With respect to the 96-hour plan, are organizations expected to remain sustainable for that period of time?

Health care organizations are not required to remain fully functional for 96-hours. Nor are they required to stock-pile supplies. They are required to develop an operational plan for 96-hour duration to fully understand capabilities and limitations in order to make effective decisions when under emergency conditions in an organized and prioritized manner.
 
Decisions would include, but not be limited, to maintaining emergency services, progressive curtailment of activities, stopping elective/non-emergency services, transfer of patients, evacuation of the facility, or returning to normal operations.  

High priority incidents identified in the hazard vulnerability analysis are the issues to be considered in the 96-hour sustainability analysis. Issues include but are not limited to the anticipated actions, emergency supply inventory, access to emergency supplies, and emergency services based upon the assessment process. Exercises should be used to validate or adjust the sustainability plan.  

For example, a hospital with a 72-hour supply of potable water at full capacity.  Consideration of reducing patient load by early discharge and halting elective procedures, could reduce water demand by approximately 50%, thereby extending the hospitals potable water supply to 96 hours.  The intent is to have a plan to stretch the supply on hand or to activate a Memoranda of Understanding (MOU) to receive more supplies, or a combination of both actions. 

If any of the organization's controlling authorities, such as a local, state, region or federal charter requires the organization to remain open for a specified period, then the organization is expected to comply. 

Reference EM.12.02.09 EP3.