The Society of Construction Law’s (SCL) Protocol and the International Recommended Practice 29R-03 Forensic Schedule Analysis from the Association for the Advancement of Cost Engineering (AACE), are the main official documents regarding delay analysis. Most of the information of this article relay on these documents.
A comprehensive delay analysis method should enable the concurrent determination of three critical aspects:
- Project Progress at the time of delay: The actual progress of the project can significantly impact certain events, while the contractual term might remain unaffected.
- Natural Change of the Critical Path: Delays affecting critical activities influence the contractual term. However, considering that the critical path may evolve during the project’s life cycle due to work progress and prior delays is crucial.
- Effects of Delay and Actions: Contractual requirements often demand that contractors take action to minimize delay effects, irrespective of their responsibility.
SCL methods
The SCL recognizes six widely-used delay analysis methods in the industry:
- As-Planned vs. As-Built (APAB) / Planned vs. Executed: A straightforward method comparing agreed planning with actual activity start and end dates. No specialized software is required; instead, analysts use their experience and common sense to determine the critical path.
- As-Planned vs. As-Built Windows Analysis (APABW): The project is divided into windows based on milestones or significant events (critical path changes). Expert reports commonly utilize this method, relying on analyst experience and common sense when updates and baselines are questioned.
- Time Slice Windows Analysis (TSW): A windowed observational approach where project updates are essential to measure delays on the contemporary critical path. Unlike As-Planned vs. As-Built Windows, the logic is dynamic and changes with project plan updates.
- Impacted As-Planned (IAP): Delay events occurring throughout the project are introduced into the agreed baseline, and the new completion date is analyzed.
- Time Impact Analysis (TIA): This modeled method uses updated schedules throughout the project’s execution, adding delay events after the update date to study changes in the actual critical path for that period.
- Collapsed As-Built (CAB): A more complex method but efficient once modeled. It allows for calculating compensable excusable delay, non-excusable delay, and non-compensable excusable delay with ease.
By exploring these methods, construction projects can conduct effective delay analysis, enabling better decision-making, improved project management, and successful project completion.