Tornadoes, evacuation

External events are accident initiators that do not fit well into the central PSA structure used for "internal events." Some "external events" such as fire due to ignition of electrical wires, or flood from a ruptured service water pipe occur inside the plant. Others, such as earthquakes and tornados, occur outside of the plant. Either may cause failures in a plant like internal events. External initiators may cause multiple failures of independent equipment thereby preventing action of presumably redundant protection systems. For example, severe offsite flooding may fli 1 the pump room and disable cooling systems. An earthquake may impede evacuation of the nearby populace. These multiple effects must be considered in the analysis of the effects of external events. 

Disasters are frequently categorized based on their onset, impact, and duration. For example, earthquakes and tornadoes are rapid-onset events—short durations but with a sudden impact on communities. Hurricanes and volcanic eruptions have a sudden impact on a community however, frequently advance warnings are issued enabling planners to implement evacuation and early response plans. A bioterrorism attack may be... 

Training is critical. Employees need awareness of the alarm systems and appropriate response to an alarm. Where the possibility exists for different types of disasters, employees need awareness of the different types of alarms. For example, a continuous bell may indicate an evacuation of the building, as with a fire. An intermittent bell may indicate employees should seek appropriate shelter in the building, as with a tornado. 

Conduct and evaluate emergency drills for severe weather, including tornadoes and earthquakes (where appropriate), every 6 months Conduct a joint fire drill/evacuation with local emergency organizations every year [2]... 

Tornado reaction is also a topic that must be covered. The emergency response plan must list the evacuation points, document drills, and determine when shelter will be sought and how the school will be alerted to an advisory. Usually, a weather alert radio will be in the front office and in another redundant location to ensure that someone will be within sensory presence of the radio. School computers can also have homepages connected to a local airport or weather site for up-to-date information. 

Procedures for emergency evacuation policy and procedure, including the type of evacuation (i.e., fire, tornado, etc.) ... 

The following steps must be followed in the event of a tornado. The evacuation type used is ... 

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