Definition of Critical Path

The critical path is the longest sequence of activities in a project plan which must be completed on time to avoid delay.

In other words , delay in any of these activities will result in delay in project completion.

Critical path activities also known as zero float activities.

Zero float” means that you can’t delay a critical task/activities, as it will cause further delays by pushing back dependent tasks/activities and then delaying the overall project.

Example:
Pipe Installation
Welding – Installation – Providing supports
Are critical activities. Delay in any one activity can delay whole project.
However painting of pipes can be done
Just after welding or after installation.
Which is a non critical activity.