Ready Pac Irwindale Facility - Executive Summary |
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RISK MANAGEMENT PLAN - Ready Pac Irwindale Facility EXECUTIVE SUMMARY Ready Pac Produce, Inc. has established a risk management plan according to EPA's regulations (40 CFR Part 68) for the Ammonia Refrigeration System at its Irwindale Facility to enhance its already existing safety programs. Ready Pac is extremely cautious in the handling of all chemicals and is very diligent about safety for its employees and its communities. Ready Pac staff is highly trained and utilizes modern equipment to provide safeguards. The Ammonia Refrigeration System, that contains the regulated substance anhydrous ammonia, is used for chilling produce and related processes. Accidental Release Prevention and Emergency Response Policies Ready Pac has an emergency response plan in effect to handle potential emergency situations at this facility. This plan was designed to meet the following objectives: 1.) To save lives. 2.) To minimize and avoid injuries. 3.) To protect the environment. 4.) To mini mize property damage. Key elements of the Emergency Response Plan include a discussion of the overall approach elected by Ready Pac for implementation at the Irwindale Facility, key phone numbers and contact points, vicinity and evacuation maps, plans for evacuation, fire, injury, threats and civil disorder, earthquake, potential imminent danger to personnel, chemical spill, and ammonia health hazards Stationary Source and Regulated Substance The Ammonia System Refrigeration System at the Irwindale Facility is a single stage system comprised of 9 compressors, five evaporative condensers, one high pressure receiver, evaporators, an ice maker, water chillers, an evaporative cooler, and two pumped accumulators. The system contains about 20,000 lb. of anhydrous ammonia that continuously circulates through the system. Vaporization of ammonia at different points of the system provides the needed cooling effect. Liquid ammonia is pumped from the accumulators to various heat exchange rs (e.g., the evaporators and chillers) where refrigeration is needed. By controlled vaporization of liquid ammonia the desired cooling effect is obtained. Vaporization is achieved by either passing the liquid ammonia through a narrow passage (an expansion valve) or by reducing the pressure inside the vessel where vaporization has to take place. From these heat exchangers, ammonia vapor (which often is mixed with liquid ammonia) returns to the accumulators. The accumulators act as a separator. The liquid from the returned ammonia accumulates at the bottom of the accumulators, from where the pumps take suction. The vapor in the upper part of the accumulator gets drawn by the compressors. The compressors pressurize ammonia vapors considerably. In this process the ammonia gas heats up as well. The discharge of the compressors passes through the evaporative condensers, where the cold water on the external side of the cooling tubes, causes the ammonia temperature to drop below its condensation point and cause the ammonia gas turn into liquid. The liquid from the evaporative condensers collects in the high pressure receiver. As the refrigeration system operates, the liquid level in the accumulators drops. The lost ammonia is replenished by the liquid in the high pressure receiver. A level switch on each accumulator causes the valves on top of the receiver to open and allow the liquid ammonia, that is at higher pressure in the receiver, than the pressure in the accumulator to open and make-up the ammonia taken by the compressors. Ammonia refrigeration system is equipped with many safety features. System control is achieved primarily by local automatic control units that control liquid level, temperature and pressure. The compressors are equipped with shutoff mechanisms based on pressure (high and low) and temperature. Every compartment of the facility, where ammonia heat exchangers are present, is equipped with ammonia detectors that alarm if presence of ammonia is detected. All relief valves discharge into a water diffusion tank, where ammonia is absorbed into water to minimize accidental atmospheric discharges. The system is controlled automatically and under normal conditions there is little need for the operators to intervene with the operation of the system. The operators, however, check the system continuously and provide the needed test, inspection and maintenance activities. All elements of the system are subjected to a periodic inspection, testing and preventative maintenance program. Hazard Assessment Summary Worst Case Release Result Summary Scenario Description: It is assumed that 20,000 lb. of liquid ammonia (the entire content of the system) is released from the largest vessel. This is a conservative assumption, because the entire content of the system is never within one vessel. Per the instructions of the regulation, the release is postulated to occur in 10 minutes. Since the vessels are located inside of a building, this passive mitigation measure was incorporated into the calculations. The most pessimistic meteorological conditions were used as specified in the regulation. The reference table included in EPA's RMP Guidance for Ammonia Refrigeration was used to determine the maximum downwind distance to 200 ppm. The result shows that offsite areas may be affected. Alternative Release Result Summary Scenario Description: A release of liquid ammonia from a hole with 1/2 inch equivalent diameter in a liquid line on the roof was postulated as an alternative release scenario that represents a realistic, but yet very unlikely event. This scenario models a leak from valve packing or a pipe connection. However, the selected hole diameter is very conservative given the typical opening sizes experienced in similar situations. The meteorological conditions specified in the regulation for alternative scenarios were used. The reference table included in EPA's RMP Guidance for Ammonia Refriger ation was used to determine the maximum downwind distance to 200 ppm. The downwind distance for this scenario is significantly less than that for the worst case scenario. However, in this case also, offsite areas may be affected. Accidental Release Prevention Program and Chemical-Specific Prevention Steps Ready Pac has implemented a Process Safety Management (PSM) program at the Irwindale Facility to manage the safety aspects of the Ammonia Refrigeration System. In addition, common industry standards, policies, and procedures are utilized to ensure safe practices are being performed. This includes common practices outlined by industry sources. In addition to the Management Programs, there are ammonia detectors situated in all those compartments where ammonia is present. In the event of an ammonia leak reaching, the detector relays an alarm to the central control station of Ready Pac. Five Year Accident History There have been no reportable releases of ammonia at the facilit y in the past 5 years that had lead to an injury, fatality or environmental impact. Planned Changes to Improve Safety Several process and management system improvements are being considered and implemented as a result of the technical studies done in the course of the development of the PSM and RMP Programs. These improvements include a few instrumentation additions to the system, installation of vehicle barriers to protect equipment from vehicles, installation of an exhaust blower in a room, modifications in the hangers and pipe racks to enhance seismic safety and several administrative changes that address specific practices and procedures regarding ammonia delivery, training and other tasks related to the operation of the Ammonia Refrigeration System. |