Fuel Fill Pipe Damage, Leakage and Fire by Tire Tread Separation

September 28, 2009 by · Leave a Comment
Filed under: Fill Pipe, Fuel Tank, Testing, Tread Separation 

TSTI Test 0013 146By Mark Arndt

Given knowledge of the dangers, the notion that tire failures occur on vehicles traveling at highway speeds is frightening. Yet, such failures occur and the general acceptance of tire failure is so deeply rooted in vehicle performance that spare tires are standard equipment. 

A specific rollover incident in which a rear tire tread separation caused tearing apart of a fuel tank fill pipe routed just behind the wheel well was recreated in a controlled test (watch video).  The incident resulted in fuel spillage, fire and burn injuries.  The October 2001 incident involved a 1995 Land Rover Discovery with a General AmeriStar tire failure.  The vehicle manufacture’s corporate representatives were shown the test in late 2002 during depositions. 

TSTI Test 0013 147High speed video captured contact between tire tread and reinforced rubber fuel hose as the flailing end of the tread separates from the tire.  Repeated contacts by the tread to the fill pipe fuel hose and vehicle underbody result in fill pipe failure and release of liquid from the fuel tank.  Tests of a peer vehicle did not produce a failure or leakage.

Regarding vehicle handling and tire tread separation, failures a relationship between vehicle design and loss of control is scientifically documented.  Only recently has an incremental improvement in vehicle handling following tire tread separation been demonstrated with Electronic Stability Control (ESC).  Regarding other aspects of vehicle performance in tire failures, specifically including tire tread separations, dangers exist that can enhance the chance of harm. 

It is a well know consequence of tire failures that the tire tread can damage the vehicle.  In tire tread separations substantial damage to the wheel well sheet metal is probable.  Tire tread failure induced damage has been documented to hydraulic brake lines, parking brake cables, tail lights, fuel fill pipes, wiring and bumpers.  Parts of a car, not to mention the tire tread, can be knocked free and onto the road surface.  Vibrations from a tire failure have tripped inertially activated fuel pump cut off switches resulting in unexpected engine cut-off.

Engineers can readily foresee similar scenarios for a variety of safety equipment that is taken for granted in motor vehicles.  For example:

  • A tire tread separation occurs at night, damages wiring that routes near the wheel well and renders driver’s suddenly blind to the road or hazards on the road,
  • A tread separation causes permanent damage to hydraulic brake lines or parking brake cables resulting in brake failure or compromised performance.
  • A tread separation causes damage to a light cover or reflector, often rear taillight breakage is observed.

That these are important events in a vehicle’s safety performance is simply supported by the fact that Federal Motor Vehicle Safety Standards (FMVSS) regulate the performance of vehicle systems that are directly dependent upon the key components described above.  

A tire failure event could be analogous to the Part 581 Bumper Standard. Low speed, often parking related, bumper contacts occur in normal driving. Comparatively, tire failures are also expected – driving manuals instruct how to react to a tire failure and most cars have spare tires. Anticipating low speed contacts, the Part 582 Bumper Standard covering all passenger motor vehicles sold in the United States prescribes protective criteria for: lamps, reflective devices and head light alignment; operation of doors; fueling and cooling systems; propulsion, suspension, steering and braking systems; impact energy absorbers; fasteners and joints; and, even separations of surface material, paints and coatings and permanent deviations of original contours.  Comparatively, following a tire failure a vehicle should be capable of performing at the minimum level of safety prescribed by applicable FMVSS.  Vehicle design interventions can effectively eliminate dangers from tire failures induced vehicle component damage.

Fuel Tank Fill Pipe Valve Prevents Leakage in Crash

September 22, 2009 by · 1 Comment
Filed under: Fill Pipe, Fuel Tank, Testing 


By Mark W. Arndt

A recent crash test conducted by the San Francisco Law Firm Lieff Cabraser Heimann & Bernstein (under the direction of Transportation Safety Technologies, Inc.) has provided an important measure of the feasibility and performance of fuel tank fill pipe valves in crash situations when the fill pipe is severed or damaged.

The valve positioned inside the fuel tank at the end of the fuel tank fill pipe was part of the Onboard Refueling Vapor Recovery (ORVR) system.  ORVR was a safety feature first dictated for passenger cars in 1998 by the US Environmental Protection Agency (EPA) to limit fuel emissions.  The ORVR required that fuel vapor generated during vehicle refueling be stored on the vehicle instead of at the gas station.  Stored refueling vapors are burned in the vehicle engine after refueling.

A common feature of ORVR systems are mechanism that minimize fuel atomization as it enters the fuel tank and limits to migration of vapors out of the tank when the fuel cap is off.  Most manufactures utilize a one way valve on the fuel tank fill pipe.  The valve is located either in the fuel tank or in-line of the fill pipe. Some vehicle manufactures have utilized valves that serve a dual purpose of vapor barrier for ORVR and liquid fuel barrier for crashworthiness.  The dual purpose valve is a preferred and logical choice given the vulnerability of some fuel tank fill pipes and fuel caps in crashed.  Sport Utility Vehicles with their high rates of rollovers are natural benefactors of valves that prevent spilled gasoline from fuel tank fill pipes.

The crash test involved a 2001 Kia Sportage with a modified rear suspension and fuel tank shield.  The vehicle was stuck by a Federal Motor Vehicle Safety Standard 214/311R (FMVSS214/301R) moving deformable barrier ballasted to 5011 pounds.  The Sportage fuel tank was filled to 15.4 gallons which is about 92 percent of its refill capacity.  The Sportage was hit squarely at the rear with the left edge of the barrier aligned 16.5 inches to the right of the Sportage centerline – a right offset rear impact.

As a result of the crash the modified rear suspension posed no threat of puncture to the fuel tank and the fuel tank shield worked.  There were no punctures of the fuel tank, but there was a separation of the fuel tank fill pipe.  A reinforced rubber interconnecting fill pipe hose tore apart in the crash.  The fill pipe failure was observable only as the fuel tank was removed. A static rollover conducted after the crash test pursuant to the rollover test requirement s of FMVSS301 demonstrated no fuel leakage from any portion of the fuel tank – proof that the one way flow valve in the fuel tank fill pipe worked.