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Construction process of cleanroom with three-level cleanliness control
2026/9/16
Level 1 Control (General Construction Control)
Applicable stage: Main structure, civil engineering, partition frame, ceiling frame, rough pre-installation of mechanical and electrical equipment, prefabricated duct installation, floor base layer.
Construction objective: Control a large amount of dust, isolate civil engineering waste, and reduce the base of subsequent pollutants.
Area isolation: Simple partition between the clean area and the ordinary civil engineering area, multiple entrances, and setting up simple dust-absorbing mats.
Personnel control: Ordinary work clothes, shoe covers; basic training on entry cleanliness standards; prohibition of eating in the clean area.
Material control: Large items can be removed from the clean area outside; wood, cardboard can be temporarily brought in; materials are stacked by zones and covered with film protection.
Work requirements: Dust-producing operations such as cutting, drilling, grinding, and welding are allowed; local negative pressure + supporting vacuuming; garbage should be bagged and removed daily.
Cleaning standards: Daily cleaning, ordinary industrial vacuuming; overall rough sweeping after completion, and completing a large sweep before entering the second-level control.
Level 2 Control (Clean Enclosure Construction Stage)
Applicable stage: Installation of color steel plate wall panels / ceilings, duct sealing, epoxy self-leveling / anti-static floor construction, mechanical and electrical piping and wiring, lighting / sprinkler installation; air conditioning system starts segmented blow-off; goal: Reduce floating dust, eliminate large-scale dust production, and protect the finished products.
Area isolation: Remove excess entrances, retain 2 or fewer entrances for entry; set up a separate material unloading area at the entrance; zone negative pressure isolation; completed walls and floors are covered with film protection.
Personnel control: Head cover + shoe covers + dust-free mask; personnel registration; strict control of external visitors; prohibition of wearing easily detachable accessories.
Material control: All packaging must be removed outside the clean area; cardboard, wood can be temporarily brought in; surface cleaning of incoming materials; sealing and protection of pipe and duct ports.
Work requirements: Prohibition of cutting, grinding, drilling, and welding in the clean area; if necessary to operate, it requires special approval + local dust-free shed + HEPA vacuuming; welding should be arranged in the prefabrication area; waste should be sealed and promptly removed.
Cleaning standards: Daily completion cleaning, using HEPA vacuuming; from top to bottom wiping of walls and ceilings; timely cleaning of seams; daily inspection of the integrity of the finished product protection film; after this stage, perform a comprehensive large sweep + continuous air conditioning blow-off for acceptance, and only after passing the acceptance can it be upgraded to the third-level control.
Level 3 Control (Before HEPA installation → System debugging, acceptance stage)
Applicable stage: Continuous air supply of the air conditioning system, maintaining positive pressure in the room, HEPA/ULPA installation, FFU installation, positioning of process equipment, system leak detection, cleanliness test; once entering the third-level control, the cleanroom is regarded as a quasi-clean area, no longer a construction site.
Area isolation: Only retain a single controlled entrance, add a wind shower room; zone pressure control; continuous placement of multiple layers of dust-absorbing mats at the entrance; non-operational areas are closed.
Personnel control: Complete clean suit, head cover, beard cover, dust-free gloves, clean shoes; holding a certificate + registration for entry; strict control of personnel quantity; prohibition of entering the area without permission; prohibition of touching the clean surface within the area.
Material control: Prohibit the entry of wood, paper, and fiber materials; all tools and components should be wiped clean at the unloading area; small items should be brought in through the transfer window / air shower; tire of the transportation vehicle should be wrapped with dust-free film.
Work requirements: Complete prohibition of dust-producing operations such as grinding, drilling, cutting, and welding; any opening operation requires special approval + local isolation; all operations should be carried out gently; The waste materials are placed in sealed dust-free garbage bags and immediately transferred out of the clean area.
Cleanliness standards: Step-by-step cleanliness from top to bottom (ceiling → wall panels → equipment → floor), with dust cloths and no residual clean solvents; continuous HEPA vacuuming; daily visual inspection of the environment + particle monitoring; after the installation of HEPA is completed, perform PAO leak detection, cleanliness, pressure difference, temperature and humidity acceptance tests.
Approval process for switching of the three-level control system
The construction general contractor submits the self-inspection report for the completion of the stage
The supervisor / cleanroom specialist conducts on-site verification and visual inspection + initial dust particle inspection
Complete the comprehensive cleaning of the entire area, air conditioning system blowdown, and cleaning of the ducts
Issue the "Confirmation Form for Upgrade of Cleanliness Control Level", officially upgrading to the next level
Downgrading mechanism: In case of large-scale dust dispersion or serious pollution incidents, immediately suspend operations, implement downgraded control, thoroughly clean again, and only resume after re-inspection is qualified
General ledger for the three-level control system
Personnel entry and exit registration
Material entry cleaning record
Daily cleanliness cleaning record
Special approval for dust-producing operations
Single pressure difference and particle count monitoring recorda
Finished product protection inspection record
