Plant Kraft - Executive Summary

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Savannah Electric serves approximately 125,000 customers in an ecologically diverse area rich in natural resources - from beaches, low-country rivers and marshes to farmlands and forests.  Since the company was founded in 1882, we have provided clean, safe electric power, earning a reputation for sensitive environmental stewardship in the communities we serve. 
Our success comes from a set of strategic priorites that we use to develop and implement plans that ensure Savannah Electric's continued role as a recognized community leader in protecting and preserving the environment. 
Savannah Electric's impressive record of compliance with air and water quality regulation exemplifies our dedication to the environment.  We devote considerable time and resources to make sure that we meet, and in most cases exceed, the requirements of federal clean air laws and other regulations. 
Propane at Plant Kraft is used as and ignition fuel for the boilers.  The propane is delivered by tanker truck to th 
e plant.  The propane is stored in a single 12,500 gallon tank.  The tank is fitted with an overpressure relief valve and an emergency shut off at the fill station.  There are several fire hydrants located near the tank and in case of a fire, the tank would be kept cool with streams of water.  The propane system is fenced in to protect it, and access to the plant is controlled by security. 
In case of an emergency, all non essential personnel would be evacuated upwind (at least 1/2 mile in all directions).  If possible, the leak would be stopped with non-sparking tools before attempting to extinguish the fire.  A water spray would be used to reduce vapors.  Savannah Electric maintains an on-site Emergency Response Team, who has been trained to deal with an emergency involving propane releases.  All plant employees have received emergency evacuation training.  In the case that our Emergency Response Team is not available the local Fire Department would handle the emergency. 
There are 1 
05 employees located at the Plant Kraft site with the majority of the employees working during the day shift.  During the evening hours there are 6 employees normally on site. 
There have been no accidental releases of propane at Savannah Electric's Plant Kraft. 
PROPANE - CAS # 74-98-6 
Synonyms: Liquified petroleum gas, LP gas or LPG. 
Physical Properties/Chemical Properties:  Propane is a colorless gas with a faint petroleum-like odor.  Odor is an inadequate warning of potentially hazardous air concentrations. 
Fire and Explosion Data: Extremely flammable. Explosive.  This material releases vapors at well below ambient temperatures and readily forms flammable mixtures with air.  Remove/avoid/isolate from open flame, sparks or any source of ignition or heat.  Evacuate all non-essential personnel upwind. 
Special Fire Fighting Procedures: Fight fire from safe distance.  Storage vessel may reach temperatures that can cause ignition and explosion.  Keep storage vessel cool with streams o 
f water.  Fog nozzles may be preferable.  Gas fires should not be extinguished unless the gas flow can be shut off immediately. 
Unusual Fire and Explosion Hazard: Extremely flammable. Explosive.  Remove all sources of ignition and heat.  Vapors are heavier than air and may travel long distances to a source of ignition, then flash back. 
Reactivity Data: Not expected to be reactive under most conditions. 
Health Hazard Data: Propane is an asphyxiant in high concentrations.  Gas is heavier than air.  Displaces O2.  Symptoms of exposure are dizziness, disorientation, excitation, excessive salvation, headache and vomiting.  NFPA rating is as follows: flammabilty-3 extreme; health-1 slight; reactivity-0 none. 
Signs and Symptoms of Exposure:  Exposure may cause rapid breathing, headache, dizziness, visual disturbances, muscular weakness, tremors, narcosis, unconsciousness and death depending on concentration and time of exposure.  Direct contact with liquefied or pressurized gas may cause  
frostbite and/or permanent eye damage. 
Emergency First Aid: Inhalation - Move affected personnel to fresh air.  For respiratory distress, provide air, O2 or CPR.  
Eye Contact - Vapors are not expected to present an eye irritation hazard.  If (eyes) contacted by liquid/solid. or vapor, flush eye(s) gently with warm water for at least 15 minutes.  Seek medical attention if pain or redness persists. 
Skin Contact - Frozen tissues should be flooded or soaked with warm water (105 -115 deg. F).  DO NOT USE HOT WATER.  Cryogenic burns which result in blistering or deeper tissue freezing should be seen promptly by a physician. 
Precautions in the event of a spill/release:  Eliminate all sources of ignition.  Evacuate all non-essential personnel upwind (at least 1/2 mile in all directions if tank is on fire).  Stop source of leak with non-sparking tools before attempting to extinguish fire.  Ventilate closed areas.  Water spray may be used to reduce vapors.  Use chemical goggles and face shield 
s when handling liquefied gases.  Use insulated, impervious plastic or neoprene coated gloves and apron, or other protective clothing to protect hands and other exposed skin.  For excessive concentrations, use only NIOSH/OSHA/MSHA approved self contained breathing apparatus.  Liquid spills will vaporize, formin cold, dense clouds that are difficult to disperse.  Avoid vapor even in SCBAs.  Releases are expected to cause only localized, non-persistent environmental problems.  Waste mixtures containing these materials should not be allowed to enter drains or storm sewers.  It is preferable to dispose of this material as a vapor (as auxiliary fuel). 
Site/Plant: Plant Kraft 
Regulated substance: Propane 
Scenario: Worst Case scenario 
Scenario description:  Entire amount of the tank is released resulting in a vapor cloud explosion with a yield factor of 10% (for TNT-equivanlency models).  The distance endpoint is defined as the distance over which a minimum pressure of 1 psia occurs from pre 
ssure wave formed by detonation. 
Model used: ARCHIE version 1.0 (TNT equivalency model) 
Model Inputs: 
Substance: Propane 
Modeling option: Evaluate the vapor cloud explosion hazards 
Lower heat of combustion: 21,646 btu/lb 
Weight of explosive gas: 52,500 lbs. 
Location of the explosion relative to the ground:  option 1 chosen.  For option 1, the model assumes that the explosion takes place at an elevation sufficient to permit omnidirectional dissipation of the blast or shockwave. 
Explosion yield factor: 0.10 (model recommends 0.03 but EPA guidance is 0.10 (10%)) 
Model Output: 
Distance from explosion       Peak Overpressure    Expected Damage 
(feet)                                     (Psia) 
24193                                    0.03                            Occasional breakage of large windows under stress 
3409                                      0.30                            Some damage to home ceilings;10% window breakage  
1272-2207                             1.00-0.50        
           Windows usually shattered;some frame damage 
1272                                      1.00                            Partial demolition of homes;made uninhabitable 
327-1272                               8.00-1.00                   Range serious/slight injuries from flying glass/objects 
768                                        2.00                            Partial collapse of home walls/roof 
586-768                                 3.00-2.00                   Non-reinforced concrete/cinder block walls shattered 
261-678                                  12.2-2.40                  Range 90-1%                                                           
                                                                                eardrum rupture among exposed population 
660                                          2.50                          50% destruction of home brickwork 
489-586                                  4.00-3.00                  Frameless steel panel buildings 
427                                          5.00                         Wooden utility poles snapped 
352-427                                  7.00-5.00                  Nearly complete destruction of houses 
290                                         10.0                           Probable total building destruction 
174-240                                  29.0-14.5                  Range for 99-1% fatalities among exposed  
                                                                                populations due to direct blast effects 
Results:  From the table the distance to 1.00 psia over pressure endpoint is = 1272 feet or 0.241miles 
Since this distance is on the plant property, an alternative scenario is not needed.
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