Per FEMA P-348 (3.2.3): although difficult to achieve, an alternative provided by NFIP regulations allows equipment to be located below the BFE, provided that the equipment is designed, constructed, and installed to “prevent water from entering or accumulating within the components during conditions of flooding.” Please note that specially designed equipment is not permitted below the BFE in buildings located in coastal high-hazard areas (Zone V) due to a requirement that space below such buildings be free of obstructions.