Saputo Cheese USA, Inc./Lena Plant - Executive Summary
EXECUTIVE SUMMARY |
Date of Most Recent Revision: June 15, 1999
--Source and Process Description:
Saputo Cheese USA, Inc., Lena, Wisconsin is a natural cheese processing facility operating a single-stage ammonia refrigeration system to provide process cooling and refrigeration storage capabilities.
The ammonia receiver is located outside of the building at the south end of the complex. Saputo's maximum intended inventory for this system has been determined at 27,185 lbs. The majority of the refrigerant ammonia piping extends from the engine room (just inside the building at the south end of the complex) to a distribution system on the roof of the facility. The system serves a number of evaporative condenser units, a shell and brine tube chiller, and an HVAC system.
--Summary of Major Hazards:
Due to the nature of ammonia, the most likely consequence of an ammonia release would be the rapid formation of a toxic gas plume. No reportable accidental releases of ammon
ia have occurred at this facility in the past five years.
--Consequences of Failure to Control the Hazards:
The offsite consequence analysis includes consideration of two ammonia release scenarios, identified as "worst-case release scenario" and "alternative release scenario". The first scenario is defined by EPA, which states that "the owner or operator shall assume that the ... greatest amount held in a single vessel ... is released as a gas over 10 minutes". The alternative scenario is defined as "more likely to occur than the worst-case release scenario that will reach an endpoint offsite, unless no such scenario exists".
EPA's RMP*Comp 1.06 program was used to model the worst-case release scenario. The model was based on a 10-minute release from the recirculator at its maximum operating capacity. Although the recirculator is not at maximum operating inventory during normal operation, it is possible to use the recirculator to pump down the system during repairs. The recirculat
or is the largest vessel in the system with a maximum operating capacity of 16,400-lb. of ammonia. The model accounts for a distance to 0.14 mg/L of ammonia from the ammonia vapor release. The EPA guidance of 3.4 miles/hour wind speed, stability class of F, and an air temperature of 77 F were used in the model.
The worst-case scenario as modeled in this plan has off-site impacts. The plan documents the radius produced by the release and includes a population estimate in the release radius. The population estimate was generated using the computer program LandViewTM III Version 1.0
Areal Locations of Hazardous Atmospheres (ALOHA 5.2.2) was used to model the alternate release scenario. The alternative release scenario involves the failure of a Safety Relief Valve (SRV) at normal operating pressure. The SRV is on a 3/4-in. line off of the high-pressure receiver located outside of the facility. The model for the alternate scenario considers the SRV failing while the system is at 175-psig
pressure, which is within normal operating pressures. The SRV relieves 32 lb./min. of ammonia at 175-psig. The time of release is 15 minutes, which is based on the time that the facility's engineering department felt it would take to discover the release and remotely shut down the system in order to control the leak. The alternate release also accounts for a distance to 0.14 mg/L of ammonia from the ammonia vapor release. The EPA guidance of 6.7 mile/hour wind speed and a stability class of D were used in the model. An air temperature of 80.6 OF and a relative humidity of 73% was used in the model which was obtained from the National Weather Service. The alternate case scenario as modeled in this plan has off-site impacts. The plan documents the radius produced by the release and includes a population estimate in the release radius. The population estimate was generated using the computer program LandViewTM III Version 1.0
--Explanation of How Releases are Prevented:
The Saputo Chees
e USA, Inc. Lena accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. All applicable procedures of the U.S. Environmental Protection Agency (EPA) Prevention Program are adhered to.
The ammonia system is equipped with the following process safety controls: relief valves, check valves, manual/automatic shutoffs, system interlocks, automatic process alarms, and safety procedures. In addition, the engine room is equipped with an automatic ventilation system, which vents to the roof and certain process areas are equipped with fixed ammonia detectors.
--Steps Taken to Address Hazards:
The Saputo Cheese USA, Inc. Lena has implemented a complete risk management program based on the following key elements:
' System design--- as safe, simple, and reliable as possible
' Management system to manage all aspects of the risk management program
' Process safety information compiled on the ammonia system
' Performance o
f process hazard analysis (PHAs) of equipment and procedures
' Operators understand the basic properties and hazards of ammonia as well as operating and maintenance requirements
' Use of accurate and effective operating procedures, written with the participation of the operators
' Continuing training efforts emphasizing the safe operation of the system
' Management of change program to minimize hazards associated with changes in the system
' Pre-startup review process
' An effective preventive maintenance program
' Implementation of an auditing and inspection program
' Incident investigation program
' Hotwork permits
' A system of ensuring outside contractors are knowledgeable of both the ammonia system and the applicable codes and standards
' Coordination efforts with local emergency response agencies
The process hazard analysis was completed for the entire refrigeration process in May 1999. Changes to improve safety (recommended actions) were identified during the process hazard an
alysis required by the EPA's Risk Management Prevention Program. These recommended actions have now been evaluated and are being implemented as required.
--Response Action in the Event of a Release:
Saputo Cheese USA, Inc. Lena has elected to rely on emergency response agencies to handle all emergency releases of the facility's ammonia system and has coordinated with the local response agencies in compliance with the EPA Emergency Response Program requirements. The RMP Emergency Response Program addresses Saputo Cheese USA, Inc.'s intent to rely on outside emergency response agencies in the event of an ammonia release. Saputo Cheese USA, Inc. Lena has coordinated its efforts with the local fire department in the event of an accidental release from the ammonia system.