Features

Concurrent Delays
A practical approach - Part I
that where there were truly concurrent delays then
the contractor was entitled to an extension of time
for the effects of the excusable delaying event. For
the second scenario, the judge observed:-

Brian E Rawling “…it is, I think, necessary to be clear what one means
Brian E Rawling & Associates by events operating concurrently. It does not mean,
in my judgement, a situation in which, work already
his is the first part of a three-part article being delayed, let it be supposed, because the
on concurrent delays – a practical contractor has had difficulty in obtaining sufficient
approach. Part one deals with time, part labour, an event occurs which is a relevant event and
two deals with money and part three provides which, had the contractor not been delayed, would
some examples and a conclusion. have caused him to be delayed, but which in fact, by
reason of the existing delay, made no difference. In
What is meant by concurrent delays? such a situation although there is a relevant event,
the completion of the Works is [not] likely to be
Concurrent delays occur when the delaying effects
delayed thereby beyond the completion date.
of two or more independent events impact upon
progress and would, each delaying effect without The relevant event simply has no effect upon the
the other, have caused delay to completion. For completion date. This situation obviously needs to
delays to be called concurrent, the effects of the be distinguished from a situation in which, as it were,
events must impact upon progress in similar time the works are proceeding in a regular fashion and
periods although, not necessarily, in exactly the on programme, when two things happen, either of
same time period; i.e. a delay from days 8 to 15 on which, had it happened on its own, would have
one programmed string of activities could be said caused delay, and one is a relevant event, while the
to be concurrent with a delay from days 12 to 19 other is not. In such circumstances there is a real
on another programmed string of activities concurrency of causes of the delay.”
because the effects would, one without the other,
have caused similar delays to completion. The relevant event in the example referred to by His
However, the effects of two delaying events, which Honour Judge Seymour QC could have been the late
impacted upon progress two months apart on an issue of information which was rendered on time as
eighteen-month contract, could not be said to be the contractor had earlier been in culpable delay due
concurrent. to labour shortages. The effects of the information
delay therefore did not cause any real delay to
Concurrent delays could be caused by the p r o g r e s s . Fo r H o n g Ko n g , w h e r e m a n y
delaying effects of events that were either subcontractors will not supply workers until they
excusable (i.e. the events for which the employer have been issued with detailed construction
takes the risk of time and for which extensions of information and can see continuity of work for one
time should be granted to the contractor) or to two months ahead, the example may not apply
culpable (i.e. events for which the contractor as the contractor could not procure labour unless
takes the risk of time). it had adequate construction information in the
first place.
There are also what are termed in the USA “pacing
delays” which are reviewed later in this article. A third scenario would be where the delaying effects
of an excusable event occurred after the delaying
Royal Brompton Hospital v Watkins effects of a culpable event had already delayed
Gray International completion. If the delaying effects of the later
excusable event caused a fur ther delay to
In the recent English case of the Royal Brompton
completion then that type of scenario was covered
Hospital NHS Trust v Watkins Gray International
in the case of Balfour Beatty Building Ltd v
(2000) His Honour Judge Seymour QC provided
Chestermount Properties Ltd (1993) and the
clarification upon what he, and English law,
extension of time should be based upon the “dot
considered to be concurrent delays. He referred
on” philosophy.
to two scenarios. In the first scenario he confirmed
Excusable and Culpable Events

There can be events, both excusable and culpable,

which do not result in delays either critical delay or
localised delay.

An example would be where a piling contractor was

in delay due to ground conditions for which it had
accepted the risk and the contract administrator was
late in issuing information for the pile caps which
information was still issued before the contractor
needed it. The late issue of information was an
excusable event but as the contractor was not
waiting for it (either in terms of planning or
procurement) and it did not cause delay to
completion, then no extension of time would be due.

However, if the contractor could have used

additional plant to overcome the ground condition
problems, but did not do so as it had advance
knowledge that the pile cap information would not create complexities for delay analysis and there
be available for continuity of working if it did increase may be occasions when the effects of excusable
its plant resources, then this is a different situation. and culpable delaying events cannot be
In such a situation, the contractor would be well distinguished. In the USA, it is established case
advised to inform the contract administrator in law, that a party cannot recover damages when
advance of implementing his intentions to avoid there are concurrent delaying events, the effects
misunderstandings later. of which cannot be apportioned i.e. the delaying
effects of excusable and culpable events were
Therefore, for an excusable or culpable event to
similar. In such circumstances, the concept of “in
become a delaying event, it must cause actual delay.
pari delicto” prevails, i.e. because both parties
In a complex structure, such as a railway station, have done wrong, neither party should be able to
there may be many changes caused by design recover its damages.
development and co-ordination. If those changes
The Protocol published by the Society of
were issued early enough then they would not
Construction Law in the UK advocates a philosophy
necessarily cause delay (unless there was extra work
for extensions of time similar to the USA case law.
or they caused revised sequencing). What is early
enough? The contractor must be able to carry out
Philosophy for Concurrent Delays and
detailed construction planning, co-ordination,
Extensions of Time
design formwork, organize subcontractors, prepare
bending schedules and the like. Therefore, four Large projects, which go awry invariably, involve
months is not an unreasonable lead-in-time from the concurrent delays caused by excusable and
start of a new activity for a contractor to be able to culpable events. This situation can arise as the
absorb changes that do not increase workload, contractor was distracted from what it would or
although small changes and detailed clarifications could otherwise have done by the effects of
for civils works can be assimilated, co-ordinated and excusable events.
implemented within two to four weeks of issue.
Case law in England appears to have established
If contractor design were involved then the the philosophy that, when assessing extensions
assimilation, co-ordination and implementation of time, the contract administrator must consider
periods would usually be longer. what the delaying effects of the excusable events
would have been absent the delaying effects of
Therefore, concurrent delays must be where there
any culpable events and grant extensions of time
were concurrent delaying effects of excusable and
accordingly. It has also been established, by case
culpable events impacting upon a string of activities
law, that the “dot-on” principle for extensions of
and each, without the other, would cause delay to
time is to be followed and that the delaying effects
completion. The effects of concurrent excusable and
of an excusable event, such as a variation order,
culpable events, which did not cause such delays,
occurring after a period of culpable delay, does
would not be concurrent delays.
not negate the culpable delay.

Complexity of Delay Analysis with However, when it comes to claims for additional
Concurrent Delays payment, the delaying effects of excusable/
compensable, excusable/non-compensable and
Concurrent excusable, culpable and pacing delays
culpable events should be considered.
GCC Clause 50 – Hong Kong Once the contract administrator has decided that
Government Form of Contract there were excusable delaying events, the
procedure for considering extensions of time
Clause 50(2) in the Hong Kong Government general
appears to be as follows (taken from pages 1033
conditions of contract for civil engineering works
and 1034 of Keating 6th edition when referring to
(the GCC) deals with extensions of time. GCC
the ICE 6th edition which is similar to the Hong
Clause 50(2) states:-
Kong Government form of contract):-
“the Engineer in determining any extension shall “ (1) The Engineer must make an assessment
take account of all the circumstances known to him of the delay suffered;
at that time, including the effect of any omission (2) He must consider whether this delay fairly
of work or substantial decrease in the quantity of entitles the Contractor to an extension of
any item of work.” the time for substantial completion.

This wording is similar to (but not the same as) (3) The Contractor is required to be notified.
that used in the ICE general conditions of contract (4) No further criteria are laid down.
4th, 5th and 6th editions used in the UK and other (5) Presumably, the second step involves
countries which used similar forms of contract. considering how far the individual
delayed items are critical to progress of
The opponents of the extension of time philosophy
the Works or any relevant Section.
referred to earlier in this article say that reference
to “all the circumstances” in GCC Clause 50(2) (6) Note that in assessing the delay suffered,
must include the delaying effects of culpable the Engineer is required to consider “all
events that caused concurrent delay and that, in the circumstances known to him at the
those circumstances, no extensions of time should time”, which may include factors outside
be granted with the conclusion that the contractor t h e g ro u n d s p u t f o r w a rd b y t h e
should pay liquidated damages irrespective of the Contractor.”
concurrent delaying effects of the excusable
Obviously the contract administrator must also
events. That opposite philosophy cannot be
have a good knowledge of the construction
correct. Not only is this interpretation of GCC
process, how a contractor operates and how
Clause 50(2) not construing the wording of that
resources respond to delaying events.
Clause correctly (the examples referred to are not
culpable delaying events, the clause does not refer
All the Circumstances
to culpable delaying events, and case law has
established that the concurrent delaying effects Had it been intended that the contractor’s culpable
of culpable events do not override the concurrent delay was to be one of the “circumstances” then
delaying effects of excusable events) but it is also GCC Clause 50 would have, and should have,
ingenuine in that it assumes that, absent the referred to it thereby creating certainty. By
concurrent delaying effects of excusable events, referring to omission of work and quantity
the contractor would not, or could not, have taken reductions it must be construed that “all the
measures to extinguish the delaying effects of circumstances” were to be similar to those quoted
culpable events. Such an assumption is contrary and were not something completely different.
to common sense as a competent contractor would
wish to avoid the imposition of liquidated Further, the clause is not wide enough to overturn
damages, incurring prolongation costs, and established case law precedents. Hence, when
causing subcontractor’s claims, if it was possible considering “all the circumstances known to him
to do so, and if the contractor did not have grounds at the time”, the contract administrator must follow
for an extension of time, it could have taken established case law precedents.
measures to reduce or extinguish the delaying
Fu r t h e r, c o n s i d e r a t i o n o f t h e “ a l l t h e
effects of culpable events.
circumstances” would include consideration of the
Where there were no contemporary complaints efficacy (or significance) of the events, criticality
about the contractor’s progress from the contract and excusability.
administrator but extensions of time were later
The English case law precedents were established
rejected on the basis of alleged concurrent
based upon different contracts to the Hong Kong
culpable delays, then the contract administrator
Government form of contract, however, the forms
did not give due weight to the likelihood that had
of contract in those cases required the contract
there not been excusable delays then the
administrator to similarly consider all the
contractor may have been able to either avoid the
circumstances known to him / her at the time.
delaying effects of culpable events or extinguish
the effects thereof.
Efficacy which prolonged the construction period and
was carried out at the same time as the
The efficacy of the events should also be considered snagging work using, say, 15 No. workers. In
by the contract administrator. If alleged culpable general, on-going snagging work should not be
delaying events (e.g. paperwork, preparatory work, held to be a concurrent culpable delay when an
cleaning up and the like) were of little significance impartial investigation would find that the main
in relation to the excusable events (e.g. delay in the cause of delay to completion was the additional
issue of information, instructions to carry out extra work and not the on-going snagging work,
work, delay in responding to submissions and the which is always done when progress is
like), then the effects of the alleged culpable approaching completion.
delaying events were not of the same significance
as, and were of lesser efficacy, than the effects of Excusable Delay in a Period of Float
the excusable delaying events. Such alleged
culpable events should not, therefore, be held to It is generally accepted that if there were delays
override the delaying effects of the more efficacious caused by the effects of an excusable event and such
concurrent excusable events. Two examples follow. delays occurred on strings of activities where there
was float that was large enough to subsume such
1. Most contracts require the contractor to submit delays without completion being delayed, then a
a method statement and receive approval from contractor was entitled to:-
the contract administrator before commencing
work. Where the contractor was late in (i) no extension of time as, either there was no
preparing or revising the method statement it delay to completion, or the delay to completion
could extinguish the effects thereof by was caused by the delaying effects of another
commencing work on time and at its own risk excusable event affecting the critical path which
until the method statement was approved. The went through another string of activities;
lateness of the method statement was,
(ii) no reimbursement of prolongation cost as
therefore, of lesser efficacy than, say, the late
construction of the works was not prolonged by
issue of information for continuity of working
the delaying effects of excusable events on the
after an activity had commenced.
strings of activities with float, however, there
2. On most contracts, even those which finished may have been additional cost associated with
on time, a contractor will have defects to rectify the delayed portion of the works, as opposed
and minor outstanding works to complete. This to the whole of the works, or a section thereof.
is often called snagging work and is always
Therefore, for the contractor to be entitled to an
carried out in the closing stages of a project.
extension of time, the delaying effects of an
The efficacy of snagging works using, say, 5 No.
excusable event must have impacted, or have been
workers was less than the efficacy of, say,
likely to impact, upon the critical path.
additional work which had to be completed
before statutory inspections could begin and
Pacing Delay in a Period of Float Therefore, a culpable delay does not really occur
when a programmed activity duration is exceeded,
As the foregoing is the generally accepted view for as the available float must also be subsumed before
the delaying effects of an excusable event in a a culpable delay is created. Just as there is no
period of float then it should also be accepted that entitlement to an extension of time where the
a similar philosophy, acting in the converse, should delaying effects of excusable events are not critical,
apply for the delaying effects of culpable events in there are no entitlements to liquidated damages
a period of float. Using float to subsume delay is where the effects of “pacing delays” are not critical.
referred to in the USA as “pacing delays”. The
delaying effects of “pacing delays” and excusable In the USA, it appears to be accepted case law that
events, both of which occurred in periods of float, float in non-critical strings of activities created by the
should be treated similarly by the contract delaying effects of an excusable event which caused
administrator. Therefore, for a “pacing delay” critical delay in a critical string of activities can be
which was subsumed by float, there would be no used to reprogramme non-critical work. “Pacing
culpable delay to completion and a contractor delays” occur when a contractor deliberately
would be entitled to:- decelerates the pace of non-critical activities to keep
pace with the delaying effects of critical excusable
(i) no liquidated damages would be payable events.
where the period of float subsumed the effects
of the “pacing delay” which, therefore, did not At page 223 of Keating 6th edition it states:-
cause delay to completion;
“Interim slowness not resulting in a failure to
(ii) a non-critical “pacing delay” should not be complete on time may not be a breach of contract at
used to offset the delaying effects of a critical all.”
excusable event when extensions of time are
This statement is referenced to case law (GLC v
being assessed.
Cleveland Bridge and Engineering (1984)) and
Therefore, the delaying effects of a culpable event provides support for using float to subsume “pacing
would not cause, or would not be likely to cause, delays” that, therefore, should not be classified as
delay to completion as they were subsumed by culpable delays as they did not cause delay to
float. Indeed, it is doubtful that such effects, when completion.
subsumed by float, could be classified as a delaying
Fo r f u r t h e r i n f o r m a t i o n , p l e a s e c o n t a c t
event at all and is better described as a “pacing
bera@netvigator.com=
delay”.
 Features

Concurrent Delays -
A Practical Approach
- Part 2
extended an extant critical path. Either way,
the del ay caus ed by a critical excus abl e
delaying event would generate float along
other non-critical strings of activities. In this
c a s e , t h e d e l a y in g e f f e c t s of a cri t i c al
Brian E RAWLING e x c u s a b l e e v e n t re n d e r e d t h e o r i g i n al
Brian E Rawling & Associates programme redundant for progressing the
works but still relevant as a pre-impacted
statement of intent.
his is the second part of a three-part
article on concurrent delays - a practical For the reasons given above, the contractor would
approach. be entitled to the benefit of float created by the
delaying effects of a critical excusable event on
Float
another string of activities, as, if the contract
Who gets first call on float in a contractor’s programme? administrator had granted an extension of time as
Opposing views have been put forward in textbooks he ought to have done when the delaying effects
and technical articles. Possibly the best two articles of the critical excusable event could be identified
on the subject which the writer has read were one by (fully or on an interim basis), then the contractor
Vivian Ramsey and another by John Molloy. could have re-arranged its plans and used the float.
The contractor could have deferred expenditure,
Obviously, if the contractor does not need the levelled resources or worked shorter hours.
float, or all of it, then the employer can have the
benefit thereof. However, what is the position if the contract
administrator does not promptly grant an
A practical approach to float is that the contractor extension of time? Does the contractor still have
must have first call on it as, otherwise, programming to meet its original programme for all of the other
would, or could, become contrived to eliminate float strings of activities and if it does not do so, has
and that would not benefit a project, an employer or the contractor caused culpable delay?
a contractor.
Additional costs incurred by a contractor in
The Critical Path mitigating the delaying effects of an excusable
event are recoverable under most forms of contract
When are activities on the critical path? In large
or at law but there can be no financial claim for
projects, the critical path is not merely the string(s) merely complying with the original programmed
of activities with zero float. Any string of activities intentions, i.e. the baseline scenario. A contractor
with less than about one week’s float is, in practical who relaxed its original programmed intentions to
terms, critical due to the time risks borne by the take benefit of float generated by the delaying
contractor. Therefore, the critical path(s) will not just
effects of a critical excusable event runs the risk
be one string of activities with zero float but there of being accused of causing culpable delay.
will be several strings of activities each with less than However, had the contract administrator granted
7 days float which are also critical. extensions of time on time then the contractor
could have benefited from the float in the other
Creating Float
strings of activities. Therefore, if the contract
Where the delaying effects of an excusable administrator did not grant timely extensions, a
event impacted upon progress it may have contractor should not be expected “to hurry up to
caused a critical path to shift or it may have wait”.
(i) If float was generated by the delaying effects of future given a particular set of circumstances in
a critical excusable event on another string of the present and the contractor’s pre-impacted
activities, then any delaying effects of a “pacing intentions.
delay” in a non-critical string of activities should not
extinguish or reduce the extension of time or The planning, recording and commercial resources
needed by the contractor, if detailed delay analysis
entitlement to reimbursement of prolongation costs
caused by the delaying effects of a critical excusable was to be done in this manner, would be significant.
Contractors do not usually establish such a resource
event as the effects of the “pacing delay” merely
at the start of a project (on the basis that the project
consumed float and did not become a culpable
delay. may not go awry) and then spend a lot of time and
effort back-tracking to prepare detailed delay
(ii) Therefore, where float occurred in a programme, analysis when things do go awry.
or was generated during construction, either an
Most forms of contract require the contract
employer, or a contractor, could use such float to
administrator to grant extensions of time as soon
absorb the delaying effects of events for which they
were responsible. as the delaying effects of an excusable event can
be estimated. This means that the delaying effects
If the contractor was updating its programme of an excusable event may be ongoing when the
regularly then its intentions should become extension(s) should be granted.
apparent from the programme updates if they were
Many contracts require the contractor to issue
properly prepared.
monthly updates of its programme along with a
Delay Demonstration progress report, claims notices and interim
particulars. Therefore, the contract administrator
With modern programming software it is possible should be able to grant the extension(s) of time on
to carry out detailed delay analysis and it is a monthly basis. In practice, however, this does
preferable if this is done as the project progresses. not happen even in the most obvious cases of
The time impact delay analysis using monthly excusable delaying events.
windows, planned intentions and as-built data is
one technique. Not only can this form of analysis Financial Claims
be used to establish the extent of the delaying
Even though concurrent delaying effects of culpable
effects of events but it can also be used to establish
events should not be the cause to override the
the effects of delay mitigation measures by creating
computerised simulations of what may have delaying effects of excusable events when
extensions of time are being considered, the
happened had delay mitigation measures not been
taken i.e. the effects of delay mitigation measures position is somewhat different for financial claims.
will be apparent in the as-built programme and do
GCC Clause 63 - Hong Kong Government Form of
not need replicating.
Contract
The accuracy of any delay analysis, whatever
Reimbursement of additional cost is covered by
technique is used, is greatly influenced by the quality
Clause 63 in the Hong Kong Government general
of information. It is usually not necessary to analyse
conditions of contract for civil engineering works.
when every nut and bolt was fitted, as the as-built
For a claim to be made under this clause the
database would become too unwieldy to be used
contractor must have incurred expenditure, not
efficiently. Further, at every step of the analysis there
reim b u rs ed u nd er any ot h er co nt ract u al
should be an empirical check. Does it look right? This
provisions, caused by disturbance to the regular
should be the question asked by the analyser.
progress of the works.
When the project is in progress, the time impact
Under Clause 63, all that the contractor can recover is
analysis technique can be used on historic data
its additional costs, which can be linked to a
but for projecting ahead, the impacts upon
compensable delaying event. The contractor is not
planned intentions have to be forecast by
entitled to profit, however, additional overheads on
developing a delay demonstration programme
or off site would be recoverable subject to establishing
which simulates what is likely to occur in the
causal nexus.
Dominant Cause damages is called the reimbursement of additional costs) is
to return the contractor to the position which it would have
In the U.K., there is case law, which provides guidance on what
been in, as far as money can do so, absent the breach (or for
is meant by the “dominant cause” approach:-
t h e H ong Kong Gove rnm ent f orm s of cont ract , t h e
“Which cause is dominant is a question of fact, which is not compensable events). This requires consideration of the
solved by the mere point of order in time, but is to be decided by following:-
applying common sense standards.” (Leyland Shipping v.
(i) was the event a compensable event?;
Norwich Union 1918)
(ii) what were the realistic effects of the event?;
Therefore, deciding dominance not only requires a review of
criticality but also efficacy. The effects of a delaying event must (iii) what was the efficacy of the event?;
have materially caused or contributed to the delay to completion.
At page 212 of Keating 6th edition it states:- (iv) what could reasonably have happened had the compensable
event not occurred?;
“the burden of proof should require the plaintiff to establish
that the loss resulted from the cause on which he relies and (v) what were the true effects of the compensable event?
that he will do so if he establishes that it was the dominant
In the circumstances that the delaying effects of a non-
cause. He should not be required additionally to disprove
compensable event were substantiated and there were
lesser alternative causes altogether.”
preceding concurrent or simultaneous excusable and
Apportionment compensable delaying events, then the contractor would, or
could, still be entitled to reimbursement of its prolongation
The alte rnative to th e dominant caus e approa ch is costs if it could be shown that:-
apportionment. At page 213 of Keating 6th edition it refers to
the U.K. Law Commissions’ Law Reform (Contributory (i) float had been created by the delaying effects of an earlier
Negligence) Act 1945 and summarised the situation as follows:- compensable event on the string of activities incorporating
the non-compensable event such that the delaying effects
“where the loss or damage suffered by the plaintiff results partly of the non-compensable event were subsumed by the float
from his own conduct and partly from the defendant’s breach of created by the delaying effects of a compensable event,
contract, it is correct in principle for the damages to be therefore, the delaying effects of the non-compensable event
apportioned.” did not delay completion but merely consumed float in the
as-built scenario. This philosophy follows the dominant
A pacing delay subsumed by programme float would not cause
approach philosophy referred to in Keating 6th edition at
loss or damage and it would not be a breach of contract. A
pages 209 to 214;
“what if ” analysis could be carried out by progressively
deducting the delaying effects of each critical excusable event, (ii) the delaying effects of the non-compensable event were not
one by one, until the as-built programme was shrunk back to of equal efficacy to the delaying effects of a concurrent
the original contract period, or the original period plus the compensable event;
delaying effects of culpable events and pacing delays.
However, such an analysis does not address reality and (iii) the contract administrator ought to have granted extensions
assumes that, absent the delaying effects of each critical of time for the delaying effects of excusable events as soon
excusable event, the contractor was helpless to mitigate delays as they could be identified, thereby reinstating float into the
caused by other delaying events or to avoid pacing delays. programme;
Therefore, when considering apportionment of additional
(iv) there was no requirement for the contractor “to hurry up to
expenditure incurred due to disturbance, which cost is not
wait”.
reimbursed under any other contractual provisions, it is not
sufficient for the contract administrator to reduce the Contract administrators often opine that the contractor is not
contractor’s financial claims on the grounds of concurrent entitled to be reimbursed prolongation costs if there were
culpable events, if the delays caused by those concurrent culpable events, the delaying effects of which would have
culpable events merely consumed float (they were “pacing caused the contractor to have incurred prolongation costs
delays”) and were avoidable. absent the delaying effects of excusable and compensable
events. Such opinion would be valid where the delaying effects
Generally, the costs of delay mitigation are less than the costs
of the culpable event could not have been mitigated and were
of prolongation and, absent the delaying effects of critical
the dominant cause of delay to completion at the time when
events, the contactor may have been able to extinguish or
they impacted upon progress. However, if the delaying effects
mitigate the delaying effects of non-critical delays.
of an excusable and compensable event were dominant, then
Additional Cost the dominant cause theory provides that prolongation costs
ought to be reimbursed.
The purpose of financial damages (in the Hong Kong
Government forms of contract reimbursement of financial For further information, please contact bera@netvigator.com
 Features

Concurrent Delays -
A Practical Approach - Part 3
Excavation for the culvert commenced 120 days In example 3, the dominant delay commenced
later than programmed and delayed completion on day 8 when uncharted utilities were found
by a similar period. The contractor claimed and the culvert excavation could not commence
additional time and money for 120 days. as the utilities had to be diverted. On day 8,
Brian E. RAWLING the dominant delay became the diversion of the
Brian E Rawling & Associates Adjacent to the culvert was a retaining wall, the
uncharted utilities and the contractor should
excavation for which was planned to commence
have been reimbursed prolongation costs for
on day 22. The retaining wall was in a non-
his is the third and final part of the all of the 120 days as the effects of the retaining
critical string of activities with 50 days float.
article on concurrent delays - a wall deferment were subsumed by float and did
The contractor delayed the start of the retaining
practical approach. not affect the date of completion.
wall by 100 days as it took benefit of the delay
caused by the diversion of the uncharted Example 4
Examples
utilities to defer expenditure on the retaining
A few examples of delay analysis are provided wall. The contract administrator, however, The contractor's programme had two critical
below. maintained that the retaining wall deferment paths both with zero float:-
constituted a culpable delay and no additional
Example 1 Path 1
payment should be made during the 100 days
of the 120 days prolongation caused by the construct the structure;
The contractor planned to commence pre-
diversion of the uncharted utilities due to
drilling for bored piles on day 8. It did not start
alleged culpable delay on the retaining wall. install the permanent lifts;
until day 25, i.e. a culpable delay of 17 days.
The contractor, however, brought additional In example 2, the dominant delay was that remove the temporary hoists;
pre-drilling and bored piling plant to site and caused by the diversion of the uncharted
the re-run programme and the contractor's curtain walling infill;
utilities and that was the first delaying event to
subsequent performance showed that the 17 occur. It was an excusable and a compensable FSD and BD inspections;
days of culpable delay was extinguished due event. It created further float in the string of
to the provision of extra resources. activities including the retaining wall which finish fitting-out.
float subsumed the effects of the retaining wall
The contractor was, therefore, not responsible Path 2
deferment which did not cause delay to
for delay to completion as the culpable and
completion. Therefore, as the contractor could appoint the curtain walling nominated sub-
non-compensable delay caused by the late
utilize this float, it should have been contractor;
start of pre-drilling was extinguished.
reimbursed prolongation costs for all of the 120
days. design development, submissions and
This is a common scenario as experienced
approvals;
contractors will look to extinguish the delaying
effects of a culpable event as it is usually less
Example 3
procurement, fabrication, delivery;
expensive than the alternative of liquidated Take example 2, but the retaining wall
damages, prolongation costs and sub- erect curtain walling;
excavation was due to start on day 1 but was
contractors' claims.
not started until day 15 and then took 15 days curtain walling infills;
longer (a total delay of 29 days). Excavation
Example 2
for the culvert was planned to start on day 8 FSD and BD inspections;
The contractor excavated trial holes as planned, but the utility diversions delayed this by 120
finish fitting-out.
commencing on day 1, and immediately found days, which caused a similar delay to
uncharted utilities which clashed with the completion. The contract administrator was late in
proposed permanent works design of a nominating the curtain walling sub-contractor
The contractor claimed reimbursement of
reinforced concrete culvert. The contractor had and then introduced variations which prolonged
prolongation costs for 120 days but the contract
planned to commence excavation for the design development, fabrication and delayed
administrator maintained that the retaining wall
culvert on day 8, but could not do so. Instead, delivery.
deferment was a culpable delay and payment
the contract administrator instructed diversion
was only due for 91 days (120 - 29 days).
of the uncharted utilities, which took 120 days.
The nomination should have been on day 15 but The contractor's tender programme for
to the basement works was as follows:-
was not made until day 50. The installation construction of pile caps, a basement and
should have commenced on day 150 but the first ground floor slab showed the contractor taking Substructure - actual first pour - day 120
delivery was not until day 200. Installation possession of site on day 1 and commencing - planned first pour - day 50
actually commenced on day 201 and delayed construction of pile caps on day 22. After
completion by 51 days. The delays were caused _______
construction of the pile caps, the remaining
by excusable and compensable events. concrete works used 60N concrete for which the - difference 70 days
contractor had to provide samples, carry out - less advance work 15 days
Meanwhile, construction of the reinforced
tests and obtain approval before 60N concrete - actual delay 55 days
concrete frame took longer than planned due
could be used. The first 60N concrete pour was
to a culpable delay of 20 days in the period from
due on day 50. The contractor claimed prolongation costs for
days 30 to 60 as the contractor took longer to
52 days. The contract administrator maintained
set up its climbing formwork system than it had The contract was awarded and the tender that the failure to obtain approval for the 60N
planned. After that, construction of the frame programme became the first construction concrete mix was a culpable delay and, as this
progressed as planned. programme. amounted to 55 days, it was dominant and no
The contractor claimed reimbursement of 51 prolongation cost were reimbursable and 3
The Authorised Person did not obtain the
days' prolongation costs but the contract days of liquidated damages was payable (an
Building Authority's (BD) approval of the pile
administrator maintained that payment was extension of time of 52 days had been granted
cap design to allow the contractor to construct
only due for 31 days (51 - 20 days). for the excusable delay to the start of pile cap
the pile caps as planned. A revised design for
construction).
the basement slab, walls, columns and ground
In example 4, the delay in nominating the
floor slab was also submitted to BD for The contractor ought to have been reimbursed
cur tain walling sub-contractor, which
approval. prolongation costs for 52 days as the delay in
commenced on day 15, generated float in the
other strings of activities, including critical path obtaining BD's approval and consent for the pile
BD's approval of the pile caps was obtained on
1, which was put into float. The contractor was caps caused the first and critical compensable
day 55 and notified to the contractor on day 58.
entitled to utilize this float and should have delay which generated float in the other strings
BD's consent to proceed with pile cap
been reimbursed prolongation costs for 51 of activities. BD's approval and consent for the
construction was notified to the contractor on
days. substructure was notified to the contractor 45
day 78. BD's approval of the revised
days after the contractor had intended to start
substructure design was obtained on day 80
Example 5 substructure work. Normally, the Authorised
and consent on day 95. Both were notified to
Person notifies the contractor when BD's
Take example 4 and reverse the events such the contractor on day 95.
approval is obtained so that the contractor
that the culpable structural delay commenced could proceed with preparatory work but, in this
The delays to the construction of pile caps was,
on day 15 and the compensable nomination case, that did not happen and the contractor
therefore, as follows:-
delay commenced on day 30. The structural was denied the oppor tunity for early
delay created float in the curtain walling string Pile caps - actual start - day 79 preparation. It was after day 110 that the delay
of activities (critical path 2) until that string of - planned start - day 22 in obtaining approval for the 60N concrete mix
activities again became critical. could have had any delaying effect. After the
________
contractor had completed preparation works on
The contractor would only be entitled to - difference 57 days
day 110, the absence of approval caused delay
reimbursement of 36 (51 - 15) days prolongation - less advance works 5 days to completion until the contractor poured the
costs, being the prolongation caused by the
- actual delay 52 days concrete at its own risk on day 120.
excusable and compensable curtain walling
string of activities over the culpable structural The contractor could not pour concrete for any The contract administrator could have assessed
delays which started first and were not of the substructure after receipt of BD's consent the effects of the late BD approvals and
extinguished. on day 98, as it had not obtained approval of consents for the pile caps and ought to have
the 60N concrete mix. Formwork and awarded extensions of time before BD's
The difference in philosophy between examples
reinforcement were fixed for the basement slab approval and consent for the substructure was
3 and 5 is that the retaining wall deferment in
and completed on day 110 but the contract obtained. This action would have enabled the
example 3 did not affect the critical path.
administrator would not allow the 60N concrete contractor to reprogramme and take advantage
Example 6 to be poured. However, on day 120 the of float created in non-critical strings of
contractor did pour 60N concrete at its own risk. activities.
This example applies to a private development Thereafter, progress was as planned. The delay
and not a Government project.
Conclusions not being granted on time (or at all) as the
contract administrator often waits to see if a
Case law in the USA and the UK can be used as
culpable event caused delay after the delaying
a guide to what should happen in Hong Kong.
effects of an excusable event were clearly
Whether it is the contractor or the employer apparent. In reality, this cannot be concurrent
who seeks damages for delay, when there are culpable and excusable delays. The delaying
allegations of culpable delay used to offset the effects of the earlier excusable event created
delaying effects of excusable and compensable float in other non-critical strings of activities
events, a detailed delay analysis is necessary and the effects of the later pacing delay never
if the parties do not reach an amicable became a culpable delay as it was subsumed
agreement. by float.

When dealing with time under GCC Clause 63, Comments by a contract administrator such as
the scheme of things should be for the contract the contractor was not waiting for the
administrator to establish when, given the information as it did not have idle resources,
delaying effects of excusable events, the or it had not erected the tower crane, or it had
contractor was likely to complete the works not delivered the materials, indicates a basic
without it having to take delay recovery ignorance of how contracting works, i.e. the
measures. This obligation should not be left contractor would not spend money on procuring
until completion of the work but should be resources, or erecting the tower crane, or
ongoing throughout the project. delivering materials when the information to
proceed with construction work was not
When dealing with financial claims under GCC available.
Clause 57, the contract administrator should
consider not only the delaying effects of Practically, in the event of delays, the worst
excusable and compensable events but also the thing that a contractor can do is not to issue
delaying effects of non-compensable events. notice(s) of delay on time. When the contractor
He should also consider if the delaying effects begins to incur additional cost, as it certainly
of compensable and non-compensable events will do on a delayed and disrupted contract,
were of equal efficacy. commercial realities have to be faced and, if
there were excusable and compensable
Where a contractor re-arranged its programme delaying events, then a contractor will make
to take advantage of float created on non- claims. It is to be hoped that, in these
critical strings of activities by the delaying circumstances, adequate records were
effects of excusable and compensable events maintained so that the post mortem delay
on the critical path, then the use of such float analysis can arrive at the correct diagnosis. Ill
should not be classified as culpable or non- will and poor records often result in a dispute.
compensable delay. In the USA, this is termed,
a "pacing delay". For further information, please contact
bera@netvigator.com
When assessing financial claims, the contract
administrator should determine the dominant
cause(s) of delay at any one time in the contract.
The cause(s) must be dominant, not just in
terms of the delay it caused, but also the
efficacy.

When faced with a notice of delay, many

contract administrators respond by examining
a contractor's performance on other work in
order to seek out concurrent delays caused by
culpable events so that the contract
administrator can diffuse a contractor's claim.
This undoubtedly results in extensions of time