v Abstract in Floatstopic: “Asthe complexity in construction projects increased, simply managing the obtainedfloat values and critical path(s) by the CPM method usually results in moredifficult schedule control and, consequently, in incorrect decision making dueto non-realistic float values. This study thoroughlyreviewed various float types in the project management systems, and discussed five managerial essentials andthree proactive strategies on mitigating challenging float-related problemsbased on the perspective of managing schedules by controlling floats.” With somecomments and suggestions, the outcomes of this study not only improve the knowledgelevel on schedule management but also provide a better understanding of floatmanagement to improve the quality of schedule management. Project float usedby developers and project managers to planning &schedule the specific timeof tasks as well as the time framed formaking decisions to best ensure construction projects come in on time. Totalfloat is the span of time between the target end date of the last task on thecritical path and the target date for project completion. “Freefloat is the time an individual task can be delayed before impacting the taskthat follows it, defined as the difference between the task’s earliest andlatest possible finish dates.
Float can allow more time for working on a taskwhen necessary. Otherwise, resources can be repurposed for another task.” Employees working withmultiple teams can put more time into other tasks that are lagging. Total floatis often represented as a positive or negative number representing the numberof days.
v Float Definition: The definition of float in general is theamount of time that a task, network path or project can be delayed without changingthe deadlines of other successor tasks or Completion date of the project and sometimes float called”slack”. v How to find Float ? Thesimplest way to compute float is to subtract the time you’ve allotted tocomplete a task from the time the task actually takes. Tasks that have zerofloat can be considered as part of the “criticalpath”, because any delay on these tasks means a delay to the projectdeadline itself. vBenefits of the floats: They are many benefits of the floats inPlanning phases, Float usage on paths ofnon-critical tasks have an effect on productivity, recourses and comfort intime activity. In the Planning phases of a project, floatcan be used to improve productivity &efficiency but at construction phasethe consumption of floats can effect negatively to these factors and they aretwo main benefits of the floats: § First one : Delay analysis: Construction projects continue to sufferdelays. Things go wrong and the project’s completion date gets pushedback, with someone to be blamed for it.
In practice, attempts are made to identify the causes of delaysand schedules are modified to incorporate revised duration andnew project time. The analysis itself is usually complexand can be aided by a computerized approach. Different delay analysistechniques are currently used by practitioners in the construction industry. · Second one: Resource Leveling: In project management, resource leveling isdefined by the (PMBOK Guide) as “A technique in which start and finishdates are adjusted based on resource constraints with the target of balancingdemand for resources with the available supply.” When performingproject planning activities, the manager will attempt to schedule certain activityssimultaneously. When more resources such as machines or people are needed thanare available, or perhaps a specific person is needed in both tasks, the activitywill have to be rescheduled concurrently or even sequentially to manage theconstraint. Project planning resource leveling is the process of resolvingthese conflicts.
It can also be used to balance the workload of primaryresources over the course of the projects usually at the expense of one of thetraditional triple constraints (scope, cost, time).Resourceleveling is also useful in the world of maintenance management. Manyorganizations have maintenance backlogs. These backlogs consist of work orders.Without resource-leveling the organization (planner, scheduler and supervisor)is most likely performing subjective selection.
§ Example of resource leveling: v Different types offloats: Theyare several different types of floats in construction management like – TotalFloat, Free float, Interfering Float, Independent Float and Safety Float. · Total Float (TF):- Totalfloat is what many of us are aware of, and is commonly referred to as a float.Total float isthe amount of time that an activity can be delayed without delaying the projectcompletion date. On a critical path, the total float is zero.Total float is calledsometimes “slack”.You can calculate the total float by subtracting theEarly Start date of an activity from its Late Start date (Late Start date –Early Start date), or Early Finish date from its Late Finish date (Late Finishdate – Early Finish date.
TF = ( LS – ES )or TF = (LF – EF). OR. TF = (LF – Duration – ES). · Free Float (FF):- Freefloat is the amount of time that an activity can be delayed without delayingthe Early Start of its successor activity.
Thefree float can be calculated by subtracting the Early Finish date of theactivity from the Early Start date of next activity (ES of next Activity – EFof current ActivityN.B. If twoactivities are converging to a single activity, only one of these twoactivities may have free float.FFi = min(ESi+1) – Efiwhere min(ESi+1) is the least (i.e., earliest) of the early start dates of succeedingactivities.
· Interfering Float (Int. F(:- Interferingfloat is the time span in which the completion of an task may occur and notdelay the termination of the project but within which completion will delay thestart of some other following task.Int. F = TF ? FF · Independent Float (Ind.
F):- Theindependent float is a very convenient measure of scheduling freedom. Theindependent float of task is the maximum time can be delayed without delayingsuccessor activities, if all prior activities are finished as late as possible.It gives a measure of time available if the worst possible conditions prevailin the predecessor activities.It also givesan indication of the possible degree of decoupling the activity from the othersin the project, hence the name independent.In other words– it’s the free float of the late dates. Ind.
F=min (ES of the Succ.) – max (LF of thePred.) – D · Safety Float (SF(:- Safety Float is the maximum time an activitycan be delayed without affecting the final project completion if predecessoractivities are completed as late as possible.
This new measure appears to beone of the more useful float measures when scheduling a particular activity. N.B.It, permitsonly successor activities to be delayed, not the entire ProjectIn other words– it’s the total float of the late dates. SF=LF – (LF ofthe Pred.) – D vWho owns the Floats? The ‘float’ is the amount of time thatnon-critical activities can absorb, in excess of their original intendedduration, without impacting on the critical path of the works as a whole.
A Contractormay argue that it ‘owns’ the float because, in planning how it proposes tocarry out the works, it has allowed additional or ‘float’ time to give itselfsome flexibility in the event that it isn’t able to carry out the works asquickly as it planned. If there is a delay to the Contractor’s progress forwhich the Contractor is not responsible, it may contend that it is entitled toan EOT, even if the delay to progress will not result in the contractcompletion date being missed but merely in an erosion of its float. Inaddition, the Contractor may want to accelerate the works to keep the float infull and claim its costs of doing so.On the otherhand, an Employer may say that the Contractor has no contractual remedy forbeing prevented from completing the works at any time prior to the contractcompletion date, and is therefore not entitled to an EOT unless the delay toprogress will result in the contract completion date being missed. So, theEmployer would say that it ‘owns’ the float.
v What does the Contract say? The issue of who ‘owns’ the float is often the cause of disputesbetween parties to a construction contract over entitlement to EOTs. The firstport of call in the event of a dispute arising on this issue will be to reviewthe terms of the contract. In the united of kingdom, the express issue of’float’ rarely appears in standard form contract conditions. However, theanswer may appear in the EOT provisions. Where the EOT clause states that anEOT is only to be granted if the Employer delays completion beyond the contractcompletion date, then the likely effect of that wording is that the total floathas to be used up before an EOT will be due (i.
e. the Employer would ‘own’ thefloat). If, on the other hand, the EOT clause states that an EOT will be duewhenever the Employer’s delay makes the Contractor’s planned completion datelater than it would have been if it were not for that delay, then the totalfloat will probably be available for the benefit of the Contractor.
However, most contracts give no indication asto whether an Employer delay has to affect the contract completion date ormerely the Contractor’s planned completion date before an EOT is due. That iswhy parties should ensure that this issue is properly addressed at contractnegotiation stage. Ifthe Contract is silent, does the Contractor own the float?Priorto the 1999 case of Ascon Contracting Limited v Alfred McAlpine ConstructionIsle of Man ltd., if the contract was silent on the issue of float, the generalapproach adopted in the UK was that the Contractor would own the float becauseit was the Contractor who had built the float into the program to provide acushion for unforeseen problems. However, the current approach as establishedin the McAlpine case and supported by the Society of Construction Law Delay andDisruption Protocol, is that an Employer delay has to be critical before an EOTwill be due. This has the effect that float is not time for the exclusive useor benefit of either the Employer or the Contractor but, rather, exists for thebenefit of all parties to the contract. So, even if an Employer delay causes adelay to a Contractor’s planned completion date, an EOT will not be due unlessthat delay resulted in a delay to the overall contract completion date.Interms of what that means for acceleration costs, in the event that a Contractorsought to accelerate the works in order to keep the float, the current positionis that, unless the contract states otherwise, such costs would not berecoverable as the float would belong to the project rather than to one of theparties.
Thisposition can lead to unfairness and ambiguity. For instance, under contractswhere Employer delay has to affect the critical path before the Contractor isentitled to an EOT; if an Employer delay occurs first and uses up all thefloat, then the Contractor can find itself in delay and paying LADs as a resultof a subsequent Contractor delay which would not have been critical if theEmployer Delay had not occurred first. However, on the other hand, undercontracts where the Employer delay only has to affect the Contractor’s plannedcompletion date, the Contractor is potentially entitled to an EOT every timethe Employer delays any of the Contractor’s planned activities, irrespective oftheir criticality to meeting the contract completion date.Theposition established in the English courts is that neither party owns the floatif the contract is silent on the issue and the Contractor will only be entitledto an EOT for an Employer delay which impacts on the critical path i.
e. thecourts have elected not to confer a benefit on either party in the event of theparties’ failure to deal with the issue in their contracts.Giventhe position taken by the Courts, it’s important to deal with the issue offloat during the contract negotiation stage.