MEP Modelling | MEP Pre-Fabrication Models and Drawings

The MEP fabrication modelling process is widely used in commercial and residential construction projects today because it improves project schedules which save costs and also improves on-site productivity as well as safety and space utilisation by shifting the fabrication process offsite. Prefabrication modelling offsite requires detailed and accurate MEP (M&E) pre-fabrication models and drawings which are not only installation-ready but should also be machine-ready for fabrication.

There are several project stakeholders who play a specific role in the MEP fabrication modelling process, from the project owner, the MEP designer, the MEP contractor and also the MEP fabricator or manufacturer. Collaboration between teams, coordination of different processes, compatibility of MEP fabrication software programs and inaccessibility to content libraries is a challenge. Here are some of the challenges faced in the industry during the MEP fabrication modelling process:

1. Collaboration and coordination of multiple stakeholders in the MEP fabrication process – Coordination and collaboration of key project stakeholders in the MEP fabrication modelling process has a significant impact on the cost, time and resources allocated. Ideally, to avoid cost overruns, save time and utilise resources strategically, the designer, general contractor, MEP contractor or consultant must adopt a top-down approach in the fabrication process. They must define, identify and implement an approach which will enable them to collaboratively work and coordinate with MEP fabricators, installers and manufacturers for the fabrication of MEP components

2. Compatibility issues of different MEP fabrication software programs used – For fabrication of MEP components, there are two main MEP fabrication software programs used in the market today, Autodesk Fabrication and Revit MEP, with MEP fabrication detailing features. Whichever of the two types of software are to be used there are several challenges as MEP (M&E) pre-fabrication models and drawings need to be compatible to have direct machine interface (DMI).

The fabrication features in Revit MEP are widely used because it is a more financially feasible option than Autodesk Fabrication, however, it is not compatible with direct machining interfaces. While fabricators and manufacturers may require models in Autodesk Fabrication format (which is required when sending for machining), most fabrication modelling companies use the fabrication features of Revit MEP, producing a format which is not compatible. To convert Revit-based fabrication drawings to Autodesk Fabrication models, almost more than 30 percent of the work has to be redone. Remodelling leads to a delay in project delivery, an increase in costs and in some cases also results in errors in fabrication of components.

3. Inaccessibility to content libraries – Access to country specific content libraries is available on Revit MEP only if Autodesk Fabrication is installed. This poses a challenge for fabrication designers who require fabrication configurations when developing Revit MEP fabrication models. While Revit has default fabrication content libraries which contain a basic of generic MEP parts, access to associated product data and fabrication content such as generic UK Metric and US Imperial content, required to develop a MEP fabrication model, is accessible only once Autodesk Fabrication CADmep is installed. If Autodesk Fabrication products such as CADmep, ESTmep and CAMduct are available, fabrication configurations can be listed and used within Revit.

4. Rework of issue drawings – Conventionally, MEP engineering design is a two-tier system wherein the MEP consultants develop plans and schematics which are then submitted to the contractor for detailing, spatial coordination, fabrication and installation. In most cases, the MEP contractor has to rework the drawings provided by MEP consultants to make the issue drawings suitable for fabrication. The 3D M&E (MEP) coordinated drawings or issue drawings provided by MEP consultants must not only be clash-free they should be installation-ready and suitable for fabrication.

Given the challenges in the MEP fabrication modelling process, it is widely adopted in building projects today and by fabricating MEP parts off site, you not only save on costs, but it also helps to improve on-site productivity, project schedules and allow for strategic utilisation of space on-site. MEP fabrication modelling helps in pre-construction planning, in predicting results from project schedules, saves on material costs and installation costs and helps in managing project resources and budgets. This provides a competitive advantage in the construction industry where there is high level of competition to deliver projects on time and within budgetary requirements.