48 CFR §19.502-1

1. (a)The contracting officer shall set aside an individual acquisition or class of acquisitions for competition among small businesses when—
   1. (1)It is determined to be in the interest of maintaining or mobilizing the Nation's full productive capacity, war or national defense programs; or
   2. (2)Assuring that a fair proportion of Government contracts in each industry is placed with small business concerns; and the circumstances described in 19.502-2 or 19.502-3(a) exist.
2. (b)The requirement in paragraph (a) of this section does not apply to purchases at or below the micro-purchase threshold, or purchases from required sources under part 8 (e.g., Committee for Purchase From People Who are Blind or Severely Disabled).