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The Process and Benefits of Creating Prefabricated MEP Modules

Published: 12/06/2019

Country: United Kingdom

There was a time, not so long ago, when prefabrication for construction was considered an impractical and expensive proposition. Well, no more. The construction method of the off-site assembly of various components and then transporting them to the construction site is now practical, able to produce assemblies, or modules, of high quality, capable of suiting budgets and more. Building Information Modelling (BIM) can combine with fabrication to facilitate integrated engineering workflows. Specifically considering prefabricated MEP (mechanical, electrical, plumbing) systems modules, it becomes apparent that accurate MEP coordination and drawings of these modules further the ease and effectiveness of designing prefabricated MEP modules.

What is an MEP Module?

The MEP industry has traditionally involved a certain degree of complexity. By enabling coordination and through the creation of precise drawings, the use of MEP modules presents a greater scope for efficiency. Typically, a module is a system of steel frames that have pipes, ventilation ducts and cable trays attached in one unit and is usually 6 to 12 metres long, depending on where you are and the transport logistics allowances. Designing an MEP module involves coordination, connection methods between modules and the calculation of the size and weight of steel beams to make the mounting frames. Modules can be assembled in a factory or workshop away from the site or in a temporary work area at the site for easy transport and installation. Such sites usually have improved space and therefore better levels of health and safety while also allowing for greater levels of efficiency.  Installation is performed by duct lifters, chain blocks or tower cranes for modules in shafts.

What exactly goes into an MEP module?

Frankly, quite a lot. An MEP module for a ceiling corridor or riser, or a packaged plant room consists of MEP services installed in a factory or off-site workshop and includes several ‘plug and play’ technologies with pipework, cable management and ductwork for building services. These modules are mounted in the ceiling, beneath the floor, in service risers or in plant spaces. Pipework systems are combined with electrical service distribution. Pre-assembled in an off-site factory, they are transported to the site and connected straight to the mains. They are created from top quality materials and a simple unit is equipped to accommodate several building services. Minimising rework and redesign of services, detection of clashes and fast modifications on MEP modules has been enabled by the vast scope of BIM technology.

For the near-flawless creation of MEP modules, a technically precise and feasible design needs to be created. The manufacture of MEP modules is markedly dependent on efficient MEP coordinated module drawings and MEP shop drawings and spool drawings. Modules are assembled based on MEP coordinated drawings and the level of detail specified in the BIM model.


The process or workflow enforced to develop MEP shop drawings goes something like this:

  • MEP consultants develop the concept design/schematic design of individual trades based on the architectural and structural building layoutsw.
  • MEP contractors/consultants/MEP prefabricators will further develop the design into MEP clash-free coordinated models and drawings, with detailed information of assemblies, quantity, size, shape, location and orientation. Elevation views showing corridors and turning points in the routing services are created. To create the final clash-free MEP coordinated drawings, the lead coordinator integrates MEP BIM models.
  • The MEP coordinated drawings are reviewed by consultants, builders and MEP contractors.
  • For fabrication and assembly, supporting frame, flanges and corners are added to the coordinated drawings, which then become known as MEP shop drawings and spool drawings.

Early on at the design stage, MEP engineers and main contractors present their design inputs so that the design is technically sound. Then, MEP coordination results in the removal of clashes and snags. Services design for modules take into account maintenance, replacement and upgradation. It is only after the completion of the MEP shop drawings that the modules can be created. The shop drawings are just a cog, albeit a critical one, in the whole process of prefabricating modules.

Once the modules are manufactured from the shop drawings, a template or jig is used to check the module’s alignments. Covering the modules in shrink wrap or tarpaulin protects them from the weather. With the help of castor wheels, the modules are then transported to the site for installation, where they are lifted and placed in position with pallet jacks, scissor lifts and forklifts.

With shop drawings, the process of creating MEP modules is much more straightforward. It generally works this way:

  • MEP design services are provided by a consultant//MEP module prefabricator/manufacturer
  • MEP coordinated drawings are developed by an MEP services provider
  • Modules are prefabricated, commissioned and tested in a factory by an MEP module prefabricator
  • Modules are transported to the site by the main contractor
  • Modules are installed by an MEP subcontractor

The use of MEP modules is becoming popular for a number of benefits they offer. Some of the advantages of prefabricated construction modelling are as follows:

1. Eco-friendly

Prefabricated MEP modules are energy efficient. Construction in a factory means that any extra materials can be recycled in-house rather than sending waste to a landfill. With significantly accurate construction, the joints are tighter and there is improved air filtration, enabling more effective wall insulation and increased energy efficiency. 

2. Faster Project Construction

Effective planning, elimination of on-site climate conditions and faster fabrication of MEP modules contribute to overall savings in time, sometimes up to 50 percent when compared to traditional construction. Multiple modules are created at the same time and delays associated with subcontractors are neutralised. Prefabrication can begin off site early, without waiting for MEP clearance from the civil team. 

3. Reduced Costs

Modular construction can be tailored for any budget. Material suppliers offer bulk discounts to prefabrication manufacturers which reduces the project cost. Even the faster construction time resulting from the use of modules saves construction costs. 

4. Adaptability

The ease of disassembly and relocation of modules cuts down on the need for and transport of raw materials and saves time. The project’s design can be flexible when using modules. When these modules are manufactured with a flexible flatpack design, they can be used with great success in cramped spaces that are difficult to reach.

5. Reliable Quality

Modules are built to a uniform quality due to a controlled manufacturing environment and processes for specific standards. Experienced workers, a weather-resistant factory and multiple quality checks contribute to the manufacture of modules. All services are supported and clearly installed. Offsite manufacture means early testing, commissioning and project assurances.

6. Minimal Site Disruption

Reduced vehicular traffic and fewer on-site personnel associated with equipment and material suppliers result from manufacturing modules in a factory. Noise, pollution and waste on site are reduced, while productivity increases. When large components are broken into smaller modules, they can be easily installed in tight spaces without disturbing other trades on site. Errors and damages to services by different trades are minimised. Also, there will be less people on scaffoldings. 

7. Safety

Dry materials used in the controlled environment of a factory result in reduced problems with moisture, environmental hazards and dirt. Workers are not exposed to health risks associated with weather and there are reduced risks of accidents. Injuries to workers are prevented due to strict procedures, reduction of high-heat tasks in restricted areas and minimal scaffolding work.

It may seem that they are perfect, but even though prefabrication for MEP modules has several advantages, there are a few instances when it is not the ideal solution. Some of the challenges associated with the use of prefabricated MEP modules are:

Dispersed locations – Modules cannot be easily installed in garages and single-family houses.

Pipework restrictions – Drainage pipework requires sloping and therefore cannot be installed modularly.

Resistance to change – Last-minute changes require additional drawings which frequently slows the installation of MEP modules.

For the majority of construction projects involving MEP modules, these challenges are easily made redundant. Though employing prefabrication for construction is growing in popularity, it is mainly office buildings, hotels, shopping malls and multi-storey residential buildings that currently benefit from MEP modular installation. The trend of using Prefabricated Construction Modelling is bound to expand to other building structures due to its resulting faster build times, high quality, cost-effectiveness and eco-friendly nature. Finally, as BIM technology makes a significant contribution to prefabricated construction modelling, MEP modules can be effectively created with the use of prefabricated construction BIM as a cost-effective endeavour by technically adept overseas BIM professionals. Offshore dedicated teams can deliver MEP module designs of high quality, capable of suiting budgets and meeting time schedules, offering a preferred alternative for main contractors and MEP fabricators in Western countries.


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