Last edited 07 Aug 2019

Project crashing

Project crashing is a process that can be used in the management of construction works when the programme is running behind schedule.

Project crashing can be necessary when:

The aim of crashing is to achieve the maximum decrease in schedule for minimum additional cost. This can be done by:

  • Addressing productivity issues being experienced by the current resources and trying to find ways of increasing their efficiency.
  • Increasing the assignment of resources on critical path activities. These could be internal resources or subcontracted recources.
  • Adopting different techniques. This might include off-site prefabrication, extra scaffolding, temporary weatherproofing and so on.
  • Overlapping activities (fast tracking).
  • Working longer hours.
  • Additional supervision.
  • Changes to design or specification (for example standardisation replacing bespoke solutions)
  • Reduction in scope (for example transferring work to a separate post-contract agreement for occupational works).
  • Early procurement of items.

Many of these strategies will necessarily lead to some additional costs being incurred, or cost uncertainty. Whilst the same number of tasks need to be performed, they are condensed into a shorter period, and so are likely to require more resources. In addition, purchasing costs may be higher due to time pressures, incomplete information and the complexity of managing the interfaces between elements. A greater number of variations are also likely than on a traditional contract.

It is important to be clear whether it is the client or the contractor that will bear these additional costs.

There are several risks attached to project crashing. While resources are typically focused on critical path activities, there is the possibility that non-critical paths will also be affected. Quality, safety and compliance should not be affected as a result of the critical path being crashed. Another risk is that new resources may not be as productive as existing resources, because they may be unfamiliar with the project, the programme and the tasks at hand.

This may require that the size of the contingency is increased.

Project crashing should be resisted if:

  • It is no longer cost effective to continue.
  • It causes another path to become critical.
  • Time reduction is no longer realistically achievable.

An alternative to project crashing is fast-track construction, which is a scheduling technique that can be used to compress the overall project schedule. Typically this is decided at the beginning of a project, organising it so that the design and construction phases overlap. This means that that activities normally performed sequential are rescheduled to be performed in parallel or partially in parallel. This will reduce the overall programme, but is likely to increase costs and risks.

For more information, see Fast-track construction.

[edit] Related articles on Designing Buildings Wiki