The Critical Path. Practical Management of Construction Delay & Disruption The Belfrey, June 14 th & 15 th 2011

Transcription

1 The Critical Path Practical Management of Construction Delay & Disruption The Belfrey, June 14 th & 15 th 2011 David Tyerman, Athena Project Services

2 Module Overview: The critical path Schedule integrity The baseline, as-planned or contract programme

3 The Critical Path

4 The Critical Path a schematic and written description of the sequence of work that a contractor plans to use to complete the project within the contractually prescribed time. It is based upon a network, which is a graphic diagram displaying all of the activities that must be accomplished to construct the project, as well as their mutual time dependencies and durations. Work activities are linked together to show their interdependency or logic. Network logic is the planned sequence in which activities are to be performed, with the start if some activities logically dependant, or restrained, by the completion of other activities, and some activities dependant of others and hence capable of being performed concurrently. A series of activities that precede and follow each other constitute a path. The critical path is the longest path from notice to proceed to project completion, or the path with the least amount of slack or float (Galaxy Builders inc. ASBCA Nos and 50136, para 6)

5 The Critical Path

6 The Critical Path the sequence of events through a project network from start to finish, the sum of whose duration determines the overall project duration BS6079-2:2000 pt2, 2.41

7 The Critical Path Task A Task B Start Finish Task C Task D

8 The Critical Path deterministic duration

9 The Critical Path O M P

10 The Critical Path

11 The Critical Path Any extension to time must prove that a delaying event has had an effect on the project critical path and has therefore extended the overall project duration Any delay on a non-critical path activity (or activities) must therefore consume the amount of float available to the work-stream Simples!

12 Schedule Integrity

13 Schedule Integrity Are the logical interdependencies applied between project events correct? Do they contain an overuse of activity lags? Are there any open-ended ended activities, that is, activities without any predecessors or successors (other than the start and finish milestones, all project activities should have at least one predecessor and successor). Are activities unduly constrained? Are the project calendars correct i.e. have they assumed the correct period of available working time? Are any resources applied to activities correct? Are the progress values assigned to project activities correct? Can they be corroborated with supporting contemporary data? Do the remaining activity durations reflect the known work content and resource productivity achieved? Can a report of assumptions be readily found and audited?

14 Useful Case Law ''The respondent was entitled to respond to the claim both by arguing that the variations, late information and so on relied on by the claimant did not cause any delay because they were not on the critical path and positively by arguing g that the true cause of delay was other matters''. Henry Boot Construction (UK) Ltd v Malmaison Hotel (Manchester) Ltd

15 Useful Case Law ''Crucial questions are (a) is the delay in the critical path and, if so, (b) is it caused by MBST? If the answer to the first question if 'Yes' and the second question is 'No' then I must assess how many additional working days should be included.'' Motherwell Bridge Construction Ltd v Micafil Vakuumtechnik

16 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

17 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

18 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

19 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

20 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

21 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

22 Useful Case Law Balfour Beatty Construction Ltd v The Mayor and Burgess of the London Borough of Lambeth '''Despite the fact that the dispute concerned a multi-million pound refurbishment contract, no attempt was made to provide any critical path. The work itself was no more complex than many other projects where a CPN [critical path network] is routinely established and maintained. It seems that BB had not prepared or maintained a proper programme during the execution of the works. By now, one would have thought that it was well understood that, on a contract of this kind, in order to attack, on the facts, a clause 24 certificate for non-completion (or an extension of time determined under clause 25), the foundation must be the original programme (if capable of justification and substantiation to show its validity and reliability as a contractual starting point) and its success will similarly depend on the soundness of its revisions on the occurrence of every event, so as to be able to provide a satisfactory and convincing demonstration of cause and effect. A valid critical path (or paths) has to be established both initially and at every later material point since it (or they) will almost certainly change. Some means has also to be established for demonstrating the effect of concurrent or parallel delays or other matters for which h the employer will not be responsible under the contract.'' t

23 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful.... His conduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

24 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful.... His conduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

25 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful.... His conduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

26 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful.... His conduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

27 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful.... His conduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

28 Useful Case Law The Royal Brompton Hospital NHS Trust v Lambeth On the evidence of [the experts] the establishment of the critical path of a particular construction project can itself be a difficult task if one does not know how the contractor planned the job. Not only that, but the critical path may well change during the course of the works, and almost certainly will do if the progress of the works is affected by some unforeseen event. [The expert] frankly accepted that the various different methods of making an assessment of the impact of unforeseen occurrences upon the progress of construction works are likely to produce different results, perhaps dramatically different results. He also accepted that the accuracy of any of the methods in common use critically depends upon the quality of the information upon which the assessment exercise was based. All of this does, of course, emphasise the vital point that the duty of a professional man, generally stated, is not to be right, but to be careful...hisconduct has to be judged having regard to the information available to him, or which ought to have been available to him, at the time he gave his advice or made his decision or did whatever else it is that he did.''

29 The baseline, as-planned or contract programme

30 Baseline, As-planned or Contract Programme City Inn v Shepherd highlights situation where the as-planned programme may be found wanting Shepherd expert did not rely on the as-planned programme and instead used as-planned v as-built analysis, this based on his assertion that he could not be confident as to the integrity of the as-planned programme Position supported by Judge (Lord Drummond Young) Skanska Construction UK v Egger (Barony) expert criticised for having reconstructed the as-planned programme for use within his time impact analysis

31 Baseline, As-planned or Contract Programme The as-planned programme (and associated critical path) must be: a solid foundation upon which there is no doubt as to its basis between the parties no doubt as to the activities contained within it and their respective interdependencies no doubt as to any changes that may be necessary for it to be used within subsequent delay analysis exercises

32 Summary Establish an agreed contract programme as soon as possible Record your assumptions in deriving the contract programme and any revisions to it (schedule integrity) Establish systems that promote accuracy of progress updates Agree the contract critical path and any subsequent revisions to it between een the parties (as single version of the truth the critical path will change during the project) Record and impact change events e contemporaneously eous (and agree or agree to disagree contemporaneously) Be careful, not necessarily right! Records, records, records!

33 Records the Sahara Syndrome the only things that are relevant are what has been written and what has been built.what is said is blown away like sand in the desert.

34 David Tyerman Managing Director Athena Project Services athenaprojectservices.com t: m: Thank You ENTITLEMENT PLANNING RISK RESOURCING