http://www.fema.gov/pdf/fima/jofb2.pdf
Here is a link to the old FEMA Technical Bulletin 1/93. I put up a page to it because it has some interesting drawings associated with flood openings in foundations. Take a look. bd
Just remember this is just for fun, the current technical bulletin one is from 2008.
FEMA Flood Vents, Non-Engineered, Meets Code :) 