FAR and DFARS: What Actually Applies to You

Every federal contract sits inside a stack of regulation. Understanding that stack, rather than memorizing it, is what lets an engineer or a contracts professional find the one rule that actually governs a specific requirement without reading the entire body of federal acquisition law first.

The FAR's part structure

The Federal Acquisition Regulation is organized into fifty-three parts, grouped into eight subchapters, running from general provisions through contract clauses. The organization is not alphabetical and not by contract type; it follows the acquisition lifecycle roughly in order. Parts 1 through 4 cover general rules, definitions, and administrative matters. Parts 5 through 12 cover the pre-award phase: publicizing requirements, competition requirements, contracting methods, and describing the government's needs. Parts 13 through 18 cover the various contracting methods, from simplified acquisition to sealed bidding to negotiated contracts. Parts 19 through 26 hold the socioeconomic and general policy requirements, including small business programs. Parts 27 through 33 cover contract-specific requirements such as intellectual property, cost accounting, and disputes. Parts 42 through 51 cover contract administration. Part 52 is the clause and provision matrix, and Part 53 covers forms.

A reader who knows this structure can jump directly to the relevant part rather than searching a keyword across the whole regulation. A question about small business set-asides belongs in FAR Part 19. A question about what happens when the government terminates a contract belongs in FAR Part 49. A question about the standard clauses that show up in nearly every contract belongs in FAR Part 52.

How agency supplements layer on

The FAR is deliberately general. It applies to the Department of Defense, NASA, the Department of Energy, and every other executive agency alike. Each agency is authorized to issue its own supplement that adds, modifies, or narrows FAR requirements to reflect its own mission and statutory obligations. The Department of Defense's supplement is the DFARS. NASA's supplement is the NASA FAR Supplement, generally cited as the NFS.

The two are not interchangeable, and a contractor moving between agencies should not assume familiarity with one supplement carries over to the other. The NFS covers matters specific to NASA's mission, including its approach to award fee contracts, its safety and mission assurance requirements, and clauses tailored to flight hardware and technical data unique to space systems. A contract can, in principle, cite the FAR, the NFS, and in some cross-agency arrangements even another agency's supplement if NASA is buying through another agency's contract vehicle. The rule of thumb is that the FAR sets the floor, and the supplement adjusts it upward or narrows it for that agency's needs; a supplement cannot contradict the FAR outright.

Clause incorporation: by reference versus full text

Contracts do not reprint every applicable regulation. Instead, Section I of a NASA contract or the corresponding section of a solicitation lists clauses two ways.

• Incorporated by reference: the contract lists the clause number, its title, and its date, without reproducing the text. The contractor is bound by the clause's actual published language, which can be looked up on acquisition.gov or in the NFS matrix.
• Incorporated in full text: the clause's complete wording is reprinted in the contract. This is typically done when the contracting officer has filled in blanks within the clause, when the clause has been modified through a deviation, or when the clause is one the government wants unmistakably visible to the contractor without a lookup step.

Both forms carry equal legal weight. The distinction is presentation, not obligation. A contractor who only reads the full-text clauses and skips the "incorporated by reference" list is reading an incomplete contract.

Prescription versus clause

Reading the FAR itself, a useful distinction is between a prescription and aclause. The prescription is the rule that tells a contracting officer when and how to use a given clause: for example, "insert this clause in solicitations and contracts exceeding the simplified acquisition threshold." The clause itself is the actual contract language the contracting officer inserts once the prescription applies. Prescriptions live in the body of each FAR part; the clauses themselves live in FAR Part 52, and the NFS carries a parallel clause matrix at NFS 1852. A reader trying to understand why a particular clause appears in a contract should look up its prescription, not just its text, because the prescription explains the underlying policy the clause is trying to implement.

Flow-down: what obligations pass to subcontractors

Many FAR and NFS clauses are written to apply not only to the prime contractor but to subcontractors as well. Whether and how a clause flows down depends on the clause's own text; some clauses state explicitly that the prime must include them, or a substantially similar version, in subcontracts above a certain dollar threshold. Others apply only to the prime and are never intended to flow down. A subcontractor's actual obligations are set by the subcontract itself, which should mirror any required flow-down clauses from the prime contract. This is discussed in more detail in Chapter 13, on subcontracting and teaming, including what a subcontractor should expect to see written into its agreement with a prime.

Finding what governs a specific solicitation

For a specific NASA solicitation, the practical research sequence is straightforward:

1. Read Section I of the solicitation for the list of clauses incorporated by reference and by full text.
2. Look up each unfamiliar clause number on acquisition.gov, which hosts the current FAR text searchable by part or by clause number, and cross-reference the NFS matrix for any clause beginning with the NFS's own numbering.
3. Check the clause's date against the version cited in the solicitation; the FAR and NFS are updated periodically, and a contract cites the version in effect when it was written, not necessarily the current one.
4. Note any deviations. Occasionally a contracting officer is authorized to depart from standard clause language for a specific procurement; these deviations are called out explicitly and should not be assumed away.

A contractor evaluating whether it can perform a requirement, price it correctly, or accept its terms should treat this clause review as part of proposal preparation, not as paperwork to be handled after award. Pricing decisions in particular depend on knowing which cost principles and audit clauses apply, a subject covered in Chapter 10, on pricing and the DCAA audit.

A note on interpretation

The FAR and NFS are regulations, not statutes, but they carry the force of contract once incorporated. Disputes over clause interpretation are resolved through the contract's disputes clause, agency boards of contract appeals, or the Court of Federal Claims, depending on the amount and nature of the dispute. For day-to-day performance, the more common and far less costly approach is to raise ambiguity with the contracting officer in writing before it becomes a compliance problem. Regulation read carefully in advance is cheaper than regulation litigated after the fact.