Last edited 15 Jun 2018

Design chill

Building design is generally an iterative process in which the design becomes more detailed and more 'fixed' as the project progresses.

At certain stages in the design process, packages of information are prepared for the client to approve, and once this approval has been given, the design is ‘frozen’ and change control procedures are introduced to ensure that no more changes are made without the permission of the client.

However, there can be an intermediate stage before design freeze, known as ‘design chill’ or ‘part freeze’.

The Construction Special Interest Group, Competency Working Group (ConSIG CWG) of the Chartered Quality Institute (CQI) suggest that:

At design chill, all aspects of the design may evolve, although formal controls are placed on any changes to issued design documents. This might mean that interim change may occur within particular aspect of the works, which, when finalised, are formally reviewed and incorporated into the design.

Design chill also has the effect of reducing possible diversions into development that over-engineers the design or introduces additional “benefits” that were not foreseen at the start of the work.

Parts of a design can be chilled whilst permitting other aspects to continue to develop; for example, the civil aspects may be chilled, allowing M&E design to continue in the full knowledge that there will be no change to the structure.

For more information see: Design freeze: a quality perspective.