Reddy-Houston North Plant - Executive Summary |
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The Reddy Ice - North Plant facility located in Houston, Texas manufactures ice for wholesale/retail distribution. The facility utilizes approximately 12,000 pounds of anhydrous ammonia as a refrigerant for ice manufacturing and storage. The Reddy Ice facility refrigeration system is a standard ammonia flooded design using anhydrous ammonia as its refrigerant. The system has six compressors operating at +15 pounds suction pressure and +170 pounds discharge pressure. Each of the compressors has numerous protective controls (motor overload, high discharge temperature, high discharge pressure, low suction pressure, and low oil pressure) that will shut down the compressor if operating limits are violated. The system also has high level controls in each of the three recirculators and one on each of the accumulators. The compressors are common suction and discharge. They receive anhydrous ammonia gas from the three recirculators and pump it through oil separators into the hot gas lin e to the five condensers located on the north east side of the facility. The evaporative condensers change the state of the high pressure hot gas (by removing the heat) to liquid which flows to the liquid receiver tank located under one of the condensers. Liquid anhydrous ammonia is fed into the block tank evaporators by direct expansion through the coils into accumulators and then back to the compressors. The liquid from the receiver is fed to each of the three recirculators which maintain their level through liquid level controls. The recirculators pump liquid anhydrous ammonia to the ice machines, vault evaporators and the rake room evaporators. From these, anhydrous ammonia gas and liquid return to the recirculators. An outside supplier will deliver anhydrous ammonia to the facility (via a tank truck) to replenish the ammonia in the system, as required. Anhydrous ammonia, when properly used, has proven to be a safe and reliable refrigerant. The sharp odor of ammonia provide s its own warning agent. Practically all accidents involving anhydrous ammonia are the result of a lack of knowledge, misunderstanding, carelessness or poorly maintained or unsuitable equipment. The Reddy Ice Houston facility is committed to operating a safe and compliant facility for the protection of its employees, the general public, and the environment. The facility has multiple safeguards pertinent to the ammonia process. These include an ammonia detection and alarm system, exhaust purge fans, controls which shut down the compressors if operating limits are violated, and the capability of shutting the entire system down if required. Administrative controls are in place which limit the utilization of vessels at approximately 50% of their intended capacities. The company has developed an emergency response and action plan which includes notification of emergency authorities/agencies and the public, to evacuation and first responder duties. MANAGEMENT SYSTEM The Reddy Ice Ho uston facility has developed a management system to oversee the implementation of the risk management program elements. A single person has been identified that has overall responsibility for developing, implementing and integrating the risk management program requirements. There may be different levels of responsibility assigned, depending on the size and complexity of the facility. A Risk Management Coordinator may be responsible for developing and implementing the overall risk management program, while other personnel may be responsible for developing and implementing the operating procedures element or developing a particular operating procedure. The management system is, therefore, operating at each of these levels depending on the way these responsibilities are carried out. The Risk Management Coordinator is responsible for all aspects of the development and update of the overall Risk Management Program. The coordinator will determine the necessity of establishing additiona l responsibilities for facility personnel concerning various operations at the facility. As other personnel are identified, they will be documented and lines of authority will be defined within the management system. By defining the lines of authority and roles and responsibilities of staff that oversee the risk management program elements it will: Ensure effective communication about process changes; Clarify the roles and responsibilities related to process safety issues; Avoid problems or conflicts among the people responsible for implementing elements of the program; and Ensure that the program elements are integrated into an ongoing approach to identifying hazards and managing risks. Management commitment to process safety is critical in the facility's risk management program. For process safety to be a constant priority, the facility will remain committed to every element of the risk management program. To maintain an integrated approach to managing risks, each RMP r ule element will be implemented on an ongoing, daily basis and become a part of the way the facility operates. Risk Management Coordinator: Ralph Kresge Title: Engineer Additional Responsible Personnel: None at this time. HAZARD ASSESSMENT As required by the Risk Management Program regulations, the Reddy Ice Houston facility has conducted offsite consequence analyses relative to the potential accidental release of anhydrous ammonia. The scenarios related to a worst case release scenario and an alternative release scenario. This involved calculating worst case and alternative scenarios utilizing the RMP*Comp modeling program. The facility considered worst case release scenarios relating to the receiver within the enclosed ammonia system, as it would house the largest mass of a regulated substance at any given time. The release model considered the potential release of 8000 pounds of liquid ammonia from the vessel, during a 10 minute release. The scenario endpoint was 1.1 mile. T his scenario generated a toxic endpoint of 200 ppm, the maximum airborne concentration below which it is believed nearly all individuals can be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individuals ability to take protective action. Alternative scenarios, or potentially more likely scenario, for the facility system were considered and it was determined that there is a potential loss of ammonia due to the breaking of a 2" line. The predicted distance to the 200 ppm endpoint is 0.6 mile. |