EPC Turnkey Contracts Explained: FIDIC Silver vs Yellow Book for Roads, Bridges and Industrial Plants

An EPC turnkey contract places engineering, procurement and construction under one contractor who hands over a completed, tested facility for a fixed price and a fixed date. The two FIDIC forms most often used for this are the Silver Book (Conditions of Contract for EPC/Turnkey Projects) and the Yellow Book (Conditions of Contract for Plant and Design-Build). Both exist in the 1999 edition and the revised 2017 edition. The difference between them is not the scope of work but who carries the risk when the work turns out to be harder than expected.

EPC turnkey contracts explained in one paragraph

In both forms the Contractor designs and builds to the Employer’s Requirements. In the Yellow Book an independent Engineer administers the contract, the Contractor can claim time and money for unforeseeable physical conditions, and the price is a lump sum that moves with variations and claims. In the Silver Book there is no Engineer, only an Employer’s Representative; the Contractor is deemed to have verified the Employer’s Requirements and the site data, and accepts the risk of unforeseeable difficulties and cost. The Silver Book is therefore the form a lender or a public employer chooses when price certainty matters more than the lowest tender.

Rule: the Silver Book buys certainty of outturn cost with a higher tender price. The Yellow Book buys a lower tender price with a residual risk of claims. Choose the form by asking who can bear a surprise, not by habit.

Where the two books differ

Contract administration

Under the Yellow Book the Engineer issues instructions, reviews the Contractor’s Documents under Clause 5, certifies payment and makes determinations under Sub-Clause 3.5 (1999) or 3.7 (2017). The Engineer must act neutrally when determining claims. Under the Silver Book the Employer administers the contract through an Employer’s Representative who acts for the Employer. That removes a layer of neutrality and is one reason tender prices are higher.

Site data and ground risk

Sub-Clause 4.12 of the Yellow Book entitles the Contractor to an extension of time and cost for physical conditions that an experienced contractor could not reasonably have foreseen. The Silver Book reverses this: the Contractor is taken to have obtained all necessary information on risks, contingencies and other circumstances, and bears the consequences. For a bridge with piled foundations in an unknown river bed, a serious bidder prices that transfer or investigates before signing.

Employer’s Requirements

In the Silver Book the Contractor is responsible for the accuracy of the Employer’s Requirements, save for a short list of items the Employer remains responsible for, such as data stated to be immutable and definitions of intended purposes. In the Yellow Book the Contractor has a limited period after the Commencement Date to scrutinise the Employer’s Requirements and give notice of errors. For an industrial plant where the process guarantee is the point of the contract, the Silver Book allocation is coherent; for a road where the alignment, land acquisition and utility diversions are the Employer’s business, it is often unfair and is amended.

Price and payment

Both books use a lump-sum Contract Price. The Silver Book typically pays against milestones in a Schedule of Payments; the Yellow Book more often pays monthly against the Engineer’s interim certificates. Under both, the 2017 editions tighten the claims procedure: a Notice of Claim within 28 days of awareness under Sub-Clause 20.2.1, failing which the claim is lost, and a fully detailed claim within 84 days.

Which form fits which project

Commercial points that are often missed

• Performance security under Sub-Clause 4.2 is normally a demand guarantee; FIDIC refers to the ICC Uniform Rules for Demand Guarantees (URDG 758) for the form.
• Materials such as cement and reinforcing steel are usually in the Contractor’s procurement scope. Specifying EN 197-1 cement, B500B reinforcement to EN 10080 or the national standard, and third-party inspection in the Employer’s Requirements is cheaper than arguing about them after delivery.
• Delay damages are capped; the cap, usually a percentage of the Contract Price, is the real measure of how much lateness the Employer has sold.
• Dispute avoidance: the 2017 editions require a standing Dispute Avoidance/Adjudication Board under Clause 21. Deleting it saves fees and removes the cheapest route to resolving a dispute.

Practical checklist before signing

1. Decide the risk allocation first, then pick the book; do not pick the Silver Book and then reinstate Yellow Book claims through fifty amendments.
2. Obtain a geotechnical baseline and attach it; it is the only objective test of what was foreseeable.
3. Check that the Employer’s Requirements state performance tests, acceptance criteria and the standards the materials must meet.
4. Align the payment schedule with the procurement of long-lead items and with the financing documents.
5. Keep the Particular Conditions short and record every deletion with its reason.

A turnkey contract does not make risk disappear. It decides who pays for it and what that promise costs at tender.