BIM and traditional documentation - Measures to mitigate the conflicts

BIM is a collaborative process to create a single source of data. Ideally, BIM shall be used since the first sketches of any facility, allowing the generation of all information from the same source of data. However, we are living a transition era where BIM documentation and traditional documentation are mixed up, creating a complex arrangement of data. Paul Prescott and Gabriel Olufemi of Pinsent Masons, a law firm, suggest some measures to mitigate conflicts for the different stages of the construction process.

‘If BIM is used on a project, hard copy drawings may continue to be used by the design team. Difficulties may, therefore, arise if there are any inconsistencies between the drawings and BIM models. For example, the drawings may show different dimensions or layouts to the configurations on BIM models.

There are some key contractual concerns to consider when using BIM on a future project.

BIM at tender stage

It is common for bidders to be issued with BIM models and drawings as part of the tender documents. If there are inconsistencies between the two, bidders may not know which to use to determine the correct quantities to calculate the tender price.

Employers must ensure that BIM models and drawings are consistent at tender stage. The tender documents should also clearly indicate the document or model, which would take precedence if there were any inconsistencies between them. If bidders do identify inconsistencies and there is no ‘priority of document’ clause in the general conditions or they make no reference to BIM models, bidders should, ideally, raise a tender clarification. In any event, bidders should always bring an inconsistency to the attention of the employer to avoid problems post contract award. 

 BIM at contract award

The contractor’s obligation is to execute the works in accordance with the design documents. If hard copy drawings are included in the contract documents, there may be inconsistencies between the drawings and BIM models. Disagreements may arise as to the extent of the scope of works under the contract (that is, whether the contractor is required to execute the works in accordance with the drawings or BIM models if there are inconsistencies between them).

While contracts usually contain a ‘priority of documents’ clause, they do not always identify which ‘design’ document is to have priority in the event of inconsistencies. In the Chartered Institute of Building Contract for Use with Complex Projects, precedence is given to BIM models over drawings. But the International Federation of Consulting Engineers Contract  – t he preferred form in Qatar – is silent on the use of BIM and so careful consideration should be given to how inconsistencies will be resolved.

Given that drawings and BIM models are both likely to be treated as design documents describing the scope of works, there should, ideally, be no inconsistencies between them.  It is therefore sensible, as they are documents forming part of the contract, that the drawings and BIM models have the same priority. However, as there is no set rule, bidders should carefully scrutinise the contract in cases where BIM is being used.

BIM post contract award

One of the challenges with BIM is to ensure that all the parties on a project buy into and use BIM software. Some design and build contractors may have challenges getting their supply chain to use BIM –  usually due to a lack of expertise or the increased cost of recruiting a BIM manager.

Some of the parties on a project are likely to continue to produce drawings, but irrespective of the priority given to the design documents in their contract, BIM models must be regularly updated throughout the design process. Failure to do this may result not only in inconsistencies but also incomplete or inaccurate design documents, which can have severe time and cost consequences.

In a traditional construct-only contract, the responsibility for correcting inconsistencies in the design documents issued to the contractor and updating BIM models should sit with the employer. The contractor should, in theory, be entitled to additional time and cost resulting from such inconsistencies if they delay the contractor in executing the works, although not all contracts will address this.’