WinCo Foods Woodburn Distribution Center - Executive Summary
RISK MANAGEMENT PLAN - WINCO FOODS - WOODBURN DISTRIBUTION CENTER - AMMONIA REFRIGERATION SYSTEM |
WinCo Foods has established a risk management plan according to EPA's Risk Management Program regulation (40 CFR Part 68) to enhance already existing safety and emergency response programs. WinCo Foods is extremely diligent in the handling of all chemicals and is very diligent about the safety of its employees and the neighboring Community. WinCo Foods staff is highly trained and utilizes modern equipment to monitor its facility to provide safeguards, while effectively and safely using anhydrous ammonia for its Ammonia Refrigeration System.
Accidental Release Prevention and Emergency Response Policies
The WinCo Foods Woodburn Distribution Center has a long-standing commitment to worker and public safety. This commitment is demonstrated by the resources invested in accident prevention, such as training personnel and considering safety in the design, installation, operation, and mainte
nance of the Woodburn Distribution Center processes. WinCo Foods' policy is to implement reasonable controls to prevent foreseeable releases of regulated substances.
Emergency Planning and Response Guidelines for the Ammonia Refrigeration System have been in-place since initial operation to handle potential emergency situations at the facility. The Emergency Planning and Response Guidelines address key regulatory requirements. These guidelines were designed to meet the following objectives:
1) To save lives
2) To minimize and avoid injuries
3) To protect the environment
4) To minimize property damage
Key elements of the Emergency Planning and Response Guidelines include:
- Facility Description
- Emergency Response Organization
- Emergency Response Procedures
- Notification Procedures
- Evacuation Procedures
- Mitigation Scenarios and Procedures
- Incident Termination
- Emergency Preparedness and Planning
The Woodburn Distribution Center does not have a designated emerge
ncy response team; however, Woodburn Fire Department and Marion County Public Works Department specialists are trained and fully equipped to respond to hazardous material releases. The Woodburn Distribution Center Emergency Preparedness Coordinator maintains the Emergency Planning and Response Guidelines for the facility.
The Emergency Planning and Response Guidelines provide the response protocols and notification procedures, evacuation routes, ammonia health hazards, and mitigation procedures, which have been implemented to respond effectively to emergency situations that may arise at the facility. The Guidelines are reviewed and updated at least once per year to ensure compliance with PSM and RMP regulations.
Stationary Source and Regulated Substance
This food distribution facility operates a two temperature, two stage, anhydrous ammonia (R-717) refrigeration system with an engine room capacity of 366 TR -300F/low stage, and 653.6 TR +180F/high stage.
This refrigeration syste
m is a liquid recirculation system and is designed to operate at an overfeed ratio of approximately 4:1. Anhydrous ammonia (R-717) refrigerant is a Group II refrigerant. Rotary screw compressors are used in the refrigeration system. The engine room electrical classification is NEMA-1.
This facility contains six separate ammonia refrigeration subsystems:
1. Low temperature system (-300F @ 1.7 in.-Hg)
2. High temperature system (+180F @ 31.4 psig)
3. High pressure receiver system (950F @ 181.1 psig)
4. Condenser system (950F C.T. 690F W.B.)
5. Compressor low temperature system (-300F @ 1.7 in.-Hg)
6. Compressor high temperature system (+180F @ 31.4 psig)
Hazard Assessment Summary
Worst-Case Release Scenario Results Summary
Scenario Description: Release of the maximum quantity of anhydrous ammonia that can be stored in the largest equipment item (the High Temperature Vertical Recirculator Vessel) - 14,275 pounds in 10 minutes. Although there are numerous controls to prevent such a
release and to manage its consequences, other portions of the Ammonia Refrigeration System are located outside, and therefore, no credit for administrative controls or passive mitigation features was taken for the worst-case release scenario. The most pessimistic meteorological conditions were used, as specified by regulation. The EPA's RMP*Comp Dispersion Modeling Software and the SLAB Dispersion Modeling Software were used to determine the maximum downwind endpoint distance to 200 ppm. The result shows that off-site areas may be affected.
Alternative Release Scenario Results Summary
Scenario Description: Release of anhydrous ammonia liquid as a result of a recirculating pump seal failure or a packing leak on a manual or solenoid-operated valve for 60 minutes, or an ammonia transfer hose failure for 1 minute. The latter scenario is the most limiting, and for this alternative release scenario, the total quantity of ammonia calculated to be released is 910 pounds.
cal conditions specified by regulation for alternative release scenarios were used, except for wind speed (5.6 m/s determined from a site-specific meteorological assessment). The EPA's RMP*Comp Dispersion Modeling Software and the SLAB Dispersion Modeling Software was used to determine the maximum downwind endpoint distance to 200 ppm. The downwind distance for this alternative release scenario is significantly less than that for the worst-case scenario. Although off-site areas may also be affected for this alternative release scenario, the maximum endpoint distance for this alternative release scenario is just beyond the Woodburn Distribution Center perimeter.
Although the storage and use of anhydrous ammonia has inherent potential risks, and worst-case release scenarios can potentially reach the Community; the WinCo Foods Woodburn Distribution Center has recognized these potential risks and structured its safety programs to make this type of event non-credible
. In addition to the safety practices of the Company and plant personnel to make this worst-case event non-credible, it should also be recognized that there are inherent analysis assumptions that make the results of the atmospheric dispersion analyses appear worse than what would actually be expected during such an event (e.g., In the event of a release, sudden rupture and flashing of ammonia would be highly turbulent. Turbulence causes entrainment of air and the released vapor dilutes much more quickly).
In addition to the use of conservative ("cautious") analysis assumptions that over-predict the effects of a potential release, other characteristics of the facility and site serve to minimize the potential risks associated with an ammonia release:
- Spray systems; provide a significant capability to emergency responders to scrub ammonia vapors from the air should there be a release.
- Valves to permit isolation of the process exist.
- Diking and floor drains in the Engine Room w
ould provide containment for liquid releases.
- Although portions of the Ammonia Refrigeration System are outside of the Engine Room, at any particular time, the majority of the ammonia is located in the Engine Room. Conservatively ("cautiously"), no credit for enclosure mitigation was taken.
- The SLAB Dispersion Modeling results showed that the release traveled a shorter distance; however, the more conservative ("cautious") RMP*Comp results were used.
- Although the regulations allow use of a less conservative "urban" topography assumption for the alternative release scenarios, "rural" topography was assumed.
- If ammonia gas is detected in the Engine Room, a blower/scrubber combination would be expected to neutralize the release; however, this feature was not credited in the analysis results.
- Sprinklers in the Engine Room would be able to scrub the majority of the released ammonia vapors; however, this feature was not credited in the analysis results.
- Personal Protective
Equipment (PPE) (e.g., protective clothing, self-contained breathing apparatus) is used by plant personnel, as necessary.
- The history of the Woodburn Distribution Center (i.e., no RMP-applicable ammonia releases) reflects the adequacy of the design and diligence of the plant staff in safely operating the Ammonia Refrigeration System.
Accidental Release Prevention Program and Chemical-Specific Prevention Steps
The Woodburn Distribution Center Ammonia Refrigeration System has an existing Process Safety Management program to safely manage the handling of ammonia. In addition, common industry standards, policies, and procedures are utilized to ensure safe practices are being performed. The PSM Program was inspected (during the course of the preparation of this RMP Submittal) and was found to meet or exceed regulatory requirements, as well as reflect a spirit of interest in the health and safety of employees and the Community, as well as for the environment.
The Woodburn Distributi
on Center has been diligently applying key Accidental Release Prevention Program elements since the implementation of the Process Safety Management (PSM) Standard:
- Process Safety Information
- Process Hazard Analysis
- Operating Procedures
- Mechanical Integrity
- Management of Change
- Pre-Startup Review
- Compliance Audits
- Incident Investigation
- Employee Participation
- Hot Work Permit
- Emergency Response
Five-Year Accident History
There have been no RMP-applicable releases of ammonia at the WinCo Foods Woodburn Distribution Center since the August 1997 start-up of the Ammonia Refrigeration System.
Emergency Response Program
See above discussion in "Accidental Release Prevention and Emergency Response Policies".
Planned Changes to Improve Safety
Several studies have been conducted over the years to examine mitigation measures to improve safety at the WinCo Foods Woodburn Distribution Center. These studies include the following: P
rocess Safety Management (PSM), Process Hazard Analysis (PHA), and Hazard Assessment. In addition, PSM Compliance Audits are currently planned to address PSM and RMP Prevention Program requirements. All outstanding recommendations from these previous studies will have been implemented by September 15, 1999.