We’ve been talking a lot about clash detection on our blogs lately, especially the ones that are focused on the subject of MEP systems. But what is clash detection, and how can it be resolved?

What is a clash?

There are five main disciplines associated with building design:

  • Architecture
  • Construction
  • Mechanical
  • Electrical Plumbing

When it comes to BIM, a “clash” occurs when components that make up a building do not coordinate well with each other and so conflict. Think about the human body – all of our organs have to function in sync in order to achieve expectations, and it is the same for a building system. All of the five systems mentioned above have to coordinate together in order for the building to operate efficiently, be sustainable and be energy efficient.

Why do clashes occur?

As we have mentioned, a range of services have to come together in order for the end building to appear. The Architect will produce a model, and then the structural engineer, mechanical and electrical engineer and the environmental engineer will all produce their own models based on that. Each of these models may contain documents, structured data files and other files which can contain non-geometric data about what is being built. These models are all then brought together into a digital model which will initially show what has been designed, and by the end of the project will show what has been built and installed.

This master model sits in the Common Data Environment (CDE) in a Level 2 BIM process, and with so many different models coming together it is inevitable that there will be clashes.

What types of clashes are there?

There are three main types of clashes:

  • Hard clash – where two components are occupying the same space, such as a pipe running through a steel beam. If this kind of clash isn’t detected until on site, then it can be costly and time-consuming to correct.
  • Soft clash – when the buffer zone of an element is breached, or it isn’t given the spatial tolerances it requires for maintenance access or safety.
  • Workflow or 4D clash – general time conflicts such as the delivery of equipment and materials, or the scheduling of contractors.

How can clashes be avoided?

The easiest way for clashes to be avoided is to document a set of standard procedures as part of your BIM Execution Plan (BEP) and also set out procedures for coordination in the Employer’s Information Requirements (EIR) – both of these are crucial contract documents.

During the design phase, therefore, the design team interface managers can then assess design decisions and clashes to determine whether they can be solved internally, and if not, they can separate the models out so that they can be reviewed by a design lead.

How are clashes spotted?

In the past, clashes tended not to get spotted until the construction phase, due to separate drawings being created – which are hard to check for compatibility.

The adoption of Level 2 BIM by the UK construction industry has meant that a master model can be produced, which is compiled of federated models. We can then use BIM integration tools and BIM modelling software to check for clashes within each individual model and the final master model as well.

How are clashes resolved?

We can use our clash detection software to scan each model and produce a report which can bring up duplicate instances of the same issue. We will then review and cancel any duplicate issues as part of the BIM process.

What does the future look like for clash detection?

BIM software tools are evolving every day and becoming more and more sophisticated allowing richer data to be combined into models. The widespread adoption of Level 3 BIM offers the most potential for improvement though, as enabling everyone to work on one coordinated and collaborative building model should mean that the number of clashes is dramatically reduced from the start.

This may all sound a little complicated, but don’t worry, you don’t have to do all of this by yourself. Working with The CAD Room will give you peace of mind, as our expert team will take care of all of the tasks associated with clash detection and BIM coordination.

Contact us to find out more by calling us on 0161 427 0348, emailing us at office@thecadroom.com or by using the contact us form on our website.