Prepared By Operations Division
April 2, 2007
Prepared By Operations Division
April 2, 2007
FIREFIGHTERNEAR MISS
Auto Fire withCompressed Natural Gas
(CNG) Fuel Tank Explosion
FIREFIGHTERNEAR MISS
Auto Fire withCompressed Natural Gas
(CNG) Fuel Tank Explosion
Seattle Fire Department22
Arson: Incident #26564 Arson: Incident #26564
• Dispatch 0230 hours for car fire (E10)
• E10 arrived and requested FIB for multiple vehicles with possible structural exposures (freeway columns and overpasses)
• 12 vehicles damaged or destroyed
• Firefighter near miss when CNG vehicle exploded as E10 crew approached with a handline (approximately 50-75’ away)
• Dispatch 0230 hours for car fire (E10)
• E10 arrived and requested FIB for multiple vehicles with possible structural exposures (freeway columns and overpasses)
• 12 vehicles damaged or destroyed
• Firefighter near miss when CNG vehicle exploded as E10 crew approached with a handline (approximately 50-75’ away)
Seattle Fire Department33
FireFireGarageGarage
FireFireGarageGarage
Seattle Fire Department44
Royal Brougham
Royal Brougham
88thth A
ve S
ou
th A
ve S
ou
th
Access GateAccess GateAccess GateAccess Gate
E10
E10
E10
E10
Seattle Fire Department55
E10 parked outsideE10 parked outsidethe gate herethe gate hereE10 parked outsideE10 parked outsidethe gate herethe gate here
Debris from the explosion was thrown up to Debris from the explosion was thrown up to 100’ in all directions including on the over-100’ in all directions including on the over-
passes above the incident.passes above the incident.
Debris from the explosion was thrown up to Debris from the explosion was thrown up to 100’ in all directions including on the over-100’ in all directions including on the over-
passes above the incident.passes above the incident.
Seattle Fire Department66
++++++++++++ ++++
BackhoeBackhoeBackhoeBackhoe
Fuel tankFuel tank(original location)(original location)Fuel tankFuel tank(original location)(original location)
Trunk lidTrunk lidTrunk lidTrunk lid
Bumper frameBumper frameBumper frameBumper frame
Roof debrisRoof debrisRoof debrisRoof debris
Roof debrisRoof debrisRoof debrisRoof debris
100’
Seattle Fire Department77
Honda CNG VehicleHonda CNG Vehicle
Seattle Fire Department88
Seattle Fire Department99
Rear of vehicleRear of vehicle
Seattle Fire Department1010
Roof is blown completelyRoof is blown completelyoff vehicle and doors blownoff vehicle and doors blownopenopen
Seattle Fire Department1111
Seattle Fire Department1212
Seattle Fire Department1313
Seattle Fire Department1414
Seattle Fire Department1515
Metal mountingMetal mountingstraps for CNG tankstraps for CNG tank
Metal mountingMetal mountingstraps for CNG tankstraps for CNG tank
Seattle Fire Department1616
Trunk lidTrunk lidTrunk lidTrunk lid
Seattle Fire Department1717
Tank landed here,Tank landed here,moved down hill to heremoved down hill to herefor extinguishmentfor extinguishment
Tank landed here,Tank landed here,moved down hill to heremoved down hill to herefor extinguishmentfor extinguishment
Seattle Fire Department1818
Rear bumper frame 90’+ awayRear bumper frame 90’+ away
Seattle Fire Department1919
Bumper shrapnelBumper shrapnelNote burn marks onNote burn marks onground. ground.
Seattle Fire Department2020
Roof section about 75’ awayRoof section about 75’ awayRoof section about 75’ awayRoof section about 75’ away
Seattle Fire Department2121
This is your only warning ofThis is your only warning ofa CNG – fueled vehicle. Typically a CNG – fueled vehicle. Typically located on the trunk lid or bumperlocated on the trunk lid or bumper
This is your only warning ofThis is your only warning ofa CNG – fueled vehicle. Typically a CNG – fueled vehicle. Typically located on the trunk lid or bumperlocated on the trunk lid or bumper
Seattle Fire Department2222
Seattle Fire Department2323
Composite tank is carbon-fiber / fiberglassComposite tank is carbon-fiber / fiberglasswrapped for strength – similar to our SCBA tanks.wrapped for strength – similar to our SCBA tanks.Composite tank is carbon-fiber / fiberglassComposite tank is carbon-fiber / fiberglasswrapped for strength – similar to our SCBA tanks.wrapped for strength – similar to our SCBA tanks.
Seattle Fire Department2424
Seattle Fire Department2525
Seattle Fire Department2626
Seattle Fire Department2727
Seattle Fire Department2828
Tank blown approximatelyTank blown approximately95’ from the vehicle95’ from the vehicle
Tank blown approximatelyTank blown approximately95’ from the vehicle95’ from the vehicle
Seattle Fire Department2929
Seattle Fire Department3030
August 07, 2003
Airport Taxis, Shuttles Convert to Natural GasNew contract requires fleet conversions to improve air quality
The Port of Seattle Commission today authorized the renewal of contracts with two major providers of ground transportation at Seattle-Tacoma International Airport. The contracts, with the Seattle Tacoma International Taxi Association (STITA) and Shuttle Express, will require the two organizations to make major investments toconvert their fleets to clean-burning natural gas.
Under its new contract, STITA will be required to convert its entire 160-cab fleet to natural gas in the next three years. By converting more quickly, STITA will earn the right to extend the contract from five to seven years.
Seattle Fire Department3131
Historical InformationHistorical Information
• Several NHTSA (National Highway Traffic Safety Administration) investigations– Example: January 27, 2003; Ford Crown
Victoria on fire with flame impingement on CNG tank. The tank failed catastrophically prior to Pressure Relief Device (PRD) functioning.
– Vehicle recall with dealers installing additional insulation behind back seat.
– Number of vehicles still needing repair???
• Several NHTSA (National Highway Traffic Safety Administration) investigations– Example: January 27, 2003; Ford Crown
Victoria on fire with flame impingement on CNG tank. The tank failed catastrophically prior to Pressure Relief Device (PRD) functioning.
– Vehicle recall with dealers installing additional insulation behind back seat.
– Number of vehicles still needing repair???
Seattle Fire Department3232
Code of Federal RegulationsCode of Federal Regulations
• CFR 49, Part 571– Standard 304
Compressed Natural Gas Fuel Container Integrity
Flame Test Standard:Flame impingement generating 1550-1650° F. at the surface for the length of the cylinder for 20 minutes or until fuel is completely vented through PRV.
• CFR 49, Part 571– Standard 304
Compressed Natural Gas Fuel Container Integrity
Flame Test Standard:Flame impingement generating 1550-1650° F. at the surface for the length of the cylinder for 20 minutes or until fuel is completely vented through PRV.
Seattle Fire Department3333
CNG PropertiesCNG Properties
• Compressed to 3,600 psi in fuel cylinder
• CNG rated at 117 octane fuel
• BTU per # = 22,800 (gasoline = 18,900)
• Not a liquid when compressed (it becomes a very close dense gas)
• Not the same as Liquified Natural Gas – LNG (cryogenic: -260° to become liquified)
• Lighter than air when released ( .6 air)
• Compressed to 3,600 psi in fuel cylinder
• CNG rated at 117 octane fuel
• BTU per # = 22,800 (gasoline = 18,900)
• Not a liquid when compressed (it becomes a very close dense gas)
• Not the same as Liquified Natural Gas – LNG (cryogenic: -260° to become liquified)
• Lighter than air when released ( .6 air)
Seattle Fire Department3434
CNG PropertiesCNG Properties
• LEL / UEL = 4 – 16% (gasoline = 1.3 – 7.6)
• 1 cubic foot of CNG = 245 cu.ft. of natural gas at sea level (uncompressed)
• 1 cubic foot of CNG weighs 13#• 5.66# = 1 Gasoline Gallon Equivalent (GGE)
• Honda Civic tank = 8 GGE• Note: 1 gallon of gasoline properly vaporized has
the explosive equivalency of 83 pounds of dynamite (CDC).
• LEL / UEL = 4 – 16% (gasoline = 1.3 – 7.6)
• 1 cubic foot of CNG = 245 cu.ft. of natural gas at sea level (uncompressed)
• 1 cubic foot of CNG weighs 13#• 5.66# = 1 Gasoline Gallon Equivalent (GGE)
• Honda Civic tank = 8 GGE• Note: 1 gallon of gasoline properly vaporized has
the explosive equivalency of 83 pounds of dynamite (CDC).
Seattle Fire Department3535
Cylinder PropertiesCylinder Properties
• Four Cylinder Types:– Type 1: all metal (steel or aluminum)– Type 2: hoop wrapped steel or aluminum– Type 3: fully wrapped steel or aluminum– Type 4: all-composite (non-metallic)*
*Early model Honda Civic uses Type 4;later models use Type 3
• Four Cylinder Types:– Type 1: all metal (steel or aluminum)– Type 2: hoop wrapped steel or aluminum– Type 3: fully wrapped steel or aluminum– Type 4: all-composite (non-metallic)*
*Early model Honda Civic uses Type 4;later models use Type 3
Seattle Fire Department3636
Honda Civic Tank DesignHonda Civic Tank Design
Seattle Fire Department3737
Honda Civic Tank DesignHonda Civic Tank Design
Note: The PRD (pressure relief device) activates similar to a fusible link (it fails versus resealing like a spring-assisted pressure reducing valve – PRV). The gas is vented out the vent tube until the tank is empty. Discharge time depends on fuel level.
Note: The PRD (pressure relief device) activates similar to a fusible link (it fails versus resealing like a spring-assisted pressure reducing valve – PRV). The gas is vented out the vent tube until the tank is empty. Discharge time depends on fuel level.
Seattle Fire Department3838
Lessons Learned /Best PracticesLessons Learned /Best Practices• Approach from 45° angle to vehicle ends
• Be aware of CNG vehicles– Cabs, city vehicles, shuttles
• Look for CNG placards
• Watch for other hazards, i.e. bumper struts; hood and tailgate struts; airbags; burning fuel runoff; hazardous vehicle contents; exploding tires; other traffic
• Consider cooling streams from a distance
• Approach from 45° angle to vehicle ends
• Be aware of CNG vehicles– Cabs, city vehicles, shuttles
• Look for CNG placards
• Watch for other hazards, i.e. bumper struts; hood and tailgate struts; airbags; burning fuel runoff; hazardous vehicle contents; exploding tires; other traffic
• Consider cooling streams from a distance