The FIDIC Yellow Book, where design responsibility shifts.
The FIDIC contract for Plant and for Design-Build works. Contractor takes design responsibility against the Employer's Requirements. We cover risk allocation, variations, delays and claims — through the lens of the schedule.
What the FIDIC Yellow Book is
The FIDIC Yellow Book — formally the Conditions of Contract for Plant and Design-Build — is used when the Contractor is responsible for designing and building 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 and similar projects where an experienced Contractor delivers a defined outcome rather than following an Employer's detailed design.
Design and Build under the Yellow Book
The Contractor takes on both the design and the construction. This shifts a substantial share of risk to the Contractor — but also gives the Contractor more control over sequencing, buildability and design optimisation. The Employer defines outcomes through the Employer's Requirements; the Contractor produces a Contractor's Proposal that responds to those Requirements.
Contractor's design responsibility
The Contractor warrants that the completed works will be fit for the purposes described in the Employer's Requirements. This is a real, contract-level liability: not merely reasonable skill and care, but a fitness-for-purpose obligation. Planning teams should treat design deliverables as contractual milestones and manage them on the baseline schedule, because late design outputs delay procurement and construction alike.
Employer's Requirements
The Employer's Requirements are the anchor document. They define performance, quality, extent and any specific design constraints. Discrepancies or errors in the Employer's Requirements are a known risk area — treatment depends on the edition and any Particular Conditions.
Risk allocation vs the Red Book
Compared with the Red Book, the Yellow Book transfers more risk to the Contractor. Design risk sits with the Contractor. Ground conditions treatment differs. The Contractor's tendered price is typically a lump sum, not a re-measured Bill of Quantities. Understanding these shifts is essential when advising on programme, pricing or claim strategy.
Variations under the Yellow Book
The Employer can instruct Variations that change the Employer's Requirements, extent, quality, sequence or timing. The Contractor may also propose Value Engineering. Variations must be valued and, where they impact the programme, entitle the Contractor to notify a claim for time and cost.
Claims, delays and EOT
The claims workflow mirrors the Red Book's structure: contractual notice, 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, and interface issues with Employer-supplied packages.
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
Learning outcomes
- Distinguish Yellow Book design responsibility from Red Book design responsibility
- Read the Employer's Requirements and flag risks before pricing
- Model design deliverables as scheduled activities in the baseline programme
- Notify and particularise EOT and cost claims in a Design-Build context
- Advise leadership on risk positions when negotiating Particular Conditions
Answers before you ask.
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