Red Book vs Yellow Book, compared.
The single sharpest structural difference in the FIDIC Rainbow Suite is where design responsibility sits. Here is how that one difference cascades through everything else.
The FIDIC Red Book and Yellow Book are both used on substantial construction projects. They share a lot of structural DNA — the notice discipline, the Engineer role, the claims workflow. But they answer one foundational question differently: who designs the works?
Get that answer right and the rest of the contract follows naturally. Get it wrong and the contract fights you at every step.
Design responsibility — the whole game
Under the Red Book, the Employer takes design responsibility. The Contractor is generally entitled to rely on the design as issued.
Under the Yellow Book, the Contractor takes design responsibility. The Employer defines outcomes through the Employer's Requirements; the Contractor produces a Proposal and delivers to it.
That difference shapes everything downstream: risk allocation, price basis, notice discipline, and the shape of any future claims.
Side by side
| Dimension | Red Book | Yellow Book |
|---|---|---|
| Full name | Conditions of Contract for Construction | Conditions of Contract for Plant and Design-Build |
| Design responsibility | Employer | Contractor |
| Design liability standard | Employer (subject to consultant appointments) | Contractor, typically fitness for purpose |
| Payment basis | Typically re-measured against Bill of Quantities | Typically lump sum |
| Anchor document | Employer's design (drawings, specifications) | Employer's Requirements + Contractor's Proposal |
| Engineer role | Full contract administrator | Full contract administrator |
| Risk allocation | Shared, moderate on Contractor | Weighted more heavily toward Contractor |
| Typical projects | Roads, bridges, water networks, Employer-designed civils | Process plant, MEP, data centres, industrial buildings |
| Ground conditions | Shared risk (edition-specific mechanism) | Shared risk, with tighter Contractor allocation |
| Best use case | Employer wants control over design | Employer wants outcome; Contractor wants design freedom |
How the design line changes claims
On a Red Book contract, a common Contractor claim category is late Employer information — drawings, RFIs, design decisions that arrive later than needed on the critical path. Because design responsibility sits with the Employer, that late information is often a contractual event.
On a Yellow Book contract, the equivalent categories are different. Design approval delays, changes to the Employer's Requirements, and interface issues with Employer-supplied packages come up more often than pure late-drawing claims. The Contractor is responsible for its own design; it cannot claim for its own design delay.
How the payment basis changes the schedule
Re-measurement on the Red Book means the BOQ drives the value of each measured item; the schedule is used for progress tracking and cash-flow forecasting. Under a Yellow Book lump-sum contract, the schedule doubles as the value baseline — typically through a schedule of values or activity-loaded schedule — and progress reporting drives payment applications directly.
Choosing between them
Two questions matter most in the choice:
- Does the Employer want to own the design? If yes, Red. If no, Yellow.
- Is the risk profile better priced by the Employer or the Contractor? If the Employer, Red. If the Contractor is genuinely better placed to price and manage the risk, Yellow.
See also: Red Book explained, Yellow Book explained, and the full four-way comparison on our course page: Red vs Yellow vs Silver vs Green.
Contracting a Design-Build outcome under a Red Book, or contracting a construction-only scope under a Yellow Book, is one of the most common and expensive procurement mistakes in FIDIC. The design-responsibility line is not a technicality — it changes the whole risk shape of the contract.
The GSTPM FIDIC Contract Management course covers all four Books and how to choose between them for real projects.