THE DIFFERENCE BETWEEN COORDINATION AND CLASH DETECTION
BIM has brought a lot of improvements to the consistency of project deliverables. The project team are agreeing how they plan to exchange information, at what regularity and for what purpose at the project outset before commencing work. Having access to this information, knowing its intended purpose enables potential problem areas to be identified at an earlier stage in the project and communicated to the project team to be resolved whist the design is being developed.
“Coordination – The organization of the different elements of a complex body or activity to enable them to work together effectively.” (https://www.lexico.com/en/definition/coordination)
Coordination, or specifically design coordination, on a construction project is the process of checking each party’s information against the rest to ensure a single, unified set of deliverables that achieves the project brief. Coordination has always been paramount to the success of any construction project. Without robust coordination there is a great risk of errors, increased costs, delays or client dissatisfaction.
Contractually, the responsibility for coordination typically falls to the lead designer. This is because they are not only in charge of spatial coordination on the project, but also the coordination of deliverables against the project programme. If there is a potential issue highlighted whilst coordinating information, the lead designer is informed. If this is a conflict that cannot be resolved, that is where the responsibility of the lead designer comes in. They make the decision on what needs to happen to resolve the conflict and instruct the team accordingly.
“Clash detection – A Model Use representing the use of 3D Models to coordinate different disciplines (e.g. structural and mechanical) and to identify/resolve possible clashes between virtual elements prior to actual construction or fabrication.” (https://bimdictionary.com/en/clash-detection/1)
One of the approaches that has enabled good design coordination and project team communication is clash detection. If this process has been allowed for in the project programme and budget, the project team members agree the process on how that will be managed and record in in the BIM Execution Plan.
Clash detection is a technical validation process which informs coordination, highlighting physical issues with the coordinated design as part of an assurance process. It cannot be considered part of the traditional role of design coordination by the lead appointed party within their normal design fees.
Managing the clash detection process can be a significant amount of work for the appointed party responsible, as they will have to:
- Build the checking rules in accordance with what has been agreed in the BEP.
- Federate the models ready for checking.
- Run the checking rules on the federated model.
- Review the checking results on the model and record the issues appropriate to the project stage in a report.
- Communicate the issues of the report to the project team.
- Hold a clash detection workshop to run through any issues highlighted within the report that need discussing in order to resolve.
- Set who is responsible for resolving each clash and deadline for their model to be updated.
- Steps 2-7 are typically repeated at regular intervals to tie in with the project team meetings.
Clash detection brings potential value by highlighting significant issues to the project team earlier in the project programme, avoiding potential costly changes to the design after packages have been procured or on-site. It is not, however, automatically a part of coordination. Coordination can be carried out without any clash detection. It is a separate task for which appropriate additional fees should be considered.