Prevention instead of damage control
Cleanrooms are costly construction projects. The investment volume ranges between €1,000 and €5,000 per square meter, and in semiconductor manufacturing, it can be significantly higher, at up to €20,000 per square meter. A cleanroom with an area of 1,000 square meters can therefore quickly reach costs in the millions. Nevertheless, many builders forego a measure that accounts for only a fraction of the total investment but can minimize key risks: flow and particle analysis using CFD (computational fluid dynamics) simulation.
Discussions with manufacturers and equipment suppliers reveal a surprisingly consistent picture: simulations are rarely used in the early stages of projects—often only when unexpected flow phenomena, particle recirculation, or dead zones occur during operation. In such cases, the causes must be identified retrospectively and corrected, which can be costly. Note CAE Solutions, which specializes in numerical simulation calculations, is often only consulted once problems have already arisen. Yet many of these challenges could be avoided in advance through digital analysis.
On average, CFD simulation accounts for around one to two percent of the construction costs of a cleanroom. For a project volume of one million euros, this corresponds to approximately 5,000 to 20,000 euros—an amount that is low in relation to potential follow-up costs. Simulation enables the predictive evaluation of air flow, the visualization of particle movements, and the analysis of temperature fields. Dead zones, unwanted turbulence, or critical particle concentrations can thus be identified before construction begins. For operators of sensitive production facilities, such as in optics, medical technology, or pharmaceuticals, this provides crucial planning reliability.
Flow processes in cleanrooms are sensitive to even the smallest changes in geometry, equipment, and operating parameters. Experience alone is therefore often not enough to reliably predict complex interactions. Simulation serves as an objective basis for designing air outlets, filter positions, or machine arrangements in such a way that the specified cleanliness classes are maintained at all times. Planning errors can cause considerable economic damage—for example, if a customer refuses to commission a facility because particle deposits impair product quality.
"With multiphysics simulations, we can now simulate cleanrooms, including the planned production and working environment. This means we not only know whether the cleanroom itself works, but also whether the planned production can run without disruptions, germs, and particles," says Dipl.-Ing. (TU) Stefan Merkle, managing partner of Merkle CAE Solutions GmbH.
Merkle CAE Solutions therefore does not view CFD analysis as an additional element, but rather as an integral part of forward-looking cleanroom planning. It helps to minimize risks, avoid rework, and ensure the functionality of highly sensitive production environments. For building owners, this means that a comparatively small amount of planning effort protects them from time-consuming and costly corrections during ongoing operations.
