fire safety of hydrogen-fueled vehicles: system-level bonfire test
DESCRIPTION
Fire Safety of Hydrogen-Fueled Vehicles: System-Level Bonfire Test. by R. Rhoads Stephenson Motor Vehicle Fire Research Institute www.mvfri.org [email protected]. High Pressure Cylinder Tests (part of FMVSS 304). Bonfire test is routinely done for CNG - PowerPoint PPT PresentationTRANSCRIPT
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MVFRI 1
Fire Safety of Hydrogen-Fueled Vehicles:
System-Level Bonfire Test
byR. Rhoads Stephenson
Motor Vehicle Fire Research Institutewww.mvfri.org
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MVFRI 2
High Pressure Cylinder Tests(part of FMVSS 304)
• Bonfire test is routinely done for CNG• A similar test has been drafted for H2• Bare tank and PRD are exposed to bonfire for
20 minutes. Must either:– Remain intact, or– Vent safely
• Problems– Fire not well specified – just temperatures
under tank– PRD must be shielded from direct flame
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MVFRI 3
304 Test on CNG Tank
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MVFRI 4
FMVSS 304 - Conclusions
• Tank Burst is very energetic– Mechanical energy is released in milliseconds– Unacceptable to have tank burst– PRD must work
• 304 is mainly a PRD test – not a tank test– No modern composite tank will last for 20
minutes
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MVFRI 5
Hydrogen Burst Test
• Goals:
(1) Study the fire resistance of the tank, and the temperature and pressure its contents prior to burst
(2) Determine the characteristics of the energy release from a fire induced burst
• Performed 304-like test w/o PRD
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MVFRI 6
Hydrogen Fuel Tank Test Setup
Instrumentation– Tank internal
temperature and pressure
– Exterior temperatures– Blast pressures at 4
locations– Visual and IR video
Tank positioned in bonfire test rig
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MVFRI 7
Burst Test
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MVFRI 8
Tank Failure Times
• The composite material on the surface of the tank ignited 45 seconds into the test
• The tank ruptured 6 minutes and 27 seconds into the test
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MVFRI 9
Burst Test Conclusions• Temperature and pressure inside tank
increased a negligible amount– Temperature up 20 C– Pressure up 200 psi (13 bar)
• Largest fragment (14 Kg) landed 80 meters (270 feet) away
• 43 psi overpressure at 2 m (6.3 feet)
• 6 psi overpressure at 6.5 m (21 feet)
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MVFRI 10
Burst Test Conclusions
It is unacceptable for a H2 tank to burst!!
The PRD valve must work!
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Conclusions (continued)• Successful operation of PRD is a system-
level issue– Number and location of tanks– Plumbing– Number and location of PRDs– Redundant PRDs?– Sizing of vent lines– Shielding and insulation of tanks– Flow of flames around fuel system
• A bare tank with a single PRD does not simulate a real vehicle
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MVFRI 12
System-Level Bonfire Test
• Europeans require bonfire test on plastic fuel tanks – ECE R-34 Annex 5
• Test is not required in the US, but most tanks sold in US are qualified with this test
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MVFRI 13
ECE R-34 Test• Whole vehicle or buck used
• Tank is filled 50% with gasoline
• Exposed to gasoline pool fire– One minute at full heat flux– One minute with ceramic screen which cuts
heat flux
• The tank “passes” if it survives for 2 minutes of exposure
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MVFRI 14
ECE R-34 Test on Vehicle
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Observations
• Tank “passed” the test at 2 minutes
• Tank failed 7 seconds later
• Two minutes may be long enough for an uninjured person to escape– It is clearly too short if the occupant needs to
be extricated
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MVFRI 16
Proposed System Level Test for H2
• Composite hydrogen tanks are plastic• Why not apply something similar to
European ECE R-34 test?• It tests the whole system• It is independent of the hydrogen storage
technology– Compressed gas– Liquid Hydrogen– Hydrides
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MVFRI 17
Modifications
• Replace gasoline pool fire with a propane planer flame – diffused through sand– Easier to control– Less air pollution concern
• Exposure duration ?– Suggest 20 minutes like FMVSS 304– Must either vent safely or stay intact
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MVFRI 18
Future Work
• Vehicle level test will be performed– Issue to study: Passenger compartment may
become untenable well before 20 minutes– Debug the test procedure
• Recommend to NHTSA
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MVFRI 19
Other Comments
• “Active PRD”
• Remote Defueling
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MVFRI 20
Questions?
Please visit our website at:
www.mvfri.org