Monday 13 January 2014

3D MEP Coordination: An Effective Way to Reduce Rework and Increase Efficiency

As the architecture, engineering and construction (AEC) industry faces tremendous pressure to deliver optimal projects within stringent deadlines, improving process efficiency and reducing rework is certainly the need of the hour. The design and construction-related rework is one of the critical factors that adversely affect productivity, profitability and timely completion of projects for both contractors and owners. Besides, it impacts designers, subcontractors, MEP (M&E) engineers, consultants and the entire downstream chain. In comparatively larger and more complex projects, the design-build rework can negatively influence the entire project workflow, delay project delivery, and cost more than what was originally estimated.

As mechanical, electrical, and plumbing systems account for a significant value of the project, the prudent use of building information modeling (BIM) tools to effectively coordinate MEP (M&E) systems helps reduce rework and increase productivity. On the other hand, the lack of well-planned interdisciplinary MEP (M&E) coordination results in duplication of efforts, major interferences and design clashes on site, as well as fabrication changes and errors.

Since BIM requires comprehensive pre-construction planning and multidisciplinary coordination, its adoption by the MEP (M&E) team increases technical interoperability among various members during building services coordination. In BIM-led MEP (M&E) coordination, building services designers, consultants, and subcontractors are involved during the design and planning stage. One of the most crucial factors for an effective and accurate coordination exercise is to decide on a specific protocol for creating virtual architectural, structural, mechanical, electrical, plumbing and fire protection models of the same facility. Subsequently, the team should agree on mechanisms to merge the models from different trades and create a combined coordinated services MEP model.

For instance, the designers use Revit Architecture application to prepare architectural BIM models that accurately represent elements, such as walls, doors, windows, ceilings, and casework. Furthermore, each of these elements has a range of parameters, including thickness, height, materials, and texture, among others. Using this architectural model as a reference point, a structural model will be created using Revit Structure which features vertical and horizontal structural framing, foundations, and slabs.

Subsequently, the MEP (M&E) contractors and subcontractors design separate models for mechanical, electrical, and plumbing systems using 3D MEP modeling software (such as Autodesk MEP and Revit MEP). Usually, the mechanical models include HVAC ducts, piping assemblies, hangers, diffusers, and pipe insulation, to name a few. The electrical models will represent details concerning conduits (feeder and underground), junction boxes, lighting systems, cable/wire bundles, and cable trays, amongst others. The plumbing system model includes storm and sewage lines, plumbing assemblies, hot/cold water piping, and other specialty equipment.

Once the respective architectural, structural, and building services models are in place, they have to be merged and taken into a clash detection application and specialist interference-checking application, such as Autodesk Navisworks. Any clashes and inconsistencies, including the geometry-related hard clashes, the clearance clashes, and workflow clashes are detected. Post clash detection, the combined services models and drawing sets have to be prepared to show how MEP (M&E) systems fit together in the same space.

As a result, the MEP (M&E) installers and fabricators receive well-coordinated and clash-free building services drawings on site, which drastically reduces the number of installation conflicts in the field. Additionally, MEP (M&E) BIM coordination leads to a greater number of assemblies being prefabricated off-site in a controlled factory environment, which in turn improves the logistical flow on site. Moreover, another positive outcome of BIM-driven MEP (M&E) coordination exercise is relatively lesser number of change orders and RFIs (request for information).

All the above positive effects of MEP (M&E) BIM coordination make the design-build process more efficient by increasing project’s schedule compliance whilst reducing design and construction-related rework.

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