2: Concept design
The project brief should continue to develop throughout this stage and it may be necessary to revise performance targets as a result of the developing concept design. The project brief may be 'frozen' at the end of this stage and change control procedures introduced.
NB Throughout this stage, the word 'supplier' refers either to an integrated supply team appointed to design and construct (and perhaps operate) the proposed development, or to design consultants if suppliers have only been appointed to design the proposed development at this stage.
Once the contract for suppliers to design (and perhaps construct, and even operate) the development has been awarded, the successful supplier submits a post-contract BIM execution plan (BEP) providing more detail about their methodology, confirming their (and their supply chain’s) BIM capabilities and providing a master information delivery plan (MIDP). The master information delivery plan sets out when project information will be prepared, by whom, using what protocols and procedures - from the supplier's perspective (the employer's information requirements sets this out from the employer's perspective).
Where more than one supplier is appointed, there may be one overarching BIM execution plan and master information delivery plan, with responsibility for its preparation set out in the appointment documents, and then secondary BIM execution plans prepared by subsequent suppliers, informed by the content of the primary plan.
The supplier may hold a project induction meeting to help develop the post-contract BIM execution plan and master information delivery plan, and to confirm capabilities and capacities, define roles and identify training needs.
The BIM execution plan should include a volume strategy, which describes how the information models will be divided into manageable spatial subdivisions. The separate volumes will be based on important aspects of the design or specialised functions, will allow multiple disciplines to work on project models simultaneously and should be sized to ensure the individual file sizes do not become too large and then become difficult to transfer and read in other software.
If it has not already been provided by the employer, the supplier should set up a common data environment (CDE) to manage the creation, sharing and publishing of project information. This is the single source of all information relating to the project and should be set up to facilitate the spatial coordination and information exchange processes described in PAS 1192.
If it has not already been done, the supplier's information manager ensures that information management solutions function properly, information management processes are in place and that participants have the appropriate skills and competences. If there are any interoperability, training or other issues, these should be resolved before design commences.
- Aesthetic intent, form and spatial arrangements.
- Outline structural and services designs.
- High-level simulation results to determine whether the design is likely to comply with requirements.
- Outline site and landscape design.
- Outline specifications.
- Schedules and reports demonstrating compliance with the project brief.
- Preliminary construction and phasing sequencing studies and general project programme information.
The information in design models, drawings and documents is collectively known as the ‘project information model’ (PIM). It will generally be made up of a number of federated models that originate with the employer, architect, structural engineer, building services engineer, contractor, sub-contractors, suppliers and so on. At this stage, the built asset might be represented by massing diagrams or 2D symbols representing generic elements, with some critical elements developed in more detail.
It can also be useful at this stage to generate presentation material such as photo visualisations and 3D walk-throughs that help facilitate employer assessments and consultations with user panels, champions, and other stakeholders.
The local planning authority should be consulted to determine the preferred form and content of the planning application, dates of planning committee meetings, committee procedures, possible planning conditions and planning obligations, the amount of the community infrastructure levy, the planning fee and the requirement to undertake an external consultation process.
For large or sensitive projects, it may be necessary to prepare an environmental impact assessment (EIA) and it may be appropriate to seek a screening decision and/or a scoping study from the local planning authority to determine whether an EIA is necessary and what information it should include.
An elemental cost plan should be produced from the project information model, accompanied by a schedule of assumptions made. This should identify any abnormal costs and whether it may be appropriate to undertake a value management exercise. A cash-flow projection should also be prepared, and an assessment of whole-life costs might be undertaken.
An end of stage report should be prepared, summarising key issues, identifying risks, setting out the project programme, identifying what else has to be designed, and assessing the likelihood of receiving planning permission and building regulations approval. It might also set out a soft landings strategy and summarise the outcome of consultations. However, the report should only include required, or key co-ordinated information and necessary interpretation. It should not be filled with unnecessary information and should not duplicate information that already exists elsewhere.
The supplier should prepare an information exchange (or 'data drop') as required by the employer's information requirements. This involves issuing published information into the employer's information environment. For level 2 BIM this information may include:
- A series of federated building information models prepared by different design teams, including non-graphical data and associated documentation, and comprising native and industry foundation classes (IFC) files. IFC is the international standard for building information modelling used for sharing data across different software applications.
- Construction operations building information exchange (COBie) files and other structured data such as schedules. COBie is a non-proprietary multi-page, spreadsheet data format focused on delivering asset data rather than geometric information.
- Drawings and reports. These may be read-only PDFs.
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Have necessary consultations been carried out?
Is planning permission likely to be granted?
Should a planning application be prepared?
Updated employer's information requirements.
Updated project management plan.
If a planning application is submitted at this stage, this might include material generated from the project information model, such as; 2D site drawings, plans, elevations, schedules of accommodation, 2D and 3D visualisations from key views, an outline specification, the project programme, the construction sequence and other managed information.
On receipt of a planning decision the employer may, if necessary, consider whether to submit a revised application or to lodge a planning appeal. It may also be necessary to update the project brief, employer's information requirements and project management plan to reflect planning conditions or planning obligations imposed upon the project.
Next stage >> 3: Developed design.