• Robert J Gemmell

DD08: Concurrent delay: it is not parallelism or pacing

Updated: Mar 31


My previous article on concurrent delay briefly explored what concurrent delay is.

To recap, the concurrent delay scenarios outlined in my previous article can be broken down into the following two broad categories:

1. Concurrent delay taking place at the same time; and

2. Concurrent delay taking place at different times but having the same effect.

Concurrent delay taking place at the same time

An example of concurrent delay taking place at the same time is where:

· there are two concurrent critical paths of work; and

· the contractor delays the work by a month on one path because its equipment arrives late on site preventing the contractor from starting work; and

· at the same time, the contractor runs into a different site condition on the other critical path that delays completion of excavation by one month and is an employer-risk delay.

In this example, both the contractor’s and employer’s delay occurred at the same time on different critical paths and each caused one month of delay independently of the other.

Concurrent delay taking place at different times but having the same effect

Could one argue that the effect of delay events may not be required to take place at the same time in order to still constitute concurrent delay? For example, an employer issues a direction in May to carry out an additional month of work on a critical path activity in July and August. Subject always to the terms of the applicable contract, this delay should then be incorporated into the next updated program. The June updated program would then incorporate the additional month of work due to the employer’s direction issued in May.

If also in May the contractor identifies deficient work that had to be rectified, and the additional time required for the rectification work planned to run an additional month through to the end of June on the critical path, this (again subject to the applicable terms of the contract) should also be incorporated into the June updated program.

Even though the additional work takes place at different times, the effect would be realised in the program at the same time and as a result the two delays could be considered to have the same concurrent effect, that is, a concurrent delay of one month.

Concurrent delay is not parallelism or pacing

It may be helpful at this point to emphasise what concurrent delay is not.

Concurrent delay is not:

· Parallellism; or

· Pacing.


Parallelism is where just one party is liable to the other for more than one cause of the same delay.

For example, two or more causes at the employer’s risk, for which one of the causes may give the contractor entitlement to both an extension of time and loss and expense, and the other an entitlement to an extension of time only. Depending on the contract terms and conditions, the contractor may be entitled to:

1. An extension of time only; or

2. An extension of time and loss and expense/compensation.


A situation in which there may appear to be concurrent delay, often referred to as ‘pacing’ by the contractor, is where:

· an employer causes delay to the construction of a project; following which

· the contractor decides to reduce its resources and/or hours of working for part of or all the employer delay period;

· the contractor knowing that its rate of progress can be slower than originally planned without causing any further delay to that caused by the employer.

On an as-built construction program, both activities may appear to have been in concurrent delay. However, if a delay analysis is conducted and the contemporaneous program shows that the employer delay started first chronologically and gave the contractor an entitlement to an extension of time, then this would have created float in the program that the contractor could use without there being concurrent delay.

In MCI Constructors, Inc the Board said:[1]

“We agree with MCI that the delays attributed to MCI by the District were not critical path delays and generally come within the category of why hurry up and wait…[W]here the government causes delay to the critical path, it is permissible for the contractor to relax its performance of its work to the extent that it does not impact project completion.”

Pacing is a conscious decision made by one party to reduce its ‘pace’ of work to maintain ‘pace’ with that of the delaying party and occurs when a party decides to take up float caused by a delay by the other party.

The AACE RP 29R-03 says:[2]

“Pacing occurs when one of the independent delays is the result of a conscious, voluntary and contemporaneous decision to pace progress against the other delay. The quality that distinguishes pacing from concurrent delay is the fact that pacing is a conscious choice by the performing party to proceed at a slower rate of work with the knowledge of the other contemporaneous delay, while concurrent delays occur independently of each other without a conscious decision to slow the work.”

The AACE RP 29R-03 points out that, by pacing its work, the contractor is exercising its option to reallocate its resources in a more cost effective manner in response to the changes in the program caused by the other delay and is thereby mitigating or avoiding the cost associated with the resource demands. In effect, the delay has created float which is consumed by pacing.

The AACE RP29R-03 also points out that this is consistent with the majority view that float, a shared commodity, is available for consumption on a ‘first come first served’ basis, but that, contracts that reserve float ownership to one party or the other may effectively preclude pacing as a management tool.

Next article

My next article, DD09, will look at interaction between the ‘prevention principle’[3] and concurrent delay.

The prevention principle comes into operation where the employer’s act or omission prevents the contractor from complying with its obligations to complete the works by the completion date. If the employer’s act of prevention causes critical delay to the works, and there is no mechanism in the contract to extend time for completion as a result of that act or omission, time may become ‘at large’. If time is ‘at large’ the contractor’s obligation will be to complete the works within a reasonable time and the employer is unable to deduct liquidated damages (unless time is again made of the essence).

If there is concurrent delay, then, doesn’t this mean that the employer is also causing delay at the same time as the contractor is causing delay? Does it then follow that, if the contractor is denied an extension of time for the employer delay/act of prevention, time is ‘at large’?


If you have any queries on concurrent delay, in relation to any of the previous articles 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

DD08: Concurrent delay: it is not parallelism or pacing

[1] MCI Constructors, Inc [1996] DCCAB No D-294, 1996 Westlaw 331 212, the US Appeals Board [2] AACE RP 29R-03, page 111 to 113 [3] Refer to article DD04 for an overview on the ‘prevention principle’.

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