Why sustainable MEP design needs more than BIM

How large should a technical system be? Which option will use less energy? Which solution comes with a lower embodied carbon footprint? And how will a design decision affect the building once it is in operation? These questions often need answering before a detailed building model even exists. For Pauli Keinonen, Director of Innovation, Research and Development at MagiCAD Group, this is one of the central challenges of sustainable MEP design. MEP stands for mechanical, electrical and plumbing — the building services that include heating, ventilation, air conditioning, sanitary systems and electrical installations. These systems influence both a building’s operational energy use and the emissions associated with manufacturing the equipment and materials installed in it.

Keinonen opens his argument with a deliberately provocative statement: “BIM is broken.” He is not suggesting that Building Information Modelling has failed as a method. His criticism is aimed at the way BIM is often used in practice: processes do not support genuine information sharing, software focuses heavily on modelling, and data management too often tries to force every piece of information into the model itself. For sustainable design, he argues, that is not enough.

Make the decisions before the detailed model

Many of the decisions with the greatest impact are made during concept design. At this stage, engineers choose systems, define main routes and select key equipment. Those choices influence construction costs, energy demand, carbon emissions and indoor climate. The difficulty is obvious: the earlier the decision, the less detailed the information available.

Sustainable design therefore needs tools that can work with limited data. Engineers need to compare options before every pipe, duct and component has been added to a BIM model.

Keinonen sets out a process that moves progressively from broad decisions to detailed design. In the concept phase, engineers can compare systems, estimate energy demand and embodied carbon, and establish the basic MEP strategy. As the project develops, detailed modelling and more precise simulations follow. Carbon performance can then be tracked and refined throughout the design process.

The principle is simple: sustainability should guide design decisions from the outset, rather than being assessed once the design is largely complete.

MagiCAD Group

Treat carbon like a budget

This becomes particularly important when considering embodied carbon — the emissions associated with producing, transporting and installing materials and building systems. Keinonen proposes treating these emissions much like financial costs. A project can set a carbon budget and track how design decisions affect it as the design develops.

To do that, several pieces have to come together. Manufacturers need to provide environmental and technical product data. Designers need to know which products they intend to use and in what quantities. An LCA tool — short for Life Cycle Assessment — can then calculate how different choices affect the building’s carbon footprint.

This changes the purpose of carbon assessment. Instead of simply calculating the impact of a finished design, the calculation becomes part of the design process itself. Engineers can see whether a proposed solution is still within the carbon target and compare alternatives before committing to them.

The BIM model does not have to contain everything

Keinonen also challenges a common assumption about BIM data. Many BIM workflows aim to store as much information as possible inside the building model. But not every piece of information needs to live there permanently. Different tasks require different types of data — and often different tools.

An MEP engineer, for example, needs geometry, technical performance data and manufacturer information. An energy calculation uses a different set of inputs from an embodied-carbon assessment. Once the building is operational, the information requirements change again.

Rather than forcing all this information into one model, the systems should exchange the data each task requires. The important point is that information is available where and when it is needed — not that everything sits in the same 3D model.

Keinonen summarises this approach in three areas: processes need to support different versions and scenarios and allow teams to track how they develop; designers need the right tools for design, energy simulation and carbon assessment; and data should remain granular enough to be used selectively for different tasks.

From manufacturer data to energy calculations

MagiCAD Group illustrates this approach through a connected set of digital tools. Manufacturers provide technical product data. A central data hub makes that information available for different planning tasks. During early design, MEP engineers can develop systems and main routes while estimating energy consumption and embodied carbon. As the project progresses, those initial assumptions can be replaced with increasingly detailed models and simulations.

MagiCAD Group uses different tools for different stages — from early-stage system design and energy analysis to carbon calculations and detailed MEP modelling. The more important idea, however, lies behind the individual products: designers should not have to wait for a fully developed BIM model before they can start answering sustainability questions.

The level of detail should grow with the project. Early assumptions become more precise. Designers can compare alternatives, revisit previous decisions and refine calculations as more information becomes available.

Sustainability needs more than another software tool

This is why Keinonen’s argument is not simply a call for another sustainability application. If an energy-analysis tool, an LCA platform and a BIM system all operate independently, they create new breaks in the workflow. Designers may need to re-enter the same information, transfer data manually or work with conflicting versions.

The process therefore matters just as much as the software. Project teams need to decide when they will calculate sustainability metrics, what information those calculations require and how that data will move between systems.

A manufacturer may provide technical and environmental product information. The engineer then determines which products and quantities are used. The LCA calculation can assess the resulting carbon impact. If the engineer changes the system, that change needs to feed into the next calculation.

Only when that information flows reliably can sustainability become part of day-to-day design rather than a separate exercise at the end.

More data does not mean better decisions

This points to a broader problem in construction digitalisation. Technology allows teams to capture ever more data, but the real question is which information they need at each stage.

A highly detailed model offers little value during concept design if the immediate task is simply to choose between two system strategies. Conversely, rough assumptions are no longer sufficient once the project reaches detailed design, procurement or final energy and carbon calculations.

Keinonen therefore argues for granular data that can be used according to the task and the maturity of the design. The BIM model becomes one part of a wider digital process rather than the single container for every piece of project information.

That is also at the heart of his criticism of current BIM practice. The problem is not the model itself. It arises when organisations treat the model as if it were the entire information-management system.

BIM needs to become a means to an end again

“BIM is broken” may sound dramatic. Keinonen’s proposed solution is far more pragmatic. BIM does not need to be replaced. Instead, the industry needs to improve the way it uses the method. Processes must allow information to flow more effectively. Specialist tools need to perform calculations when they are actually needed. And data has to remain usable across different systems.

For sustainable MEP design, that means bringing energy and carbon into the design process from the beginning. Engineers need to consider both while developing system concepts and continue checking them as the project moves towards detailed design.

The later a team discovers that a chosen system uses too much energy or pushes the project beyond its carbon budget, the harder -and more expensive - it becomes to change course.

That may be the most important lesson from Keinonen’s approach: even the most sophisticated BIM model has limited value if the information needed to make better decisions arrives too late.