Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
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65 Fall 2015 Proceedings www.uscg.mil/proceedings The reason for the sharp drop is unknown. Furthermore, some uncertainty still exists with regard to understanding Bakken crude properties. One main argument is that not all Bakken crude oil is the same. There may be variations from one well to another, and weather, seasons, and trans- portation may alter the crude's physical properties. Data from the American Fuel and Petrochemical Manufacturers shows that during the summer months, Bakken crude's Reid vapor pressure decreases signifcantly. Other properties that have raised concern and could impact transportation are the amount of dissolved gases present in the crude oil as well as the crude's corrosiveness. Approvals Process Whether or not Bakken crude is carried as Grade B or lower or as a Grade A cargo, the construction standards for tank vessels, including tank barges, are virtually the same. The Coast Guard's Marine Safety Center personnel review and approve plans to ensure that tank vessels can safely carry a Grade A or Grade B cargo. The plan submitters must request the grade of cargo for which they seek approval, usually before tank vessel construction begins. Once approved, the tank vessel's certifcate of inspection is endorsed with the grade of cargo that the vessel is autho- rized to carry. Both Grade A and B cargoes require safety relief valves on cargo tanks, double-hull construction, and gauging systems to measure liquid cargo levels. Different structural standards are applied to tank barges once the RVP of the cargo exceeds 25 pounds per square inch (psia). Liquefed fammable gases, which have even more robust construction and safety requirements, are any fammable gas cargo with a RVP exceeding 40 psia. In Sum Current data for Bakken crude suggests that the existing maritime regulations for fammable and combustible liquids are adequate to safely transport on U.S. waterways. Depart- ment of Transportation initiatives to emphasize proper clas- sifcation for rail shipments and American Petroleum Insti- tute recommended best practices for rail crude oil shipment have helped raise awareness of the safety hazards associ- ated with Bakken crude. These initiatives have beneftted all modes of transportation. The new energy landscape that is being driven in part by Bakken crude has put to test the current regulatory struc- ture for not just the Coast Guard, but the entire federal gov- ernment. As the collective understanding of Bakken crude properties further evolves, the Coast Guard and partner agencies will continue to evaluate and, if necessary, update existing safety and construction standards to minimize risk to the public and prevent signifcant disruption of vital maritime resources. About the author: LT Andrew Murphy is a staff engineer in the Coast Guard's Hazardous Materials Division. He has served in the U.S. Coast Guard for more than seven years. He holds a chemical engineering master's degree from the Uni- versity of Rhode Island. Endnote: 1. The American Society of Testing Materials maintains a standard test method, known as the Reid method, to determine vapor pressure. Bibliography: Transportation Safety Board of Canada Railway Investigation R13D0054, Runaway and Main Track Derailment Lac-Megantic, Quebec 06 July 2013. Britton, L.G., "Survey of Fire Hazard Classifcation Systems for Liquids," Process Safety Progress, 18, No. 4, Winter, 1999. U.S. Coast Guard Report of Investigation into the Circumstances of the Explosion, Fire, and Sinking of the Tank Barge EMC 423 with One Loss of Life on the Chicago Sanitary and Ship Canal on 1/19/2005. North Dakota Petroleum Council Bakken Crude Characterization Task Force Pre- sentation of Preliminary Results, Williston Basin Petroleum Conference, Bismarck, North Dakota, May 20, 2014. American Fuel & Petrochemical Manufacturers Survey of Bakken Crude Oil Char- acteristics, May 14, 2014. American Petroleum Institute Staff Analysis of Crude Oil Samples Submitted to PHMSA, May 19, 2014. Department of Transportation Operation Safe Delivery Update, 2014. Marathon Petroleum's Capline Pipeline Unit publishes current crude oil infor- mation on hundreds of different crude oils from around the world. See www. caplinepipeline.com/Default.aspx. RVP Comparison Crude Name Country RVP Brent U.K. 5.61 Eagle Ford API 57 Texas, U.S. 9.30 Hibernian Canada 3.18 Light Louisiana Sweet Louisiana, U.S. 4.52 North Dakota Sweet North Dakota, U.S. 5.19 Purovsky Russia 7.74 Saharan Blend Middle East 6.82 Arabian Extra Light Saudi Arabia 5.39 Comparison of RVP and other properties among different crude oils.