Introduction

Imagine the site team telling you that while installing equipment on a project they found a major issue with the drawing in which a pipe and a beam are occupying the same space. To resolve this issue you rework the design, by which the project schedule is impacted and the construction is halted until the issue is fixed. But the impact on the project cost and schedule is irreversible.

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Using traditional tools and techniques it becomes difficult for the project team to identify conflicts like these before the construction begins since a construction project involves multiple disciplines and the amount of information the project members must account for is substantial and vulnerable to human error. The emergence of the Building Information Modelling(BIM) process, has transformed how construction projects used to be done, the constructability issues can be identified in the pre-design stages to avoid errors in the design and one such BIM technique is the Clash Detection.

What is Clash Detection?

To understand what is Clash Detection first one needs to understand, what is a clash? A clash occurs when two elements in the design occupy the same space, for example, a pipe passing through a duct. 

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These clashes can be both intradisciplinary or interdisciplinary meaning the MEP elements may clash with other MEP elements or Structural elements. Navisworks is a powerful tool used to generate a detailed clash report with individual images showing the clashes between the elements in the model.

The clashes can be classified as Hard, Soft, and Workflow clashes. The clashes where two elements in the design are interfering or colliding with each other are Hard Clashes, whereas if the design demands certain geometric tolerance between the elements and the design lacks that space it is a Soft clash, for example, an HVAC system requires space to allow for maintenance workers to operate into service the system, a Workflow clash occurs when there is a scheduling issue between work crews and equipment fabrication, delivery and installation in the project timeline. 

Clash detection, therefore, is the technique of identifying if, and where, or how, two parts of the building are interfering with one another. Hence, Clash detection is a powerful BIM technique for identifying the conflicts within the virtual design. 

Constructability and Clash Detection

Constructability is a project management tool to analyze construction processes from start to finish during the pre-construction stage to avoid any obstacles in the actual construction stage. Clash detection is a vital part of the constructability analysis to review and solve the issues arising with the building elements interfering with each other in conflict with the design demands. BIM Coordination Process includes Clash Detection reports, constructability reviews, and virtual or personal coordinated meetings with concerned stakeholders.

Due to the growing adoption of building information modeling in the construction projects, it has allowed for easier sharing of information between all project stakeholders using Integrated Project Delivery(IPD), where the project consultants, contractors, architects/designers, and the client has access to every development in the project. This collaboration has empowered architects, structural engineers, and MEP engineers to review the clashes and resolve them in the live model, avoiding the traditional RFI’s(Request For Information) and change orders. 

Benefits of Clash Detection

Clash detection is the essential part of the design process in the BIM workflow and can bring benefits to every stakeholder in the Construction project by :

• Reducing the number of change orders during construction leading to less human errors saving time, money, and resources for contractors, companies, and building owners.
• Encouraging the collaboration between architects, engineers, contractors to resolve issues early on and make the project design precise and accurate.
• Clash detection helps in maximizing the building space utilization, as the design teams of various services will be aware of where they could model elements in the given space without interfering with other services.
• Reduced variation between construction drawings and as-built drawings.
• Clash detection aids in reducing wastage, conflicts, and installation issues.
  

Conclusion

Clash detection benefits through advanced and robust technology are driving project owners, contractors, architects, engineers, and stakeholders in the construction industry to embrace BIM to maximize productivity.

Clash detection helps in real-time review and resolution of clashes, saving on rework and material costs, and keeps projects within the budgets and schedule.