There are a million ways to design a cleanroom, and the right one depends on what you manufacture and how often the process changes. Ballroom cleanroom design puts tools, people, and material flow under one cleanroom ceiling instead of dividing the facility into isolated process bays, so the layout can change as products and equipment do. The trade-off is a larger volume of air to control and an open floor where contamination can travel.
Getting that layout right comes down to a short list of decisions: how zones are defined, how the envelope is built, and how the room grows.
A ballroom cleanroom is an open-plan cleanroom where production tools share a single controlled space, with interior partitions creating higher-classification zones where processes require them.
The alternative is a bay-and-chase layout, where tools sit in isolated bays and service access runs through separate chases. Bay-and-chase keeps maintenance traffic out of the cleanest air. A ballroom layout gives up some of that isolation in exchange for easier tool installation, shorter material paths, and a floor plan that can change when a product line does.
In a ballroom layout, cost scales with floor area, because every ISO class is maintained by supplying filtered air, and the tighter the class, the more filtered air each square foot needs per hour, which takes more filters, larger air handlers, and more energy. The more efficient approach is to set the whole floor at the baseline class most processes require and raise the class only inside the zones that need it.
Start with the baseline class the whole floor needs, then nest higher-class zones inside it around the processes that require them.
A typical electronics layout might assign classes like this, with your process owner setting the final values:
| Zone | Example process | Example ISO class |
| Inspection | Final visual and metrology checks | ISO 6 |
| Assembly | Component and device assembly | ISO 7 |
| Packaging | Final packaging and staging | ISO 8 |
A pressure cascade helps maintain the zones and avoid contamination in more sensitive areas. Air moves from the cleanest space toward the least critical one. Each zone is held at a slightly higher pressure than the one next to it, typically by 0.05 to 0.08 inches of water gauge (roughly 12 to 20 pascals), a difference too small to feel but enough to keep air moving in the right direction.
Modular construction delivers the entire ballroom cleanroom as one coordinated system, from the outer shell and ceiling to the interior partitions that define each zone.
In conventional brick-and-mortar construction, walls begin as raw material that is cut, taped, sanded, and painted on site. This sheds particles into the space and leaves compounds that can outgas, which is a long-term contamination risk. A modular unit takes this contamination out of the equation by moving the finishing into a controlled factory.
When a lease prohibits attaching a cleanroom to the host building, modular construction is the best solution in this case. A freestanding modular envelope stands independent of the building, so the tenant can carry out its process without altering the property.
In seismic regions such as California, the Pacific Northwest, and parts of the Southwest, that freestanding structure also has to resist lateral loads on its own. Starrco modular wall systems can be designed to meet seismic loading requirements, and a freestanding West Coast semiconductor cleanroom built with one was rated for Seismic Design Category D.
Ceiling height in a ballroom cleanroom is usually set by the tallest element in each zone: the tool envelope, any overhead transport, and the ceiling plenum with its filter modules. Giving every zone the height of the tallest one conditions more volume than the lower zones need, so heights step from zone to zone.
Each step is a structural and sealing detail that has to be coordinated. Starrco gasketed ceiling grid systems have been delivered at 9′, 10′, and 14′ within a single project to achieve the necessary stepped ceiling height for a cleanroom.
Unlike conventional construction, where expansion calls for demolition and rebuilding, modular interior walls can be removed and repositioned to add zones or change boundaries, so the cleanroom can grow with production. The easiest time to plan for that growth is before the cleanroom is built.
The financial case supports the same long-term view. Modular structures may be classified as tangible personal property, which can qualify for a seven-year depreciation schedule instead of the 39 years that applies to conventional construction. A shorter schedule lets you recover the investment faster and paves the way for your future growth.
Starrco has manufactured modular interior systems since 1965, and every cleanroom project is custom engineered to the facility it serves.
A well-planned ballroom cleanroom design starts with the right partner. Starrco brings the ISO classification knowledge and a modular system that covers everything from the outer shell to the interior partitions, so the room you build today can support where your production is headed.
Ready to get started on your next project? Request a quote from our team.