FIDIC claims: how prolongation and disruption quantum is actually proved

Most rejected FIDIC quantum claims fail for the same reason: the contractor has lumped everything into a single number and called it prolongation. The engineer, and later the tribunal, sees a figure that cannot be traced to a cause, a period or a record. It is dismissed, not because the money was not spent, but because the entitlement was never proved.

Prolongation and disruption are separate heads of claim. They arise from different events, are supported by different records and are calculated by entirely different methods. Treating them as one is the most common and most expensive mistake in claims preparation across India, the UAE, Oman and KSA.

What is prolongation cost, and over what period is it valued?

Prolongation is the time-related cost of an extended project period. When a compensable event pushes completion beyond the contractual date, the contractor keeps site establishment, supervision, plant and preliminaries running for longer. Those costs are the prolongation claim.

The critical point: prolongation is anchored to an extension of time, but it is not the same as one. An EOT protects against liquidated damages. Prolongation cost is a separate entitlement that must be independently proved, and it is valued over the period of the delaying event, not the overrun period at the end of the job. This distinction, drawn clearly in the SCL Delay and Disruption Protocol, is where many submissions quietly collapse.

An extension of time buys you relief from damages. It does not, by itself, buy you a single dirham of prolongation cost. The two must be proved separately, or the claim is only half made.

What is disruption, and what evidence actually proves it?

Disruption is the loss of productivity caused by an event, labour and plant achieving less than they should have. It can occur with no delay to completion at all. A crew that should have laid 100 units a shift manages 60 because of out-of-sequence working, trade stacking or repeated design changes. The extra hours are real, but they never show on the critical path.

Because disruption does not depend on delay, it cannot be proved with a programme. It is proved with productivity evidence, ranked here from most to least persuasive:

• Measured mile, comparing an undisrupted period of the same activity against the disrupted period. The gold standard, because it uses the project's own actuals and strips out arguments about the contractor's baseline efficiency.
• Earned-value analysis, where clean cost and progress data exist, comparing planned versus achieved output over defined windows.
• Industry productivity studies, MCAA, published factors and similar. A last resort only. Tribunals treat generic factors with suspicion when project records should have existed.

The measured mile fails without like-for-like data, so the records must be captured while the work is live. Retrospective reconstruction is always weaker.

Which formulae are used for head-office overhead, and where does each fall down?

Where prolongation deprives a contractor of the chance to earn contribution to head-office overhead elsewhere, the Hudson, Emden and Eichleay formulae are often deployed. They are useful, but they are not evidence in themselves.

• Hudson uses the tender overhead percentage, circular, because it relies on the contractor's own pricing.
• Emden uses actual overhead from the accounts, more defensible, if the accounts support it.
• Eichleay allocates recorded overhead across the delay period, but demands proof the contractor was genuinely prevented from taking on replacement work.

No formula rescues a claim where the underlying overhead cannot be evidenced from audited records. They quantify a loss; they do not prove one.

Why does FIDIC quantum fail without a proven delay and timely notice?

Every prolongation claim rests on a delay analysis that establishes cause, criticality and the length of the compensable period. If the delay is not proved, through a robust time-impact or windows analysis, the quantum has nothing to stand on. This is also where concurrency bites: employer and contractor delays running together can strip prolongation entitlement even where an EOT survives.

None of this works without FIDIC Clause 20 notice discipline. Under the 2017 forms, a claim not notified within 28 days of the contractor becoming aware of the event can be time-barred outright, the best-quantified claim in the region is worthless if the notice was late. Notice, contemporaneous records and a clean delay narrative are the foundation; the quantum is only the roof. The differences between forms matter too, as we set out on NEC4 versus FIDIC EOT claims.

If you are building or defending a FIDIC claim and need the delay foundation and quantum to hold together under scrutiny, our project planning and controls team can help. And our QS Intelligence and Schedule Intelligence tools show where your records stand today.