Precautions for the entire construction process of a cleanroom project
I. Preliminary Design and Drawing Stage
●Cleanliness Level Matching Process Requirements
Food, medical device, electronic chip, and laboratory GMP standards are separated. Air exchange rates, pressure differentials, illuminance, temperature, and humidity parameters corresponding to Class 10,000, Class 1000, and Class 100 workshops are locked in advance to avoid later modifications. Dust-generating, moisture-generating, and acid/alkali corrosion-prone processes are separately zoned, with anterooms, buffer rooms, and air showers.
● Personnel, Material, and Clean/Contaminated Flow Separation Planning
Personnel, material, and waste passages are completely independent to avoid cross-contamination; changing rooms are divided into first-stage, second-stage, and buffer zones; raw material inlets and finished product outlets are separated, and contaminated outlets are set with negative pressure.
●Pressure Differential Gradient Design
Clean area > Buffer room > Corridor > General production area; adjacent rooms maintain a positive pressure differential of 5–10 Pa; toxic, dust-generating rooms and disinfection rooms use negative pressure to prevent contaminant spillage.
● HVAC and Equipment Location Planning
AHU (Air Conditioning Unit), FFU (High-Efficiency Unit), Venturi Valves, Dehumidifiers, Exhaust Ducts, Process Cooling Water, Pure Water, and Compressed Air Pipelines should be pre-positioned; Ceiling load calculations should be performed, and FFUs, lighting fixtures, and ductwork should not interfere with each other.
●Flooring and Wall Material Selection Adapted to Working Conditions
For general workshops, use color steel sandwich panels; for fire-resistant requirements, use rock wool core material; for damp, frequently cleaned areas, use PVC roll flooring and epoxy self-leveling anti-static flooring; for electronic workshops, use anti-static wall panels and anti-static flooring; for acid and alkali workshops, use corrosion-resistant resin.
II. Material Arrival and Warehousing Management
●Cleanroom-Specific Materials Stored Separately
Cleanroom color steel panels, aluminum profiles, sealing strips, high-efficiency filters, and PVC flooring should all be sealed and packaged. Storage areas should be dustproof and moisture-proof; open-air storage is prohibited. High-efficiency filters must not be opened and stored to prevent dust accumulation and deactivation.
● Material Cleanliness Inspection
The surface of the panels should be free of scratches, powder, and rust; the sealant should be a neutral, mildew-resistant silicone sealant that does not release volatile organic compounds; wires and pipes should be free of oil and dust and wiped clean before entering the site.
●Fire Safety Compliance Verification
Cleanrooms have strict fire safety requirements. The fire resistance rating of sandwich panels, fire-resistant sealing materials, fire-resistant partitions, fire sprinklers, and smoke detector locations must be inspected simultaneously. The use of flammable foam sandwich panels is strictly prohibited.
III. Core Controls During On-Site Construction (Top Priority)
● Construction Zoning and Dust Control
Civil engineering, water and electricity, and cleanroom construction should be carried out in sections. Unfinished areas should be temporarily enclosed with corrugated steel sheets; dust-generating processes such as cutting, grinding, and welding should be carried out outdoors or in independent negative pressure construction areas. Temporary dust collectors should be activated during construction to prevent dust from adhering to wall panels and the inside of air ducts.
●Key Points for Enclosure Structure Installation
1.The seams between the color steel panels must be fully sealed with sealant. Rounded aluminum profiles (R50 rounded arc) should be used for both internal and external corners to prevent dust accumulation.
2.Doors and windows should be double-layered hollow cleanroom doors with observation windows. The door frames should be fully sealed on all sides, and the double doors should be properly interlocked.
3.Ceiling panels should be smoothly joined. All pipe penetrations through the ceiling should be sealed to prevent air leakage and dust accumulation. The junction between the floor and walls should be rounded to avoid right angles where dirt can accumulate.
● Ductwork and Air Conditioning System Construction
1.The ductwork is made of galvanized steel sheet. Upon arrival, it is wiped clean to remove grease, ensuring the inner walls are free of oil and dust, and that the sealant is intact.
2.The duct flange gaskets are complete and leak-proof. After installation, the ductwork is wiped clean in sections, sealed for protection, and never left open.
3.Pre-filters and medium-efficiency filters have protective screens installed first. High-efficiency HEPA filters must be installed only after the entire cleanroom is completed and thoroughly cleaned. Pre-installation makes them prone to clogging and failure due to construction dust.
4.Exhaust ducts are equipped with separate check valves to prevent backflow of outdoor air into the clean area.
●Water, Electricity, and Process Piping Construction
All pipe penetrations through walls and ceilings are sealed. Electrical wires are run through cleanroom-specific conduits, and the wire troughs are free of debris. Compressed air and pure water pipes have polished inner walls and are cleaned in sections to prevent impurities from entering the production area. Cleanroom recessed lights with dust-free frames are used.
●Flooring Construction Precautions
The subfloor must be fully dry, and construction should only proceed when the moisture content meets the standard. Epoxy/PVC construction must be dust-free throughout, and proper curing is essential. Personnel are prohibited from walking on the floor before it has cured. The surface resistance of the anti-static flooring must meet industry standards.
IV. Cleaning, Blowing, and System Debugging Phase
●Graded Cleaning Process
Preliminary cleaning (construction waste, dust) → Wipe walls, floors, and ceilings with pure water → Vacuum clean the entire house (high-efficiency vacuum) → Mop three times, cleaning from top to bottom to avoid secondary dust generation; use dedicated cleaning tools, separating clean and ordinary areas, and use lint-free cloths for specific areas.
●Air Duct System Blowing
Continuously blow the air conditioning system under no-load conditions. Regularly replace the pre- and medium-efficiency filters until the dust particle count at the air outlets meets standards before installing the high-efficiency filter.
●Equipment Standalone and Integrated Commissioning
Commissioning of AHU (Air Heater Unit) temperature and humidity, air exchange rate, room pressure differential, and FFU (Fan Filter Unit) air velocity; calibration of air shower blowing time and air velocity; calibration of exhaust air volume in negative pressure rooms; integrated testing of the automatic control system, pressure differential monitoring, and temperature and humidity recorder.
V. Final Acceptance and Testing Key Points
●Mandatory tests for third-party cleanliness inspection: dust particles, airborne bacteria, settled bacteria, pressure differential, air exchange rate, temperature and humidity, illuminance, noise, static electricity, and airtightness.
●Airtightness inspection: Smoke leak detection of HEPA filters, no air leakage in door seams and wall panel gaps;
●Acceptance of supporting functions: Air shower, pass-through window, interlocking door, disinfection UV lamp, and ozone disinfection system are operating normally;
●Document archiving: Material qualification certificates, fire prevention test reports, HEPA filter leak detection reports, cleanliness test reports, as-built drawings, and equipment manuals are all retained for GMP/Environmental Impact Assessment audits.
VI. Post-Construction Maintenance Pre-installation Considerations
●Inspection Port Provision:Removable inspection panels are installed at the locations of ceiling-mounted FFUs, duct valves, and unit filters.
●Pre-installation of differential pressure gauges and sampling ports for convenient routine and periodic testing.
●Disinfection Design:Ozone and hydrogen peroxide vaporization disinfection interfaces are provided; walls and floors are resistant to disinfectant corrosion.
●Separate washing and disinfection rooms and tool storage rooms are provided, clearly separating clean and contaminated equipment storage areas.
VII. General Safety and Compliance Considerations
●Construction electrical safety standards are followed; explosion-proof lighting and fans are used in explosion-proof areas of the cleanroom.
●Construction waste liquids and construction debris are disposed of properly and not accumulated in the workshop.
●Compliance with industry-specific standards: Medical devices comply with GMP; electronic semiconductors comply with ISO14644; food workshops comply with food production cleanroom standards.
●Protecting finished products throughout the construction process: High-efficiency filters and cleanroom doors and windows are protected with protective film to prevent damage from impacts.