Dresick Cooling - Executive Summary
1. THE DRESICK COOLING, RISK & PROCESS SAFETY MANAGEMENT PROGRAM |
This is to inform all interested persons, including employees, that Dresick Cooling has prepared a unified Risk & Process Safety Management Program. The program is in compliance with California's Accidental Release Prevention (CalARP) Program (in California CCR Title 19, Chapter 4.5 Program Level 3 Elements. At the Federal level, Title 40 CFR Part 68), and California OSHA's "Process Safety Management (PSM) of Acutely Hazardous Materials" standard (in California CCR Title 8, Section 5189, "Process Safety Management of Acutely Hazardous Materials," and Federally Title 29 Code of Federal Regulations (CFR) 1910.119). This program is being prepared to address the risks involved with the presence of anhydrous ammonia in an amount in excess of 10,000 lbs., which is contained in our refrigeration system.
Our program will promote overall plant, worker, and public safety. The program will enable our facility to prevent the occ
urrence, and minimize the consequences, of significant releases of anhydrous ammonia. Overall, the program is designed to prevent accidental fatalities, injuries and illnesses and avoid physical property damage.
Our company has an exemplary safety record, one that we are quite proud of. Our company has many policies and procedures in place to promote overall plant, worker and public safety. The Risk Management Plan unifies our efforts, and sets forth rules, procedures and practices which will help our employees protect themselves and our neighbors.
2. DESCRIPTION OF AMMONIA SYSTEM
We operate a commercial packinghouse for row crops, for example lettuce and cantelopes. We store all of our packed product in cold storage. Our facility has an ammonia system that provides refrigeration capacity to three cold rooms equipped with forced air cooling, three cold rooms for storing palleted produce, and typically three outdoor vacuum tube chillers.
Nearly all refrigeration systems operate in a s
imilar manner. High-pressure liquid ammonia is transferred from high-pressure receivers to surge tanks, pump traps, or accumulator vessels via a liquid feed manifold. The liquid ammonia passes through an expansion valve as it enters the vessels, which lowers the temperature and pressure. Cold liquid ammonia is then pumped or fed by gravity into cooling devices such as evaporator coils, ice makers, or hydrocoolers. As the cooling device absorbs heat the liquid ammonia is vaporized. The low temperature ammonia vapor is transferred back to the starting vessel, and the vapor is then pulled to the compressors. Passage through the compressor raises the temperature and pressure of the ammonia vapor. Compressor discharge (hot gas) is sent to the condensers. Water sprayed over the condenser coils removes heat from the high-pressure ammonia vapor and condenses it to a high pressure liquid, which is returned to the high pressure receivers.
There is only one ammonia system at our facility.
Therefore, we are treating our facility as a single process.
3. AMMONIA RELEASE SCENARIOS
3.1 Worst Case Scenario
Our worst case scenario is the failure of our high-pressure receiver containing 40,000 lbs of ammonia. Following the instructions set forth in EPA's "Risk Management Program Guidance for Ammonia Refrigeration (40 CFR Part 68)," we considered the failure of one vessel. We did not include any liquid ammonia in pipework connected to the failed vessel or in any other vessel that could discharge directly into pipework connected to the failed vessel. This scenario would result in a 10-minute release of the entire contents of the high-pressure receiver, 40,000 lbs. of ammonia. We considered passive enclosure mitigation because the vessel is located inside the engine room.
Using RMP*Comp the estimated distance that the ammonia would travel before dispersing enough to no longer pose a hazard to the public is 2.6 miles (rural conditions). The potentially affected area can be fo
und on a site map in Appendix A.
3.2 Alternative Case Scenario
Our alternative release scenario is as follows. A high pressure safety relief valve lifts and fails to reseat. The rated release rate for our high pressure safety relief valve is 70 lbs/min. We assume the leak would continue for 10 minutes until the header pipe was switched over to the backup safety relieve valve. Following industry practice, our relief valves are installed in pairs with a switch over valve, and the discharge is piped to a release point that is remote from the valve. Under this scenario 700 lbs of ammonia would be released over a time period of 10 minutes. Using RMP*Comp we estimate that the ammonia would travel 0.2 miles (rural conditions) before dispersing enough to no longer pose a hazard to the public. A map showing the area that would be affected is attached.
4. GENERAL ACCIDENT RELEASE & AMMONIA SPECIFIC PREVENTION STEPS
The ammonia refrigeration systems at the Dresick Cooling facility are an in
tegral part of the overall business. Together, the systems contain a total charge of approximately 40,000 lbs. It is extremely important that it is maintained and operated in a safe and efficient manner. Management is committed to making sure that all employees are made aware of the potential danger of an ammonia leak.
Our refrigeration personnel monitor the ammonia refrigeration system/process and keep an active journal of all procedures and transactions that pertain to ammonia. The system/process is checked frequently by our outside refrigeration contractor, the Stellar Group, who also assists us in performing an annual pre-season preventative maintenance review of our system/process equipment. In addition, an outside contractor, Western Precooling, provides services in the startup and maintenance of the tube chillers.
We inform our employees of the dangers of an accidental release of ammonia in a tailgate safety meeting. New employees are made aware of the potential risk of ammo
nia in an employee orientation meeting. During these meetings we also discuss preventative measures, such as evacuation, in order to be prepared for a release.
Our ammonia refrigeration system was designed and built by professional refrigeration engineers in accordance with ANSI/IIAR 2-1992 "Standard for Equipment, Design, and Installation of Ammonia Mechanical Refrigerating Systems." It was also built in compliance with the Uniform Building Code and Uniform Mechanical Code applicable at the time of construction.
Our ammonia refrigeration system is equipped with safety relief valves. These valves limit the operating pressures of the entire system, and prevent failures due to overpressurization. In the event of a valve lift, ammonia would not be released to the atmosphere because the relief valves are plumbed to a common header pipe which the vapor into a water diffusion tank.
5. FIVE YEAR ACCIDENT HISTORY
Dresick Cooling has not had any reportable accidents within the last five ye
6. EMERGENCY ACTION PLAN
This facility's emergency response program is based on the Cal/OSHA requirements for Emergency Action Plans (in California CCR Title 8, Section 3220, "Emergency Action Plans." Federally, Title 29 CFR 1910.38 and 1910.119), HAZWOPER (standard (in California CCR Title 8, Section 5192, "Hazardous Waste Operations and Emergency Response," and Title 29 CFR 1910.120).
Strategically, we will respond Defensively to a release. Under this plan our ammonia refrigeration personnel will initially take defensive take steps to bring a release under control. The first priority will be to operate the ammonia system to bring a release under control safely, from a distance, without donning personal protective equipment. Steps might include stopping the flow of ammonia to a leak point, or using the compressor to suck ammonia away from a leak point.
Every year at the beginning of the season we review with our employees our evacuation procedures in the event of an emergency
, including an ammonia release. We have a windsock at our facility that employees can use to determine the "upwind" side of any point of release.
7. PLANNED CHANGES TO IMPROVE SAFETY
Our company has an outstanding safety record, one that we are quite proud of. Many policies and procedures have been implemented to promote overall plant, worker and public safety. Nevertheless, Dresick Cooling continually strives to improve in all areas, including safety.
One change has been to group the plan elements to align with Dresick Cooling' business practices rather than the order presented in the law. Safe Operating Procedures are now grouped together for the benefit of our system operators. Safe Operating Policies are now grouped together so that appropriate office staff may administer them. The Emergency Action Plan is now separated out and distributed widely through the plant for easy reference.
A second change has been to ensure that plan documentation forms and company policy forms
pertaining to employee, contractor, and community safety are merged together to prevent unnecessary complexity and redundancy. Forms in the plan that are not being used will be discarded and replaced with more relevant documents. Alternatively, forms that are being used at Dresick Cooling that meet plan documentation requirements, but which weren't acknowledged by the plan, are now included.
A third change is that operators have assisted in the writing of Standard Operating Procedures for ease of use. In addition, there is now a method for receiving operator feedback and making changes in the future.
The last, but perhaps most fundamental change, is that the Risk & Process Safety Management Program is now thought of as a "living document". It is an interactive framework that guides safe action for Dresick Cooling employees. Through the Risk & Process Safety Management Program Dresick Cooling will continue to profit while maintaining overall plant, worker and public safety.