by Uditha Tharanga, FCIArb
Concurrency is among the most discussed and complicated areas of the construction industry, and the identification and assessment of concurrent delays, is arguably one of the most contentious technical matters in forensic delay analysis. While, in many jurisdictions the matter is still evolving, it has been subject to different treatment under common law and civil law jurisdictions.
However, it is evident that the major controversy of concurrency is related to its practical application in prevailing legal authorities. On immediate observation, the lack of agreement between contracting parties for a clear definition of concurrent delay and the lack of understanding of the core legal principles can be identified as primitive causes. The author has come across several cases where the above elements of concurrency are at dispute.
Contracts’ not having clear terms
As a foremost consideration, the author believes that many standard contract forms published till date are not sufficiently capable of catering to such disagreements. The un-amended FIDIC contracts, which are widely used in the Middle East and many other countries across the world, do not address concurrent delay in their contract terms. However, even when the concurrency is addressed in the contract, the definition, technical aspects and procedures are not captured sufficiently to avoid any disputes.
Seeking a definition
The term “concurrent delay” means the occasion where the project completion is overrun by two or more delay events at the same time, one being an event for which the employer is culpable and the other being an event for which the contractor is responsible under the contract. It is sometimes said that the effect of the two delays should be precisely simultaneous to be considered as a concurrent delay. This is considered a narrow definition of concurrent delay, also known as “true” concurrency.1 However, it has been argued that ‘true concurrency’ is mostly hypothetical and will only arise in exceptional factual circumstances.2
In line with the above definition, the SCL protocol3 in its section B.10.3 describes concurrent delay as follows:
“True concurrent delay is the occurrence of two or more delay events at the same time, one an Employer Risk Event, the other a Contractor Risk Event, and the effects of which are felt at the same time. True concurrent delay will be a rare occurrence.”
Then, the protocol goes further and explains that more common usage of the term ‘concurrent delay’ concerns the situation where two or more delay events arise at different times, but the effects of them are felt at the same time.4 Although there were many subsequent definitions suggested, the one that has been put forward by John Marrin KC5 has been approved by the courts as a useful working definition and adopted for situations involving concurrent delays.6 The said definition is as follows:
“a period of project overrun which is caused by two or more effective causes of delay which are of approximately equal causative potency”7.
As it captures key elements in defining concurrency (effectiveness of cause and effect, criticality and causative potency) it has since then been used as a reference in many subsequent disputes. However, the principles of this definition are not often seen to be adopted properly when it comes to implementation. For this reason, the result of the concurrency analysis substantially varies and often depend on the expert who carries out the analysis.
Practical application of concurrency
The SCL protocol is one the many practical guidelines, often being used as a reference. The most interesting discussion with regards to concurrency in the protocol is pertaining to the timing of the delay events. The SCL protocol in its section B.108 identifies four key points regarding concurrency as follows:
- the concurrency situation where the employer’s risk event and the contractor’s risk event occurred at the same time and their effects are felt at the same time;
- the concurrency situation where two or more delay events occurred at distinct times but the effect is felt within the same time;
- the delay must affect the completion, and by implication, both should be on the critical path and should be effective causes of delays; and
- CPM analysis is essential in determining concurrency.
Although, the protocol set out some important considerations as above, in the author’s opinion, it provides few references to the form of analysis and the timing of the analysis in connection with the above concerns. Similarly, there are other issues that are related to the practical application which are not detailed therein. Perhaps, the best outcome of the SCL protocol regarding the concurrency is to encourage the use of common sense approach thereby highlighting that the margin of imprecision should be taken into account in reaching the conclusion on concurrency.9 The recent decision of the England and Wales High Court, Thomas Barnes & Sons PLC v Blackburn With Darwen Borough Council [2022] EWHC 2598 (TCC), has also emphasized that courts will prefer a pragmatic, common sense approach to assessing delay, over the opinions of delay experts.
By providing a theory to assist the practical application, the AACE International Recommended Practice No. 29R-03 (RP29R-03) introduces the concept of “literal” and “functional” concurrency which is related to the timing of the delay events occurrence. The difference inevitably depends on the method analysis as well as the duration of analysis.10
The ‘literal’ and ‘functional’ theories are described as follows:
“Under the Literal Theory, the delays have to be literally concurrent in time, as in ‘happening at the same time.’ In contrast, under the Functional Theory, the delays need to be occurring within the same analysis period.”11
The functional theory seems to be more liberal in identifying and quantifying the concurrency as the delays may occur within the same measurement period to qualify as concurrent delays while the literal theory is similar to true concurrency, as defined under the SCL protocol. Under the latter theory, a delay at any point in the critical path creates a float through the entire network which makes the subsequent delay non-critical until the completion of the first delay event. It is sometime argued that the exact simultaneity is impossible. If the CPM schedule considers the “day” as the smallest unit of time, then both delays have to start on the same day regardless of the time, in order to be concurrent delays.
Under the former theory of ‘functional concurrency’ it is possible that the employer’s delay occurring at the beginning of the month (first week) of the analysis period becomes concurrent with the contractor’s delay occurring in the last week of the update period as long as the other tests are met.12 This way, it is common that the literal and the functional theories provide significantly different results and the practitioner who adopts functional theory will generally find more concurrency than one who adopts the literal theory. The difference in outcomes is sometimes significant. Hence, the decision as to which one of these conceptual approaches should be employed, can be dispositive of a delay dispute.
Additionally, the discussion extends further than to the simple decision of “literal” or “functional” theory when analysing concurrency, as there are several other issues that will inevitably affect the outcomes of the concurrency analyses.
As AACE (RP29R-03) suggests, these are the matters of:
- how the delay is determined (whether based on the cause or effect as they are both permitted under the protocol);
- the Contract’s definition of criticality and how the critical path is determined;
- the time period of the analysis (frequency, duration and placement of analysis periods);
- the order of the insertion or the extraction of delay events in connection with the selected methods of delay analysis; and
- whether the analysis is being performed in hindsight (retrospectively) or blind-sight (knowledge-at-the-time) or in other words whether it is being performed contemporaneously or forensically.
Therefore, the protocol stresses on the requirement of proper agreement between parties for the definition of the concurrent delay as well as the other aspects of the CPM and the delay analysis as above. The solution is to ensure that contracts include the clear agreed terms to deal with all possible areas of disagreements related to concurrency. This should include a framework of definition as well as the detailed implementation protocol of analysis, amongst others.
The issue of additional costs
As regards to the matter of additional costs, the contractor fails to recover his additional cost for the duration of concurrent delay as the ‘but-for’ test of causation cannot be met. This outcome coincides with the SCL Protocol, English law and it also coincides with the conventional approach to such problems applied by tribunals in the United States.13
This could be reviewed alongside the literal and functional theories to assess whether the parties’ delay costs can be apportioned. There should also be an agreement between the parties to specify the matter of recovery of additional costs in case of delay.
- The Royal Brompton Hospital NHS Trust v Hammond (2001) 76 Con. L.R. 148,
- J Stephen Forts QC and The Hon Sir Vivian Ramsey (editors), Keating on Construction Contracts (9th edition, Sweet & Maxwell, 2012)
- Society of Construction Law Delay and Disruption Protocol (SCL 2017), <www.scl.org.uk>
- ibid Note 03, Section B.10.4
- It is included within a paper produced for the Society of Construction Law in 2002
- Adyard Abu Dhabi v SD Marine Services [2011] EWHC 848 (Comm)
- John Marrin QC, SCL paper, note 1, page 2. John Marrin QC, ‘Concurrent Delay’, SCL paper 100 (February 2002)
- Society of Construction Law Delay and Disruption Protocol (SCL 2002), <www.scl.org.uk>
- Ibid Note 04 Section 10.11
- AACE® International Recommended Practice No. 29R-03 FORENSIC SCHEDULE ANALYSIS TCM Framework: 6.4 – Forensic Performance Assessment < https://web.aacei.org/docs/default-source/toc/toc_29r-03.pdf
- ibid [1, (Section 2.D.1)]
- Ibid Note 10
- Blindennan Construction Co. y. United States, 695 F.2d 552,559 (Fed. Cir. 1982), quoting Coath & Gross, Inc. y. United States, 101 Ct. CI. 702,714-715 (19U)
Uditha Tharanga is a Fellow of the Chartered Institute of Arbitrators and a member of the Royal Institution of Chartered Surveyors. He is a practitioner in the field of Arbitration and both a Quantum and Forensic Delay Expert in the construction field. His research interests include Construction ADR, Multi Party Arbitration and Third Party Funding in international Arbitration. He can be contacted on udtharangaw@gmail.com
The views expressed in this article are those of the author and do not necessarily reflect those of the Chartered Institute of Arbitrators.
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