Global construction practice has seen substantial changes over recent years, with the arrival of BIM being a key factor. Building Information Modelling, known as BIM, is a process that involves the creation of 3D models, which enables designers and engineers to create accurate construction scheduling, estimate costs and adapt intelligently to design changes. Accurate building information models and precise building designs are created from the outset, which benefits all stakeholders in the construction process, particularly MEP (mechanical, electrical and plumbing) designers. MEP (M&E) designers or engineers design MEP services, while MEP contractors are then responsible for spatial coordination, detailed design, fabrication and installation. Though BIM drives an effective process for MEP (M&E) design services, there are some risks involved. We look at how these risks can be mitigated.
Firstly, it is useful to understand exactly what the BIM process contributes to MEP engineering design. A BIM model helps visualise spatial MEP requirements. Detailed views are created for analysis, and any clashes of spatial requirements are identified and can be resolved at an early stage. Designs can be altered to mitigate any clashes, and these changes can be seen in the model.
The progress of the MEP design and coordination workflow process has been supported and driven by technological advancements. BIM technology has played an important role in making this possible, especially the use of 3D models through Autodesk’s BIM 360 tool. BIM 360 is a cloud-based software platform developed primarily for construction, which employs checklists, equipment tracking and the monitoring of tasks to improve quality and on-site safety. Within BIM 360, models can be utilised for 2D construction documentation and the 3D coordination of trades. BIM 360 permits the control of processes by project managers, subcontractors, designers and architects at all design stages. It enables the sharing of vast amounts of information between stakeholders and easy communication.
MEP designers can utilise architectural, structural and trade models to plan in detail from the onset of a project by designing in 3D. In general, the process involves MEP design and installation workflows that will streamline planning, designing, coordination, fabrication, installation and construction of a project. Following architectural design, the MEP design engineer develops building services design elements, such as lighting, cooling, heating, drainage, waste, fire prevention and protection services. In most cases, the design engineer is not involved with the detailed spatial design of building services. Usually, it is the MEP, or trade, contractor who carries out the detailed spatial design and installation. It falls to the MEP contractor to convert the consultant’s design into an installation-ready MEP format and provide MEP shop drawing services. At times, fabricators creating ductwork or pipework elements, electrical ladders or sprinklers in a module also contribute.
The BIM process brings all stakeholders on to the same platform at every design stage.
Therefore, an effective collaboration tool would be required to:
- Enable access to MEP designers, architects, structural designers, MEP contractors
- Host various formats for files and documents
- Ease communication
- Permit designers and shareholders to work on the same models and share design data
BIM 360 Team with Collaboration for Revit (C4R) offers this. It integrates stakeholders and project information into a single cloud-based platform and improves quality while reducing rework. Checklists can monitor safety on site, equipment can be tracked and asset data can be collated. Any problems can be resolved early in the design process, minimising delay, cost and rework.
BIM Process Risks for MEP
If architects, modellers and designers do not communicate properly, designs may not be properly integrated and the occurrence of errors in the MEP model will increase.
Building Code Understanding
Client needs and local code requirements are of paramount importance and must be clearly understood. If misunderstandings of building codes and client requirements occur the MEP design will be negatively impacted.
Stakeholders must coordinate effectively. Any modification executed by any MEP service should be communicated to all other trades. Failure to do so can create hazards at the project implementation stage.
The BIM process can help determine overall costs and take off quantities. MEP resources, labour and prices are considered, but materials availability and costs may vary over the duration of the design and implementation, affecting cost estimation.
Effective BIM usage requires in-depth knowledge of BIM technology and Revit, Navisworks, etc. to develop precise MEP designs. Errors could prove costly.
Incomplete BIM Use
In common practice, BIM is used for a specific MEP objective rather than for each and every part of the design process. These include:
- Remodelling or renovation
- Material takeoffs and estimation
- Design models by contractors
- Detailed models of MEP components
Unless the BIM scope and output are accurately defined, the intended use of the BIM model may not occur.
BIM Model Not Shared with Construction Team
When 2D documents are printed from the model, some of the 3D data may not be transferred. The construction team may need to design a new 3D model, leading to unexpected changes. Designers may not share models with contractors because they are incomplete or do not tally with the construction documents, creating errors and tensions.
Not Possible to Model Everything
Creating models is time consuming. Many details, such as size, shape, location, quantity, and orientation with detailing, fabrication, assembly and installation information, can be included. It may not be possible to create models for every portion of the design, resulting in an incomplete overall picture.
MEP Design Handoff
Contractors traditionally received 2D line diagrams, schedules and specifications of the design from MEP designers. Currently, an increasing number of MEP design engineers create models, raising confusion about who is responsible for duct placement, equipment placement and coordination responsibility – designers or contractors. Models created by MEP designers may not be spatially accurate enough during the early stages.
However, there are several ways to mitigate these shortfalls, such as:
- Early BIM Adoption (During Design Stage)
All project stakeholders should be encouraged to use BIM from the design stage, with clear guidelines for its use. If BIM is adopted at a later stage without clear specification of its purpose, the results could be confusion, wastage of time and increasing costs.
- Defined Roles within the BIM Process
Design and modelling roles must be clearly defined before beginning design. If MEP subcontractors need to provide MEP BIM, with accurate routing, attachment details and equipment connections, they must be clearly informed of this and it should be part of the contractual obligations. They will not be able to rely on MEP consultant models in such a case.
- Improved Coordination Skills
MEP design in BIM currently utilises improved spatial coordination skills during the design phase. This could be a result of employing more technically qualified professionals for these services, and as a consequence, contractors are presented with more accurate models to work with.
- Accountability for Coordination
Internal coordination is necessary for a viable BIM model, much like a 2D drawing set used to be. Revisions, modifications and file versions must be coordinated as well. Since 3D models are complex, coordination must be monitored and controlled to prevent expensive and unnecessary rework. Even though files can be hosted in the cloud, it is advisable to maintain backups.
It is a certainty that precise, effective design with fewer errors is possible using BIM but there may be challenges in achieving those designs. Specifying the role of BIM, its usage, the stakeholders involved and the challenges to be expected can help optimise the benefits of using BIM and minimise its risks. The positive impact of building information modelling will be felt for some time. Analysing and mitigating the risks involved in its use can only benefit the industry and its players.