Each impounding system serving an LNG storage tank must have a minimum volumetric liquid impoundment capacity of:
    
    
        
        (a) 
         110 percent of the LNG tank's maximum liquid capacity for an impoundment serving a single tank;
     
    
        
        (b) 
         100 percent of all tanks or 110 percent of the largest tank's maximum liquid capacity, whichever is greater, for the impoundment serving more than one tank; or
     
    
        
        (c) 
         If the dike is designed to account for a surge in the event of catastrophic failure, then the impoundment capacity may be reduced to 100 percent in lieu of 110 percent.
     
    [Amdt. 193-17, 65 FR 10960, Mar. 1, 2000]