TruServ Manufacturing - Executive Summary |
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1.0 SOURCE AND PROCESS DESCRIPTION 1.1 SOURCE The TruServ Manufacturing Company (TruServ) facility located in Cary, Illinois, is subject to the United States Environmental Protection Agencys (USEPAs) Risk Management Program (RMP) for Accidental Chemical Release regulation (40 CFR 68) because it has two independent processes that contain mixtures of propane (Chemical Abstract System [CAS] number 74- 98-6) and n-butane (CAS number 106-97-8) exceeding 10,000 pounds. The mixtures are used as propellant for aerosol paint cans. The two processes are: (1) propellant injection into aerosol cans (the propellant process), and (2) finished goods warehousing. Propellant is a gas at ambient temperature and pressure and is stored in an 18,200-gallon water capacity storage tank at a pressure of approximately 70 to 80 pounds per square inch gauge (psig). Administrative controls in place at the facility, including written loading procedures, limit the tank fill volume to 85 percent of capacity, resulting in a maximum on-site propellant mass of 68,548 pounds. The storage tank and transfer piping are located outdoors. Finished goods are transferred to the on-site warehouse for storage and distribution. Mixtures of propellant, flammable liquids, and paint solids are stored in 15- to 20-ounce cans. Approximately 250,000 pounds of propellant may be stored in the well-protected warehouse at any one time. Propellant is a flammable and potentially explosive gas. The propellant is not inherently toxic. 1.2 PROCESS DESCRIPTION The TruServ propellant filling system consists of the single storage tank, piping from the storage tank to a small propellant fill room, and two aerosol can filling machines. A pump is used to transfer the propellant from the storage tank into the propellant fill room. The filling machine regulates the incoming pressure of the propellant and injects the propellant into 15- to 20-ounce aerosol cans. The equipment and interconnectin g piping are part of a closed system, thereby minimizing the potential of a large release. The propellant filling system is protected by specific safety systems and hardware which include safety relief valves, excess flow valves, and safety interlocks and alarms. Safety relief valves protect the storage tank and the piping to the propellant filling machine. Excess flow valves are located at all inlet and outlet connections to the storage tank. The excess flow valves close if a larger-than-normal flow of propellant from the vessel were to occur. Gas detectors and alarms within the filling room monitor the ambient air to ensure proper operation of the system. Abnormally high concentrations of propellant within the propellant fill room will actuate special exhaust equipment and, if levels continue to rise, shut down the process. Once filled and packaged, cartons of aerosol cans are transferred to the finished goods warehouse. In the warehouse, the cans are stored in a fully sprinklered rack system until they are shipped off site. 2.0 POTENTIAL RELEASE SCENARIOS 2.1 PROPELLANT PROCESS Propellant filling is accomplished in a closed system. Historical releases of propellant have included only small volumes infrequently released from the filling machine inside the propellant fill house. While these incidents can impact employees, they have not historically lead to a release that would result in a potential off-site impact. Consistent with the RMP rule requirements, two specifically defined release scenarios, a worst-case release and an alternative release, were analyzed to determine the maximum distance to predetermined endpoints. The release scenarios analyzed and the endpoints evaluated are based on the guidance contained in the USEPAs Risk Management Program Guidance for Propane Storage Facilities (The Propane Guidance), dated March 4, 1998, and the USEPAs Offsite Consequence Analysis Guidance (OCAG) dated April 1998. 2.1.1 Wor st-Case Scenario The worst-case scenario assumes that a catastrophic failure of the propellant storage tank results in a release of the largest quantity of propellant stored at the facility. Administrative controls limit this maximum quantity to 15,470 gallons or 65,548 pounds. In the worst-case scenario, the released material is assumed to form a vapor cloud which comes into contact with an ignition source and detonates. The endpoint for this release is defined as an overpressure of 1 psi caused by the explosion and is considered the threshold for potential serious injuries to people as a result of property damage caused by an explosion. The distance to the endpoint for the worst-case scenario is 0.33 miles (1,745 feet). Although the worst-case consequence analysis is required by the RMP rule, a worst-case occurrence is considered a highly unlikely event. The likelihood of a catastrophic failure of the storage tank is extremely remote because of the following: Th e storage tank is designed and constructed in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Section VIII). The tank is operated well below its design pressure of 250 psig and, because of safety factors built into the ASME Code, significantly higher pressures would be required to cause catastrophic failure of the tank. Access to the tank by unauthorized personnel is prevented through fencing and guarded entranceways. The tanks placement separated from most plant activities minimizes the potential for inadvertent contact with plant traffic. The appearance of the external surface of the storage tank is visually inspected on a routine basis and repairs are arranged when necessary. The vessel is designed, installed, operated, and maintained in accordance with National Fire Protection Association (NFPA) Liquefied Petroleum Gas Code (NFPA 58). The vessel is protected from overpressure through the installation of two safety relief valves (SRVs). The propellant is non-corrosive. 2.1.2 Alternative-Release Scenario USEPA specifies that an alternative-release scenario be evaluated that is more likely to occur than the worst-case scenario and is significant enough to impact off-site areas (i.e., the endpoint must be located beyond the facility boundary). Because the TruServ facility has not experienced a propellant release to use as a model alternative scenario, the scenarios discussed in the USEPAs OCAG and Propane Guidance documents were considered the most appropriate for analysis. The release scenario chosen assumes that the two safety relief valves lift for a 5-minute period. The resulting vapor cloud is assumed to contact an ignition source and a vapor cloud fire results. No active or passive mitigation is assumed for this scenario. The endpoint for this release, the lower flammability limit (LFL), is considered to provide a reasonable, but not overly conservative, es timation of the possible extent of a vapor cloud fire. The LFL for the propellant is 1.8 percent. The distance to the endpoint for the alternative-release scenario is 0.10 miles (528 feet). Although an alternative-case release consequence analysis is required by the RMP rule, a release that is large enough to reach an endpoint beyond the facility boundary is not likely to occur. The facility has never experienced an SRV release resulting from vessel overfilling. Additionally, the facility has a training course for propellant system operators that includes the vessel filling task, requires its operators to regularly monitor the level gauge during filling operations, and requires operators to remain present during all offloading operations. Also, propellant vapor that is released may disperse without harmful effects. 2.2 FINISHED GOODS WAREHOUSE 2.2.1 Worst-Case Scenario Consistent with the RMP rule requirements, a worst-case release from the largest single container w as analyzed to assess the maximum distance to a flammable endpoint. The release scenarios analyzed and the endpoints evaluated are based on the guidance contained in the USEPAs Propane Guidance and the OCAG. The worst-case scenario assumes that failure of the largest single container, a 20-ounce aerosol can, results in a release of propellant and flammable liquid vapor. The released material is assumed to form a vapor cloud which comes into contact with an ignition source and detonates. The endpoint for this release is defined as an overpressure of 1 pound per square inch caused by the explosion and is considered the threshold for potential serious injuries to people as a result of property damage caused by an explosion. Based on the contents of a 20-ounce aerosol can, the distance to the endpoint for a worst-case release is 35.3 feet (0.007 miles), which is contained within the building. No public receptors are located within the endpoint distance. 3.0 ACCIDENT H ISTORY There have been no accidental releases of propellant at the TruServ Cary facility in the last 5 years that have resulted in death, injury, or significant property damage on site or off-site death, injury, property damage, evacuation , sheltering in place, or environmental damage site. 4.0 PREVENTION PROGRAM 4.1 PROPELLANT PROCESS TruServe has carefully considered the potential for accidental releases of propellant, such as the aforementioned occurrences of the worst-case and alternative-release scenarios. To help minimize the probability and severity of a propellant release, a prevention program that satisfies the Occupational Safety and Health Administration (OSHA) Process Safety Management (PSM) of Highly Hazardous Chemicals standard (29 CFR 1910.119) has been implemented at the Cary, Illinois, facility. The major objective of this prevention program is to implement a management system that prevents releases of propellant, especially in situations that could expo se employees and others to serious hazards. The program employs a systematic approach to evaluating the whole process including process design, process technology, process changes, operational and maintenance activities and procedures, non-routine activities and procedures, emergency preparedness and procedures, training programs, and other interrelated elements that effect the propellant system. The key components of the prevention program are summarized below: Process safety information regarding the propellant system has been developed, documented, and made available to facility operators. This information is used to fully understand and safely operate the propellant system. The performance of a formal process hazard analysis (PHA) on the propellant system using the What-if... technique. A team with expertise in engineering, operations, maintenance, and safety evaluates the existing system in depth and developed recommendations to improve the safety and opera bility of the propellant system. The PHA addresses: (1) process hazards; (2) previous incidents; (3) engineering and administrative controls applicable to the hazards; (4) the consequence of control failure; (5) facility siting; (6) human factors; and (7) a qualitative evaluation of possible safety and health effects of control system failures. The PHA resulted in multiple procedural and/or hardware recommendations to improve the safety and operation of the propellant system. TruServe has resolved all of the PHA recommendations. The PHA will be updated and revalidated every 5 years. Written standard operating procedures (SOPs) are used to provide the basis for proper and safe operation of the propellant system. The SOPs include procedures for normal operation, startup, shutdown, emergency operation, and emergency shutdown. Formal authorization systems are in place to ensure that system changes or expansions are as safe as the original design, and that an indepe ndent recheck confirms that the changes are consistent with the engineering design and can be safely operated prior to startup. Operators and mechanics working in the propellant fill building or who are responsible for unloading propellant from tank cars receive training on the process hazards, process safety information, SOPs and emergency response actions related to the propellant system. The training program ensures that the operators understand the nature and causes of problems arising from system operations and serves to increase awareness of the hazards particular to the propellant system. A mechanical integrity program has been implemented and includes: (1) routine system inspections to identify unusual or increasing vibration, incipient leaks, or other indications of potential upsets or failures; (2) replacement or testing of pressure relief valves on the storage tank every 10 years; and (3) periodic testing of gauges, monitoring devices, and safety interloc ks. Prior to the performance of any hot work (i.e., spark or flame producing operations such as welding, cutting, brazing, grinding), the work must be approved by executing a written hot work permit to verify precautions have been implemented to prevent fire. Contractors that are hired to work on, or adjacent to, the propellant system are pre-qualified based on their knowledge of propellant systems and their demonstrated ability to work safely. All incidents that cause or might have caused an accidental or unexpected release of propellant are subject to a formal investigation. A compliance audit of the prevention program is completed every 3 years to verify that the appropriate management systems are in place and are being properly implemented. The prevention program includes an extensive employee participation program involving TruServ employees from all levels of the organization and from all areas within the plant (i.e., production and maintenance). This program considers that employees who work on the propellant system are the most knowledgeable about it and are best able to easily, effectively, and regularly recommend changes or improvements which enhance safety. 4.2 FINISHED GOODS WAREHOUSE Although a formal, documented prevention program is not required by the RMP rule for Program 1 processes, a number of design and operational controls are in place to decrease the severity or prevent the occurrence of a fire or explosion. The most significant controls are described below. The warehouse is designed as an aerosol storage area per the NFPA Manufacture and Storage of Aerosol Products (NFPA 30B). The rack storage system is designed for flammable materials storage per the NFPA Code for the Rack Storage of Material (NFPA 231C). Potential sources of ignition are restricted from the warehouse. The warehouse and rack system are fully sprinklered. 5.0 EMERGENCY RESPONSE PROGRAM The TruServ, Cary facility has imple mented a detailed written Emergency Action Plan (EAP). The EAP is intended to address all emergencies at the facility, including incidents related to a release of propellant. The EAP includes awareness and response training for plant employees, coordination with the local fire department, and evacuation of personnel in the facility. The EAP identifies specific individuals and their responsibilities, and identifies procedures for emergency medical care. CERTIFICATION BY SOURCE In accordance with 40 CFR 68.185, I hereby certify that the information and Risk Management Plan for anhydrous ammonia, contained herein, is to the best of my knowledge, information, and belief formed after reasonable inquiry, true, accurate, and complete. ________________________________ Signature ________________________________ Robert E. Simmons Vice President of Manufacturing Title Active mitigation means equipment, devices, or technologies that require hu man, mechanical, or other energy input to function. Active mitigation for compressed gases may include automatic shut-off valves, rapid transfer systems, and scrubbers. Passive mitigation means equipment, devices, and technologies that function without human, mechanical, or other energy input. Examples include enclosures (e.g., buildings) for compressed gases and secondary containment dikes for liquids. Please note that the USEPAs RMP*Submit software, version 1.0.7, does not allow entry of such a small release amount and endpoint distance. The release amount in the data elements section of RMP*Submit is, therefore, reported as 1 pound and the endpoint distance as 0.01 miles. |