How clash detection in BIM could change builder's duty to warn

Responsibility for the information entered 

Often the BIM model is filled with data by different parties involved.
In principle, each party is liable for the accuracy of the information and designs they supply and enter. However, that liability may be limited by the obligation to warn that rests on the builder. There may also be such a warning obligation on consultants involved, such as an architect and/or structural engineer, for example under the DNR 2011.  

Warning obligation

Both the law, the UAV 2012, and the UAV-GC 2005 impose a warning obligation on the builder: 

1. The law(Article 7:754 BW) - no general terms and conditions
   
   The builder is obliged to warn its client about inaccuracies in the order insofar as it knew or should have known about them, including design errors.
2. The UAV 2012 (Section 6 paragraph 14)
   
   The UAV 2012 slightly limits the duty to warn under the law. The builder is obliged to warn the client of apparent errors and/or defects in, among other things, the prescribed constructions, working methods, orders and instructions. The builder is not obliged to check the design in detail: the builder tests marginally.
   
   
3. The UAV-GC 2005 (paragraph 4 (7))
   
   The UAV-GC also imposes a somewhat stricter requirement on the duty to warn because, just as under the UAV, the builder is obliged to warn about manifest errors in, among other things, the specifications, the annexes to them, the basic contract and the information made available by the client. In contrast to the UAV 2012, the builder is obliged under the UAV-GC 2005 to fully check the design. 

The consequences of failing to warn under the UAV 2012 and UAV GC 2005 are substantial: the builder is directly liable for the consequences of failing to warn, minus at least the costs and any own fault correction. When there is a design defect, it is often debated in practice whether the builder should have warned the client of a design defect. Whether the builder should have warned depends, among other things, on the following circumstances: 

• The (purported) expertise of the builder;
• The severity of the error;
• The visibility of the error (does the error "stand out");
• Principal's expertise and assistance;
• Is there a risky design;
• The time the builder had to check the pieces. 

Possibly rather a "cow of an error" (an error you know or should know about) by BIM? 

The clash detection of BIM particularly affects whether the error is "eye-catching.
Because of BIM, the builder usually has earlier access to more specific building information (think of building physical properties of a specific part in the building and access to the digital building library) to assess whether a design is feasible compared to during a traditional (not digitized) construction process. BIM can thus help ensure that design errors can be identified at an earlier stage.

What to do if clash detection detects an error?

When the clash detection detects the error, it can be argued that there is a "cow of an error" because the software detects this error. The builder is made aware of this by the software and knows or should know about the error. So in that case, the builder should warn the client about the error. Then make sure:

• The warning is given in writing at all times;
• The warning is concrete and specific;
• You do not take on responsibility that does not belong to the builder according to the contract, but let the client come up with a solution for those cases himself. That is a change in the contract with corresponding consequences.

Note that if the information entered is incorrect, the outcome of the clash detection will also be incorrect. Thus, it is important for the builder not to rely solely on the outcome of clash detection.

Tips for practice

Clash detection is a great tool that can reduce failure costs and help a builder meet its duty to warn. To ensure that the builder actually benefits from clash detection, the following is important:

• Make clear agreements as to which party will perform the clash detection and who will be responsible for it;
• Make sure that at all times it is recorded/traceable which party entered and/or changed certain information and the corresponding times. This is important because in this way can be traced:
  1. whether the clash detection could have detected the error based on the information known in BIM at that time;
  2. which party entered the incorrect information and/or design error, so that the builder can (potentially) hold that party liable for it;
• Never rely solely on the outcome of clash detection.