Scheduling terms
The critical path is the chain of linked activities that decides your finish date. Slip any one of them by a day and substantial completion moves by a day, while everything off the chain has float to spend. This page explains the method in plain terms, works one tenant improvement by hand, and shows which part Fidrel does for you and which part stays your judgment.
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The path is the longest chain through the logic, not the trade with the largest contract or the most people on site. A superintendent who watches the biggest crew and ignores a short inspection hold that sits on the chain loses days that the plan never had to spare.
A Gantt chart is a picture of dates. If the links behind the bars are missing, the chart looks finished but the critical path is only a guess, because the method needs every activity tied to what it waits for and to what waits for it.
A framing crew that finishes early and a long-lead item that arrives late can swap which chain controls the finish. A path read out at the kickoff meeting is usually stale by the second month, so it has to be read again after each update.
The method needs four inputs: activities with durations, the logic that links them, a calendar that says which days are work days, and a finish to measure against. Add the durations along every chain from start to finish and the longest chain sets the earliest possible finish. A forward pass gives each activity its earliest dates, a backward pass from the finish gives its latest dates, and the gap between the two is total float: the working days an activity can slip before the finish moves. Activities with zero float are the critical path. A job can have more than one critical chain, and an activity with a day or two of float is near-critical, which means it is one bad week away from the path.
Scheduling
Take six steps, all finish-to-start with no lag: demolition 3 days, framing 4, electrical rough-in 5, plumbing rough-in 3, drywall 6 after both rough-ins, paint 4, and a 2-day millwork install that waits for paint and for a 10-day cabinet fabrication that can start once demolition is done. The longest chain is demolition, framing, electrical, drywall, paint and install: 3 + 4 + 5 + 6 + 4 + 2 = 24 working days. Plumbing runs beside electrical and has 2 days of float. The cabinets start on day 4 and are not needed until day 23, so they have 9 days of float, and if the shop slips more than that, the cabinets become the critical path and the install date moves with them.
Step 1
Select an activity and add its Predecessor under Dependencies, choosing the Type (FS, SS, FF or SF) and a Lag in working days. An activity with no links cannot sit on any chain, so link everything before you read the path.
Step 2
Choose the Working weekdays and add the Non-working dates, such as public holidays and shutdown days, because the path counts working days only. Fidrel can suggest holidays, but you confirm the local ones for the project.
Step 3
Open the View menu and tick Critical path. Activities with zero total float are drawn in a separate color on the chart, and the Critical quick filter, or the Critical path box under Filter, narrows the list to those activities alone.
Step 4
Enter progress and actual dates each week and the path is worked out again from the plan as it stands. Use Save baseline first, and the schedule shows Baseline finish, Forecast finish and Variance beside the chain so you can see how far it has moved.
Fidrel works a backward pass on the actual plan: an activity that has started keeps its actual start, each link holds its successor back by its lag in working days, and the working calendar decides what a day is. Zero total float marks the activities that control the forecast finish, including a last activity with no successors whose own finish is the latest. On the chart those activities are drawn in a different color, and an activity can also be blocked by an open RFI or an open issue, so you can see what is holding the plan. Only project and organization administrators can change links and dates; participants and guests with access to schedules read the same path.
Fidrel shows which activities are critical, not the total float of each activity in days, and near-critical activities are not marked. There is no schedule risk analysis, no delay or time-impact analysis and no resource leveling in Fidrel, so the path comes from the logic and the calendar alone. Primavera P6 files are not read; the import takes a plan saved by Microsoft Project as XML, an Excel or CSV sheet, or a Fidrel schedule. If you need to prove a delay to an owner, the path shows where the plan stood, and the analysis stays with you.
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The project system of the future connects people, documents and decisions. Discover the thinking behind Fidrel.
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On site, answers need to be close at hand. Fidrel displays DWG drawings in your mobile browser, within the project’s document structure.
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When everyone can see the next step, moving the project forward becomes easier. Fidrel brings activities, dates and reported progress together in a shared Gantt view.
Read moreScheduling terms
Anything else on your mind? We are happy to help.
Talk to usIt is the longest chain of linked activities from start to finish. Every activity on it has zero float, so a one-day slip on any of them moves the completion date by a day.
Yes. When two chains are exactly as long, both have zero float. Fidrel marks every activity with zero total float, so parallel critical chains are all highlighted.
It can. Actual starts, late deliveries and early finishes change which chain controls the finish, and Fidrel works the path again from the plan as it stands after each update.
Yes. Tick Critical path in the View menu and the activities with no float are drawn in a different color. The Critical quick filter lists only those activities.
Fidrel reads Microsoft Project saved as XML, Excel and CSV sheets, and its own schedule file. Primavera P6 files are not read, so a P6 plan has to be exported to one of the supported formats first.
Project administrators and administrators of the organization change activities, links and dates. Participants and guests with access to schedules see the result but cannot move a bar.
