Prefabrication and modular construction are getting popular globally to enhance construction productivity and efficiency. The Building and Construction Authority (BCA) of Singapore has even published a guidebook on prefabricated MEP to equip Singapore practitioners with better understanding of its modules and benefits.

Challenges in current practices

In Hong Kong, following the success of modular integrated construction (MiC), the government is requiring and providing incentives for the adoption of multi-trade integrated mechanical, electrical and plumbing (MiMEP) in tender specifications. However, the journey is still at its early stage, primarily hindered by the traditional sub-let MEP trade practices which affect the re-manufacturability and reusability of the systems.

For convenience, contractors in Hong Kong are currently using design for manufacturing and assembly (DfMA) to tailor bulky multi-trade pieces with supporting frames for delivery for specific projects. They are not reusable in other projects, which limits mass production for further and wider use, and complicates maintenance.

Furthermore, coordinating the delivery and installation of MEP equipment involves multiple sub-contractors, which complicates the process and fuels the need for skilled workers.

A shift towards re-manufacturable and reusable MiMEP

To facilitate broader adoption of MiMEP, we propose a modular approach featuring the 3S: ‘simplification’, ‘standardisation’, and ‘single integrated element’. The first two can avoid complex construction details and lower the demand for skilled on-site workers, whereas the ‘single integrated elements’ – combining related components into a single element for prefabrication – will minimise construction waste while improving quality.

The key is the early adoption of MiMEP in the design stage and including detailed shop drawings in tender documents. This ensures the quality of design, construction, and site delivery, aiming for consistency, and betterment of manufacturability and reusability for economies of scale.

Modular design video cover
Arup's innovative modular MiMEP design ensures the quality of design, construction, and site delivery.

Simple plug-and-play

By looking at common needs across various buildings, such as office buildings, data centres, railway stations and hospitals, we can identify standard block modules for systems such as chillers, fire services, water supply, power supply and ceiling/riser services. 

These modules, made up of sub-modules, can be pre-fabricated off-site using DfMA techniques and installed on-site with a plug-and-play approach, accelerating on-site construction efficiency.

This standardisation preserves flexibility, allowing us to arrange the types and quantities for sub-modules and modules to accommodate different MEP plant capacities.

Five common modules video
By looking at common needs across various buildings, we can identify standard block modules for each system respectively.

Saving time, cost and carbon

With this modular approach, consultants can provide a complete set of standardised designs, including detailed shop drawings, early in the design stage. This facilitates the mass prefabrication of block modules and sub-modules off-site, enhancing production quality, simplifying installation, and easing MEP system maintenance. It is estimated that this approach can reduce the related design, manufacturing, coordination and installation man-hours by about 30%, saving both project costs and construction time.

By standardising MiMEP execution designs in tender specifications rather than addressing detailed MiMEP designs after the tendering process, greater accuracy in pricing and cost management can be achieved. We have been trying this approach in a few on-going local railway and large-scale date centre projects, and the estimation suggests that preliminary construction costs can be reduced by at least 20%.

This approach also enables project owners to estimate the total carbon footprints of their projects by simply adding up the actual quantity of MEP block modules needed. With all carbon data on hand, project owners can make informed decisions and sort out ways to achieve their decarbonisation goals.

Wider adoption on the horizon

This innovative modular MiMEP design can help popularise prefabricated MEP designs, significantly enhancing productivity and quality with time and cost savings. Given that MEP equipment is essential in structures across the globe, this approach can be applicable to all kinds of buildings, including data centres which have strict requirements for power and cooling supply.

In Hong Kong, the government is advocating the renovation of existing industrial buildings into data centres. We are applying this approach to design and expedite the renovation of a modular data centre, meeting the soaring local need for such mission-critical facilities. As the need for improving construction productivity is universal, we anticipate that other cities and regions will leverage this approach to accelerate the adoption of prefabricated MEP designs and boost construction productivity. This method is particularly relevant for areas with a high demand for power-intensive infrastructures like data centres.