FIDIC Yellow Book, explained.
The Plant and Design-Build contract. The Contractor takes design responsibility and delivers to the Employer's Requirements. Here is how it operates.
The FIDIC Yellow Book — the Conditions of Contract for Plant and Design-Build — is used when the Contractor is responsible for both designing and constructing the works to meet the Employer's Requirements. It is the standard FIDIC choice for design-and-build delivery of process plant, industrial facilities, MEP-heavy works, data centres, and similar projects where an experienced Contractor delivers a defined outcome rather than executing an Employer's detailed design.
Design-and-Build under the Yellow Book
The distinguishing feature of the Yellow Book is that the Contractor takes design responsibility. The Employer defines outcomes through the Employer's Requirements. The Contractor produces a Contractor's Proposal in response, and delivers a completed works package that meets those requirements.
This shifts a substantial share of risk to the Contractor, but also gives the Contractor more control — over sequencing, buildability, and design optimisation. On projects where the Contractor has genuine design and delivery expertise in the specific technology, the Yellow Book can be a strong fit.
The Contractor's design responsibility
The Contractor typically warrants that the completed works will be fit for the purposes described in the Employer's Requirements. This Fitness for Purpose obligation is materially stronger than a reasonable-skill-and-care standard: the works must actually work, not merely represent a competent effort.
Planning teams should treat design deliverables as scheduled activities on the baseline programme. Late design outputs delay procurement and construction; on a Yellow Book contract, design float is one of the highest-value schedule assets to manage carefully.
Employer's Requirements — the anchor document
The Employer's Requirements define what the completed works must do, what performance criteria they must meet, and any specific design constraints. They are the anchor document of the contract.
Discrepancies, ambiguities or errors in the Employer's Requirements are a known risk area. Treatment depends on the edition and any Particular Conditions — some contracts place the risk on the Employer, some on the Contractor, and Particular Conditions frequently rebalance the default position.
Risk allocation vs the Red Book
Compared with the Red Book, the Yellow Book transfers more risk to the Contractor. Design risk moves to the Contractor. Ground conditions treatment differs. The tendered price is typically a lump sum rather than a re-measured BOQ. Understanding these shifts is essential when advising on programme, pricing, or claim strategy.
For focused reading on the differences: Red vs Yellow Book.
Variations under the Yellow Book
The Employer can instruct Variations that change the Employer's Requirements, the scope, quality, sequence or timing of the works. The Contractor may also propose Value Engineering. Variations are valued in accordance with the contract's valuation mechanism — typically by agreement, quotation, or the Engineer's determination if agreement is not reached.
Where a Variation extends the programme or affects delivery, the Contractor is entitled to notify a claim for time and cost consequences.
Claims, delays and EOT
The claims workflow is structured similarly to the Red Book: contractual notice within the applicable time-bar, particulars, and Engineer's determination. Grounds for Extension of Time are similar in spirit but the design-and-build context creates additional interfaces — design approval delays, changes to Employer's Requirements, interface issues with Employer-supplied packages.
Under FIDIC 1999, the primary notice provision is Sub-Clause 20.1 with the 28-day time-bar. Under FIDIC 2017, Contractor claims run under Sub-Clause 20.2. Deeper reading: Extension of Time guide and FIDIC claims guide.
Practical applications
- Process plants where the Contractor engineers, procures and constructs
- Industrial buildings with heavy MEP content
- Data centres delivered under Design-Build
- Turnkey packages within larger EPC programmes
- Standalone MEP or specialist works
Both transfer design responsibility to the Contractor. The Yellow Book keeps the traditional Engineer role and shares some risks; the Silver Book pushes further, transferring ground conditions and other risks to the Contractor. The gap between the two is the risk allocation, not the delivery model.
The GSTPM FIDIC Contract Management course covers the Yellow Book alongside Primavera P6 discipline, claims workflow and delay analysis.