Cassco Ice Mid Atlantic Plant #2 - Executive Summary

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The Cassco - Pleasant Valley facility manufactures ice for wholesale/retail distribution.  The 345,000 square foot facility utilizes approximately 75,000 pounds of anhydrous ammonia as a refrigerant within four separate, enclosed systems for ice manufacturing and storage. 
 
The complex consists of four individual ammonia refrigeration systems with a standard refrigeration design using anhydrous ammonia as its refrigerant.  These systems are contained in Building #2, Buildings #11 and #12, Building #14, and Buildings #15 and #16.  Within all four systems the compressors have 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 compressors are continually monitored; the Building #14 system compressors are also controlled by a computerized operating system. 
 
The Building #2 ammonia system consists of three compressors operating  
at +10 F.  The compressors receive ammonia gas from two refrigerant recirculators, compress the gas, and discharge the hot, high pressure ammonia through oil separators to three condensers located on the roof.  The evaporative (forced air, water cooled) condensers transfer the ammonia's heat to the atmosphere and return the condensed (liquid) ammonia to the high pressure receiver.  High pressure liquid ammonia is then transferred to the two recirculators.  The liquid ammonia is pumped at an approximate two to one ratio from the recirculators to the ice machines through liquid flow regulators where the flashing ammonia removes heat from the water, creating ice.  From the ice machines the ammonia gas and liquid combination returns to the recirculators to begin the refrigeration cycle over again. 
 
Buildings #11 and #12 are a freezer warehouse complex consisting of 81,753 square feet.  Both warehouses are operated from a common anhydrous ammonia refrigeration system.  The system consists o 
f ten ammonia compressors operating as a two stage system.  Four compressors operate as "low" side compressors (-30 F) with six operating as "high" side compressors (+10 F). 
 
Building #14 is a warehouse complex consisting of 65,800 square feet.  The anhydrous ammonia refrigeration system consists of five ammonia compressors operating as a two stage system.  Two compressors operate as "low" side compressors (-30 F) with three operating as "high" side compressors (+10 F). 
 
Buildings #15 and #16 are a freezer warehouse complex consisting of 104,206 square feet.  Both warehouses are operated from one anhydrous ammonia refrigeration system.  The ammonia refrigeration system consists of eight ammonia compressors operating as a two stage system.  Four compressors operate as "low" side compressors (-30 F) with four operating as "high" side compressors (+10 F). 
 
The refrigeration systems which service Buildings #11 and #12, #14, and #15 and #16 complexes are operated in a similar manner.  The c 
ompressors receive ammonia from several different recirculators.  The low side compressors receive ammonia gas from the low side recirculators (-30 F) and discharge it through oil separators to the intermediate recirculator vessels (+10 F).  The high side compressors receive the cooled low side ammonia gas from the intermediate pressure vessels, compress it, and discharge the hot, high pressure ammonia gas through oil separators to condensers located on the roof.  The evaporative (forced air, water cooled) condensers transfer the ammonia's heat to the atmosphere and return the condensed (liquid) ammonia to the high pressure receiver.  High pressure liquid ammonia is then transferred to the intermediate pressure recirculators.  The liquid level is maintained in the intermediate vessels.  Liquid is transferred from the intermediate vessel to the "low" side recirculators.  The liquid ammonia is pumped at an approximate two to one ratio from the recirculators to the various evaporative air 
units through liquid flow regulators where the flashing ammonia removes heat from the freezers and the products being frozen.  From the evaporators the ammonia gas and liquid combination returns to the recirculators to begin the refrigeration cycle over again. 
 
An outside supplier delivers anhydrous ammonia to the facility (via a tank truck) one or two times a year to replenish the ammonia in the system. 
 
Anhydrous ammonia, when properly used, has proven to be a safe and reliable refrigerant.  The sharp odor of ammonia provides 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 Cassco - Pleasant Valley 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 to between 30% to 40% 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 Cassco - Pleasant Valley 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 additional 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 re 
lated 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 rule element will be implemented on an ongoing, daily basis and become a part of the way the facility operates. 
 
Risk Management Coordinator:    Jerry Judy 
Title:    Engineer 
Additional Responsible Personnel:    None at this time 
 
HAZARD ASSESSMENT 
 
As required by the Risk Management Program regulations, the Cassco - Pleasant Valley facility has conducted offsite consequence analyses relative to the potential accidental release of anhydrous ammonia.  The scen 
arios related to a worst case release scenario and an alternative release scenario.  The facility considered worst case release scenarios relating to the four separate ammonia systems in their respective buildings.  This involved calculating worst case scenarios utilizing the RMP*Comp modeling program. 
 
The Building #2 model considered the release of 5,870 pounds of liquid ammonia from an intermediate pressure vessel, during a 10 minute release.  This was used as the release source as it is the vessel which would house the largest amount of regulated substance at any given time for this system.  The scenario endpoint was 0.3 mile.  This 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. 
 
The scenario for Building 
#12 consisted of the catastrophic loss of 6,167 pounds of liquid ammonia in a 10 minute release from a high pressure receiver.  In this scenario the toxic endpoint was 0.7 mile. 
 
The modeled scenario for the Building #14 system was the catastrophic release of 7,666 pounds of ammonia in a 10 minute release.  Although somewhat larger than the amount released in Building #12, the toxic endpoint for the Building #14 model was only 0.4 mile.  In this scenario the ammonia is liquid due to refrigeration as opposed to pressure and the size of the building then contributed to additional mitigating circumstances. 
 
The final scenario for the Building #16 system consisted of the release of 4,055 pounds of liquid ammonia during 10 minute release.  As in Building #16 the ammonia is liquified under pressure and the toxic endpoint was 0.6 mile. 
 
In reviewing the four worst case scenarios it was noted that the release from Building #12 would cover the same area as any release from the other three syst 
ems, with additional area exposed.  Therefore, the Building #12 scenario was used to determine the consequence analysis component for the worst case scenario. 
 
Alternative scenarios for the four systems were considered and it was determined that due to the facility administrative controls, the multiple safeguards pertinent to the ammonia process, and the fact that there has never been an offsite release at this facility in the past 30 years, there was no alternative scenario which would have an offsite consequence.  However, if there is a potential loss of ammonia it would be due to a possible loss from a relief valve within the system.  The predicted release would consist of approximately 50 pounds of anhydrous ammonia released over a ten minute period.  The release inside the building would have no offsite consequence.  An outside release would possibly have a 0.1 mile offsite consequence, yet would probably not leave the property, and there would be no offsite receptors affected.
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