Maintenance criteria for high-efficiency air supply ceiling filters (including pre-filter), applicable on-site and easy to use I. Core point: Check the pressure difference (priority, based on national standards) 1. High-efficiency filters (end H13/H14) Initial resistance at factory: 220-250 Pa Trigger for replacement: Measured resistance ≥ 2 times initial resistance Example: Initial resistance 250 Pa → Must replace when it reaches 500 Pa Daily control: Continuous rapid increase in pressure difference (short-term surge) → Pre-filter failure, conduct early investigation 2. Medium-efficiency filters (F8/F9) Initial resistance: 80-120 Pa Replacement: Resistance exceeds 1.8 times initial resistance / Pressure difference gauge reaches full scale, air volume decreases 3. Primary-efficiency filters (G4) Recoverable type: Dirty blockage, blackening, pressure difference rises → Clean 2-3 times and then directly scrap and replace One-time type: Significant increase in pressure difference / Severe visible dust accumulation directly replace II. Check detection data (GMP / Cleanroom must check) PAO leak detection fails: frame leakage, filter material leakage. No matter what the pressure difference is, replace immediately Room cleanliness not up to standard， particle count exceeds limit， after excluding other leakage points， directly replace the end high-efficiency filter Outlet air speed significantly low， no wind locally / Outflow skewed， filter material

Daily Maintenance Tips for Air Supply Ceiling «Easy to Leak, but Crucial» (In addition to changing filter elements and checking pressure difference, focus on sealing, cleanliness, airflow, anti-corrosion, and compliance) 1. Sealing and Leak Prevention is the Top Priority (90% of pollution comes from this) Weekly Inspection: Check the efficient frame sealing strips, silicone sealing pads, and ceiling joint seams Yellowing, hardening, cracking, detaching, accumulation of black dust → Immediately replace the sealant / repair the sealing glue Install screws evenly and tightly, don’t tighten one side and loosen the other, it will leak After disinfection and fumigation / formaldehyde sterilization: Must check for aging seals, high temperature and high humidity are most prone to detaching and leaking 2. Cleaning must be done carefully (to avoid secondary pollution + damage to filter membranes) Outer panel / uniform flow board: Use a lint-free cloth + neutral water / 75% alcohol to gently wipe Prohibited: High-pressure water gun flushing, strong alkaline disinfectant solution, hard-bristled brush scraping (will damage PTFE membrane / filter material) Never allow to randomly wipe the dust inside the air supply ceiling, the accumulated dust can only: Stop the machine → Negative pressure vacuum cleaning → Professional personnel operation

I. Core conclusion (by scenario) Conventional cleanrooms (electronics / packaging materials / general cosmetics, low dust, daily use 8-12 hours): H13/H14 high-efficiency filters: theoretical design life 1-2 years; based on pressure difference compliance, most can last 18-24 months. High dust / high frequency use (multiple material transfers, heavy industry support, daily use over 16 hours): actual lifespan: 6-12 months is likely to exceed pressure difference and get clogged. Aseptic pharmaceuticals / biosafety / high-grade clean areas (GMP strict control): even if pressure difference is normal, it is recommended not to exceed 12-18 months for mandatory re-inspection + assessment for replacement to avoid leakage risks. II. Key reminder: Lifespan ≠ time; prioritize 3 hard indicators Pressure difference: increase to 1.5 times the initial pressure difference / exceed 500 Pa → must replace; PAO leak detection / particle scanning: leakage, frame leakage → replace immediately; Air velocity: outlet continuously lower than 15 m/s, excluding fan and primary filter blockage → efficient filter must be scrapped. III. Core factors affecting lifespan Regular replacement of the front-end primary filter (3-6 months once), can significantly extend the lifespan of the efficient filter; Outdoor pre-treatment of goods and dust removal are in place, reducing the dust

Automatic double-door cargo airlock room – Filter lifespan | Key influencing factors 1. Pre-filter protection (most significant impact) Maintenance / replacement frequency of primary filters (G3/G4) – If the front-end primary filters are not cleaned or replaced frequently, large particles will directly reach the high-efficiency filter, causing rapid blockage of the pressure difference and halving or even reducing the lifespan to 1/3; Specification: The primary filters should be blown clean weekly and replaced every 3 to 6 months. Whether there is a transitional intermediate filter duct / return air with an intermediate filter can significantly reduce the load on the high-efficiency filter and extend its lifespan. 2. Dust concentration in the usage environment External areas with high dust (processing, packaging, raw material transfer, dust-filled workshop) → The incoming air contains high dust, and it will be blocked quickly; Clean areas without pre-dust removal, no wind shower buffer, and inadequate dust removal for personnel and materials → The high-efficiency filter accumulates dust rapidly, accelerating its failure. 3. Equipment operation conditions Daily operation duration of 24 hours without shutdown, frequent incoming and outgoing goods, frequent air blowing, high air flow load, and rapid resistance increase; Regular use for 8 hours per day,

Negative pressure weighing room comprehensive maintenance (GMP compliant version, easy to understand and implement) 1. Daily inspection (must be done every shift / every day) Appearance and cleanliness No dust or accumulated materials on the inner walls, workbench, return air filter, operation port; wipe with dust-free cloth + purified water / 75% ethanol, prohibit corrosion of the cabinet by strong acids and strong alkalis. Parameter confirmation Check the pressure difference gauge: the indoor negative pressure is stable at **-15~-30Pa**; Check the wind speed: the vertical wind speed at the working surface is 0.35~0.45m/s; The fan, lighting, and alarm functions are normal, without abnormal sounds or air leakage. Operation norms Do not knock on the HEPA high-efficiency filter, do not stack materials at the air outlet; start self-cleaning for 10~15 minutes before feeding and weighing. 2. Weekly maintenance Deep cleaning: disassemble and wash the primary filter and return air filter (wash and dry with water, strictly prohibit sun exposure); Check the cabinet sealing: no cracks or air leakage at the door frame, maintenance port, and glass rubber strip; Calibrate pressure difference and wind speed sensors, record the ledger. 3. Monthly maintenance Check the dust accumulation of the medium-efficiency filter, if the

I. General Standards (Pharmaceutical Factory / GMP mainstream) Normal operating conditions (ordinary raw materials and excipients, low dust): HEPA high-efficiency filter: 12-24 months High dust / high activity / toxic powders (anti-cancer drugs, hormones, sterile powders, fine powders of traditional Chinese medicine): HEPA high-efficiency filter: 6-12 months. Forced shortening II. Not based on time, but on pressure difference (most accurate, GMP recognizes this) Based on the initial pressure difference of the equipment: When the final pressure difference reaches twice the initial pressure difference / the upper limit of the manufacturer’s calibration → immediately replace, don’t wait for the cycle Daily pressure difference increase is fast: indicates a large dust load, replace in advance III. Reference period for matching filters (companion notes) Primary efficiency: 1-3 months of cleaning, 3-6 months of replacement Intermediate efficiency: 6-12 months of replacement (protecting the high-efficiency filter, frequent replacement of intermediate efficiency = prolonging the life of HEPA) IV. Key mandatory requirements (must be inspected by inspection agencies) After each replacement of the high-efficiency filter: must conduct PAO leak detection + wind speed balance test + re-calibration of pressure difference, and retain the verification report.

The core principle of the negative pressure weighing chamber is: through vertical unidirectional flow + local exhaust to form a stable negative pressure, locking dust / pollutants within the operation area and preventing them from leaking out, while ensuring the cleanliness of the operation area. I. Core Structure (Key Components of Air Flow Path) Primary / Intermediate Filter: Pre-filters large particles to protect the fan and the high-efficiency filter. Centrifugal Fan: Provides power to drive the air circulation and exhaust. High Efficiency Filter (HEPA): Captures particles of 0.3μm with a retention rate of ≥ 99.99%, ensuring the cleanliness of the supply air. Equalizing Mesh / Equalizing Membrane: Forms a uniform vertical laminar flow (about 0.45m/s). Return / Exhaust System: Collects the dust-containing air flow, partially recycles and partially discharges. Pressure Difference Control System: Maintains a relative negative pressure of the operation area to the external environment (usually -15~-30Pa). II. Operating Process (Air Flow and Negative Pressure Formation) Return Air Purification Dust-containing air in the operation area enters through the bottom return mesh, and passes through the primary / intermediate filters successively to remove large particles. Supply Air Purification The purified air is sent by the fan into the high-efficiency filter

Frequency of integrity testing for high-efficiency filters in the automatic double-door cargo washing room According to GMP, cleanroom acceptance standards and common industry practices, the frequency is divided into the following levels. You can directly follow and implement them: 1. Routine usage frequency (most commonly used) Test once every 6 months Applicable to: cargo washing rooms in electronic, food, and ordinary pharmaceutical cleanrooms. 2. High-purity clean environment Test once every 3 months Applicable to: sterile drugs, medical devices, biological laboratories, high-level cleanrooms (10,000-level / 10,000-level / 100-level). 3. Immediate testing situations (no fixed cycle) Test immediately if any of the following conditions are met: High-efficiency filter has just been replaced or installed The cargo washing room box or high-efficiency filter has been disassembled, moved, or collided Pressure difference is suddenly abnormal (too high / too low) The particle count in the clean area exceeds the standard, suspecting it is a filter problem Water leakage, moisture, mold, chemical contamination After a long shutdown, reactivation 4. Industry’s lowest mandatory requirement New installation acceptance: 100% leak testing must be conducted After normal use: At least once a year for integrity testing

Here is a set of standard operating procedures for the **High Efficiency Filter Integrity Testing (PAO Leak Detection Method)** commonly used in cleanrooms, specifically for automatic double-door and shower rooms. It is simple, practical, and concise. High Efficiency Filter Integrity Testing (PAO Aerosol Leak Detection) Procedure I. Preparation Tools Aerosol Generator (PAO/DOP) Aerosol Photometer (particle counter can also be used as a substitute) Clean cloth, alcohol, marker pen, record sheet Personnel Wear clean suits, gloves, and masks Equipment Status The door of the shower room is closed, and the room is kept sealed. Clean the outlet surface and nozzles of the high-efficiency filter in advance. II. Dust Generation (Establishing Upstream Concentration) Place the PAO aerosol generator at the inlet end of the shower room (outside the primary filter or in the return air box). Turn on the generator and let the PAO oil mist enter the duct along the airflow and pass through the high-efficiency filter evenly. Take samples in the upstream duct of the high-efficiency filter using the photometer, Adjust the dust generation rate to make the upstream concentration reach 10% to 20% of the photometer’s measurement range and stabilize. Purpose: To ensure that the downstream can accurately detect

Below is a list of the most commonly used and essential tools and materials for installing the main structure of the clean room (generally made of aluminum profiles / square steel / corrugated sheet), which can be directly used for construction, procurement, or scheme writing. I. Common Materials for the Main Structure The main structures of the clean room are usually three types: Industrial aluminum profiles (most commonly used, easy to disassemble, high cleanliness) Galvanized square tubes / square steel (strong load-bearing, low cost) Stainless steel frame (high cleanliness, corrosion-resistant) The following are common tools and materials. II. Essential Installation Tools 1. Measuring and Laying Tools Laser level / level Steel tape measure, right-angle ruler, ink roller Marker pen, chalk 2. Cutting and Processing Tools Profile cutting machine (for aluminum profiles only) Hand drill, impact drill Angle grinder (for grinding, deburring) Drilling tool, drill bit set 3. Fastening Installation Tools Hex key wrench set (for aluminum profiles only) Adjustable wrench, socket wrench Rubber hammer, rubber mallet Screwdriver (cross / flat head) Level, straightedge 4. Auxiliary Tools Ladder, scaffolding Gloves, safety goggles, mask Cables, wiring board III. Installation Materials for the Main Structure 1. Main Frame Materials Industrial aluminum profiles (4040/4080/5050

The selection of the main structure material for the clean room is centered around achieving a balance among cleanliness, load-bearing capacity, corrosion resistance, cost, and ease of installation. The mainstream frameworks include aluminum profiles, stainless steel square tubes, and powder-coated iron square tubes. The enclosures commonly use anti-static PVC curtains, acrylic/PC panels, tempered glass, and color steel plates. 1. Frame Material (Core Load-bearing Structure) 1. Aluminum Profiles (Most Commonly Used) Applicable scenarios: Medium-low cleanliness (ISO 7–8 levels), small and medium-sized, temporary / mobile clean rooms, general areas of electronics / semiconductors. Advantages: Lightweight, quick installation, can be assembled by one person, no heavy equipment required. Surface is anodized, smooth, dust-free, easy to clean, and not prone to dust accumulation. Modular, reusable for disassembly, highly expandable. Disadvantages: Limited load-bearing capacity, not suitable for hanging heavy FFU / equipment. Weak impact resistance, prone to oxidation and discoloration in humid / acid-base environments over long-term use. Selection tips: Prefer 40×40/40×80 industrial purification aluminum profiles, with anodized surface and anti-static treatment. 2. Stainless steel square tubes (304/316, preferred for high-end applications) Application scenarios: High cleanliness (ISO 5–6 levels), pharmaceutical / biopharmaceutical / GMP, food, humid / acid-base corrosive environments. Advantages: 304 Resistant to daily

Wind shower transfer window high-efficiency filter – Standard installation steps I. Pre-installation preparations Stop the machine, disconnect the power supply, and hang the “Equipment maintenance, do not close the switch” sign. Tools needed: Cross-head screwdriver, clean cloth, gloves. Clean the top/back of the transfer window’s fan compartment, wipe off dust. Check the new high-efficiency filter: No damage, no deformation, no moisture or mold Frame is intact, sealant strips are complete The shell has an air flow direction arrow II. Disassembly of the old high-efficiency filter Open the filter maintenance cover (usually on the top or back of the transfer window). Loosen the tightening bolts / clasps, slowly remove the old filter. Clean the installation slot and the interior of the air duct again, without dust or debris. III. Installation of the new high-efficiency filter (key steps) Confirm the direction The air flow arrow on the filter → towards the wind shower chamber and nozzle direction. Place the filter smoothly in the installation slot Hold the frame with both hands, do not touch the filter paper Place it gently in position, without twisting or squeezing Complete the sealing around it Ensure that the sealant strips are fully adhered, without warping or