Unless otherwise authorized under this chapter, a contracting officer shall use firm-fixed-price contracts to procure construction.
A contract may be priced on a lump-sum basis (when a lump sum is paid for the total work or defined parts of the work), on a unit-price basis (when a unit price is paid for a specified quantity of work units), or a combination of both methods.
The contracting officer shall use lump-sum pricing in preference to unit pricing except when any one (1) of the following circumstances exists:
If an economic price adjustment provision is customary in contracts for the type of work being procured, or when omission of an adjustment provision would preclude a significant number of firms from submitting bids or would result in bidders including unwarranted contingencies in proposed prices, fixed-price contracts with economic price adjustments may be used in accordance with the applicable provisions of chapters 15 and 24 of this title.
D.C. Mun. Regs. tit. 27, r. 27-2605