DD07: What is concurrent delay? An overview
Updated: Mar 31
My previous article DD06 provided an overview of the different types of delay that can occur on construction projects, namely: non-excusable delay, excusable non-compensable delay, excusable compensable delay, and concurrent delay.
This article will aim to provide an overview of what concurrent delay is before taking a deeper dive to examine concurrent delay in more detail in the next few articles in order to provide some clarity on the subject.
What is concurrent delay?
There is no single definition of concurrent delay. Various definitions have been put forward and in this article the author will review a selection of the definitions and descriptions of concurrent delay put forward by Marrin, Keating, the court in City Inn, the court in Adyard, the SCL Protocol 2nd edition and some views from the United States. There are others but it is beyond the scope of this paper to review them all.
Concurrent delay has been defined by Marrin as project delay caused by two or more effective causes of delay which are of approximately equal causative potency. In this case, there would only be concurrent delay if the effect of the delay by the employer and contractor event is felt at the same time.
Only in exceptional circumstances is concurrency of the kind Marrin defines likely to occur and this narrow definition is therefore possibly too limited.
Keating says that it is probably sufficient to say:
· each delay event, in the absence of any competing event, has caused delay;
· each delay event is on the critical path; and
· the delays caused by the employer and the contractor overlap.
In City Inn v Shepherd Construction, the court emphasised that there are problems in using expressions such as ‘concurrent delay’ or ‘concurrent events’ and said:
“One of the problems in using such expressions as “concurrent delay” or “concurrent events” is that they may refer to a number of different situations. Confining attention for a moment to concurrent delaying events, which may be taken to mean relevant events and other events, or causes of delay, which are not relevant events, there would seem to be several possibilities. Such events may be described as being concurrent if they occur in time in a way in which they have common features.
One might describe events as concurrent on a strict approach only if they were contemporaneous or co-extensive, in the sense that they shared a starting point and an end point in time. Alternatively, events might be said to be concurrent only in the sense that for some part of their duration they overlapped in time. Yet again, events might be said to be concurrent if they possessed a common starting point or a common end point. It might also be possible to describe events as concurrent in the broad sense that they possessed a causative influence upon some subsequent event, such as the completion of works, even though they did not overlap in time. In other words, they might also be said to be contributory to or co-operative in bringing about some subsequent event.”
To summarise, the court in City Inn said:
· On a strict approach:
o Events are concurrent only if they were contemporaneous or co-extensive, in the sense that they shared a starting point and end point in time.
o Events may be concurrent:
§ If part of their duration overlapped in time;
§ If they possessed a common starting point or a common end point;
§ If they possessed a causative influence upon some subsequent event, such as the completion of works, even though they did not overlap in time.
Although the court in City Inn refers to the “events” being concurrent, it is submitted that the court is referring to the delay to progress rather than the event that caused the delay.
Sebsequent to City Inn, in Adyard, the court considered that:
“…there is only concurrency if both events in fact cause delay to the progress of the works and the delaying effect of the two events is felt at the same time.”
The court in Adyard also said:
“… act relied must actually prevent the contractor from carrying out the works within the contract period or, in other words, must cause some actual delay.”
SCL Protocol 2nd edition
The SCL Protocol 2nd edition contains various definitions and examples of how the analysis of delay events sould be considered, including matters on ‘delay’ and ‘concurrent delay’. It should be noted however, that each project including the applicable contract, will have its own unique variables and delay events, which may not be relevant to the models and procedures detailed for guidance in the SCL Protocol second edition.
The SCL Protocol 2nd edn defines concurrent delay as follows:
“10. Concurrent delay – effect on entitlement to EOT
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. For concurrent delay to exist, each of the Employer Risk Event and the Contractor Risk Event must be an effective cause of Delay to Completion (i.e. the delays must both affect the critical path) ...
10.1 Concurrency is a contentious issue, both because there are differing views on the correct approach to dealing with concurrent delay when analysing entitlement to EOT and because there are differences about the meaning of concurrent delay itself.” [Author’s emphasis added]
The SCL Protocol 2nd edn’s definition of ‘true concurrent’ delay is similar to Marrin’s ‘narrow’ definition; that is, the occurance of two or more delay events at the same time, one an employer risk event and the other a contractor risk event, the effects of which are felt at the same time. However, the SCL Protocol adds to Marrin’s definition that “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” in addition to the effects of the delaying events being felt at the same time.
The SCL Protocol 2nd edn also clarifies that for concurrent delay to exist, the employer and contractor delay events must both affect the critical path.
The SCL Protocol 2nd edn also acknowledges:
“10.4 In contrast, a 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.”
An SCL Protocol 2nd edn scenario
The SCL Protocol 2nd edition gives the following scenario as to whether an employer delay is an effective cause of delay to completion if that employer delay occurs after the commencement of the contractor delay to completion but continues in paralled with the contractor delay:
“10.7 From a legal perspective, there are two competing views as to whether an Employer Delay is an effective cause of Delay to Completion where it occurs after the commencement of the Contractor Delay to Completion but continues in parallel with the Contractor Delay. This can be illustrated by the following example: a Contractor Risk Event will result in five weeks Contractor Delay to Completion, delaying the contract completion date from 21 January to 25 February. Independently and a few weeks later, a variation is instructed on behalf of the Employer which, in the absence of the preceeding Contractor Delay to Completion, would result in Employer Delay to Completion from 1 February to 14 February.”
In relation to the two competing views in the above scenrio, the SCL Protocol 2nd edn says:
“10.8 On one view, the two events are both effective causes of Delay to Completion for the two week period from 1 to 14 February because they each would have caused Delay to Completion in the absence of the other (with the subsequent delay from 15 February to 25 February caused by the Contractor Risk Event alone). This view may be supported by older English appeal court cases (no doubt predating critical path analysis) which provide that if the failure to complete the works is due in part to the fault of both the Employer and the Contractor, liquidated damages will not be payable. In a situation like the example described in paragraph 10.7 above, it can be argued that both the Employer Risk Event and the Contractor Risk Event are in part the cause of the Delay to Completion.
10.9 On the other view, the Empoyer Delay will not result in the works being completed later than would otherwise have been the case because the works were already going to be delayed by a greater period because of the Contractor Delay to Completion. Thus, the only effective cause of the Delay to Completion is the Contractor Risk Event. This is the consistent position taken in recent lower level English court decisions.”
What view does the SCL Protocol 2nd edn recommend?
“10.10 The Protocol recommends the latter of these two views, i.e. where an EOT application relating to the situation referred to in paragraph 10.7 above is being assessed, the Employer Risk Event should be seen as not causing Delay to Completion (and therefore there is no concurrency). Concurrent delay only arises where the Employer Risk Event is shown to have caused Delay to Completion or, in other words, caused critical delay (i.e. it is on the longest path) to completion. The Protocol cautions that this recommendation would have to be re-considered were an appeal court to take a different approach to this issue.”
The SCL Protocol 2nd edn recommends the view that the employer risk event should not be seen as causing delay and that therefore there is no concurrency. The SCL Protocol 2nd edn is saying, in line with current English precedent on the point, that concurrent delay only arises where the employer risk event is shown to have caused delay to completion.
The Court of Federal Claims in George Sollitt Co v U.S., sets out the following definition of concurrent delay:
“The exact definition of concurrent delay is not readily apparent from its use in contract law, although it is a term which has both temporal and causation aspects.
Concurrent delays affect the same “delay period”. A concurrent delay is also independently sufficient to cause the delay days attributable to that source of delay.”
The industry standard for delay analysis in the U.S., the American National Standards Institute / American Society of Civil Engineers / Construction Institute 67-17 says “concurrent delay can be described as a situation where two or more critical delays are occurring at the same time during all or a portion of the delay time frame in which the delays are occurring.”
Terms and definitions used when referring to concurrent delay are, as illustrated above, variable, inconsistent and can be somewhat confusing.
However, the following, it is submitted, is consistent in all definitions:
· Two or more delay events (causes of delay) which delay work/activities that is required to complete the project; and
· At least one delay is the responsibility of the employer and the other the responsibility of the contractor.
Question: for there to be concurrent delay, is it necessary that the delays, as a result of the delay events, commence at approximately the same time or have the same impact on the projected completion date? Put another way, is it possible to have concurrent delay where the delays, as a result of the delay events, commence at different times but at some point, they overlap, and hence each delay treated in isoloation to the other would have different impacts on the completion date.
In Adyard, the court said that “there is only concurrency if both events in fact cause delay to the progress of the works and the delaying effect of the two events is felt at the same time.” If this is correct, then in relation to the above question, isn’t the first delay merely creating, as a matter of fact, float for the second-in-line delay, meaning that, in such a situation there is no concurrent delay?
The next few articles will seek to answer and add clarity to the above and other questions, by examining concurrent delay in further detail and leading to some recommendations on how to define and assess concurrent delay.
If you have any queries on concurrent delay, in relation to the previous articles DD01 to DD06 or any other matter, please do not hesitate to contact us.
This and previous articles
This and previously published DD articles on the DD Quantum Expert website blog page are:
DD01: Why is it necessary to distinguish between delay and disruption? What’s the distinction?
DD02: A global claim is doomed to fail, unless…
DD03: Comply with the notice provisions in the contract, or else…
DD04: ‘Prevention’ causing ‘time at large’: what does this all mean?
DD05: Float: what is float, who owns the float and how is float different to contingency?
DD06: Construction project delays 101 – plus concurrency!
DD07: What is concurrent delay? An overview
 John Marrin QC, “Concurrent Delay” (2002) 18 Construction Law Journal 6 at 436, approved in Adyard Abu Dhabi v SD Marine Services  EWHC 848 (Comm); J Marrin, “Concurrent Delay Revisited” (February 2013, SCL Paper No 179), M Cocklin, “International Approaches to the Legal Analysis of Concurrent Delay: Is There a Solution for English Law?” (April 2013, SCL Paper No 182); V Moran, “Causation in Construction Law — The Demise of the Dominant Cause Test?” (November 2014, SCL Paper No 190).  Stephen Furst and Vivian Ramsey, Keating on Construction Contracts (10th ed, Sweet & Maxwell, 2016), [8-025].  Stephen Furst and Vivian Ramsey, Keating on Construction Contracts (10th ed, Sweet & Maxwell, 2016), [8-025].  City Inn v Shepherd Construction Ltd (2010) CSIH 68 CA101/00 at   Adyard Abu Dhabi v SD Marine Services  EWHC 848 (Comm) para 279  Adyard Abu Dhabi v SD Marine Services  EWHC 848 (Comm) para 282  Scl Protocol 2nd edition, guidance part B: Guidance on core principles page 30 to 32  George Sollitt Co v U.S., 64 Fed. Cl. 229, 239 (2005).