Triad Terminal Company - Executive Summary |
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1.0 EXECUTIVE SUMMARY 1.1 Accidental Release Prevention and Emergency Response Policies Triad Terminal Company of Greensboro (Triad-Greensboro) operates a gasoline and distillate fuel storage terminal in Greensboro, North Carolina. Triad-Greensboro utilizes butane in gasoline blending operations at the facility. Butane is a flammable gas, and is regulated under the EPA Risk Management Program (RMP) rules (40 CFR Part 68). This makes it necessary to observe safety precautions in handling butane in order to prevent unnecessary human exposure, to reduce the risk to on-site employees, and to reduce the risk to nearby members of the community. Triad-Greensboro has coordinated emergency response measures with the Greensboro Fire Department. Representatives of the fire department conduct periodic inspections of the butane system, and have familiarized themselves with the layout of the facility. In the event of an accidental release of butane, facility personnel have been instructed t o evacuate the facility and notify the Greensboro Fire Department. Fire department personnel will respond to the release and attempt to bring the release under control. Fire department personnel will notify any additional emergency response agencies, if necessary. 1.2 Stationary Source and Regulated Substances Handled The only regulated substance presently in use at Triad-Greensboro is butane. Butane is used in the butane blending system, where it is mixed with gasoline. Butane is received at the facility by truck, and is stored in a 30,000 gallon steel tank. The tank is located outside the spill containment dike, on the west side of the facility. Access to the tank is restricted by a chain link fence which surrounds the facility property. The maximum amount of butane that can be stored at the facility is 143,000 pounds. 1.3 Worst-Case Release Scenario The worst-case release scenario for butane assumes catastrophic failure of the butane tank. The entire contents of the tank (143,000 pounds) are released over a 10-minute period, and the released butane comes into contact with an ignition source. In accordance with the EPAs Risk Management Plan Offsite Consequence Analysis Guidance, ten percent of the released butane is assumed to participate in the resulting vapor cloud explosion. The distance to the endpoint of 1 psi overpressure for this scenario is 0.42 miles. 1.4 Alternate Release Scenario The alternate release scenario for butane assumes failure of the piping, valve, or connection leading to the butane header line. The failure results in the release of the entire contents of the butane tank (143,000 pounds) over a sixty-minute period. The butane is assumed to come into contact with an ignition source, resulting in a vapor cloud fire with an effective radius equal to the distance to the lower flammability limit for propane. Assuming an atmospheric stability rating of D, and a wind speed of 3.0 meters per second, the distance to the lower flamma bility limit (LFL) of 36 mg/l for this scenario is 0.06 miles. 1.5 General Accidental Release Prevention Program Triad-Greensboro complies with EPAs Accidental Release Prevention Rule, and with all applicable state codes and regulations. The butane tank was constructed in 1994, and was designed to meet the 1994 revision of the ASME Code for Pressure Vessels, Section VIII, Division I. The butane tank is supported by a steel saddle, which is anchored by two steel-reinforced concrete piers. The saddles and piers meet the requirements of the 1995 revision of NFPA 58 2-2.5.1. The transfer pump is rated for LP gas service, and has a maximum discharge pressure of 350 psi, in accordance with the 1995 revision of NFPA 58 2-4.4. The pressure relief valves are constructed to comply with NFPA 58 2-3.2. The tank is labeled with a nameplate in accordance with the 1995 revision of NFPA 58 2-2.6.3, and is maintained with a 3 mil coating of white paint, in accordance with STI Standard F941-94. The piping from the unloading area to the butane tank and from the butane tank to the blending manifold is welded schedule 40 steel piping which complies with ASTM A53 specifications for steel pipe. The above ground sections of piping are cathodically protected against corrosion, while the underground sections are coated with a corrosion-resistant material. The piping has been tested to a pressure of 1000 psi for the 3-inch pipe and 1200 psi for the 4-inch pipe. Safety systems which have been installed as a part of the butane transfer and storage system include the following: 7 A grounding lead for tanker trucks at the unloading station; 7 Check valves on the truck-to-pipeline transfer hose, butane storage tank, and blending manifold to prevent reverse flow of butane in the pipeline; 7 A pressure relief valve on the pipeline to the tank, set to open at 255 psi; 7 A vapor relief line running from the butane tank to the unloading station to relieve excess pressure in the butane tank ; 7 An automatic shutoff switch on the vapor relief line to protect against accidental drive-off of the tanker truck; 7 Three pressure relief valves on the butane tank, set to open at 250 psi; and 7 Pressure gauges at the unloading station, butane storage tank, and blending manifold. The electrical wiring which is located at the truck unloading station and in the vicinity of the butane tank and relief valves meets the requirements of the 1995 revision of NFPA 70. The truck drivers who deliver butane to the facility have been trained in safe unloading and handling procedures. The RMP Manager shall be responsible for ensuring that only truck drivers who have received proper training in the handling and unloading of butane are allowed to deliver butane to the facility. 1.6 Five-Year Accident History Triad-Greensboro has not had any incidents or accidental releases involving the butane blending system since it was installed in 1996. 1.7 Emergency Action Program Triad-Greensboro does not currently maintain a written Emergency Action Program (EAP). In the event of a butane release or emergency involving the butane blending system, Triad-Greensboro has coordinated emergency response measures with the Greensboro Fire Department. 1.8 Planned Changes to Improve Safety Triad-Greensborot does not currently have any plans to upgrade or modify the butane blending system. Triad-Greensboro does plan to upgrade the system in order to comply with future changes to NFPA 58, or to ASTM or ASME standards. |