Key Issues in the Engineering Design and Construction of Cleanrooms

Among factory cleanroom fit-outs, Class 10,000 and Class 100,000 cleanrooms are the most common. For large-scale enterprise cleanroom projects, aspects such as design, infrastructure fit-out, and equipment procurement must comply with market requirements and construction engineering standards.

1. Telephone and Fire Alarm Systems

Installing telephones and intercoms in cleanrooms reduces personnel movement within the clean area—thereby minimizing particle generation—and facilitates timely external communication in the event of a fire, while also supporting routine operational communication. Additionally, fire alarm systems must be installed to prevent major economic losses resulting from fires going undetected by those outside the facility.

2. Ductwork Requirements: Balancing Economy and Efficiency

In centralized or purification air conditioning systems, ductwork must be both cost-effective and efficient at air delivery. Economic considerations include low cost, ease of installation, low operating costs, and smooth internal surfaces with minimal airflow resistance. Efficiency requirements entail high airtightness (no leakage), resistance to particle generation and accumulation, non-contaminating properties, and resistance to fire, corrosion, and moisture.

3. Prioritizing Energy Efficiency in Air Conditioning and Purification

Air conditioning and purification systems are major energy consumers; therefore, energy-saving measures must be prioritized during design and construction. Energy consumption is influenced by numerous factors, including system and zone partitioning, supply air volume calculations, temperature and humidity settings, cleanliness levels and air change rates, fresh air ratios, duct insulation, seam types (affecting leakage rates), connection angles between main and branch ducts (affecting airflow resistance), flange seal integrity, and the selection of equipment such as air handling units (AHUs), fans, and chillers. Consequently, all these details must be carefully considered.

4. Selecting Air Handling Units Based on Climatic Conditions

The selection of air handling units should take the local climate into account. For instance, in northern regions characterized by low winter temperatures and high airborne dust levels, standard units should be supplemented with a fresh-air preheating section and utilize a water-spray air treatment method; this allows for simultaneous dust removal and heat/moisture exchange to achieve the required temperature and humidity levels. In southern regions characterized by humid climates and lower airborne dust concentrations, preheating the fresh air supply during winter is unnecessary. Air filtration and the regulation of temperature and humidity are handled through a multi-stage process: primary filtration, followed by temperature and humidity adjustment via surface cooling coils (which may also include dehumidification), and finally, medium-efficiency filtration followed by terminal high-efficiency or sub-high-efficiency filtration. It is advisable to equip air handling units with variable-frequency fans; this not only saves energy but also allows for flexible adjustment of airflow volume and pressure.

5. Air handling unit rooms should be located adjacent to the cleanroom

Locating the air handling unit room next to the cleanroom offers several advantages: it saves energy, facilitates efficient air duct layout, optimizes airflow patterns, and reduces construction costs.

6. Multi-unit chiller systems offer greater flexibility

When high cooling capacity is required, a single large chiller unit is less desirable than a multi-unit system. Motors should utilize variable-frequency speed control to reduce startup power requirements. A multi-unit configuration allows for flexible operation, avoiding the energy waste associated with "oversized equipment for small loads" (i.e., running a large unit at low capacity).

7. Automatic control systems ensure continuous regulation

Currently, some manufacturers rely on manual methods to adjust airflow and pressure. However, since the control valves are located in technical interstitial spaces—and the ceilings often consist of suspended color-steel panels—these settings are typically established only during initial installation and commissioning; they are rarely, if ever, adjusted thereafter, and in practice, are often inaccessible for adjustment. To ensure normal production and operations within the clean facility, a comprehensive automatic control system should be installed to perform the following functions: monitoring cleanroom air cleanliness, temperature, humidity, and pressure differentials, as well as regulating air dampers; detecting temperature, pressure, and flow rates for high-purity gases, purified water, and circulating cooling water; and monitoring gas purity and purified water quality.