48 CFR § 6.401 - Sealed bidding and competitive proposals.
(a) Sealed bids. (See part 14 for procedures.) Contracting officers shall solicit sealed bids if -
(1) Time permits the solicitation, submission, and evaluation of sealed bids;
(2) The award will be made on the basis of price and other price-related factors;
(3) It is not necessary to conduct discussions with the responding offerors about their bids; and
(4) There is reasonable expectation of receiving more than one sealed bid.
(b) Competitive proposals. (See part 15 for procedures.)
(1) Contracting officers may request competitive proposals if sealed bids are not appropriate under paragraph (a) of this section.
(2) Because of differences in areas such as law, regulations, and business practices, it is generally necessary to conduct discussions with offerors relative to proposed contracts to be made and performed outside the United States and its outlying areas. Competitive proposals will therefore be used for these contracts unless discussions are not required and the use of sealed bids is otherwise appropriate.