Architects when designing cleanrooms, considerations should include but not be limited to cleanroom classification, inclusion of airlock/gown room, recirculating vs. one pass design, and cleanroom flooring selection.
Architecture is art that we live, entertain, and work in. Cleanrooms are places where we safely and cleanly work. Cleanrooms are not a standard architectural type of construction; cleanrooms are more like a large piece of equipment. For example, an architect will specify the size of a walk-in cooler and maximum temperature (per client’s request) but would leave the design to the cooler manufacturer. Similarly, an architect would specify what size and classification (per client’s request) the cleanroom needs to be but would leave the design to the cleanroom manufacturer. Architects should consider the additional heat load cleanrooms can produce, while designing the cooling system for the surrounding non-cleanroom space.
Class | Maximum Particles/ft³ | ISO equivalent | ||||
>0.1 um | >0.2 um | >0.3 um | >0.5 um | >5 um | ||
1 | 35 | 7 | 3 | 1 | ISO3 | |
10 | 350 | 75 | 30 | 10 | ISO4 | |
100 | 100 | ISO5 | ||||
1000 | 1000 | 7 | ISO6 | |||
10,000 | 10,000 | 70 | ISO7 | |||
100,000 | 100,000 | 700 | ISO8 |
Cleanrooms have an atypical wall thickness (for example: 2” or 3”), varies on R-value drastically, and varies on fire rating – depending on the wall materials.
Most cleanroom designs will have a gown room / airlock to allow a buffer between outside air and the main cleanroom. There should not be any doors (other than emergency exits) from the main cleanroom to the surrounding space. If there were doors to the surrounding space, this would allow an uncontrollable amount of contamination into the cleanroom. The goal of a cleanroom is to control the number of particles that enter the clean space.
There are typically two airflow designs for a cleanroom: recirculating and one-pass. Recirculating and one-pass design rely on the design of a plenum space above the cleanroom. In a recirculating design, cool air will mix with the recirculating cleanroom air and this air mixture will be forced from the plenum thru a HEPA FFU into the cleanroom space. The HEPA FFU removes all particulates from the air.
In a one-pass cleanroom design, air is drawn from the surrounding space into the plenum and forced thru a HEPA FFU into the cleanroom space and back out into the surrounding space thru a low wall air vent. Architects would need to take this into consideration when designing for a cleanroom space. Cleanrooms would typically need additional space above the internal ceiling height to allow for a plenum.
The flooring for a cleanroom space could also differ from the surrounding spaces. Depending on the required class of cleanroom, flooring will vary from welded sheet vinyl, epoxy to sealed concrete. Architects would need to keep this in mind while completing their code review for the building space and specifying different flooring thresholds.
Lastly, some cleanrooms will have a raised floor to allow air to be returned to plenum thru the floor . With this the Architect will need to consider the length and space for an accessible ramp into the cleanroom space. In conclusion, coordination between the Architect and the cleanroom manufacturer is essential for a properly planned cleanroom, that meets the intent of the final user.
Summary: When designing a building with a cleanroom, an architect needs to be knowledgeable about cleanroom design criteria. These include but are not limited to cleanroom classification, inclusion of airlock/gown room, recirculating vs. one pass design, and cleanroom flooring selection.
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