No, unless it is in a high-rise building. See the requirements in the International Building Code. If the building is insured by a highly protected risk insurer they may require it but it is not required by the IBC or the International Fire Code.
Check out this web site, we had a long discussion on this a few weeks ago. If u use the 2007 of NFPA 20 depending on the reliability of the electric supply u may need back up power. NFPA 20 has not defined what a reliable electric supply is.