Design Framework for Building Services 5th Edition (BG 6/2018), written by David Churcher, John Sands & Martin Ronceray, and published by BSRIA in June 2018 defines a clash as: ‘Two distinct elements occupying the same space. Space for access, installation and maintenance must be allowed for.’
It identifies three types of acceptable clash:
- Critical: Major clash - must be resolved at this stage.
- Moderate: Easily resolvable – does not have a major impact on ongoing design. Can be resolved at a future stage.
- Allowable: Acceptable clash – resolution not required in the design model.
See also: Clash avoidance.