48 C.F.R. § 922.103-4
(1) Where the cost to the Government may be affected, approval of hours of work in excess of the normal workweek is justified only in those instances and for those employees where it can be shown that overtime would provide needed and demonstrable impetus to the accomplishment of Department of Energy (DOE) objectives and that all other means of meeting these objectives have been considered and found inadequate or not feasible. Accordingly, the Heads of Contracting Activities shall—
(i) Establish controls to prevent excess casual overtime and to assure that such overtime work is in the best interest of the Government. Casual overtime means—
[49 FR 11998, Mar. 28, 1984, as amended at 59 FR 9106, Feb. 25, 1994; 74 FR 36365, July 22, 2009]