Nashville Refrigerated Services, Inc. - Executive Summary
Executive Summary |
A. Describe Accidental Release Prevention and Emergency Policies
It is the policy of N.R.S., Inc., to provide a safe working environment for all employees. The safety of everyone is very important to N.R.S., Inc. We expect our employees to cooperate with us for their own safety and the safety of their fellow employees.
To attain the maximum results from our program we are dedicated to the idea that every accident can be prevented and the facts making up our safety program are sound and necessary for the attainment of this objective. Sincerity of purpose is the most valuable ingredient each of us must add to insure the successful achievement of each program step along the way. We deeply believe it is worth our time and effort to prevent even one serious injury.
Accidental Release Prevention and Emergency Policies are designed to comply with OSHA+s Process Safety Management (PSM) standard (Process Safety Management of Highly Hazardous Chemicals, 29 CFR 1910.11
9) and EPA+s Risk Management Program (RM program) regulation (Risk Management Programs for Chemical Accidental Release Prevention, 40 CFR Part 68). The Vice President, Operations, is responsible for the management of the accidental release prevention and emergency action programs.
The purpose of the accidental release prevention and emergency action programs is to prevent the occurrence, and minimize the consequences, of significant releases of toxic substances as well as fires, explosions, and other types of catastrophic accidents. Overall, these programs prevent accidental fatalities, injuries and illnesses and avoid physical property damage.
B. Stationary Source and Regulated Substances Handled
This company operates a freezing and storage warehouse for the perishable food industry. This facility operates an ammonia refrigeration system to provide cooling and freezing capabilities. The amount of anhydrous ammonia (CAS #7662-41-7) contained in this system is in excess of 10,00
0 pounds. The ammonia inventory of this system is approximately 13,045 lbs. Since ammonia releases from this system could pose a risk of offsite public impact and is regulated under the OSHA PSM standard (29 CFR 1910.119), the system is subject to the Program 3 requirements of the EPA+s RM program.
The closed loop ammonia refrigeration system at the NRS, Lebanon, Tennessee, facility provides (1) major suction pressure (temperature) for use in the preservation of perishable food products. Through the use of multiple stages (2) of compression the refrigeration system provides refrigerant temperatures of (-47|F.) with the use of low suction booster compressors and provides temperatures of +20| to +35|F. with the use of intermediate high stage compressors. The higher pressure portions of the system include the condenser, located on the roof, along with refrigerant vent lines where any leaks can dissipate to the air, joining ammonia produced by lightning where it can be consumed as it g
oes through a natural biodegrading process. Normal safeties include: high pressure cut-outs, relief valves, and ventilating systems for machine room areas.
C. Summary of Worst-Case and Alternative Release Scenarios
The Worst Case Release Scenario is determined to be a catastrophic release from V-4 or V-5 vessels. Each of these vessels operates at 40|F. and approximately 75 psig.
Each of these vessels is 4.5 feet in diameter and 12 feet in length. When 40% filled, vessel capacity is approximately 3,039 pounds of anhydrous ammonia.
Assumed is that the release occurs through a circular hole located at the bottom of the vessel. For this Worst Case Release Scenario, the distance from source to toxic endpoint is 0.62 miles.
The worst-case release scenario is unlikely for the following reasons:
The worst-case weather conditions which were used for this scenario are uncommon;
Industry standards were followed for the manufacture and quality control of these vessels;
Ammonia is not
corrosive in this service;
Pressure safety valves limit operating pressures in these vessels and vessels have design margins of safety of about 4 to 1.
Alternative Release Scenario Analysis
An Alternative Release Scenario is chosen as a pipe failure. The potential for a pipe failure is significant given the extensive ammonia piping system extending throughout the Facility.
Assumed is the failure of a 3/4-inch pipe connected to either the V-4 or V-5 vessel. Using EPA-suggested meteorological parameters for alternative scenarios and following a one-hour release, the distance from release point to the toxic endpoint is 0.36 miles.
The Alternative Release Scenario is unlikely for the following reasons:
The high pressure liquid lines are located in enclosed areas that could help to contain such a release;
Industry standards were followed for the manufacture and quality control of these lines;
Ammonia is not corrosive in this service;
Vessel design uses a factor of approximately
4 to 1 margin for safety;
Active mitigation considered would be the Emergency Shutdown System which permits system to equalize to 50-60 psig.
D. Description of the Accidental Release Prevention Program
The prevention program (OSHA Process Safety Management CFR 1910.119) consists of the following elements:
Process Safety Information
Process Hazard Analysis
Pre-startup Safety Review
Hot Work Permit
Management of Change
E. Five-Year Accident History
No ammonia-related incidents were identified for the facility in the previous five years which resulted in significant on-site or off-site consequences.
F. Description of the Emergency Response Program
This facility has an Emergency Action Plan. The plan contains procedures describing how the facility will respond to ammonia spills and other emergencies, including evacuation procedures, escape routes, cri
tical operations shutdown procedures, procedures to account for all employees, rescue and medical duties assignment, means of reporting fires and emergencies, name of responsible person, alarm system, training and fire prevention.
G. Planned Changes to Improve Safety
A Process Hazard Analysis was conducted on November 21, 2000. Any recommendations resulting from this analysis will be evaluated and implemented as required.