Is the Plant Room Really Too Small? – The Real Value of 3D Modeling and BIM

There are cases where a contractor takes one look at a plant room, turns around, and refuses to install the system as drawn in the schematic — convinced that not all the equipment will actually fit. Instead of these costly trial-and-error attempts, our team relies on 3D modeling, which lets us state up front, precisely, what will fit and what won’t.

When we receive a floor plan as MEP designers, we’re often already facing fixed constraints on room sizes. It’s the fortunate cases where we’re involved from the start of a project and can advise the architect on the optimal plant room size. At our office, every project begins with a detailed needs assessment.

Project overview: the plant room of a 3-unit apartment building

On one of our recent projects, we took a close look at the mechanical room of a 3-unit apartment building. The developer’s requirements were: heat-pump-based heat generation, a separate electricity meter per unit for energy billing, and underfloor heating, ceiling heating/cooling and fan-coil circuits (the latter for rapid cooling and humidity control).

The system ended up consisting of 3 indoor heat pump units with integrated hot water tanks, 3 heating/cooling circuits per unit, and the potable water lines — a total of 27 pipes that had to be routed out of the plant room.

For this job, we were given a mechanical room of just 10.23 m². That’s generous for a single-family house, but distinctly small for such a complex multi-unit system. The heat pumps’ indoor units alone (3 units, each 80×80×180 cm) plus the 3 associated 100-liter buffer tanks take up an enormous amount of space, not to mention the pump groups and mixing valves.

The modeling process and its practical value

During design, we pay particular attention to making the system serviceable, so that a single person can comfortably access the equipment for future maintenance. We keep pipe functions clear in the model through a consistent color code: green for cold water, orange for hot water, dark pink for circulation, red for the heating/cooling flow, and blue for the heating/cooling return.

Our 3D model clearly proved that the complex system could indeed be squeezed into the available space. When we handed this model to the contractor, they were able to lower their initial quote, since the precise visualization minimized unexpected risks and costs.

Summary

In our experience, 3D (BIM) modeling in MEP design is exactly the kind of tool that saves significant time and money during construction.