In the field of cleanroom engineering, modular technology has long been perceived as only suitable for small-area, small-scale projects. Many practitioners hold the prejudice that when cleanroom areas exceed 1000㎡, especially reaching large scales of 1500–5500㎡, modular solutions are unfeasible due to insufficient structural stability and difficulties in system coordination, making traditional civil engineering cleanrooms the only viable option. However, based on the design and implementation experience of multiple 1500–5500㎡ large-scale modular cleanrooms in the engineering design department, modular technology not only adapts to large-scale projects but also demonstrates advantages that traditional civil engineering solutions cannot match in key dimensions such as schedule management, cost control, quality assurance, and post-construction operation and maintenance. This article, from a practical engineering design perspective, breaks down the design logic and system planning focus of large-scale modular cleanrooms, clarifies their core engineering differences from traditional civil engineering cleanrooms, identifies the key prerequisites for modular technology to adapt to large-scale projects, and provides practical reference for similar engineering designs.
1.Breaking Misconceptions: The Core Logic of Modular Adaptation to 1500–5500㎡ Large Cleanrooms
Modular cleanrooms are often misunderstood as "only suitable for small projects." The core reason lies in the fact that early applications were concentrated in small laboratories and temporary clean areas of a few hundred square meters, gradually leading to the ingrained perception that "modularization = miniaturization." However, with the continuous iteration of modular technology, especially the ongoing improvement in standardized module development and system integration capabilities, its core advantage in adapting to large projects is gradually becoming apparent. Essentially, the core characteristics of modularization—"prefabrication, standardization, and integration"—are highly compatible with the core needs of large cleanrooms—"large-scale layout, standardized management, and efficient implementation"—and are not a technology solution limited by area.
Large cleanrooms of 1500–5500㎡ are mostly used in high-end manufacturing fields such as semiconductors, medical devices, and biopharmaceuticals. These projects generally face three core pain points in practice: First, stringent construction period requirements. Traditional civil engineering cleanrooms, from main construction to cleanroom decoration and system commissioning, typically take 6–12 months, making it difficult to meet the needs of enterprises for rapid production and market penetration. Second, high difficulty in quality control. Large clean areas have extremely high requirements for the flatness and sealing of walls, floors, and ceilings. Traditional on-site construction is greatly affected by the skill level of workers and on-site environmental conditions, easily leading to uneven quality and incomplete sealing. Third, insufficient flexibility in post-construction operation and maintenance. High-end manufacturing processes iterate rapidly, requiring adjustments to the layout and cleanliness level of clean areas. Retrofitting traditional civil engineering cleanrooms is difficult and costly, making it difficult to adapt to the needs of process updates.
Modular cleanrooms effectively address the aforementioned pain points: Prefabricated production allows over 80% of construction processes to be completed in standardized factory workshops, requiring only simple on-site procedures such as module assembly and system integration. This shortens the construction period to 3-6 months, significantly improving project implementation efficiency. Standardized module production ensures full control, with dimensional accuracy and sealing performance meeting uniform standards, effectively mitigating quality fluctuations during on-site construction. This is particularly suitable for the stringent quality uniformity requirements of large-area cleanrooms. The modular structure's disassembly and reconfigurability allows for flexible adaptation to later process adjustments, reducing renovation costs and extending the overall project lifespan.
Furthermore, large cleanrooms of 1500–5500㎡ typically have clearly defined functional boundaries, such as production areas, inspection areas, storage areas, and auxiliary areas. The cleanliness levels, temperature, humidity, and pressure differential requirements of each functional area differ significantly. Modular design allows for the breakdown of areas with different functional needs into independent modules, enabling "zonal design, zonal construction, and zonal commissioning." This improves design and construction efficiency and facilitates subsequent zonal operation and maintenance management. It is evident that modular technology is not limited to small projects. In large-scale cleanroom projects, its advantages of standardization, integration, and flexibility can be fully realized.
2. Structural Logic of Large-Area Modular Cleanrooms: From "Module Stacking" to "Overall Collaboration"
The core of the structural design for 1500–5500㎡ large-scale modular cleanrooms is to move away from the crude thinking of "single module stacking" and construct a complete logical system of "overall planning, zoned decomposition, module collaboration, and structural stability." The design focuses on four core dimensions: the main frame, modular units, sealing connections, and load transfer, ensuring structural stability and cleanliness sealing under large-area layouts, meeting the long-term operational needs of large cleanrooms.
The main frame, as the "core skeleton" of the large-area modular cleanroom, must simultaneously consider load-bearing capacity and flexibility. Unlike small modular cleanrooms that rely solely on the module's own frame, large-scale projects require the construction of an overall load-bearing frame (preferably a steel structure frame). The frame's span and spacing must be precisely calculated based on the cleanroom's area, functional zoning, and equipment layout to ensure stable support for the module's own weight, equipment weight, personnel load, and the weight of ancillary facilities such as ceilings, ducts, and pipelines. Simultaneously, the overall frame must allow for reasonable expansion and contraction space to accommodate structural deformation caused by temperature changes, preventing gaps at module joints that could affect cleanliness. The frame design must adhere to the principle of "standardized modules," ensuring that the module's width, height, and length precisely match the frame module, providing a foundation for future module splicing and project expansion.
The modular unit is the "core carrier" of the structural logic, employing a design approach that combines standardization and customization. Large cleanroom modules are not simply repetitive applications of a single size. Instead, they are divided into standard and customized modules based on functional zoning requirements: standard modules (such as 3m×6m or 4m×6m) are used for general areas like standard production areas, enabling mass production in the factory, reducing production costs, and improving efficiency. For customized areas such as equipment rooms, testing laboratories, and special process areas, module sizes and internal layouts are flexibly adjusted based on equipment dimensions and process requirements to ensure adaptation to specific functional needs. Each module unit undergoes prefabrication of walls and ceilings in the factory, with pre-embedded ducts and pipeline interfaces. Each module possesses independent cleanroom sealing performance, and after assembly, it can quickly form a complete cleanroom space.
Sealing connections are a "key guarantee" for large-area modular cleanrooms and a core design element that distinguishes them from smaller projects. During the assembly of large-area modules, leaks can easily occur at the joints between modules, between modules and the main frame, and between modules and the floor/walls/ceiling, thus affecting the cleanliness level. Therefore, the structural design employs a "multi-layered sealing" logic: customized sealing strips (adapted to module dimensions, possessing corrosion resistance, aging resistance, and strong sealing properties) are used at module joints, simultaneously reinforced with sealing pressure strips; flexible sealing materials are used at the junctions between modules and the floor and walls, balancing sealing performance with structural flexibility.
Load transfer is the "core logic" for ensuring the stability of large-area structures. Various loads in large cleanrooms need to be transferred to the main frame through module units, and then from the frame to the foundation. Therefore, the design of the connection points between modules and the frame is crucial. Detachable high-strength connectors are used at the connection points, ensuring both the strength of the connection and effective load transfer, while also facilitating the disassembly and reassembly of modules later. Simultaneously, in large-span, column-free structures, load-bearing beams are used to increase the strength of the ceiling mesh, enhancing stability and cleanroom sealing.
Overall, the structural logic of large-area modular cleanrooms is based on "an overall framework, modular units as carriers, sealed connections as guarantees, and load transmission as the core," achieving "modular design and integrated collaboration." This completely eliminates the crude design of single structures, ensuring structural stability and cleanliness standards in large-area layouts of 1500–5500㎡.
3.System-level Planning: The Core of Large-Area Modular Cleanroom Design, Not Simply "Assembling Structural Blocks"
For large-scale modular cleanrooms of 1500–5500㎡, the core design is not "simple assembly of modules," but "system-level overall planning"—deeply integrating the cleanroom's HVAC system, electrical system, water supply and drainage system, automatic control system, and fire protection system with the modular structure. This achieves synergistic linkage between modular units and system units, and precise matching of local functions with overall requirements, ensuring the stable, efficient, and energy-saving operation of the entire cleanroom system.
System-level planning follows the core principle of "overall first, then local; system first, then module," and can be divided into three practical levels to ensure the feasibility and implementability of the design scheme:
First, overall functional and system requirement planning. In the initial design phase, considering the project's production processes, cleanliness level requirements (e.g., different areas are Class 100, Class 1000, and Class 10000), personnel movement, and equipment layout, the core system requirements of the entire cleanroom are clearly defined. These include the HVAC system's airflow, temperature and humidity control range, and differential pressure gradient; the electrical system's power load and distribution layout; and the monitoring points and control precision of the automation system. Simultaneously, the overall cleanroom zoning (production area, auxiliary area, public facilities area, etc.) is planned, clarifying the functional boundaries and system requirements of each zone, laying the foundation for subsequent module decomposition and system layout. Taking a large cleanroom in the semiconductor industry as an example, the production area needs to prioritize the stability and cleanliness of the HVAC system; the equipment room needs to reserve sufficient space for the installation of HVAC units and distribution cabinets; and the auxiliary area needs precise matching of the water supply, drainage, and fire protection system layout.
Secondly, collaborative planning of module units and system units is crucial. After decomposing each functional zone into independent module units, the corresponding system interfaces and layouts are precisely planned for the functional requirements of each module, ensuring seamless connection and collaborative operation of all systems after module assembly. For example, each production module has pre-embedded duct interfaces and electrical wiring interfaces in the walls. The interface locations and specifications must be consistent with the overall layout of the HVAC and electrical systems. Equipment modules have pre-reserved installation openings and pipeline channels to ensure quick system integration after equipment installation. Within the cleanroom module ceiling, pre-reserved installation locations for HVAC vents, lighting fixtures, and monitoring probes are implemented concurrently with the module structural design. This "modular and system-synchronous design" approach avoids system modifications after module assembly, significantly improving design and construction efficiency.
Third, system integration and optimization planning. Large modular cleanroom systems are numerous and require integrated planning to avoid conflicts and resource waste between systems. For example, the HVAC system duct layout is integrated with the module ceiling structure using an embedded design, saving space and ensuring uniform airflow distribution. The electrical and automatic control systems are deeply integrated to achieve precise control of temperature, humidity, pressure differential, and lighting in each module, improving system energy efficiency. The sprinkler heads and smoke detectors of the fire protection system are precisely matched with the module wall and ceiling design to ensure comprehensive coverage without affecting the cleanroom's airtightness. Furthermore, system planning must also consider the convenience of later operation and maintenance. For example, inspection ports should be set up within modular units to facilitate equipment inspection and maintenance; remote monitoring functions should be added to the automatic control system to achieve real-time monitoring and control of the entire cleanroom system.
In summary, the core of system-level planning for large-area modular cleanrooms is to break down the separation between modules and the system, achieving a unified "structure, function, and system," ensuring that the modular cleanroom is not only a "space pieced together" but also a "highly efficient and collaborative operating system" that meets the large-scale and standardized operational needs of large cleanrooms.
4. Fundamental Differences Between Modular Cleanrooms and Traditional Civil Engineering Cleanrooms at the Engineering Level
Large-scale modular cleanrooms (1500–5500㎡) and traditional civil engineering cleanrooms differ fundamentally at several key levels, including engineering design, construction implementation, quality control, and later operation and maintenance. The core difference stems from the shift in construction scenarios and the different design logics—modular cleanrooms use a "factory prefabrication, on-site assembly" model, while traditional civil engineering cleanrooms use a "on-site construction, gradual stacking" model. Specific differences are reflected in the following five practical engineering aspects:
Firstly, differences in design logic. Modular cleanrooms employ a "pre-planned, standardized, and integrated" design. At the initial stage of the project, comprehensive planning of overall functions, system requirements, and module dimensions is required. All module designs adhere to standardized principles while also considering system integration needs. The design cycle is relatively concentrated, with fewer design changes. Traditional civil engineering cleanrooms, on the other hand, adopt a "post-planned, personalized, and decentralized" design. The main civil engineering design is usually completed first, followed by cleanroom decoration and system installation design. The design process is decentralized and greatly affected by on-site construction conditions, making design changes more likely and impacting project progress.
Secondly, there is a difference in construction methods. This is the most crucial difference between the two. Modular cleanroom construction consists of two parts: "factory prefabrication" and "on-site assembly." Over 80% of the processes (module production, interior decoration, and pipeline pre-installation) are completed in the factory's standardized workshops. On-site work only requires simple procedures such as module assembly, system connection, and debugging. The construction cycle is short (approximately 3-6 months for a 1500–5500㎡ project), requires fewer on-site construction personnel, and is less affected by external factors such as weather and environment. Traditional civil engineering cleanroom construction is carried out entirely on-site, from main civil engineering pouring, wall plastering, and floor leveling to cleanroom decoration, system installation, and debugging. All processes must be completed on-site, resulting in a longer construction cycle (approximately 6-12 months), a larger on-site workforce, and construction quality significantly affected by personnel skills and weather conditions.
Thirdly, there are differences in quality control. Modular cleanrooms exhibit centralized and standardized quality control. Module production is completed entirely in the factory, which possesses standardized production processes and precise testing equipment. The dimensional accuracy, sealing performance, and finishing quality of each module can be rigorously tested. Substandard modules can be directly reworked, resulting in lower quality control difficulty and better consistency. In contrast, traditional civil engineering cleanrooms exhibit decentralized and differentiated quality control. Wall, floor, and ceiling finishing are all done manually on-site, leading to significant variations in construction quality between different areas and by different workers. Quality testing is difficult, and issues such as unevenness and sealing leaks are prone to occur, especially in large-area cleanrooms where quality uniformity is hard to guarantee.
Fourth, there is a difference in flexibility and scalability. Modular cleanrooms offer significant advantages such as being "disassembleable, reconfigurable, and expandable." For large cleanrooms, if functional zoning needs adjustment or area expansion, existing modules can be directly disassembled and reconfigured or new modules added without affecting the normal use of the original clean space. This results in a short renovation cycle and low cost. In contrast, traditional civil engineering cleanrooms have a cast-in-place concrete structure, making large-scale renovations difficult once completed. Expansion or layout adjustments require demolishing the original structure and restarting civil engineering construction, leading to long renovation cycles, high costs, and disruption to normal production.
Fifth, there are differences in cost and construction time. Modular cleanrooms are characterized by "high initial design costs and low subsequent construction costs." Factory prefabrication requires investment in molds and equipment, and the initial design must balance modular standardization and system integration, resulting in relatively high design costs. However, on-site construction cycles are short, labor costs are low, design changes are less frequent, and overall project costs are more controllable. Traditional civil engineering cleanrooms, on the other hand, are characterized by "low initial design costs and high subsequent construction costs." Initial design is relatively simple and inexpensive, but on-site construction cycles are long, labor costs are high, design changes are more likely, and subsequent quality rectification costs are also high, leading to greater fluctuations in overall project costs. For large projects of 1500–2500㎡, the time advantage of modular cleanrooms can directly translate into cost advantages, such as shortening the enterprise's production cycle and helping the enterprise generate economic benefits earlier.
5. Under what conditions are modular cleanrooms more suitable for large projects?
Not all modular solutions are suitable for large-scale cleanroom projects. Based on practical experience designing 1500–5500㎡ projects, the advantages of modular cleanrooms are more pronounced when the project meets the following five conditions, offering greater cost-effectiveness and feasibility compared to traditional civil engineering solutions:
▶ High degree of project standardization and clear functional zoning. If the functional zoning of a large cleanroom is clear (e.g., well-defined boundaries between production, testing, and auxiliary areas), and the internal layout of each functional area is relatively standardized, it can be disassembled into independent modular units, making the modular solution more advantageous. For example, in medical device manufacturing projects, the aseptic production area, testing area, and storage area can be disassembled into standard modules to achieve mass production and rapid assembly, improving project design and construction efficiency.
▶ Tight project schedule and rapid commissioning. If the company requires the entire process from design and construction to commissioning and production to be completed within 9 months, modular cleanrooms are the optimal choice. For example, biopharmaceutical companies building new production lines and semiconductor companies expanding their capacity often need to quickly launch and start production to seize market opportunities. The modular "factory prefabrication + on-site assembly" model can significantly shorten the construction period and precisely meet the company's need for rapid production.
▶ Limited project site conditions. If the project site is located in an industrial park, with limited on-site construction space, strict restrictions on construction noise, or complex geological conditions (such as soft soil foundations), traditional civil engineering construction is difficult and time-consuming. Modular cleanrooms offer greater advantages. Modular on-site construction procedures are simple, require fewer personnel, and produce less noise, reducing the impact on the surrounding environment. At the same time, the modular structure is relatively lightweight, has lower foundation requirements, and can reduce foundation treatment costs, especially suitable for sites with poor geological conditions.
▶ Frequent process adjustments and flexible expansion. If a company's production processes iterate rapidly, the functional zoning and cleanliness level of the cleanroom may need frequent adjustments, or there may be future expansion needs (such as expanding from 1500–5500㎡). The disassembly and reconfigurability of modular cleanrooms can be fully utilized. Traditional civil-construction cleanrooms are difficult and costly to modify; in contrast, modular cleanrooms allow for the rapid reconfiguration of modules and the addition of new areas in response to process adjustment needs, all without disrupting ongoing production operations.
▶ High Cleanliness Class Requirements and Strict Quality Uniformity Standards. If a project requires a generally high cleanliness class (e.g., Class 1000 or higher) and mandates uniform cleanliness quality across large areas (such as in semiconductor manufacturing zones or sterile medical device production areas), a modular cleanroom is the more suitable choice. Standardized factory production ensures consistent sealing performance and dimensional precision for every module, effectively mitigating the quality fluctuations often associated with traditional on-site construction, and is better equipped to meet the demands of large-scale, high-cleanliness environments.
6. Key Design Considerations for HVAC Systems (General)
The HVAC system serves as the "vital lifeline" of a cleanroom, directly determining its cleanliness class, temperature and humidity control efficacy, and the stability of its pressure differential gradients. For large-scale modular cleanrooms (typically ranging from 1500–5500㎡), the core design philosophy for the HVAC system centers on "system integration, zone-specific control, and energy efficiency." This requires deep integration with the modular structural framework and functional zoning scheme. The specific key design considerations are outlined below:
First: Comprehensive System Planning. Based on the cleanroom's total area, functional zoning, and required cleanliness classes, the overall architecture of the HVAC system (e.g., centralized or semi-centralized) is determined. Precise calculations are performed to determine the total airflow volume, as well as the cooling and heating loads required by the system, thereby enabling the appropriate selection of HVAC unit models and quantities. For large-scale modular cleanrooms, a "hybrid" architecture—combining centralized and zone-specific systems—is recommended. The centralized units handle the overall supply and return air processing, while the zone-specific units provide precise environmental control for areas with differing cleanliness requirements, thereby balancing both system stability and energy efficiency.
Second: Integrated Design with Modular Structures. The layout of HVAC ductwork and utility piping must be developed in parallel with the modular structural design. During the module manufacturing phase, specific interfaces for ductwork and dedicated channels for utility lines are pre-allocated. This ensures that—once the modules are assembled on-site—the ductwork and piping systems can be seamlessly interconnected, thereby avoiding the need for subsequent structural modifications (such as cutting or chiseling into the modules) that could compromise the cleanroom's airtightness and sealing integrity. For instance, space for duct installation is reserved within the modular ceiling plenum, while return-air panels and connection ports are pre-embedded into the wall panels; by standardizing the specifications of these interfaces to align perfectly with the modular dimensions, the efficiency of on-site assembly is significantly enhanced.
Third, Zonal Control Design. To address the varying requirements for cleanliness levels, temperature and humidity, and pressure differentials across different functional zones within a large-scale cleanroom, independent HVAC zonal control systems are designed. For instance, a Class 100 production zone and a Class 10,000 auxiliary zone require separate supply and return air systems to regulate distinct airflow volumes and pressure gradients, thereby ensuring that the cleanliness parameters in each area meet the required standards. Concurrently, an accompanying automatic control system is implemented to enable real-time monitoring and precise regulation of temperature, humidity, pressure differentials, and airflow volumes within each zone, thereby enhancing both system stability and energy efficiency.
Fourth, Energy Conservation and O&M Design. By taking into account the specific energy consumption characteristics of large-scale cleanrooms, energy-efficient HVAC equipment (such as high-efficiency filters and variable-frequency fans) is selected, and supply and return air pathways are optimized to minimize energy loss. Furthermore, maintenance-friendly access structures are designed—such as incorporating HVAC access ports within modular units and arranging ductwork and piping in a clean, orderly layout—to facilitate future equipment servicing and filter replacement, thereby reducing operation and maintenance costs.
Fifth, Sealing and Leak Prevention Design. At HVAC system duct joints and points where piping penetrates walls, the design must be coordinated with the modular sealing structure. Specialized sealing materials are employed to ensure airtightness and prevent airflow leakage that could compromise the cleanroom's cleanliness classification and pressure differential control. Particular emphasis is placed on high-cleanliness zones, where additional sealing reinforcement measures are implemented to minimize the risk of leakage to the greatest extent possible.
7. Conclusion
The design and implementation of large-scale cleanroom projects ranging from 1,500 to 5,500 square meters have conclusively demonstrated that modular cleanrooms are not limited to "small-scale projects" alone. Their core characteristics—standardization, integration, and flexibility—not only enable them to accommodate the large-scale requirements of major projects but also allow them to exhibit advantages in critical dimensions—such as construction duration, quality, operation and maintenance, and cost—that are difficult for traditional civil-construction cleanrooms to match. The essence of such engineering design lies in transcending the simplistic, "building-block assembly" mindset. Instead, it centers on a core logic of "holistic planning, system integration, and modular synergy" to execute robust structural design and system planning, while simultaneously assessing the suitability of the modular solution based on the actual requirements of the project regarding schedule, quality, and process specifications. In the future, as modular technology continues to evolve and the high-end manufacturing sector’s demand for "efficiency, precision, and flexibility" in cleanrooms intensifies, modular cleanrooms will find widespread application in projects of larger scale and higher cleanliness grades, emerging as a key choice for major cleanroom engineering initiatives. Our Engineering Design Department will remain deeply committed to the practice of designing large-scale modular cleanrooms—continuously refining design schemes and overcoming technical challenges—to provide enterprises with cleanroom solutions that offer superior cost-effectiveness and are precisely tailored to their practical needs, thereby contributing to the high-quality development of the high-end manufacturing industry.
