Tunnelling projects are complicated, and all parties — the customer, EPC contractors and subcontractors — expect the work to be done on-time and on budget but delays and cost overruns happen.

Whether it be assessing insurance claims, variation claims, or the remediation of defective works, a quantum expert is called upon to provide an independent subjective opinion to assist an insurer or a tribunal or, in some cases, to help parties settle a matter outside of formal proceedings.

A lot has already been written about various delay analysis methodologies. The purpose of this article is to summarise the pros and cons of the most commonly accepted methodologies and highlight where they might best be used.

Project teams are often told to keep daily or even hourly records of events that occur on-site if a claim for additional time and cost arises. These records are known as contemporaneous records in that they are ‘recorded’ when the event occurs.

An independent delay expert needs to be impartial when engaged in providing early delay and planning advice, so clients understand their actual liabilities or opportunities.

Prolongation or delay costs must reflect the actual losses incurred by a claimant unless otherwise stated in the contract.

More often than not, claimants derive prolongation costs by determining an average daily rate taken from the preliminaries and/or indirect costs listed in the contract and multiplying that rate by the number of days delay.

Delay analysis is not the “dark art” it is often perceived to be. It is simply how to prove the purported delaying events impact (the cause) on time (the effect). The analysis must provide a clear and succinct distinction of the chain of events that have hindered progress and ultimately caused the delay(s) to completion.

An independent quantum expert needs to be impartial when engaged in providing early quantum advice, so clients understand their actual liabilities or opportunities.

When drafting a quantum and/or delay claim based on several events, claimants commonly use inference rather than causation to build their arguments. This approach is sometimes used by claimants as they tend to focus on the monetary amounts lost and/or the delays they have incurred, rather than identifying causation.