48 CFR §19.502-3

1. (a)The contracting officer shall set aside a portion or portions of an acquisition, except for construction, for exclusive small business participation when—
   1. (1)Market research indicates that a total set-aside is not appropriate (see 19.502-2);
   2. (2)The requirement can be divided into distinct portions;
   3. (3)The acquisition is not subject to simplified acquisition procedures;
   4. (4)Two or more responsible small business concerns are reasonably expected to submit offers on the set-aside portion or portions of the acquisition that are competitive in terms of fair market prices, quality, and delivery;
   5. (5)The specific program eligibility requirements identified in this part apply; and
   6. (6)The solicitation will result in a contract other than a multiple-award contract (see 2.101 for definition of multiple-award contract).
2. (b)When the contracting officer determines that a requirement is to be partially set aside, the solicitation shall identify which portion or portions are set aside and not set aside.
3. (c)The contracting officer shall specify in the solicitation how offers shall be submitted with regard to the set-aside and non-set-aside portions.
4. (d)Offers received from concerns that do not qualify as small business concerns shall be considered nonresponsive and shall be rejected on the set-aside portion of partial set-asides. However, before rejecting an offer otherwise eligible for award because of questions concerning the size representation, an SBA determination must be obtained (see subpart 19.3).