests were not
conducted following any of the frontal or rear impact NCAP tests. Some
of these vehicles were retested at 30 mph (48.3 kmph), but none failed.
In 1993, NCAP resumed examining FMVSS No. 301 fuel spillage
requirements, and added a rollover test following the frontal impact
tests. To date, only one of the approximately 80 vehicles tested leaked
at a rate above the requirements of the standard at the higher speed.
Between April and June 1993, the agency conducted six baseline
vehicle crash tests (all 1993 models) as part of its initial research
effort for exploring potential upgrades to FMVSS No. 301. In addition,
the Federal Highway Administration (FHWA) conducted a seventh crash
test for the agency. Information on the seven tests has been entered
into the docket.
The test conditions for the seven crash tests represent a baseline
of delta-v (change of velocities), impact barrier, and impact location.
The tested cars were chosen based on their high sales volume as well as
agency experience with the cars in other test programs.
The six NHTSA tests include two in each of the crash modes:
frontal, side, and rear. Three tests used a 4,000-pound (1,814-kg)
moving contoured barrier--a frontal impact into a Chevrolet Corsica at
65 kmph (40.5 mph), a side impact into a Toyota Corolla at 49.4 kmph
(30.7 mph), and a rear impact into a Ford Escort at 56.6 kmph (35.2
mph). None of these three tests resulted in a loss of fuel system
integrity.
The other three tests were: a frontal impact of a Chevrolet Corsica
into a 305-mm (12-inch) diameter stationary pole at 56.3 kmph (35 mph),
a side impact into a Toyota Corolla with a 1,361-kg (3,000-pound)
deformable moving barrier (FMVSS No. 214 side impact barrier) at 87.1
kmph (54.1 mph), and an offset rear impact into a Ford Mustang with the
same type of FMVSS No. 214 moving barrier at 84 kmph (52.2 mph).
The only fuel system failure was a ruptured fuel tank from the rear
impact to the Ford Mustang by the FMVSS No. 214 deformable moving
barrier, resulting in a delta-v of about 39 kmph (24 mph). The head and
chest injury measurements on the instrumented driver and passenger
dummies exceeded the criteria specified in FMVSS No. 208, Occupant
Crash Protection. Thus, the survivability of this crash in the absence
of a fire is questionable. However, the agency would like to point out
that FMVSS No. 208 is for frontal tests and the test dummies used for
the tests were not specifically designed to collect impact data for
rear impact tests.
The crash test conducted by FHWA was on a Toyota Corolla, which was
crashed into a 203-mm (8-inch) diameter stationary pole directed at the
fuel tank location, in a side impact orientation at 32.2 kmph (20 mph).
There was no fuel system integrity failure. No dummy instrumentation
was used in this test.
The agency also conducted other frontal impact tests. These tests
primarily consisted of high speed, vehicle-to-vehicle offset crashes.
In addition, several side impact tests were conducted using the FMVSS
No. 214 test procedure. Since December 1990, a total of 25 crash tests
have been conducted. One test, involving a Chevrolet Corsica, resulted
in a small fuel leak from the fuel return line (within FMVSS No. 301's
limit). This test was conducted in an oblique configuration with a
Honda Accord striking the left front corner of the Corsica.
At the request of NHTSA's Office of Defects Investigation (ODI),
the Vehicle Research Test Center (VRTC) conducted 24 side-impact crash
tests (including one test with no instrumentation to determine
appropriate test speed) of the 1973-1987 General Motors full-size
pickup trucks and peer pickup trucks of the same vintage. These tests
were conducted as a part of a safety defect investigation, EA 92-041.
Seven of these tests were FMVSS No. 301 type side impact tests, three
were FMVSS No. 214 moving deformable barrier tests, three were vehicle-
to-pole side impact tests, and eleven were various vehicle-to-pickup
side impact tests. Reports of these tests are included in the public
file for EA92-041.
The summary report for this test program notes that the FMVSS No.
301 type tests produced no leaks in a test of a new replacement fuel
tank; however, one of the four GM trucks tested with ``as received'' GM
tanks leaked an amount in excess of the FMVSS No. 301 requirements in a
rusty area. Non-tank components of one Ford and one GM truck did leak
during the static rollover test.
In the three GM truck tests using the FMVSS No. 214 barrier, one at
53.1 kmph (33 mph) and two at 72.4 kmph (45 mph), one caused a leak in
the seam of the tank which resulted in a damp area, while the other two
did not leak.
In the vehicle-to-vehicle tests, the ride height of the striking
vehicle was adjusted to simulate heavy braking. At 72.4 kmph (45 mph)
with a Taurus striking car, the GM fuel tank significantly leaked at
the sending unit, filler nose, and a rusty area and small cut in the
tank. Although no leakage was noted from the fuel tank during a similar
test of a Ford F-150, significant fuel leakage was noted from the fuel
reservoir mounted on the inside of the left rail.
For the 80.5 kmph (50 mph) tests, significant leaks were noted from
the GM vehicles (in ``as received'' and new condition), but no leaks
were noted during a similar test on an F-150.
In the 96.6 kmph (60 mph) tests, both the GM and Ford F-150
vehicles leaked significant amounts, with the GM truck rupturing and
the Ford F-150 trucks being punctured, forming small holes.
One pole test was conducted at 48.3 kmph (30 mph) on a GM pickup
truck with significant vehicle damage and significant fuel leakage. In
the pole tests, at 32.2 kmph (20 mph) the GM tank leaked significantly,
but in a similar test of a Ford F-150, no leakage was observed.
Data Analysis of Real-World Crashes
Accurate data on vehicle fires are scarce, which makes it difficult
to define cause/effect relationships under all circumstances. Unlike
many other crashes, investigations of crashes involving fire are
hampered by the destruction of evidence needed for crash reconstruction
and analysis. The origin of fire in vehicle crashes needs to be
understood better to help define possible countermeasures and
performance requirements.
NHTSA has reviewed real-world crashes involving fuel system
integrity at great length. This analysis includes a review of the
National Accident Sampling System (NASS) file, a recent analysis by the
agency of the Fatal Accident Reporting System (FARS) data, a detailed
hard copy study of accident cases involving fire from NASS and
[[Page 18570]] FARS, and an analysis of State accident files.
The NASS review referenced in the December 14, 1992, Request for
Comments notice, ``Fires and Burns in Towed Light Passenger Vehicles''
(Docket No. 92-66-N01-001), noted that most fires occurred in crashes
with a delta-v of less than 32.2 kmph (20 mph). This figure is from all
fires, regardless of injury level.
When the same NASS files were analyzed for occupant burn injuries
at AIS 2 or greater, the sample size was very small, even after the
1991 data were added. The delta-v for frontal impacts resulting in fire
was estimated to be from 33.8 to 106.2 kmph (21 to 66 mph), with a 66
kmph (41 mph) median, based on 14 cases. The delta-v for side impacts
was estimated to be from 16.1 to 66 kmph (10 to 41 mph), with a 43.4
kmph (27 mph) median, based on seven cases. The delta-v for rear
impacts was to be estimated from 12.9 to 96.5 kmph (8 to 60 mph), with
a 41.8 kmph (26 mph) median, based on 11 cases.
The following are estimates of the delta-v's. For vehicle- to-
vehicle crashes, a 32.2 to 64.4 kmph (20 to 40 mph) delta-v range could
result from impact speeds in the 64.4 to 128.8 kmph (40 to 80 mph)
range for equal mass vehicles. Similarly, the same delta-v range could
be the result of other high impact speeds for crashes involving unequal
mass vehicles.
The FARS study analyzed real-world crash data related to vehicle
fires to establish which barrier design most closely replicates the
damage seen in real-world fatal crashes involving fire. Preliminary
results of the agency's FARS study indicate that the combined 1979-1992
data from FARS for light vehicles of model years 1978 and later include
9,440 vehicles with a post- crash fire, of which 2,840 were crashes
where fire was classified as the most harmful event. Of the latter
vehicles, approximately half were involved in single-vehicle crashes,
and half were in multi-vehicle crashes.
For frontal and side fatal crashes involving a fire, approximately
60 percent involved multiple vehicles, while for rear-impact crashes
involving in a fire, approximately 90 percent of the crashes involved
multiple vehicles. Narrow objects, including trees and poles, account
for approximately 40 percent of the objects struck in single vehicle
crashes resulting in a fire.
The agency recently completed a detailed hard copy study of a
sample of accident cases involving fire from NASS and FARS. The
detailed case study report has been entered into the docket of this
notice. The title of the report is: ``Fuel System Integrity Upgrade--
NASS & FARS Case Study,'' a NHTSA sponsored research study, by GESAC,
Inc., DOT Contract No. DTNH-22-92-D- 07064, March 1994.
The GESAC study selected 150 NASS cases for detailed analysis,
which were selected from recent years and involved fire with any
occupant injury of AIS 2 or greater. One of the objectives of the
analysis was to suggest a laboratory simulation for accidents that led
to vehicle fires. The suggested crash simulations include impact mode,
speed, barrier, location, and orientation.
The report presents information on a possible barrier test that
most accurately ``simulates'' crashes that resulted in ``moderate'',
``severe'', and ``very severe'' fires. A ``moderate'' fire is defined
as fire damage to between 25% and 50% of the vehicle surface, a
``severe'' fire has fire damage to between 50% and 75% of the vehicle
surface, and a ``very severe'' fire has fire damage to more than 75% of
the vehicle surface.
For this analysis, only the cases for which a simulation was
defined were included. Simulations were not defined, for example, for
cases where the fire originated outside the vehicle or where the crash
conditions were too complicated--these events included multiple
impacts, undercarriage impacts, or rollover events, etc. Based on these
criteria, there were 64 vehicles selected for simulations.
For vehicles receiving frontal damage, the report indicates that a
pole would be the most common simulation barrier type. For rear damage,
a moving deformable barrier with a partial overlap (a partial width of
the vehicle involved in the crash) was cited most often as a simulation
procedure. For side impacts, a pole impact was the most common
simulation procedure. The GESAC report also presents information on
impact speed for these simulations.
For frontal impacts, the delta-v ranged from 23 kmph to 105 kmph
(14 to 65 mph) with a 55 kmph (34 mph) medium delta-v. For rear
impacts, the delta-v ranged from 11 kmph to 73 kmph (7 to 45 mph) with
a 42 kmph (26 mph) medium delta-v. Overlap, which is defined as the
percentage of the frontal or rear width engaged in a crash, ranged from
40% to 100% for frontal crashes, with an average level of 72% overlap.
For rear crashes, the overlap ranged from 30% to 95% with an average
level of 71%. This real-world crash is similar to the Ford Mustang
test, discussed in the previous section, that resulted in a ruptured
fuel tank.
Based on these analyses, NHTSA tentatively concludes that in
developing any new performance requirements, it should consider
alternatives to the FMVSS No. 301 barriers in addition to possible
changes in impact speeds. Possible alternatives to be considered are
changes to simulate single vehicle crashes, pole tests, and offset
tests.
NHTSA also needs to consider the likelihood of an occupant
surviving the crash forces in high severity crashes that are associated
with many fire fatalities. To address this issue, the agency may have
to develop new test dummies that are capable of collecting meaningful
data at higher impact speeds and in rear impacts.
To further define crash conditions that lead to fires, NHTSA
anticipates conducting additional analysis of the FARS and NASS files,
the GESAC study, and experimental crash testing. Additional full-scale
crashes are being considered to help identify possible upgraded
performance requirements.
Response to the Request for Comments Notice
Impact Speeds
FMVSS No. 301 specifies that the frontal and rear crash tests be
conducted at 30 mph (48.3 kmph) and the lateral crash test be conducted
at 20 mph (32.2 kmph). The December 1992 notice asked about appropriate
test speeds.
In response to that notice, Advocates and CAS supported testing
with increased impact speed. Specifically, Advocates stated that impact
testing for all crash modes should be conducted at least at 56.3 kmph
(35 mph). It also stated that the current side impact 32.2 kmph (20
mph) test speed of existing FMVSS No. 301 is especially inappropriate
in light of the agency's current consideration of dynamic lateral test
regimens for light trucks. CAS stated that based on crash protection
technology in new vehicles, the standard should be amended to provide
for no fuel leakage in a 72.4 kmph (45 mph) frontal fixed barrier
crash, a 72.4 kmph side moving barrier, and a 72.4 kmph fixed rear
barrier.
In contrast, Mazda, Mitsubishi, Volkswagen (VW), Toyota, GM,
Chrysler, Mercedes-Benz, BMW, Ford Motor Company and the American
Automobile Manufacturers Association (AAMA) questioned the need for
testing at higher impact speeds or stated that more data are needed
before considering such an increase. For instance, Toyota stated that
the data and analyses on injuries and deaths from vehicle fires are
insufficient to support a compliance test requirement for higher impact
speeds. Similarly, Mercedes stated that increased impact speed as part
of a compliance test does not appear to have [[Page 18571]] great
potential for increasing real-world fire safety. AAMA stated that the
difference in impact speeds for side versus front and rear tests is
representative and reasonable.
Impact Barrier, Location, and Orientation
FMVSS No. 301 requires either fixed or moving rigid impact barriers
for the crash tests as described previously in this notice. In the
December 1992 notice, NHTSA posed several questions about the
appropriate barrier, including whether the current impact barriers
should be replaced by the moving contoured rigid barrier for testing
large school buses.
National Truck Equipment Association (NTEA), Mazda, Advocates, VW,
Toyota, AAMA, BMW, and Ford said no; and no commenter favored this
approach. NTEA objected to extending the existing contoured barrier to
other vehicles because of economic considerations. Mazda stated that
the FMVSS No. 214 barrier represents real-world crashes better than the
contoured barrier.
In the December 1992 notice, NHTSA also asked whether the current
barriers are representative of typical real-world crash situations.
While GM and BMW stated ``yes,'' Advocates, Ford, and Volvo said
``no.'' GM stated that the FMVSS No. 301 moving barrier side impact
test is an appropriate surrogate for real-world side impact
circumstances because it properly measures the fuel system performance
regardless of component location. Advocates stated that the current
perpendicular barrier crash test conditions for frontal and rear impact
tests should be replaced by offset and angle impacts. Advocates also
suggested that the current side impact test should be replaced by a
pole impact test, claiming that such a test is more representative of
real-world situations.
The December 1992 notice also asked whether all vehicles with GVWR
of 10,000 pounds (4,536 kg) or less should be subjected to the impact
test requirements for large school buses. Advocates, VW, Toyota, AAMA,
Mercedes, BMW, and Ford all opposed this approach, while no commenter
favored it. These commenters stated that the contoured barrier does not
simulate vehicles in use now.
Another question was whether the FMVSS No. 214 dynamic side impact
test should be incorporated into FMVSS No. 301, thereby replacing FMVSS
No. 301's current lateral requirements. Of the twelve commenters
responding to the question 11 answered ``yes'' (Mazda, Advocates,
Mitsubishi, VW, GM, Chrysler, AAMA, Mercedes, BMW, Ford, and Volvo).
Only Toyota said ``no.'' In general, the commenters stated that the
FMVSS No. 214 side impact test conditions are more representative of
real-world accidents than the current FMVSS No. 301 side impact test
requirements. GM and AAMA also suggested allowing the FMVSS No. 214
test as an optional test to the FMVSS No. 301 side impact test. In
contrast, Toyota stated that available accident data do not demonstrate
the need to replace the FMVSS No. 301 test with the FMVSS No. 214 test.
B. Origin of Fires
The origin of fire in vehicle crashes needs to be understood better
to help define possible countermeasures and performance requirements.
The agency's NASS collects information on the origin of fires in
towed light vehicles. NASS classifies fires as either minor or major.
Fires were classified as major if they involved the whole passenger
compartment or several different compartments such as the engine
compartment, trunk compartment, undercarriage, etc. Approximately 65
percent of crash-induced light vehicle ``major'' fires began in the
engine compartment, 28 percent began in the fuel tank or another part
of the fuel system, which includes the fuel supply lines, vent lines,
and tank filler neck, and seven percent others.
A recently published British article also concluded that the engine
compartment was the most common source of fires. This was attributed to
the varied electrical and mechanical systems. The article stated that:
``Investigators found that a disproportionately high number of crash/
collision fires start in cars built after 1985--especially where the
vehicles are fitted with a fuel-injection system. The investigations
also showed that fuel line integrity was more at risk from heat and
fire than from impact damage.'' (Ref: ``CACFOA Urges Action by Car
Manufacturers on Fire Risks,'' Fire Prevention, October 1992.)
C. Vehicle Age and Fires
Both the FMVSS No. 301 evaluation report referenced in the December
14, 1992, Request for Comments notice and more recent analysis of real-
world crash results indicate that older vehicles involved in crashes
represent a disproportionate number of cases in which there was a fire
compared to newer crash vehicles. The agency's FARS analysis showed
that vehicle age has a statistically significant relationship to fire
in fatal crashes. The agency is conducting an extensive statistical
analysis of fire occurrence in fatal and other crashes, as a function
of the factors that may influence the likelihood of post-collision
vehicle fires. Fire occurrence in FARS was examined in fatal crashes
with any occurrence of a fire and in those crashes for which the fire
was the ``Most Harmful Event.'' Preliminary results indicate that as
vehicles (especially passenger cars) age, the likelihood of a fatal
fire increases. The preliminary findings also indicate that while
trucks involved in fatal crashes have a somewhat higher rate of fire
occurrence than cars, there is not an increase in the likelihood of
fire as light trucks age.
Preliminary findings indicate that for cars, light trucks, and vans
as a group and with all other factors held constant, a vehicle that is
ten years older than another is on average, 29.3 percent more likely to
be involved in a fatal fire. Most of this increase is found in cars.
Although there is an indication that as light trucks and vans age the
probability of a fire increases in fatal crashes, the estimated
increase is less than the increase for cars only. However, the number
of cases in the current data base is insufficient to produce
statistically significant results using vehicle age as a variable.
The combined data for cars, light trucks, and vans do not suggest
any relationship between vehicle age and likelihood of involvement in a
fatal crash where the most harmful event is fire. Nevertheless, post-
crash fires should be avoided to the extent practicable. The possible
effect of vehicle aging, therefore may need to be addressed in an
upgrade of FMVSS No. 301.
To address the problems associated with older vehicles,
requirements may need to address such factors as corrosion, stress
cracking, fatigue, and mechanical damage. Various aging tests are
available, such as the Salt Spray (Fog) Test (ASTM B117), Humidity
Test, Laboratory Cyclic Testing and Electrochemical Testing to simulate
corrosive environments. However, if the problem of aging in relation to
fuel system leakage and fires were attributed to cracking of fuel
hoses, etc. then there are other options. Standards with performance
requirements for aging of fuel lines and tanks may be one approach to
mitigating this problem.
A question related to this subject was posed in the December 1992
notice. Eight commenters did not support setting up an aging test
standard within FMVSS No. 301 (Mazda, Mitsubishi, Toyota, GM, AAMA,
Mercedes, BMW, and Ford). Advocates and Volvo [[Page 18572]] supported
a component test procedure for aging. VW opposed aging tests on a total
vehicle basis but not for components.
Mitsubishi indicated that the design of various replacement parts,
their materials and conditions of use and exposure will all vary, and
it is not practical to set up a standard specifying time or mileage
limits for each part. BMW stated that age-related degradation can occur
not only in fuel system components, but also in other parts,
components, and structures and could be a significant factor related to
degradation, along with differences in vehicle use, operational and
environmental conditions and maintenance.
Mazda, VW, and Volvo recommended periodic inspection or replacement
of certain fuel system components. Mazda recommended it be performed by
the vehicle owner and VW suggested upgraded periodic inspections for
vehicle condition be performed under local or state government
programs. Mazda also stated that, in the long term, durability testing
of critical fuel system components may be advisable.
Advocates strongly supported simulation of fuel system component
deterioration and overall system performance loss due to aging effects.
Advocates suggested utilizing test standards to detect the deleterious
effects of aging and/or exposure to operating or environmental
conditions that degrade fuel system integrity.
The agency requests specific comments on the wisdom and
practicability of adopting existing test procedures or developing new
component test procedures related to aging effects. Individual fuel
system components could be evaluated using accelerated aging or
corrosion treatment tests.
Phased Rulemaking Approach
Based on the above discussions and preliminary analyses, the agency
is considering research and rulemaking activities to amend FMVSS No.
301 to address the following areas:
1. The definition of performance criteria for fuel system
components directed at mitigating the cause and spread of vehicle
fires.
2. The modification of the existing FMVSS No. 301 crash test
procedures and performance criteria to better simulate the events that
lead to serious injury and fatalities in fires.
3. The definition of the role of environmental and aging factors
such as corrosion and vibration as it affects fuel system integrity,
and, if appropriate, the specification of performance criteria related
to this area.
The agency is considering whether to initiate rulemaking using a
phased approach. The basis of this approach lies in the varying
complexity of addressing the different issues listed above. The initial
phase would focus on requirements for component performance, the second
phase would address system performance, and the third phase would deal
with issues related to environmental and aging effects.
Phase 1: Component Level Performance
A. Objectives of Component Approach
The first phase would focus on the specification of performance
criteria, at a component level, to attempt to ensure that the flow of
fuel from the fuel tank or fuel lines will stop in a crash. It would
also focus on minimizing the possibility of an electrical spark of
sufficient intensity to act as an ignition source. These specifications
would primarily affect fires that originate in the engine compartment.
However, they would also help to shut off the fuel flow for all crash
modes, including a rollover crash.
Shutting off the fuel flow quickly during or immediately after a
crash will eliminate a major fire and fuel source and therefore should
both reduce fire incidents and limit the spread of fire, if one were to
start. It also appears that many new vehicles incorporate different
techniques for addressing this problem. An electric current shut-off
device would minimize the possibility of a spark. The performance
associated with the fuel shut-off and the electric current shut-off
devices can be incorporated into the present crash tests in FMVSS No.
301 or other compliance tests such as those conducted as part of FMVSS
No. 214.
As discussed below, the agency is also seeking comment about
component test requirements for fuel tanks, fuel pumps, the vehicle's
electrical system, and engine fire extinguishes.
The agency requests information on the performance, cost, and
practicability aspects of various systems in shutting off the fuel flow
and the electric power. The agency also requests comments on ways to
develop a practicable test procedure and to define specific criteria
with sufficient objectivity that test variability is reduced to a
minimum. In the event that other, more appropriate, component tests
would satisfy the objectives of the Phase 1 effort, interested parties
are requested to provide this information to the agency.
B. Components Now in Use
The agency believes that technology already exists for detecting
and identifying conditions when the fuel flow should be shut off. Most
new vehicles sold in the United States are already equipped with
devices that shut off the fuel pump in any collision that causes the
engine to stop.
In some vehicles, sensors detect the consequence of severe engine
damage (rotation stops for camshaft, crankshaft or alternator) and
immediately shut off the fuel pump. Often, signals from more than one
sensor are used to determine if the engine has stopped running and the
decision for fuel pump shut-off is left up to the vehicle's onboard
computer (such as the Engine Control Unit or Electronic Control
Module). Manufacturers also use a ``central'' for collecting and
routing crash signals through a central collision detection bus.
Other vehicles are equipped with an inertia switch. Inertia
switches can be used to shut off the fuel flow as well as the electric
current. Inertia switches operate on sudden impact to open the
electrical circuit to the fuel pump or the battery during the crash. An
inertia switch can be designed to operate at various levels of impact
intensity and direction, and thus could be effective in all crash
modes.
The agency requests information on the different components used in
vehicles for shutting off the fuel flow or electric current.
C. Component Test Procedures
Fuel system components must operate in a real-world environment
surrounded by extreme conditions imposed by modern engine technology.
The materials and parts used to assemble fuel system components are
already subject to manufacturers' specifications, often derived from or
directly related to other engineering standards such as the
publications of the American Society for Testing and Materials (ASTM).
Some of the test requirements are generic to many of the ASTM
standards, for example: vibration, shock, endurance testing,
temperature cycling, temperature extremes, compatibility with other
materials, etc.
Comments are requested regarding the extent and scope of component
test requirements that should be developed as part of the FMVSS No.
301.
The agency has identified the following fuel system and vehicle
components as potential candidates for this approach:
a. Fuel tank, including filler pipe
b. Fuel pump(s) [[Page 18573]]
c. Vehicle's electrical system
d. Engine fire retardant/extinguisher
The agency has not included fuel lines in this proposed list
because the potential to shut down the entire fuel delivery system when
the fuel pump shuts down already exists. Comments are requested about
this decision.
a. Fuel tank, including filler pipe. During a vehicle crash, the
fuel tank may receive crash forces great enough to move or dislodge the
tank from its mountings and/or to rupture the tank. If the tank moves
significantly, the filler pipe, which is attached to the vehicle body
to provide access during refueling, may rupture or break away. If the
filler pipe ruptures, fuel could spill. Fuel spillage can be expected
under some crash conditions even if the fuel pump is shut off.
One concept would include a check valve located in the filler pipe
that is normally closed to prevent fuel flow but that would open
automatically during refueling. For example, inserting of the pump
filler nozzle could cause the closed check valve to open to permit fuel
flow; withdrawing the nozzle would cause the valve to close.
Another concept would use a check valve similar in function to the
valves used on heavy truck crossover fuel lines. Applied to the filler
neck, this concept would require a large valve, normally open, that
would close automatically upon detachment of the filler neck due to a
crash.
Comments are requested on how filler check valves should be
evaluated during safety compliance tests. For example:
1. Should the filler valve pass a simple go no-go test or should
the valve be subjected to many cycles of operation?
2. What test condition would be appropriate for filler check
valves: dynamic pendulum or other impact tests?
3. What are the critical engineering parameters that would
characterize the proper operation of a filler pipe check valve?
4. Are there alternative ways to control spillage from broken
filler pipes?
b. Fuel pump(s). Today's passenger cars, light trucks, and vans use
electrically operated fuel delivery pumps almost exclusively. Some
electric fuel pumps shut down if certain engine operating parameters,
such as crankshaft rotation, indicate that the engine has stopped. The
agency is interested in how manufacturers use engine sensing to control
fuel pump operation and under what conditions the fuel pump is shut
off. Specifically:
1. Is current sensing time response adequate to prevent fuel
spillage? If not, what would improve response time?
2. How does cessation of engine rotation typically relate to the
frontal crash pulse; i.e., after engine disintegration begins, how long
does it take for the rotating parts to stop?
3. During this time interval, how much fuel spillage could occur,
assuming that the crash has damaged the fuel lines, making fuel
spillage imminent?
4. How would sensing engine rotation provide benefit to vehicles
involved in a rear impact? rollover? side impact? in any crash where
engine damage may be slight?
5. With regard to vehicle rollover, would a separate rollover
switch prevent fuel spillage? Could this function be practicably
combined in a single switch that would respond to all crash modes?
6. Does fuel pump shut-off prevent gravity-induced fuel flow
through the pump?
7. Should a single fuel pump cutoff switch be used to replace the
functions currently performed by sensing engine rotational parameters?
8. What advantages/disadvantages would such an installation incur?
Some manufacturers currently use inertia switches to interrupt the flow
of electricity to the fuel pump when a crash is sensed, thereby causing
the fuel pump to shut down.
1. Could an inertial switch be substituted for the systems that
sense engine shut down to disable fuel pumping?
2. Under what conditions would such a substitution be impracticable
or too costly?
3. What sensitivity of operation should an effective inertia switch
have?
4. Can inertia switches be manufactured with sufficient durability
and reliability to function for long periods of time unattended in a
relatively harsh automotive environment?
5. Are there any other features of an inertia switch that would be
detrimental to occupant safety; e.g., what measures must an occupant
take to restart the vehicle after an inertia switch has stopped fuel
flow?
The agency is also interested if manufacturers or others have any
alternative techniques for accomplishing fuel shut-off during a crash.
c. Vehicle's electrical system. Other means exist to cause the fuel
pump to shut down in a crash. For example, a battery shut-off device
could remove all electrical power from the vehicle at the onset of a
crash. However, battery shut-off may have unintended consequences if
electrically operated door locks or windows are rendered inoperative
during a crash. Comments are requested regarding the relative costs and
practicability of battery shut-off devices.
d. Engine fire retardant/extinguisher. After ignition takes place,
vehicle fires could be controlled or extinguished if the proper
equipment were available and functioning. Examples of equipment that
could help control or extinguish a fire include an onboard fire
extinguisher mounted in the engine compartment and fire retardant
blankets. A fire extinguisher using carbon dioxide or other gaseous
mixtures could be operated by means of existing vehicle sensors (such
as the inertia switch) or by other signals. Fire retardant blankets
attached underneath the vehicle's hood could drop down onto the engine
to smother a fire in the event of a crash. Comments are requested on
the costs and practicability of these concepts.
Phase 2: System Level Performance
The second phase would focus on the process of defining upgraded
crash test performance for frontal, side, and rear impacts. The present
crash tests specified in FMVSS No. 301 require a frontal fixed barrier
impact at 30 mph (48.3 kmph), a moving barrier impact of 20 mph (32.2
kmph) into the side of a stationary vehicle, and a moving barrier
impact of 30 mph (48.3 kmph) into the rear of a stationary vehicle.
From the information discussed in this notice, it appears that the
present tests in FMVSS No. 301 may not be representative of the
severity of the crash conditions associated with fatal and severe
injury-causing fires. However, it is difficult at this time to define
specific upgrades to these crash conditions without further tests. Some
potential tests that appear promising for upgrading FMVSS No. 301 test
procedures are the offset/oblique tests in the frontal mode, the FMVSS
No. 214 offset barrier in the rear test mode and a pole impact or FMVSS
No. 214 barrier for the side impact.
As identified in the GESAC study, a key objective for such tests
may be to limit the engagement to a narrower area than engaged with
current barriers. The specific crash conditions that cause fuel system
loss of integrity must be defined, along with an understanding of which
crashes would be survivable if fire was avoided. Accident data analyses
and crash testing are being considered to further explore these issues,
which is expected to be the second phase of [[Page 18574]] rulemaking,
which may be conducted concurrently with the first phase.
The agency requests comments on the performance aspects and
practicability of this approach.
Phase 3: Environmental and Aging Effects
The third phase would explore the issue of environmental and aging
effects on vehicle condition and the possible relationship to fire
occurrence. The agency's preliminary analyses of FARS and State
accident files indicate that the likelihood of fire increases with the
age of the vehicle. The analysis also attempted to determine the
possible differences, if any, in the occurrence of fire in fatal
crashes in states that typically experience more inclement weather
(i.e., snow and ice) and as a result, use more salt and other corrosive
substances on public roadways, when compared to other states.
Passenger cars registered in the ``salt belt'' states and involved
in fatal crashes were found to have an approximately 25 percent greater
rate of fire occurrence in fatal crashes, compared with passenger cars
in fatal crashes in the ``sun belt'' states. (It should be noted that
when the fire itself was deemed to be the most harmful event in the
vehicle, the ``salt belt'' states had a lower rate compared to the
``sun belt'' states.) It is not clear at this time whether this
possible relationship between vehicle aging, weather and use of salt
and similar substances and fire occurrence may be due to environmental
characteristics, to changes in vehicle design, to differences in
operator characteristics, or a combination of these factors. If this
disparity can be attributed to environmental factors, it may be
possible to add environmental tests, such as corrosion, to FMVSS No.
301.
Further work is needed to associate vehicle fires with
environmental and aging factors and to define possible performance
tests. Because of this, the agency is considering addressing this
problem in a third phase of rulemaking.
The agency requests comments on this phased approach. This approach
may be implemented either sequentially or concurrently, depending on
the timing of the research.
Rulemaking Analyses
NHTSA has considered the impact of this rulemaking action under
Executive Order 12866 and the Department of Transportation's regulatory
policies and procedures. The agency has determined that this notice is
significant under Department's policies and procedures. The agency
notes that the increase in vehicle production costs and corresponding
increases in consumer costs that would result from upgrading the
requirements of FMVSS No. 301 would depend on the stringency and nature
of the new requirements and the extent to which present and planned new
production vehicles would already meet them, i.e., the type and extent
of vehicle changes that would be necessary. Since the agency is still
in the research and analysis phase of the rulemaking, including
assessing new vehicle hardware and fuel system crash integrity, it
cannot provide a cost estimate at this time. Nevertheless, a more
comprehensive discussion of this notice's cost impacts is discussed in
the Preliminary Regulatory Evaluation, which has been placed in the
public docket.
Submission of Comments
Interested persons are invited to submit comments on the proposal.
It is requested but not required that 10 copies be submitted. All
comments must not exceed 15 pages in length (49 CFR 553.21). Necessary
attachments may be appended to these submissions without regard to the
15-page limit. This limitation is intended to encourage commenters to
detail their primary arguments in a concise fashion.
If a commenter wishes to submit certain information under a claim
of confidentiality, three copies of the complete submission, including
purportedly confidential business information, should be submitted to
the Chief Counsel, NHTSA, at the street address given above, and seven
copies from which the purportedly confidential information has been
deleted should be submitted to the Docket Section. A request for
confidentiality should be accompanied by a cover letter setting forth
the information specified in the agency's confidential business
information regulation 49 CFR Part 512.
All comments received before the close of business on the comment
closing date indicated above will be considered, and will be available
for examination in the docket at the above address both before and
after that date. To the extent possible, comments filed after the
closing date will also be considered. Comments received too late for
consideration in regard to the ANPRM will be considered as suggestions
for further rulemaking action. Since NHTSA will continue to file
relevant information as it becomes available in the docket after the
closing date, it is recommended that interested persons continue to
examine the docket for new material.
Those persons desiring to be notified upon receipt of their
comments in the rules docket should enclose a self-addressed, stamped
postcard in the envelope with their comments. Upon receiving the
comments, the docket supervisor will return the postcard by mail.
Issued on April 6, 1995.
Barry Felrice,
Associate Administrator for Safety Performance Standard.
[FR Doc. 95-9025 Filed 4-11-95; 8:45 am]
BILLING CODE 4910-59-P
