Concurrent delay: the defense every engineer eventually raises

Of every defense an Engineer or Employer can raise against an extension of time claim, concurrent delay is the one most likely to turn a clean claim into a contested one. It is also one of the most misunderstood, on both sides of the table.

What “true” concurrent delay actually means

The SCL Delay and Disruption Protocol, 2nd Edition, defines true concurrent delay narrowly: two or more delay events happening at the same time, one an Employer Risk Event and one a Contractor Risk Event, where both are independently causing delay to completion at the same moment. The Protocol is explicit that genuinely true concurrency, meeting that full definition, is relatively rare in practice. Far more common is a looser situation where an employer delay and a contractor delay simply overlap in time without both independently driving the completion date, which the Protocol treats differently.

Time, yes. Money, usually not.

Where true concurrency exists, the generally accepted position, rooted in the prevention principle of English contract law, is that the contractor should still receive a full extension of time for the period of the employer's delay, since an employer cannot benefit from its own act of prevention by later penalizing the contractor for a completion date the employer itself helped push back. Compensation is a different question. On the same concurrent period, additional cost recovery, such as prolongation cost, is generally not available, because the contractor would have incurred those costs anyway due to its own concurrent delay.

FIDIC 2017 addressed it directly

Sub-Clause 8.5 of the FIDIC 2017 suite now speaks to concurrent delay explicitly: where a concurrent delay exists, the contractor's entitlement to an extension of time is to be assessed in accordance with any Special Provisions the parties agreed, or otherwise fairly, taking due regard of all the circumstances. That is a meaningful shift from the 1999 edition, which left the whole doctrine to case law and the SCL Protocol to fill in.

How to prepare for it before it is raised

Because concurrency is a records-driven argument, contractors that flag potentially overlapping events as they happen, rather than discovering the overlap during a dispute, are in a far stronger position to either rebut a concurrency argument or accept a fair, records-based apportionment. A delay register that only shows single, isolated events, with no visibility into what else was happening on the critical path at the same time, cannot support that conversation either way.

This article is general information about how these contract mechanisms typically work. It is not legal advice, and it is not a substitute for review of your specific contract by a qualified professional.