HRSC Milk Plant - Executive Summary
The HRSC Milk Plant is a milk products manufacturing 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 HRSC Milk Plant 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 18,000 pounds.
The HRSC Milk Plant 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 ha
s 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 18,000 pounds of anhydrous ammonia in the refrigeration system over a 10 minute period. The analysis showed that the ammonia vapor could travel approximately 3872 yards or 2.2 miles. There are approximately 29,363 residents which could be potentially affected in the identified radius. There are other public receptors (schools, day cares, nursing homes, recreational areas, hospitals, and industrial/commercial buildings) in the potentially affected area
The alternative release scenario, which is the most likely scenario, considered a release of ammonia from a broken pipe inside the building. A release of 3000 pounds of ammonia over a 15 minute period was considered. The computer model showed that the ammonia vapor could travel approximately 368 yards or 1104 feet. There are no residents, but other public receptors (recreational areas and industrial/commercial buildings) are located in the potentially affected area. No administrative controls or mitigation measures were used to limit the chemical release distances for either scenario.
The HRSC Milk Plant 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
. Maintenance 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 HRSC Milk Plant wanted to evaluate the potential failures of the refrigeration system, and if the safeguards were sufficient to prevent a catastrophic release of ammonia. An initial Process Hazard Analysis was completed on the refrigeration system in June, 1995. 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.