AFG Industries, Inc. - Victorville - Executive Summary

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   AFG Industries, Inc. - Victorville 
 
   Executive Summary 
 
 
a.    AFG Industries Inc. - Victorville Plant's 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 AFG emergency response policy involves the preparation of a response plan which is tailored to the facility and to the emergency response services available in the community, and is in compliance with the EPA Emergency Response Program requirements. 
 
b.    An ammonia injection system (Thermal DeNOx) is used as a control device for the nitrous oxides emissions from the glass furnace.  An 18,000 gallon ammonia tank is located away from the furnace building and enclosed by a fence.  Ammonia is piped from this location into the furnace.  
 
c.    The off-site consequence analysis includes consideration of two ammonia release scenarios, identified as " 
worst-case release" and "alternative release".  The first scenario is defined by EPA, which states that "the owner or operator shall assume that the ... maximum quantity in the largest vessel ... is released as a gas over 10 minutes," due to an unspecified failure.  The alternative scenario is defined as "more likely to occur than the worst-case release scenario". 
 
   Atmospheric dispersion modeling has to be performed to determine the distance traveled by the ammonia released before its concentration decreases to the "toxic endpoint" selected by EPA of 0.14 mg/l, which is the Emergency Response Planning Guideline Level 2 (ERPG-2).  This is defined by the American Industrial Hygiene Association (AIHA) as the "maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action" 
.  The residential population within a circle with a radius corresponding to the toxic endpoint distance has to be defined, "to estimate the population potentially affected". 
 
   The worst-case release scenario at the AFG plant involves a failure of the 18,000 gallon ammonia storage tank (a total of 78,795 pounds of ammonia).  The off-site consequence analysis for this scenario was performed for using the RMP*Comp modeling program, developed by the EPA. f conditions.  The worst-case release scenario followed conditions pre-defined by EPA, namely ERPG-2 as the toxic endpoint, and consideration of the population residing within a full circle with radius corresponding to the toxic endpoint distance.  EPA-mandated meteorological conditions, namely Stability F, wind speed of 1.5 m/sec, highest daily maximum temperature (116 F), and average humidity (65 percent) were used for both sets. 
 
   When atmospheric dispersion modeling for the worst-case scenario was performed using the EPA assumptions,  
a distance to toxic endpoint of 5.1 miles and an estimate of residential population potentially affected of 82,364 was obtained.  
 
   The alternative release scenario involves the rupture of a 11/2 inch diameter ammonia gas supply line, possibly due to an external shock (i.e. earthquake) or human error (i.e. forklift accident).  The RMP Offsite Consequences Analysis Guidance was used to calculate the release rate of ammonia gas from the pipe.  The amount of ammonia released is 71.8 pounds per minute over a ten minute release duration (based on response procedures to system alarms using shutoff valves).  The typical meteorological conditions (set by RMP*Comp) used were Stability D, wind speed 3.0 m/s, and average air temperature of 77 F.  When atmospheric dispersion modeling for the alternative release scenario was performed using these assumptions, a distance to toxic endpoint of 0.2 miles and an estimate of residential population potentially affected of 396 was obtained.  
 
   Active mitig 
ation by using shutoff valves was accounted for in the release duration.  Active mitigation by using the water cannon located near the ammonia tank was not taken into account for the alternative release, since the plant leaves the determination for using the water cannon up to the local fire department. 
 
d.    The general AFG accidental release prevention program is based on the following key elements: 
 
        Operator training 
        Preventative maintenance program 
        Use of process safety equipment 
        Use of accurate and effective operating procedures 
        Performance of the hazard review of equipment and procedures 
        Implementation of an auditing and inspection program 
    
   The ammonia injection system contains manual valve shut-offs, pressure release valves, and high and low pressure alarms.  All personnel are instructed to evacuate in the case of an accidental release. 
 
e.    No accidental releases of ammonia have occurred at this facility in the past five years. 
 
f.    The facility has an emergency 
response program, which has been coordinated with the Victorville Fire Department.  This program includes the procedures to be followed during an accidental release scenario, including a notification plan.  Emergency operation and response procedures are reviewed periodically. 
 
g.    Currently, the plan has been effective in preventing accidental releases of ammonia.  No necessary changes were identified to improve safety.
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