Perishable Distributors of Iowa - Executive Summary |
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The Ankeny Perishable Warehouse is grocery products storage and distribution facility that contains refrigerated areas. The refrigerated areas are cooled by an anhydrous ammonia refrigeration system. Anhydrous ammonia, a substance regulated by EPA, is one of the most economical refrigerants available. However, the properties of ammonia makes it necessary to observe certain safety precautions while operating the refrigeration system to prevent employee exposure, and to reduce the threat of exposure to nearby members of the community. The Ankeny Perishable Warehouse chose to follow the EPA's Chemical Accident Prevention Rule, Program Level 3, to prevent a release of ammonia from the refrigeration system. The amount of ammonia estimated to be contained inside the refrigeration system is 13,000 pounds. The Ankeny Perishable Warehouse complies with EPA's Accidental Release Prevention Rule, and applicable state codes and regulations to prevent a catastrophic release of ammonia. The ammonia refrigeration system has been constructed according to the International Institute of Ammonia Refrigeration guidelines (IIAR). The operators of the systems are required to complete a training and certification program to operate the ammonia refrigeration system. The Accidental Release Prevention Program does not guarantee against an accidental release. An offsite consequence analysis was completed using a computer model to simulate a release of the ammonia from the refrigeration system. The worst case scenario considered the loss of the total charge of 13,000 pounds of anhydrous ammonia in the refrigeration system over a 10-minute period. The analysis showed that the ammonia vapor could travel approximately 3344 yards or 1.9 miles. There are approximately 1246 residents who could be potentially affected in the identified radius. There are other public receptors (schools, day cares, and industrial/commercial buildings) in the potentially affected area. There is one en vironmental receptor in the potentially affected area. The alternative release scenario, which is the most likely scenario, considered a release of ammonia from a compressor seal failure inside the building. A release of 1000 pounds of ammonia over a 20-minute period was considered. The computer model showed that the ammonia vapor could travel approximately 181 yards or 543 feet. There are no public receptors located in the potentially affected area. No administrative controls or mitigation measures were used to limit the chemical release distances for either scenario. The Ankeny Perishable Warehouse has an established Emergency Action Plan to respond to emergencies. The plan was developed in accordance with 29 CFR 1910.38 Emergency Action Plan. The plan requires employees to exit the facility during a fire or ammonia release to a safe area. The emergency agencies will be notified of the emergency. The emergency agencies will notify any potentially affected neighbors. Mai ntenance personnel will be available as a resource during an ammonia release emergency. The plan also addresses natural hazard emergencies, fires, bomb threats, civil disturbances, and utility outages. This location has not experienced an ammonia release in the past 5 years. The Ankeny Perishable Warehouse wanted to evaluate the potential failures of the refrigeration system, and if the safeguards were sufficient to prevent a catastrophic release of ammonia. A Process Hazard Analysis was completed on the refrigeration system in February, 2000. Planned changes to improve safety resulting from this analysis are documented in the Process Hazard Analysis report in the Accidental Chemical Release Prevention Program. Also, the guidelines from the International Institute of Ammonia Refrigeration (IIAR) will be followed where applicable, to manage the refrigeration system. |