Presentation Transcript
Graniteville, SC: Graniteville, SC Hazardous Materials
Chlorine Release:: Chlorine Release:
Tank car punctured
About 60 tons of poisonous liquefied chlorine gas released
Ninth of 42 freight cars
Chlorine Gas:: Chlorine Gas:
Poisonous by inhalation
Liquefied gas
Vaporizes rapidly
Volumetric expansion: 450 to 1
Heavier than air
Punctured Tank Car:: Punctured Tank Car: Manufactured in 1993
tested to 500 psig
(¾ inch thick steel shell)
Normalized steel
Improved fracture toughness
Lower ductile-to-brittle transition temperature
One of the strongest tank cars in service
Minot, North Dakota: Minot, North Dakota Canadian Pacific Railway
January 18, 2002
5 tank cars catastrophically ruptured
147,000 gals anhydrous ammonia were instantaneously released
1 fatality and 11 serious injuries
Minot Conclusion:: Minot Conclusion: The low fracture toughness of the non-normalized steels used for the tank shells of the five tank cars that catastrophically failed in this accident contributed to the cars’ complete fracture and separation.
Minot Recommendations to FRA:: Minot Recommendations to FRA: Validate a predictive model that will quantify the dynamic forces acting on a tank car during an accident
Develop and implement tank car design-specific fracture toughness standards for materials used to manufacture pressure tank cars
Chlorine Gas Releases:: Chlorine Gas Releases: 12 Fatalities
Graniteville, South Carolina (9)
Macdona, Texas (3)
Large lethal clouds are generated within minutes
Little time to alert citizens
Reduction of Public Risk:: Reduction of Public Risk:
Operational changes are needed to reduce the vulnerability of tank cars transporting poisonous by inhalation gases.
Transportation Studies:: Transportation Studies:
The rear one-quarter of a train is the most desirable location for Haz Mat
Reducing speed
Reducing the length of trains