Understanding FIDIC Silver Book 2017 – Clause 13: Variations and Adjustments

The FIDIC Silver Book (2017 Edition), officially titled Conditions of Contract for EPC/Turnkey Projects, is specifically designed for Engineering, Procurement, and Construction (EPC) projects where the Contractor undertakes full responsibility for delivering a complete, functioning facility at a fixed price and within a fixed timeframe. Unlike the FIDIC Red or Yellow Books, the Silver Book allocates greater risk to the Contractor, especially regarding cost overruns, schedule delays, and design responsibility.

Within this context, Clause 13 – Variations and Adjustments emerges as one of the most crucial clauses in the contract. It governs how the Works may be varied, how the Contract Price is adjusted, and how procedural and valuation mechanisms are applied when changes arise. Proper understanding of Clause 13 is vital because EPC/Turnkey contracts are inherently inflexible, and any mismanagement of variations can lead to costly disputes.

This article provides a detailed, practical, and comprehensive guide to Clause 13, including its sub-clauses, purpose, practical implications, and best practices for Contractors, Employers, and legal professionals.

Overview: Purpose and Structure of Clause 13

Clause 13 is organized into seven sub-clauses, each serving a distinct function in managing variations and adjustments:

Sub-Clause	Title	Key Purpose
13.1	Right to Vary	Establishes who can initiate a Variation and under what circumstances.
13.2	Value Engineering	Encourages the Contractor to propose cost-saving or performance-improving alternatives.
13.3	Variation Procedure	Details the formal process for initiating, evaluating, and instructing Variations.
13.4	Payment in Applicable Currencies	Ensures consistency of payment across multiple currencies when a Variation affects price.
13.5	Provisional Sums	Covers the management, use, and valuation of Provisional Sums (if any).
13.6	Adjustments for Changes in Laws	Provides for cost and time adjustments due to new or amended legal requirements.
13.7	Adjustments for Changes in Cost	Addresses how cost escalation or inflation is treated, if applicable.

Sub-Clause 13.1 – Right to Vary

Purpose:

Sub-Clause 13.1 establishes that the Employer is the sole authority to initiate Variations. The Contractor cannot unilaterally alter the Works, ensuring that all changes are formally approved and controlled.

Key Provisions:

Employer’s right: The Employer may instruct Variations at any time before issuing the Taking-Over Certificate.
Employer’s Representative: In the Silver Book, the traditional role of the Engineer is largely replaced by the Employer’s Representative, who can issue Variation Proposals or Instructions on behalf of the Employer.
Contractor’s obligation: Once a Variation is instructed in compliance with contract procedures, the Contractor must execute it, unless it is fundamentally impossible, illegal, or beyond the Contractor’s capacity.
Limits to Variations: Variations cannot fundamentally change the nature of the Works, nor exceed the technical or financial capabilities of the Contractor.

Practical Insight:

While the Silver Book shifts risk to the Contractor, this sub-clause protects against unlimited exposure. Contractors are safeguarded against variations that would make the project fundamentally different from the original scope, thereby preserving commercial and technical feasibility.

Sub-Clause 13.2 – Value Engineering

Purpose:

This clause incentivizes the Contractor to propose innovative, cost-saving, or performance-enhancing changes. Unlike traditional variations, these are often initiated by the Contractor, not the Employer.

Key Provisions:

Contractor proposals: The Contractor can suggest changes that:
- Reduce project costs,
- Shorten completion times,
- Improve operational efficiency or safety.
Contract adjustments: If the Employer accepts the proposal, the Contract Price and/or Time for Completion are adjusted accordingly.
Shared savings: Contracts may specify how any cost savings are shared between Employer and Contractor; if not, the parties must negotiate.

Practical Insight:

Sub-Clause 13.2 encourages collaboration even in risk-heavy Silver Book contracts. Strategically, Contractors can:

Introduce modern technologies or construction methods,
Propose material substitutions to reduce costs,
Optimize work sequencing for faster completion.

Value Engineering creates a win-win scenario: Employers save money, and Contractors may receive additional compensation or goodwill.

Sub-Clause 13.3 – Variation Procedure

Purpose:

This is the procedural backbone of Clause 13, detailing how Variations are initiated, evaluated, instructed, and implemented.

Step-by-Step Breakdown:

Employer’s Request or Instruction:
- The Employer may request a proposal from the Contractor or issue a direct instruction for a Variation.
Contractor’s Proposal (if requested):
- Must include:
  - Description of the proposed change,
  - Adjustments to Contract Price, Completion Time, and Performance Guarantees,
  - Supporting technical or cost documentation.
Employer’s Response:
- Options include approval, modification, rejection, or requesting further information.
Implementation:
- Approved or instructed Variations are binding, and the Contractor must execute without delay.
Valuation:
- Sub-Clause 13.3.2 outlines valuation rules:
  - Use agreed Contract rates if available,
  - Otherwise, apply the principles of the original Contract,
  - If unresolved, determine reasonable cost including overhead and profit.

Practical Insight:

Procedural compliance is critical. Failure to submit proposals timely or follow instructions can result in loss of entitlement to additional payment or time. Contractors must maintain meticulous records to support claims.

Sub-Clause 13.3 – Variation Procedure (Step Diagram)

Step 1: Employer Initiates
   ├─ Request Contractor Proposal (optional)
   └─ Issue Direct Variation Instruction

Step 2: Contractor Response (if requested)
   ├─ Describe Proposed Change
   ├─ Provide Adjustments to:
   │     • Contract Price
   │     • Completion Time
   │     • Performance Guarantees
   └─ Submit Supporting Documentation

Step 3: Employer Review
   ├─ Approve Variation
   ├─ Modify Proposal
   ├─ Reject Proposal
   └─ Request Further Details

Step 4: Implementation
   └─ Contractor Executes Variation
       (Without Delay)

Step 5: Valuation
   ├─ Use Agreed Contract Rates (if available)
   ├─ Apply Original Contract Principles (if not)
   └─ Determine Reasonable Cost including Overhead & Profit (if unresolved)

Sub-Clause 13.4 – Payment in Applicable Currencies

Purpose:

In multi-currency contracts, this sub-clause ensures consistency in how Variations affect payments.

Key Points:

Variations affecting the Contract Price are allocated in the same proportion as the original contract.
- Example: If the contract price is 70% USD and 30% EUR, a $1 million Variation will be split $700,000 USD / $300,000 EUR.

Practical Insight:

This prevents currency risk disputes. Contractors and Employers can budget accurately and avoid disagreements over payment distribution.

Sub-Clause 13.5 – Provisional Sums

Purpose:

Provisional Sums are allowances for undefined work or services included in the contract. This clause governs how they are used and valued.

Key Provisions:

Employer’s instruction required: Provisional Sums can only be used with Employer approval.
Valuation: When executed, actual costs are added to the Contract Price, including overhead and profit if specified.

Practical Insight:

Provisional Sums are rare in Silver Book EPC contracts, as these are typically fully defined and lump-sum. However, they may appear for third-party services or uncertain works, such as utility connections or site investigations.

Sub-Clause 13.6 – Adjustments for Changes in Laws

Purpose:

This clause provides for cost and time adjustments if legal requirements change after the contract’s Base Date.

Key Provisions:

Eligible events: Changes in laws, regulations, or statutory requirements that affect cost or time.
Contractor entitlement: May claim additional payment and/or extension of time.
Notice requirement: Contractor must notify the Employer within 28 days of becoming aware, following Clause 20.2 (Claims).
Valuation and adjustment: Calculated using the Contract’s claim procedures.

Practical Insight:

Clause 13.6 protects Contractors from unforeseen legal or regulatory shifts, e.g., new environmental rules or import restrictions. Timely notice is essential; failure may result in forfeiting the entitlement.

Sub-Clause 13.7 – Adjustments for Changes in Cost

Purpose:

Addresses cost escalation due to inflation, labor/material price changes, or market fluctuations.

Key Provisions:

Conditional applicability: This clause is usually activated only if stated in the Particular Conditions.
Adjustment mechanism: Typically formula-based or indexed against an agreed cost index.
Common practice: In Silver Book EPC contracts, this clause is often deleted, as the price is intended to be lump-sum and fixed.

Practical Insight:

Although not always active, it may be relevant in long-duration projects or volatile markets. It allows fair allocation of economic risk without disrupting the fixed-price nature of the contract.

Practical Takeaways:

Understand the Power Balance: The Silver Book favors Employers, but Clause 13 protects Contractors from unmanageable Variations.
Procedural Discipline is Critical: Timely notices and detailed proposals are essential. Non-compliance can forfeit entitlement.
Document Everything: Maintain contemporaneous records of all Variations, instructions, approvals, and communications.
Distinguish between Variations and Claims:
- Variation: Initiated by the Employer and instructed under Clause 13.
- Claim: Arises from unforeseen events outside both parties’ control, managed under Clause 20.
Strategically Use Value Engineering: Sub-Clause 13.2 can yield financial savings, improved efficiency, and stronger relationships with the Employer.
Be Mindful of Currency Implications: Sub-Clause 13.4 ensures consistency in multi-currency contracts, avoiding potential disputes.
Manage Legal and Cost Changes: Clauses 13.6 and 13.7 ensure fair adjustments for changes in laws or cost fluctuations.

Summary:

Clause 13 of the FIDIC Silver Book 2017 is more than a mechanism for changing drawings or materials. It governs how an EPC/Turnkey project can adapt to change while maintaining contractual balance. Mastery of Clause 13 requires:

Understanding who can instruct changes,
Following formal procedures for proposals and approvals,
Accurately valuing Variations,
And recognizing the interplay with claims under Clause 20.

When correctly applied, Clause 13 ensures that Variations are transparent, fair, and contractually enforceable, helping both Contractors and Employers manage risk while keeping the project on track.

In EPC/Turnkey contracts, where time, cost, and quality are tightly interlinked, Clause 13 is the key to controlled flexibility. Contractors who grasp the legal, procedural, and practical nuances of this clause are better positioned to maximize efficiency, protect rights, and reduce disputes.

(The views and opinions expressed in this article are solely those of the author and do not necessarily reflect the official policy or position of any organization or entity.)

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