MEP is an acronym used for Mechanical, Electrical and Plumbing systems for building projects. With the increasing complexity and functionality of each system, MEP activities are not confined to the traditional mechanical, electrical and plumbing system but also include fire protection, gas piping, process piping, pneumatic tubing, data systems etc. This article assumes that the design has been completed by ‘Design Consultants’ to a certain stage and then handed to ‘Installation Sub-Contractors’ who will validate the design and value engineer the design through the process of spatial coordination and procurement of components to meet the requirements of the design. The coordination of Mechanical, Electrical and Plumbing (MEP) systems amongst themselves and with other building systems including architectural and structural disciplines is a critical, challenging and time consuming task, especially in complex building projects with intense MEP requirements. The coordination process of Mechanical, Electrical and Plumbing (MEP) systems involves defining the exact location of each building system component throughout the building within the constraints of the envelope defined by the architectural and structural systems to comply with diverse design and operations criteria avoiding any interferences/clashes amongst building systems. Assuming that most companies undertake the task of MEP Coordination, without which the site installation from a ‘design only’ set of drawings would be too much of a risk, there are two ways by which the following process takes place:
2D MEP Coordination
The process starts with the design from the Design Consultant. The Sub-Contractor team will manually update the 2D CAD drawings or create their own set from the start. In creating these drawings a number of sections will be drawn and frequent attention given to ceiling void spaces in which the systems and services are being laid out. In an ideal world 2D MEP Coordination can work as long as all services and systems are assessed adequately and then drawn into a 2D drawing. The sizes of the systems would need to be manually added as would the heights and distances from gridlines or walls. The contractor will have teams of people for each system (HVAC, plumbing, electrical etc) creating their drawings based on the architectural ceiling void. In this method, there is no automated system to identify the conflicts in the MEP system and therefore there is a high degree of reliance on the intuition, imagination, technical knowledge and experience of the team members to lay out the services without site teams experiencing clashes.
Visualizing the potential clashes is made more difficult due to changes in ceiling profiles, not to mention the challenge of having to understand the impact of all systems as well as structural and architectural elements that may impede or impact a system or service route. What makes things worse is that a third party cannot easily review the drawings for any errors, nor can the design be easily reviewed or communicated with a project team. Additionally, if there are changes to the design or procurement-led changes then the process of undoing and re-doing 2D MEP Coordination projects becomes very cumbersome. The inherent weaknesses of 2D CAD software also come into play, one can draw something of one size and label it as something completely different. As the systems and services drawings are not checked in some form of automated method there is no guarantee that the 2D MEP coordination process will generate a clash free drawing. During the time of complex projects, it requires multiple section viewings which consuming a lot of time. These time commitments come with additional costs to each contractor.
3D MEP Coordination
This process is more collaborative and allows the ability to communicate the progress of the project quickly and easily, providing 3D visuals that resemble the final system and service installation. It starts with a clear direction in terms of spatial zoning which is then used as the basis to start modeling the HVAC, piping, plumbing and electrical services. As the architectural and structural models form part of the model, it is easier to insert services and systems without creating clashes. Once the model is complete and all systems and services have been added, the ability to identify problems becomes much easier compared to the 2D Coordination method. Firstly, one is able to walk through the model using roaming software to review the model and, secondly the use of clash detection software, such as Navisworks, highlights all clashes whether these are systems against other systems or systems against structure or architecture. Once highlighted, all clashes can then be corrected during the coordination stage of the project. Only once the model is interference free are drawings created. This leads to another set of benefits, unlike 2D coordination where each section must be drawn, the 3D software allows the creation of sections that are directly taken from the model. Additionally, as the 3D software is so intelligent, the sizes of systems are directly taken from the 3D model and therefore there is no chance of services or systems being modelled as one size and then labeled as another. Beyond the coordination stage, there are several other benefits from the 3D model, including use during facilities management, energy analysis and so on.
Irrespective of the MEP Coordination method used, the need for MEP Coordination arises due to the lack of detailed coordination during the design stage. Additionally, the need for fabrication and installation of building systems in accordance with industry and Sub-Contractor best practice requires MEP Coordination to be carried out by them. The 2D MEP Coordination process provides a limited interference-checking capability and therefore can and will result in more problems on site including additional re-work, change orders and inflating budgets. All of this makes 3D MEP Coordination a more efficient and the increasingly preferred method for the long term.
Current trends in the MEP industry show the evolution of a few more specific methods of MEP coordination, with varying degrees of involvement by the design consultants and the MEP contractors.
These methods are:
- Design consultant provides 2D, 3D designs and MEP coordination to the MEP contractor.
- The MEP contractor generates the 2D, 3D designs and MEP coordination himself/herself.
- Design consultant provides 2D design to MEP contractor, who then creates 3D models and handles MEP coordination.
The first, and one that is gaining increased popularity, workflow method is one where design consultants provide a spatially coordinated BIM model with MEP specification components, structural and architectural changes. Therefore, the BIM model is usable by the contractor.
The second method involves the MEP contractor designing all the models, both 2D and 3D, for installation. One of the disadvantages in this method for the contractor is added stress, since the contractor is responsible for the design and may not be able to employ designers with requisite expertise and he/she may even have to provide design liability insurance. There are benefits though, one is removal of abortive work for BIM modelling due to efficient use of time and thus, increased profit.
Method No. 3 sees the design consultant supply architectural, structural and MEP designs in 2D to the contractor, who then creates a 3D model to assess the design. This method may face hiccups in the process because certain disciplines will be represented in 2D and some will be in 3D, with different software used for each. So, if the contractor faces any issues, s/he may necessarily revert to the designer, who will alter the 2D design, and then the change has to be represented in 3D. Obviously, delays could result.
Additionally, useful features of the process have mushroomed. Quantity take-off analyses projects with a new degree of detail, taking into account quantities, locations and ultimately costs. Further, just as 3D BIM permits visualisation of the completed project, 4D BIM scheduling movies lets owners, traders and teams see how the building comes together. It can be used to monitor the project on-site. Also, BIM 360 Glue generates a coordinated model, consisting of individual models that all team members can look at. This can be ‘glued’, or updated models can be uploaded, on a regular basis. Each user can resolve clashes faster by comparing models and directly communicating with each other.
In the dynamic world of MEP coordination, new methods and features promise to crop up with unceasing regularity. The key is finding the method that works best for you.