FIDIC contracts, explained.
The four principal FIDIC contract forms and how to think about which one fits which project. Written for engineers, not lawyers.
FIDIC publishes a suite of standard construction contracts. Four of them — the Red, Yellow, Silver and Green Books — are what most planners, quantity surveyors and project managers will encounter in practice. Each one is designed for a specific delivery model with a specific risk profile. Choosing the wrong one is one of the most consequential decisions in FIDIC procurement.
This article walks through the four forms and gives you a decision heuristic for choosing between them. If you want a plain-English introduction to FIDIC first, read what is FIDIC.
The Red Book — Employer-designed construction
Full name: Conditions of Contract for Construction. Used when the Employer takes responsibility for the design and the Contractor delivers construction against that design. Traditional civil infrastructure — roads, bridges, tunnels, water networks — is the classic Red Book territory. The contract is administered by an Engineer acting on the Employer's behalf, and payment is typically re-measured against a Bill of Quantities.
Deeper reading: FIDIC Red Book explained.
The Yellow Book — Design and Build
Full name: Conditions of Contract for Plant and Design-Build. Used when the Contractor takes on both the design and the construction. The Employer specifies outcomes through the Employer's Requirements; the Contractor produces a Proposal and delivers to it. Standard on process plants, industrial buildings, data centres and MEP-heavy works. Design risk sits with the Contractor.
Deeper reading: FIDIC Yellow Book explained.
The Silver Book — EPC / Turnkey
Full name: Conditions of Contract for EPC / Turnkey Projects. Used when the Employer wants cost and time certainty and is prepared to pay a risk premium for the Contractor to take single-point responsibility for Engineering, Procurement and Construction. LNG plants, refineries, power generation and complete process facilities are typical Silver Book territory. This is the most Contractor-heavy form in the Rainbow Suite — ground conditions risk and Employer's Requirements errors are largely transferred to the Contractor.
Deeper reading: FIDIC Silver Book explained.
The Green Book — Short Form of Contract
Full name: Short Form of Contract. Used for smaller, straightforward, or short-duration works where the full FIDIC machinery would be disproportionate. Simpler payment mechanism, lighter dispute-resolution provisions, reduced administrative overhead.
Deeper reading: FIDIC Green Book explained.
A decision heuristic
Choosing the right Book usually comes down to three questions.
1. Who is doing the design?
If the Employer is designing, the natural starting point is the Red Book. If the Contractor is designing, the natural starting point is the Yellow Book or the Silver Book. This is the single sharpest structural difference in the Suite.
2. How much risk does the Employer want to transfer?
If the Employer wants a standard risk-sharing arrangement with an Engineer administering the contract, Yellow Book. If the Employer wants a lump-sum, turnkey outcome and is prepared to pay for the Contractor to take extra risk, Silver Book. The gap between Yellow and Silver is not the delivery model — both are Contractor-designed — it is the risk allocation.
3. How large or complex is the project?
If the project is small, straightforward, or short in duration, the Green Book's lighter machinery is probably right. If value and complexity justify it, use one of the Rainbow Suite Books.
Employer-designed civil / infrastructure → Red. Design-Build industrial / MEP → Yellow. Turnkey EPC on process, energy or power → Silver. Small or straightforward → Green. This is a starting point, not a rule — every project has features that can push it one way or another, and Particular Conditions can modify any form significantly.
How the four Books compare, at a glance
A complete side-by-side comparison across nine dimensions is on our course page: Red vs Yellow vs Silver vs Green. For focused pairwise reading:
- Red vs Yellow Book — the design-responsibility line
- Silver vs Red Book — turnkey EPC against traditional construction
The forms are not interchangeable
The most common procurement mistake is using the wrong Book for a project. A Silver Book contract on a scope the Contractor cannot fully control produces a hostile, claim-heavy delivery. A Red Book on a project where the Employer wanted a single-point EPC outcome creates constant interface friction. A Green Book on a project that really deserves a Yellow leaves both parties without the machinery they need when something goes wrong.
Getting the choice right at procurement is one of the highest-leverage moments in the project lifecycle. It is also the moment when a project controls professional with a working understanding of FIDIC can make the biggest early difference.
GSTPM's FIDIC Contract Management course covers all four Books in depth, plus the claims, EOT and delay-analysis machinery they use.