FIDIC Red Book vs Yellow Book, Which Contract Are You Bidding On?

The FIDIC suite is the dominant international construction contract family, and the Red and Yellow Books are its two most common forms. They look almost identical at first glance, same drafting style, same clause numbering, same Engineer role, but they allocate design responsibility in opposite directions. Bidders who do not understand which book they are responding to consistently misprice and mis-resource.

Red Book, employer designs

The Red Book (Conditions of Contract for Construction) is used where the employer has produced the design, typically through a consultant, and the contractor's role is to build that design. Risk for design adequacy sits with the employer. The contractor's pricing is built around a Bill of Quantities or measured works, and variations are valued against contract rates.

Yellow Book, contractor designs

The Yellow Book (Conditions of Contract for Plant and Design-Build) is used where the employer issues a set of Employer's Requirements and the contractor is responsible for the design, procurement, installation, and commissioning. Risk for design adequacy sits with the contractor. Pricing is typically lump sum against a Contractor's Proposal.

Why this changes your bid completely

• Design fee allocation: under the Yellow Book you carry the design team, under the Red Book you do not (or only a coordination element).
• Risk premium: design risk on a complex plant or process project under the Yellow Book often justifies a 5–12% risk premium that is unnecessary under the Red Book.
• Programme: Yellow Book programmes include design phases (concept, basic, detailed) that the Red Book does not.
• Variations: under the Red Book, variations are measured and valued, under the Yellow Book, the contractor is generally entitled to adjust the lump sum only where the Employer's Requirements are changed.
• Defects and performance: Yellow Book responses must address performance guarantees (Schedule of Guarantees) that have no Red Book equivalent.

When each book is typically used

Red Book procurements dominate traditional civils, roads, bridges, water networks, and building works where the employer has appointed a designer of record. Yellow Book procurements dominate process plant, power, district cooling, MEP-heavy fit-outs, and most public-private partnership or EPC-style projects in international markets. If your tender is from a multilateral development bank (World Bank, ADB, EBRD), expect a harmonised version of either the Red or Yellow Book with bespoke Particular Conditions.

The Silver Book is a third, and increasingly common, option

Worth noting: the Silver Book (EPC/Turnkey) is the high-risk cousin of the Yellow Book. It shifts almost all risk to the contractor, including site conditions, and is used for projects with a fixed price, fixed completion date, and minimal employer involvement during execution. Pricing under the Silver Book is materially different, most contractors carry a 10–15% additional risk allowance.

The five-minute check before you bid

Open the tender, read the first page of the Particular Conditions, and look for the title, Conditions of Contract for Construction (Red), Plant and Design-Build (Yellow), or EPC/Turnkey (Silver). Then check who owns the design in the General Provisions. Two minutes of clarity now saves a week of misdirected pricing later.