Del Mesa Farms Demopolis Corn Dog Plant - Executive Summary

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Anhydrous Ammonia Refrigeration System 
June 1999 
Del Mesa Farms (Foster Farms) prepared a chemical risk management program (RMP) for its Demopolis, Alabama corn dog plant in accordance with Title 40 of the Code of Federal Regulations (CFR), Part 68.  The Federal Environmental Protection Agency (EPA) promulgated the RMP regulations as required in the 1990 Amendments to the Federal Clean Air Act.  The goal of the RMP is to prevent accidental releases of substances that can cause serious harm to the public and the environment from short-term exposures and to mitigate the severity of releases that do occur.  The RMP regulations apply to facilities that handle, manufacture, use, or store toxic and flammable substances listed in the regulations above specified threshold quantities. 
Foster Farms prepared an RMP to satisfy regulatory requirements and to demonstrate a commitment to evaluate and improve anh 
ydrous ammonia handling systems and practices at the facility. Foster Farms incorporated many state-of-the-art safety features into the ammonia refrigeration system at the facility as part of the original system construction and system modifications.  In the unlikely event that a chemical release does occur at the facility, Foster Farms personnel are trained in the appropriate response measures, relying on support services provided by the local fire department and hazardous materials response team.  Foster Farms will continue to improve ammonia-handling safety through the implementation of the prevention program elements of the RMP. 
The Foster Farms facility is located in an industrial park approximately one and one-half miles south of Highway 80 in Demopolis.  Highway 80 is on the southern edge of the developed area of Demopolis.  Foster Farms and only a few other facilities occupy the industrial park.  The area surrounding the industrial park is rural agricultural with scattered res 
idential sites.  Several tree plantations are within site of the plant.  The facility is surrounded by chain-link fencing and has a secured entrance that is staffed by security personnel 24 hours per day, 365 days per year. 
The Foster Farms Demopolis plant was constructed in approximately 1994.  Foster Farms purchased the facility approximately three years ago to expand the company's corn dog production capabilities.  Foster Farms expanded the facility to include a cook plant in late 1998.  The corn dog plant receives ground meat products from Foster Farms and other meat processing facilities, produces and cooks franks, produces corn dogs and packages corn dogs for distribution.   
Anhydrous ammonia is used in a refrigeration systems at the facility.  The ammonia refrigeration system, which is a closed system, contains approximately 17,000 pounds of anhydrous ammonia. The system provides cooling for production areas, product cooling, water chilling, product freezing and cold storage.  
The desired temperatures are maintained by controlling the flow of ammonia with manually and electrically operated valves, float switches, transfer pumps, and compressor controls.   
The RMP regulations require a review of the five-year accident history at the regulated facility.  Foster Farms reported no reportable accidental releases of ammonia in the past five years. 
The RMP regulations require facilities to identify and evaluate chemical release scenarios resulting from potential failures of the chemical handling systems covered by the RMP.  Program 3 requirements of the RMP apply to the Foster Farms facility due to the quantity of ammonia used.  Program 3 facilities are required to evaluate a worst-case release scenario (release parameters are defined by the regulations) and an alternative release scenario. The regulations define a worst-case release scenario as "the greatest amount held in a single vesselreleased as a gas over 10 minutes."  An alternative release scenario is  
identified as a release that is more likely to occur at the facility. 
The largest ammonia vessel at Foster Farms, the high-pressure receiver, has a capacity of approximately 3,540 pounds of ammonia at a liquid level of 80 percent, the safe fill level of the vessel.  Therefore, the worst-case release scenario for the facility is a release of 3,540 pounds of ammonia in 10 minutes.  Catastrophic failure of the high-pressure receiver would be required for this scenario to occur.  As required by the RMP regulations, pessimistic atmospheric conditions, very conservative chemical dispersion characteristics, and a toxic endpoint of 200 parts per million (ppm) ammonia vapor were assumed.  The predicted distance to the toxic endpoint for the worst case release scenario is approximately 0.52 miles.  The SLAB Model was used for modeling the worst case release scenario.  SLAB was first developed by Lawrence Livermore National Laboratory under contract with the U.S. Department of Energy.  SLAB has  
been revised and updated by the USAF Engineering and Services Center and the American Petroleum Institute.  SLAB is commonly used to simulate the atmospheric dispersion of denser-than-air releases. 
Foster Farms used the alternative release scenario described in the Environmental Protection Agency's (EPA) Model Risk Management Program and Plan for Ammonia Refrigeration, November 1998.  The release scenario is described as a <-inch effective diameter orifice leaking liquid ammonia and resulting in an airborne release, representative of a pipe connection leak or a gasket rupture.  The evaluation used a release rate of 88.9 pounds/minute and average weather conditions.  The predicted distance to the toxic endpoint for the alternative release scenario is approximately 0.10 miles.  The SLAB Model was used also for modeling the alternative release scenario. 
The RMP regulations require a review of the accidental release prevention program and chemical specific prevention steps used by the fa 
cility.  Foster Farms has incorporated many safety features in the ammonia refrigeration system to prevent system failures and to mitigate potential releases.  The predominant safety concern with closed-loop ammonia systems is an inadvertent buildup of pressure exceeding pressure ratings or capacities of equipment due to ammonia expansion.  The Foster Farms ammonia system is continuously monitored by automated control systems that shut down components if deviations from normal operating conditions occur.  The major pressure vessels in the system are connected to a diffusion panel.  Ammonia from the vessels can be vented to atmosphere at panel.  Further, all pressure vessels in the system are equipped with pressure relief valves. 
Other safety features at the facility include:  
7 Emergency shutdown systems 
7 Component specific safety shutdowns 
7 An ammonia leak detection system is installed in the engine room and cook plant 
7 Pressure relief valves on all vessels, compressors, and sever 
al other areas in the system where trapped ammonia could build pressure 
7 Pressure vessels are connected to a fire diffusion panel 
7 Many of the ammonia pipes, valves and components are labeled 
7 Pressure relief valves are replaced at least every five years 
7 A fire alarm and sprinkler system is installed in the plant 
7 Engine room is ventilated 
7 Operators receive ongoing training in operations, maintenance and emergency response 
In addition to the physical features of the ammonia refrigeration system at the facility, Foster Farms has extensive administrative controls to maintain safe operation of the system.  Administrative controls include, but are not limited to: formal training programs for system operators and mechanics, emergency training, a hot work permit program, a lock-out/tag-out program, a contractor safety program, incident investigation program, mechanical integrity program, management of change program, pre start-up safety review program, and a RMP auditing and inspect 
ion program.  Written standard operating procedures (SOPs) have been prepared for the ammonia system at the facility.  The SOPs provide a basis for site specific operator training and a ready reference for operating and trouble-shooting the systems. 
Foster Farms is committed to maintaining the mechanical integrity of the ammonia refrigeration system.  A preventive maintenance system is being developed to manage the maintenance of the refrigeration system.  Preventive maintenance at the facility includes shift, daily, weekly, and periodic inspection; calibration; testing; and overhaul of ammonia system equipment.  The system will be used to track equipment performance and to create reports that are used by maintenance personnel to monitor the frequency of repairs and deviations from normal operating parameters. 
Changes to improve safety at the facility are ongoing.  Some of the mitigation measures suggested by the process hazard analysis team have already been implemented.  Others wil 
l be implemented within the next two to three years.  The status of significant mitigation measures is as follows: 
7 Review and revision of SOPs is nearly completed 
7 Foster Farms is evaluating a program to test all safety alarms and shutoffs at least annually 
7 Line labeling and valve tagging will be completed 
7 Foster Farms is evaluating the installation of spring return valves for all oil draining 
7 Foster Farms is reviewing the preventive maintenance program to verify that all ammonia system components are included and maintenance frequencies are appropriate 
7 Foster Farms is evaluating equipment protection issues at the plant 
7 Foster Farms is evaluating the installation of an audible/visible alarm in the production area that will be actuated by refrigeration system safeties 
7 Foster Farms is evaluating replacement of the High Pressure Receiver 
7 Equipment and critical valve access issues are being evaluated 
Foster Farms will respond to all suggested mitigation measures.  Foster 
Farms is establishing schedules of proposed actions.  Management responses and support will be consistent with Foster Farms' commitment to safe and environmentally responsible operations.
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