Concurrent delay: what the SCL Protocol says and how to analyse it

Events may overlap without producing concurrent delay to completion. That distinction, between things happening at the same time and things delaying completion at the same time, is where most concurrency questions are decided.

Concurrency matters because it can affect both time and money positions under many contracts, and because it is often asserted before the programme effect of each event has been analysed. This article explains what the SCL Delay and Disruption Protocol means by concurrent delay, the alternative explanations an analysis needs to distinguish, the Protocol's approach to time and compensation, and a practical sequence for analysing the question. Assessment requires consideration of timing, criticality, the effect of each event, the applicable contract and the project records.

This article provides general technical information on programme and delay analysis. Contractual and legal consequences depend on the applicable contract, amendments, governing law and facts, and should be reviewed with the appropriate legal advisers.

What the Protocol means by concurrent delay

The SCL Delay and Disruption Protocol (2nd Edition) describes true concurrent delay as the concurrent operation of two effective causes of delay, one an employer risk event and one a contractor risk event, whose effects are felt at the same time, and each of which would, on its own, have delayed completion. The demanding part is the last element: each event must be an effective cause of delay to completion, not merely to an activity somewhere in the programme.

The Protocol is industry guidance. It is not legislation, it does not override the contract or the governing law, and courts and tribunals may have regard to it without being bound by it. It provides a useful framework for analysing delay and concurrency, and its terminology is widely used, but it is not the only formulation encountered in practice.

What analysis needs to distinguish

Whether true concurrency exists can only be determined from the timing and programme effect of the relevant events. Overlapping events may, on analysis, turn out to involve:

• Overlapping events with non-overlapping effects: effects felt at different times, or on different paths through the programme.
• Sequential criticality: the critical path ran through one event and later through the other. Consecutive rather than concurrent, though the sequence itself needs to be established from the programme history.
• Separate events affecting different work, only one of which affected completion.
• Float consumption: an event that consumed float without affecting completion at the time. Float consumption may still be relevant to later criticality, mitigation, sequencing or cost, and float ownership may depend on the contract.
• Pacing: work deliberately slowed in response to another delay. The factual and contractual position requires careful review, and where a pacing decision is reconstructed after the event rather than recorded at the time, the assumptions involved should be identified.
• Events each capable of affecting completion through the same period: the case the Protocol describes as true concurrency.

The SCL Protocol's approach to time and compensation

Where true concurrent delay is established, the Protocol's general approach distinguishes entitlement to additional time from recovery of prolongation compensation for the same period: an Extension of Time may be due despite the contractor's own concurrent delay, while the associated prolongation costs may not be recoverable for that period.

That is the Protocol's guidance, not a universal rule of law. The contract may deal with concurrency expressly, the legal effect depends on the wording, the governing law and the facts, and entitlement and financial consequences should be addressed with the appropriate legal advisers.

The contract may allocate the risk

Parties sometimes deal with concurrency expressly. In North Midland Building Ltd v Cyden Homes Ltd [2018] EWCA Civ 1744, the Court of Appeal of England and Wales considered a contract that expressly allocated the risk of concurrent delay and upheld the parties' freedom to agree such a provision. The effect of any similar clause depends on its wording and context, and is a matter for legal advice. The practical point for the analyst is narrower: before concurrency is analysed, the applicable contract terms should be identified.

How to analyse a concurrency question

1. Identify the relevant events and the responsibility alleged for each.
2. Establish the programme position during the relevant period from the available baselines, updates and progress records.
3. Assess whether, and when, each event affected completion.
4. Distinguish overlap, sequential delay, pacing and float consumption.
5. Identify assumptions, limitations and missing records expressly.
6. Pass the contractual and legal consequences to the appropriate advisers.

Window-based analysis can be useful where the project history and update records support it, because it examines criticality period by period. The appropriate method, however, depends on the question and the available information: see Time Impact Analysis and Windows Analysis: choosing an appropriate method and our approach to method selection.

Concurrency sits where delay analysis and contractual interpretation meet. The technical analysis establishes the timing, criticality and effect of the events; the contractual and legal consequences are a separate exercise. The two address different parts of the problem and are most useful when coordinated.

References and further reading

• Society of Construction Law, Delay and Disruption Protocol, 2nd Edition (2017): scl.org.uk
• North Midland Building Ltd v Cyden Homes Ltd [2018] EWCA Civ 1744: bailii.org
• AACE International, Recommended Practice 29R-03, Forensic Schedule Analysis: aacei.org

Related services: Forensic Delay Analysis · Claims Review and Rebuttal · Delay Advisory for Legal and Claims Teams
Related insights: How to respond to an Extension of Time claim · Time Impact Analysis and Windows Analysis: choosing an appropriate method