Saturday, July 14, 2012

I stand corrected: ‘clash detection is not a con!’

It is a ‘cop out’ by the AEC consultants-sector from doing what they supposed to, as per the definition of their profession.
It is a way of legitimising half-baked designs, badly documented in unnecessarily inflated mounds of documents.
It is a smokescreen to not doing the job right in the first place.

There are of course, mitigating factors that could possibly discharge some of the responsibility from the design consultants for this state of affairs on their projects.
Clients demanding cheaper and cheaper services, contractors getting more and more contractual and armies of PI insurers’ agents breathing down their necks enforcing limitations to liabilities.
Yet, there is certainly a threshold where an engineer (or architect for that matter) should not be allowed to use such label.
For me, this is when they become walking/talking ‘post boxes’ – moving documents from one party to another, adding ‘engineering’ looking things to them, but ultimately never fully achieving a working product, until a tedious (and expensive) process of ‘design development’ (often using real building elements) by the building contractors and their subbies.

So, forgive me if I find the practice of these same consultants paddling ‘cash detection’ as the magic bullet for their clients – a bit rich, if not outward hypocritical.
Clash detection has its place – as an auditing system, a safety net, a value-engineering tool, a refining instrument.
Performed by an independent party.

(picture borrowed from


  1. This is an interesting and polemic topic, and you've covered it in a fair fashion. There is a point of design refinement that only the owner and/or contractor may care to achieve. As you said, design pros don't usually get paid to reach a very high level of coordination.

    This is where an experienced architect becomes worth his weight in gold or more: by providing adequate space for equipment and laying things out in a manner that is efficient. I often cringe when I see "mile" long cooling and other similar pressure lines / pipes. Too much energy is waste routinely fighting friction.

    As a society, we must find a way to reward excellent design.

  2. There are a few glimmers of hope in the darkness.
    We had a mechanical engineer who gave us a (2D) ventilation design for an addon for a private hospital. I modeled the main ducts as there was some particularly tight areas, to find that the design had the main fresh air supply running along a grid line, i.e. through a line of columns. When flagged at a design meeting, we were told that they were commissioned to provide a working design, not one that fits... Instead of the usual expectation of additional fees to rework the design, they went away and made the design work, free of charge in an incredibly short time....

    So having the toolset, is a gentle way of encouraging the consultants (and any other participants) to pick up their game. I still fail to see why clients aren't withholding payments if the design they have asked for is incomplete and doesn't work!

    Clash detection can also be used for other purposes. I am working on a method for crane studies, which speeds up the whole process of analyzing and documenting, as well as adding accuracy. In residential, it can be used for ensuring smoke detectors are adequately positioned. It can be used for egress confirmation (unless you own a tool that has specific tools to check this, i.e. Solibri) and any thing else that requires tolerances.


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