How Important Is the Air Shower to Control Contamination in Cleanrooms?

The Critical Role of Air Shower in Cleanroom Contamination Control

  Air Shower (Air Shower) is a very major part of the cleanroom system, widely used in the pharmaceutical, electronics, biological, food and other industries, especially playing the role of pollution control as the first barrier in the personnel in and out of the clean area.

1.What's air shower？
Air shower room is a type of local purification equipment with strong generality, installed between clean room and non-clean room. People and goods need to be blown through the air shower room when they enter the clean area, the clean air can remove the dust carried by people and goods,  effectively blocking or reducing the dust source into the clean area. The front and rear doors of the air shower room / goods air shower room are electronically interlocked, which can also play the role of airlock, preventing the non-clean air from entering the clean area and maintaining the indoor air pressure balance and cleanliness.

 What's the working principle of air shower? 
▶ High-speed circulating airflow: the clean air filtered through the high-efficiency filter in the air shower room is pressurized by the fan and then sprayed out at a high speed through the nozzle to form a high-speed clean airflow (usually air velocity≥20m/s), blowing the personnel or objects that enter the clean area to remove the dust, hair, dander and other pollutants adhering to the surface.
▶Blowing process: when personnel or materials enter the air shower, the front door closes, the fan starts; the air is filtered by the primary and high efficiency filters, and then sprayed through the nozzle at a high speed to cover the whole body or the surface of the objects, blowing down the pollutants and discharging them through the return air outlet.
▶Dust collection: after the blowing completed, the rear door will be opened, so that the personnel or objects can enter the clean area, and the dust blown off will enter the return air system with the airflow, and will be discharged after filtering again to avoid secondary pollution.
▶Timing sensor control: when personnel or goods enter the air shower from non-clean area to clean area, the front door closed (electronic lock locked) and trigger the infrared sensor or manually start the switch. Then the fan starts blowing, the blowing time is set by the control system (e.g. PLC) (usually 1-60 seconds), after the countdown, the front door kept locked, the rear door unlocked and opened, and the personnel or goods enter the clean area. If the door is opened in the middle of the process or the system fails, the blowing shower is automatically suspended and alarmed to ensure the integrity of the process.

What's the differences between air shower & pass box? 
▶ Function
Air Shower: Mainly used for the purification of personnel and bulky goods before entering the clean area, blocking pollutants from being brought in with the personnel/items. The air shower can also be equipped with anti-static function to reduce the accumulation of static electricity, at the same time prevent cross contamination between different production areas.
Pass box: mainly used for transferring small objects between clean and non-clean areas, with an airlock function to prevent high-pressure from being discharged in high-level clean rooms. The pass box blows objects in the transfer process to ensure that the objects entering the clean area are clean and reduce cross contamination.
▶Structure
 Air shower: usually divided into personnel air shower and goods air shower, which has complex structure and larger size, with nozzles installed on both sides or on the top (number ≥ 8), multi-angle blowing human body or the surface of goods, with obligatory blowing time 10-60 seconds. The air shower contains primary filter and HEPA filter (air volume ≥2000m³/h), which is purified by high-speed clean airflow (20-25m/s).
Pass box: relatively simple structure, usually it's made of left shell, right box, upper shell, bottom box and so on. The front and rear doors are interlocked (mechanical or electronic locks), ultraviolet lamps (sterilization) and laminar flow fans can be equipped as required. The blowing air volume (≤1000m³/h), air speed (10-15m/s) and blowing time (5-10 seconds) are relatively shorter.

What's the Industrial application of air shower? 
▶Electronic semiconductor industry: In clean rooms of semiconductor, integrated circuit, electronic component production lines, etc., air shower can effectively remove dust particles from employees' bodies, ensuring the cleanliness of the clean room.
▶In the fields of medicine and biopharmaceuticals: In clean workshops such as drug production and medical device manufacturing, air shower can remove bacteria, viruses and other microorganisms from the surfaces of personnel and items, preventing them from entering the production environment, thereby ensuring the production quality and safety of drugs and medical devices.
▶Food and health products industry: At the entrance of production workshops for beverages, dairy products, baked goods, etc., air shower reduces the pollutants brought into the production workshop by employees, ensuring the safety and hygiene of food. 
▶Research and laboratory application: In places such as biology laboratories, chemistry laboratories, school research laboratories, product development laboratories, etc., air shower can remove dust, microorganisms, and other pollutants from experimental personnel to ensure the accuracy of experimental results.
▶Aerospace and precision manufacturing: Air shower are used to blow operators and fixtures to remove dust carried by personnel, and prevent particles from falling off and adhering to the surface of machine parts in a vacuum environment, affecting component performance or causing equipment failure.
▶Special industries and processes: In the special processes of different industries, the role of the air shower is also indispensable. For example, at the entrance of the car painting workshop, the air shower prevents external workers from bringing in smoke and metal dust, ensuring the actual effect of vehicle painting. Explosion proof air shower rooms have stronger safety performance and are suitable for flammable and explosive environments in production workshops and warehouses in industries such as petroleum and chemical.

2.The location and process of air shower in the clean room 
Where is the location of air shower in the cleanroom?
Located in the buffer section of non clean and clean areas：The standard procedure for personnel access in the clean room is as follows: non clean area → changing room → buffer room → air shower  → clean area. The air shower is usually close to the main entrance of the clean area, forming a dual protection of physical barrier+airflow purification. 
At the junction areas among different cleanliness : If the clean room contains multiple clean class areas (such as class 10000 → class 1000→ class 100 ), the air shower can be set at the junction of different level areas as a transitional facility for class upgrading to avoid cross contamination.

The Role of Air Shower in Personnel Purification Process
▶ Function：
Remove dust particles: The air shower filters out dust particles from the air through HEPA filter, ensuring that items and personnel entering the clean room without any dust particles. 
Reduce pollution: Air shower can effectively reduce the pollution of personnel and items for the clean room, thereby ensuring the cleanliness of the clean room.
Balance pressure difference: The air shower can balance the pressure difference in the clean room, ensuring the correctness of the airflow direction.‌
▶The role of air shower in personnel purification process
The personnel purification process in the clean room: 
① First change (changing shoes, taking off clothes, washing hands and disinfection) → ② Second change (wearing clean clothes, masks, gloves) → ③ Air shower → ④ Entering the clean room. 
  In the process of personnel purification, the air shower uses high-speed clean airflow to remove surface pollutants from the human body, ensuring that personnel entering the clean area minimize the particles and microorganisms carried. At the same time, the air shower inside maintains positive pressure to prevent external air from flowing back, and its airflow direction (such as blowing from the top downwards) is compatible with the airflow organization of the clean area (such as one-way flow), avoiding the disruption of the airflow balance in the clean area. It is a key equipment in the personnel purification process of the clean room.

3.Introduction to types and structures of air shower
Types of Air Shower
Classified by airflow form and blowing direction
▶Single blow: 
structural feature: nozzles are set on one side (left or right), the airflow blows in single direction; The number of nozzles is relatively small (4-6pcs), and the air speed ≥ 25m/s.
▶Double blow: 
structural feature : symmetrical arrangement of nozzles on both sides (left and right), forming a cross airflow; The number of nozzles is 8-12pcs.
▶Three blow type: 
structural feature : nozzles are set at the top and on both sides, forming a 360 ° surrounding airflow; The top nozzle blows downwards towards the head, with air speed of up to 30-40m/s.
▶Vertical flow: 
Structural feature: top air supply, bottom air return, and airflow blowing vertically downwards from the top ; Similar to the principle of unidirectional flow cleanroom, the particle removal efficiency is higher.
▶Horizontal flow: 
structural feature: horizontal air supply on both sides, with airflow blowing from one side to the other; Compact structure, suitable for areas with limited space.

Classified by number of users and space scale
▶Single air shower：The internal dimension is about 1.0*0.8*2.0m, and only one person is allowed to enter each time, suitable for small-scale personnel purification (such as research and development laboratories).
▶Double/multi person air shower: with wider or longer dimension (such as 2.0m*1.0*2.0m), which can accommodate 2-5 people at the same time and is commonly used in production lines with high foot traffic (such as electronics factories and food factories).
▶Channel air shower: with a long cuboid structure (length 3-5m), personnel can pass through in single direction, suitable for continuous pedestrian flow places (such as car spraying workshops, large medical clean areas).

Classified by function and special requirements
▶Explosion-proof air shower: Electrical components need explosion-proof treatment (such as explosion-proof fans, explosion-proof control boxes), suitable for places where flammable and explosive gases exist (such as chemical clean areas).
▶Anti-static air shower: The inner cabinet is made of anti-static stainless steel or PVC material, and the nozzle and filter bracket are treated with anti-static technology, used in the semiconductor and microelectronics industries.
▶Intelligent induction air shower: equipped with infrared sensors or facial recognition system, automatically starting blowing; integrated PLC control system to record blowing time and personnel information (such as pharmaceutical GMP compliance requirements).
▶Sterilization air shower: built-in ultraviolet lamp and ozone generator or hydrogen peroxide spray device, which can sterilize the personnel's surface and clothes while blowing, suitable for biological pharmacy and vaccine production.

Air Shower Components
Cabinet structure
▶Construction Material
Cabinet material：Common materials including stainless steel (such as 304/316), cold-rolled steel plate with spray coating, stainless steel is corrosion-resistant and easy to clean, suitable for high cleanliness areas such as medicine and food; Spray coated steel plates cost lower, which is suitable for general industrial environments.
Door design: The door sealing strip should be resistant to aging and good-sealing, commonly made of EPDM or silicone material. The transparent window can be made of tempered glass for easy observation of the internal condition.
▶Structure Design
Modular assembly (easy for transportation and installation), sealant treatment at joints (to prevent air leakage);
Inner wall arc angle treatment (R ≥ 50mm) to avoid dust accumulation and comply with GMP  requirements.
▶Viewing Window
Adopting tempered glass or acrylic panel, embedded installation, sealed and anti-fog, easy to observe the internal state from the outside.

Air supply system
▶Adopting variable frequency centrifugal fan (with high air pressure & stable air speed, adjustable speed), the power is configured according to the air volume requirements, air speed standard is ≥ 20-25 m/s.
▶Fan Filter Unit (FFU):
Primary filtration: Medium efficiency filter (F8), filters out large particles dust;
Terminal filtration: HEPA (H13-H14 grade) or ULPA (U15-U17 grade), filtration efficiency ≥ 99.97% @ 0.3μm (ULPA commonly used in the semiconductor industry, filtration efficiency ≥ 99.999% @0.12μm).
▶Blowing nozzle: Made of corrosion-resistant stainless steel or engineering plastic, the side nozzle is tilted 20°-30°towards the human body to enhance the performance; The top nozzle tilts downwards at a 45°angle, covering the head. The nozzle diameter is generally 3-5mm, and the higher the air speed, the smaller the diameter to ensure sufficient airflow.

4. How to dsign and choose the right air shower for your cleanroom?
Design Points of Air Shower
The air shower design including the following aspects:
Structural Design
▶Cabinet design: select materials such as spray coated steel plates, stainless steel, composite plates, etc., which are corrosion-resistant and easy to clean. The plates thickness should be ≥ 1.0mm to ensure structural strength and avoid deformation and air leakage.
▶Door design: adopting interlocking (electronic or mechanical interlocking) and door closer, automatically close the air shower door to maintain the sealing performance of clean environment. And ensure that both doors cannot be opened simultaneously to prevent cross contamination in the clean area.
▶Blowing method
Single blowing: single-sided blowing, suitable for places with few people and low cleanliness requirements.
Dual blowing: blowing on both sides, with a wider coverage area and higher dust removal efficiency.
Three blow: blowing on both sides+top, 360° no dead angle blowing, suitable for high cleanliness areas (such as ISO 5 and above).
Cargo air shower: It is necessary to add bottom blowing or rotating trays to ensure that the surface of the material is fully blown.
▶Fan filtration system: including primary and high-efficiency filters (HEPA or ULPA). Primary filters are used to remove larger particles, while high-efficiency filters remove dust and microorganisms in extremely small particle sizes.
▶Control panel: used for intelligent control of the entire air shower, including functions such as start, stop, and time setting.

Airflow and Air Speed Design
▶Air speed requirement: regular air speed of air shower room is ≥ 25 m/s, but for high cleanliness areas, the air speed should be ≥ 30m/s, and strong air speed can effectively remove particles. In addition, the deviation of air speed at each outlet is ≤ 15% to ensure the uniform air speed, which can be adjusted through anemometer by multi-point detection.
▶Airflow organization: Air shower adopts mode of top supply air+bottom return air, forming a vertical unidirectional flow to avoid dead corners. HEPA/ULPA high-efficiency filters are installed at the top to ensure the cleanliness of the air supply.

Electrical and Control Design
▶Control system: PLC intelligent control of the air shower, equipped with an automatic sensing system (infrared sensing or photoelectric sensing), which achieves functions including start, stop, time setting, etc. After personnel enter air shower, it will automatically start blowing, and the time can be set (usually 10-60 seconds). Furthermore, the intelligent control system also supports functions such as password unlocking, recording the showering times etc, which are suitable for GMP compliance areas.
▶Fan and motor: Use low noise centrifugal fan, air pressure ≥ 500Pa to ensure stable air speed; The motor needs to be explosion-proof (for example in explosion-proof areas).
▶Safety protection: emergency stop button, door magnetic switch (prohibit starting when the door is not tightly closed), to prevent injury or misoperation.

Dimension & Capacity Design
▶Personnel air shower:
Single air shower: internal size (W*D*H) approximately 800*1000*2000mm, holding one person at a time.
Multi person air shower: Designed according to the flow of people, for example 2000*2000*2000mm, which holds 2-3 people.
▶Cargo air shower:
The size should match the maximum of the goods, such as width ≥ cargo width+300mm, depth ≥ cargo length+500mm, to ensure that the goods are transferred smoothly.

Suggestions for Selection of Air Shower
Selection by Application
When selecting air shower, the cleanliness, pedestrian flow rate, and cargo size of the application places should be take into consideration, while considering additional requirements such as material, explosion-proof, and energy-saving. Generally, the higher the cleanliness requirements, the more air shower surfaces and higher filtration efficiency should be selected.
▶The electronic semiconductor and pharmaceutical GMP industries: generally ISO5-7, select stainless steel triple air shower with air speed ≥ 30m/s and equipped with ULPA filters.
▶ Food and beverage, cosmetics: generally ISO 7-8, select stainless steel double blowing air shower  with air speed ≥ 25m/s and waterproof design.
▶General industrial clean room: ISO 8-9, and cold-rolled steel plate with spray coating single/double air shower can be used. The air speed requirement is ≥ 20m/s, which is economical and practical.
▶Cargo air shower: According to the corresponding clean area, use large air shower for cargo (with a turntable), also known as cargo shower, with air speed ≥ 25m/s and load capacity≥ 500kg.

Selection by Function
Explosion proof requirement: Chemical and dust workshops need explosion-proof air shower, and motors and electrical components must comply with ATEX or IECEx certification.
Fast passage: In areas with high pedestrian flow, the fast rolling shutter door air shower can shorten the opening time and reduce airflow leakage.
Energy saving design: Optional variable frequency fan, automatically adjusts air speed according to pedestrian flow to reduce energy consumption; LED lighting reduces power consumption.

Selection by Brand & Certification
Qualification certification: The pharmaceutical industry has to comply with GMP and FDA requirements, and choose brands that have passed CE and ISO 14644 certification.
After sales service: Priority should be given to manufacturers with local service outlets to ensure timely maintenance and response for installation, commissioning, filter replacement.
Other precautions
▶Installation space: reserve maintenance space (rear ≥500mm, top ≥1000mm) for easy filter replacement.
▶Match with clean area: The pressure of the air shower should be consistent with the clean area (usually+5-10Pa) to avoid back-flow.
▶Cost budget: Stainless steel material is 30% -50% more expensive than spray coated steel plate, and the triple blow air shower is 20% -40% more expensive than double blow. Consider the performance & demands according to the budget.

5.Operating procedures and management standards for air shower (suitable for GMP customers)
Correct Procedures for Personnel Entering Air Shower

Entering air shower
 

Leaving air shower

Daily Inspection and Maintenance of Air Shower
Daily inspection items and standards

Hardware Facility Inspection
▶Door & Interlock system
Inspection items: Check the sealing of the entrance and exit doors, the sensitivity of the door magnetic switch, and whether the interlock is working well (the two doors cannot be opened at the same time).
Judgment criteria: No obvious gap when door closed, no shaking when manually pushing the door; The response is rapid when the door is opened by induction or manually, and the other door cannot be forcefully opened when the interlock device is working.
▶Fan & Air velocity
Inspection items: Check if any abnormal noise (such as friction or vibration noise) during the fan working, and whether the air velocity of air outlet meets the design standard (usually≥25m/s, depends on the cleanliness).
Judgment criteria: Fan noise ≤ 70 dB (test 1m away from the equipment), using anemometer to detect air velocity at different positions of the air outlet. The deviation each point should not exceed ± 10% of the average value.
▶Filter condition
Inspection items: Dust accumulation on the surface of the primary filter (inspecting through observation window or disassembly), usage time of the HEPA filter, and pressure gauge reading (if available).
Judgment criteria: Clean or replace the  primary filters when the visible dust coverage area on the surface of the primary filter exceeds 50%; It's time to test or replace the HEPA filters when the reading of the differential pressure gauge is 1.5 times the initial value.
▶Control panel & Indicator
Inspection items: Check whether the display screen is clear (time, shower countdown, fault code, etc.), whether the start and emergency stop button are sensitive, and whether the operation indicator lights (power, shower, fault) are working well.
Judgment criteria: Clear feedback after pressing the button, and no garbled or black screen; The status of the indicator light is consistent with the operating mode of the device (such as the "running light" being constantly on during showering).

 Function Testing
▶Blowing test
Operation steps: Simulate personnel or goods entering, start blowing program, check whether the blowing time is consistent with the set value (such as setting 30s, actual operating error ≤± 2s), and whether the nozzle airflow direction covers the entire cabinet.
Exception handling: If the blowing time abnormal, check the timer settings or control system; If the airflow is uneven, clean out the nozzle blockage (such as dust, fibers).
▶Emergency function test
Operation steps: Press the emergency stop button and check if air shower stops working immediately; Simulate a power outage state and test whether the emergency unlocking device can manually open the door.
Judgment criteria: Emergency stop response time ≤ 0.5s, emergency door opening force ≤ 50N (can be easily opened by one person).

Daily maintenance operation guide
Cleaning and maintenance process
▶Internal surface cleaning
Frequency: After daily use
Operating instructions: dipped in 75% ethanol or specialized cleaning agent with dust-free cloth to wipe the inner cabinet, door inner side, floor, and nozzle surface. For stubborn stains (such as scratches or residual marks during cargo handling), gently scrape with a soft plastic scraper before wiping，avoiding metal tools to damaging the stainless steel surface.
▶Primary filter maintenance
Frequency: once a week(3 times a week when heavy polluted)
Operating instructions: Open the filter maintenance door, take out the filter (mostly plate or folded non-woven fabric type), blowing from the filter back with compressed air (pressure ≤ 0.4MPa) , or soaking in neutral detergent for 10 minutes and rinse with water, air dry and reinstall.
After cleaning 3-5 times or using for more than 3 months, replace a new one (depending on the pressure difference or degree of dirt).

Measurement for common exceptions
Here are some common faults and solutions for air shower rooms:
 

Maintenance Records and Management
Standardized Record Table
It is recommended to use a table to record the following content for easy traceability and analysis:
 

Periodic maintenance plan:
 

Professional Maintenance Tips
Precautions for Filter Replacement:
The replacement of high-efficiency filters should be done while the clean area is shut down. Operators should wear clean clothes and use specialized tools to avoid touching the surface of the filter material.
Ensure that the sealing strip is intact during installation, and seal the filter and frame with a knife holder or liquid tank. After installation, a scanning test (such as PAO testing) should be conducted to confirm no leakage.

Electrical Safety Regulations
Disconnect the main power supply of the air shower before maintenance (hang a "in maintenance" warning sign), and prohibit electrical operation.
The insulation resistance detection of the motor requires 500V megohmmeter, resistance value of ≥ 2M Ω. Otherwise, the motor needs to be dried or replaced.

Suggestions for Data Management
Draw a trend chart of air speed data for 3 months. If the rate decrease exceeds 5% per month, filter should be replaced in advance.
Enter maintenance records by scanning code, the system automatically generates maintenance reminders (such as push notifications 3 days before the expiration of the initial filter cleaning).

6.Common Problems & Solutions
Door Problems
The door cannot be opened/closed normally
Common reasons and solutions
▶The door magnetic switch is misaligned or damaged
Description：The induction door does not work, or the door magnetic indicator light does not light up when manually pushing the door
Solution：calibrate the position of the door magnet (gap should be ≤ 3mm) with spirit level, and replace the malfunctioning door magnet sensor
▶The spring of the door closer is loose or broken
Description：The door automatically pops open after closing, or closed too slowly;
Solution: Adjust the speed control valve of the door closer (clockwise acceleration, counterclockwise deceleration), and replace the spring when it breaks
▶Foreign objects stuck in the door crack
Description: There is a stuttering sound when the door moves, and dust or fiber can be seen in local gaps
Solution: remove debris with tweezers from the door gap, and gently tap the deformed door frame with a rubber hammer to reset it

Interlock function failure (both doors open simultaneously)
Emergency response process:
① Step 1: Immediately press the emergency stop button to prevent contamination of the clean area;
② Step 2: Check if any burnt marks on the interlock control module (usually inside the electrical control box), measure the voltage of the door magnetic switch signal line with a multimeter (normally DC24V), and replace the cable if short circuit. If malfunction of the photoelectric sensor, wipe the sensing head with an alcohol swab and adjust the transmission reception alignment angle (deviation ≤ 5 °

Fan & Air Speed Problem
Fan does not start or stop
Troubleshooting steps：
 

Air Velocity Lower than Standard Value
Solution：
▶Filter clogged
Primary filter：Replace it when it's used over 3 months or pressure difference>25Pa (non-woven fabric material is recommended to be cleaned no more than 5 times)
HEPA filter： if the pressure difference ≥ 400Pa or it’s used for more than 2 years (differs from  cleanliness ), PAO leak detection should be done after replacement
▶Fan performance degradation
Dust accumulation on impeller: Disassemble the fan casing and blow the impeller with compressed air (keeping dynamic balance)
Belt slack: Adjust the motor base bolts to tighten the belt, and replace the V-belt (model such as SPZ1250) if it is severely worn
▶Air leakage in the air duct
Check the sealing strip at the joint between nozzles and air duct, and replace the silicone strip (cross-sectional size 5*10mm) if it ages,
Test the weld seam of the air duct with smoke tester, and apply food grade sealant (such as Dow Corning 730) to the leaking area for repair
Control system malfunction

Control panel no display or garbled text
▶Hardware troubleshooting:
Power adapter malfunction: check the output terminal voltage (DC24V), and replace the adapter if the voltage fluctuation exceeds ± 10% (power ≥ 30W).
▶Loose display cable: open the control panel after turning off, unplug and fix the cable again (it is recommended to tie it with zip ties to prevent it from falling off)
The main control board program has encountered an error.
▶Long press the reset button for 5 seconds to restart the system. If it doesn't work, contact the manufacturer to download the firmware and re burn it

Blowing program failure (inaccurate time/failure to start)
Combining software and hardware processing：
① Reason for malfunction: Incorrect setting of time relay
Solution: Enter the parameter setting mode (long press"Settings" button for 5 seconds), reset the shower time to the standard value (such as 30 seconds)
② Reason for malfunction: Infrared sensor failure.
Solution: check the output signal of the sensor with multimeter (when there is human obstruction, it jumps from high level to low level). If it is damaged, replace the reflective sensor (detection distance ≥ 5m).

PLC program failure
Connect the programming computer to read the error code. Common E03 indicates that the shower has timed out. It is necessary to check whether the feedback signal of the fan operation is working.

Other typical issue
Abnormal noise during operation (noise>75dB)
Targeted solutions:：
①Bearing wear：
Remove the fan cover, rotate the impeller by hand to feel the resistance, and replace the 6204-2RS bearing when there is obvious abnormal noise (both sides of the bearing should be replaced simultaneously)
② Component resonance
Check if the damping pad of the fan base (thickness ≥ 10mm) is aging, replace it and tighten it with bolts (torque 15-20N · m)
③  Loose nozzle
Tighten the nozzle fixing nut with a wrench (torque 8-10N · m) and install a locking washer to prevent secondary loose

The pressure difference of filters C continuously increasing
Graded processing solution：
 

Emergency Response and Prevention Measurement
Emergency Response Process for Sudden Malfunctions
① When there is leakage (leakage protector tripping) or smoke, immediately cut off the main power supply and hang a "Do not close" warning sign, use insulated tools (such as rubber handled screwdrivers) to inspect electrical components. If burnt marks are found, take photos and record them. Contact the manufacturer and ask for technical support and inform the fault symptoms and equipment model.
② Preventive maintenance recommendations:
Establish a three-level maintenance system
▶ Daily：Record air speed and pressure difference data daily (mark when deviation exceeds 10%)
▶ Regular：Check the amplitude of the fan with a vibration detector monthly (allowable value ≤ 0.08mm/s)
▶ Professional：Hire a third-party testing agency to conduct cleanliness verification annually (ISO5 level requires particles detection ≥ 0.5 μm)
③ Life management of key components
▶ HEPA filter：attach label of installation date and set a 30 day warning before expiration
▶ Fan capacitor: Measure the capacity once 2 years (standard value ± 5%), and replace it if the decrease exceeds 20%
▶ Door sealing strip: Apply silicone based lubricant (such as MOLYKOTE G-N+) annually to extend the life span.

7.The technological trend and intelligent development direction of air shower
Technical Trends 
Air shower technology is developing towards efficient purification, energy-saving intelligence, customization and other directions to meet the increasingly strict cleanliness requirements of different industries. The specific technological trends are as follows:
(1)Efficient purification technology upgrade:
▶Improved filtration efficiency: With the continuous improvement of cleanliness requirements in industries such as electronic manufacturing, air shower filtration materials will be higher grade. At present, high-end air shower products in China have achieved a 0.1 μ m particle filtration efficiency of 99.9995%, reaching ULPA level. In the future, the filtration efficiency may be further improved to meet the needs of ultra clean environments such as more advanced process chip production.
▶Optimization of airflow organization: Through computational fluid dynamics (CFD) simulation technology, precise control of airflow organization to achieve turbulence degree ≤ 15%, allowing clean air to be blown more evenly onto the surface of personnel or goods, improving dust removal efficiency.
(2)Development of energy-saving technology:
▶Popularization of frequency conversion control: The energy consumption of air shower that adopting frequency conversion control technology can be reduced by 35% compared to traditional products. In the future, more air shower will apply this technology to automatically adjust the fan speed according to actual needs, achieving energy-saving goals.
▶Application of new energy-saving components: New energy-saving components such as magnetic levitation fans will gradually be widely used, which is expected to further improve the energy efficiency ratio of equipment and reduce operating noise in the future.
(3)Improved level of intelligence
▶Intelligent sensing & control: The penetration rate of air shower products equipped with intelligent sensing systems continuously improving. In the future, more sensors will be integrated, such as pressure sensors, temperature and humidity sensors, etc., and AI algorithms will be used to dynamically adjust air speed and intelligently control blowing time, further improving personnel efficiency and user experience.
▶IOT and remote monitoring: The remote monitoring system based on the industrial Internet will become the standard configuration of the air shower, which can monitor the pressure difference, air speed, temperature and humidity and other parameters in real time. The accuracy of fault early warning will also be improved, facilitating users' remote management and maintenance.
(4)Innovation in Materials and Processes:
▶Application of new materials: Nano coating technology will be widely used to reduce the surface roughness of stainless steel to Ra ≤ 0.2 μ m, lowering the particle adhesion rate, and there may be more new anti-pollution and corrosion-resistant materials applied in the manufacturing of air shower.
▶ Manufacturing process improvement: Adopting more advanced manufacturing processes, such as laser welding technology, to improve the sealing and overall quality of the air shower, reducing air leakage and other problems, while improving production efficiency and reducing production costs.
(5)Modular and customized development:
▶ Modular design: The market share of modular air shower will be expanded continuously, and the installation cycle can be shortened to one-third of traditional products, making it easy to install and disassemble quickly and meeting the needs of enterprises for rapid expansion or transformation. Meanwhile, modular design is also beneficial for future maintenance and component replacement.
▶ Customized solutions: The demand for air shower varies greatly among different industries. In the future, air shower will provide more customized solutions based on the features of each industry, such as VHP sterilization combined systems in the pharmaceutical industry, static elimination devices in electronic factories, low-temperature air shower for cold chain food processing, etc.

The intelligent development direction of air shower 
The intelligent development direction of air shower is mainly reflected in the following aspects:
(1)Automated control and intelligent systems:
▶ Multi modal detection system: integrating infrared, pressure, and visual sensors to achieve personnel/cargo identification, clothing compliance inspection (such as anti-static clothing wearing detection), and limb morphology analysis. For example, automatically adjusting the angle and air speed of the nozzles based on human posture to ensures full coverage without blind spots, improving dust removal efficiency more than 15% compared to traditional fixed mode.
▶ Real time cleanliness closed-loop control: By particle sensors and pressure difference monitoring, the fan speed (± 10% dynamic range) and shower time (5-60 seconds intelligent adjustment) are dynamically adjusted to meet cleanliness requirements while reducing energy consumption by 20%.
▶  The intelligent air shower is equipped with an ARM controller and dual CPUs, with real-time dynamic images, data visualization, and automatic fault alarm functions, which can accurately indicate the location of the fault and facilitate non professionals to solve it. 

Human-computer Interaction Innovation：
（1）No impact operation experience
▶  Biometric recognition technology: facial recognition (accuracy ≥ 99.7%), fingerprint/iris recognition for management of permissions grading, automatic matching personalized shower parameters (such as different air speed requirements of R&D personnel and production line workers).
▶  Voice and gesture control: Supporting multilingual voice commands (such as "start fast mode") and gesture recognition (waving to open the door), reducing operational complexity, especially suitable for situations where protective equipment is worn.
（2）Immersive interactive interface
▶  Holographic projection navigation: By using AR projection, display operation guidelines, real-time airflow paths, and cleanliness data, which replaces traditional LED screens and enhances user experience.
▶ Tactile feedback system: pressure sensors are embedded in door handles and operation panels to provide vibration feedback on the operating status (such as vibration reminders when the door is not tightly closed). 

 IOT fully connected: from standalone intelligence to network collaboration
(1) Industrial Internet platform integration
▶  Real time data center: collects 20 parameters such as air speed, pressure difference, temperature and humidity through an industrial intelligent gateway, and transferring to a cloud platform for visual management. The IOT solution supports automatic alerts via WeChat and SMS, reducing the fault response time to 0.5 second.
▶ Cross device linkage: deeply integrated with cleanroom PLC systems, access control gates, fire protection systems, etc., for example, automatically starting backup channels and triggering sound and light alarms when positive pressure imbalance is detected. The pharmaceutical GMP workshop requires fault reporting and handling to be completed within 30 minutes.
（2）Remote operation and digital services
▶ AR assisted maintenance: Technicians remotely guide on-site operations through AR glasses, increasing maintenance efficiency by 40%. For example, an AI visual inspection air shower system developed by a company in Shenzhen supports remote diagnosis and firmware upgrades.
▶ Data value-added services: Provide customers with derived services such as cleanliness trend analysis and energy optimization suggestions, such as customizing a "cleanliness-capacity" balance solution for semiconductor factories through big data analysis.

8. How AIRKEY customizes air shower suitable for customers' overall cleanroom solutions
Factors to consider when customizing a suitable air shower 
As a professional and technologically mature enterprise, AIRKEY fully considers the following factors when customizing air shower for customers:
(1)Industry features
There are significant differences in the requirements for air shower among different industries. The following are some common industry requirements for air shower:
▶Semiconductor industry: Even in ISO6 area, wafer fabs need to be equipped with air shower with ESD function, and nozzles require special anti-static design with surface resistance controlled between 108 -109 Ω. 
▶ Pharmaceutical industry: GMP A/B clean areas require air shower to be equipped with HEPA leak detection ports, pressure differential monitoring devices, and materials shall meet 316L stainless steel standards.
▶ Food industry: class 100,000 workshops may still require air shower, with a focus on anti mold design, such as using antibacterial coatings, curved corner structures, etc.
▶ Laboratories such as biology and chemistry require air shower to remove impurities from the surfaces of personnel and objects, to prevent contamination of the experimental environment.
▶ Automotive industry: Air shower is used to solve the problem of external personnel bringing dust into the spraying workshop through strong winds, ensuring the surface quality of cars during painting and brushing processes. 
(2)Space adaptation
①Size requirements: The size design of the air shower should be based on actual site conditions and user needs. The standard size is 1200x1000x2180mm, but it can be customized according to customer requirements to accommodate different spatial layouts. In addition, the internal space of the air shower should be large enough to ensure the smooth passage of personnel or goods, while ensuring the performance of the air shower.
②Layout requirements: The layout of air shower should be reasonable to ensure smooth passage of personnel or goods. Usually, the front and rear doors of the air shower adopt an electronic interlocking system to ensure that one door can only be opened after the other closed during the blowing process, avoiding cross contamination between non-clean air and clean room air. In addition, the design of the inlet and outlet positions also need consider the airflow organization and convenience of personnel flow. 
③Coordination with other equipment: Air shower is usually used in conjunction with other clean equipment such as changing rooms, buffer rooms, etc. For example, buffer rooms can be set up before and after the air shower to control air flow through pressure gradient and reduce the risk of cross contamination. In addition, the design of the air shower should comply with the overall layout and process requirements of the clean room to ensure the effective operation of the entire clean system.
(3)Technical parameters
▶ Filter system configuration
Filter combination:
Primary filtration: G4 pre filter (filtration efficiency ≥ 90% @ 5 μ m);
Medium filtration: F8 medium efficiency filter (≥ 95% @ 1 μ m);
Terminal filtration: H14 HEPA (≥ 99.995% @ 0.3 μ m) or U15 ULPA (≥ 99.9995% @ 0.12 μ m).
Airflow calculation: Designed based on a cross-sectional air speed of 0.45m/s ± 20%, for example,  1m × 1m channel requires a fan airflow of ≥ 1620m ³/h.
▶ Air Organization Type
Single side air shower: suitable for light personnel pollution areas (such as entering clean areas from offices), with low cost but coverage efficiency ≤ 70%;
Double side blowing: Conventional configuration, nozzle angle tilted at 45 °, coverage efficiency ≥ 90%;
Three side air shower: used in high-end areas such as semiconductors, combined with a raised floor, the dust removal efficiency increased to 99%.
(4)Special functional requirements
The special functions of the air shower mainly include the following aspects:
▶ Interlocking system:
Mechanical interlock: suitable for low-frequency usage scenarios, low cost;
Electronic interlock: Infrared induction linkage, response time ≤ 0.5 seconds, supporting forced unlocking of fire signals.
▶Disinfection module:
UV lamp: wavelength 254nm, irradiation intensity ≥ 40 μ W/cm ², disinfection time ≥ 30 minutes;
Ozone generator: concentration ≥ 20ppm, suitable for unmanned environments, requiring ventilation and emission systems.
▶ Modular design: The air shower supports modular design and can be customized with non-standard dimensions according to actual demands to meet the needs of different scenarios.
▶ Explosion proof design: For specific application scenarios, such as the chemical industry, air shower  need to be explosion-proof design to ensure safe use in potential explosive environments. 

Customization process of air shower 
The customization process of an air shower usually includes the following steps:
▶Requirement analysis and confirmation: Firstly, the sales team contact with the customer to understand their customized requirements, including site conditions, cleanliness requirements, budget, frequency of use, number of people or item sizes passing through each time, cleanroom clean class, and specific dimensions of installation space.
▶On site survey: Dispatch a professional team to the customer's site for survey, understand the actual situation and measure the dimensions, in order to more accurately formulate the design plan.
▶Design and planning: Based on customer requirements, professional design engineers carry out drawing design, including the structure, dimensions, internal layout, etc. After the design completed, confirm the design plan with the client to ensure it meets their expectations. 
▶Production and processing: The procurement team purchases the required raw materials as the design drawings, such as purification plates, stainless steel, etc. The production team processes, welds, and assembles according to the drawings to ensure the quality and performance of the air shower. 
▶Assembly and debugging: Assemble the processed components to form a complete air shower structure. Debug the various functions of the air shower, including air speed, filtration efficiency, control system, etc., to ensure its normal operation.
▶Performance testing: Make performance testing on the air shower that has been debugged, including cleanliness testing, noise testing, etc., to ensure that its performance meets the design requirements. 
▶Installation and training: Deliver the air shower to customer's site for installation and commissioning to ensure its normal operation. Provide operation and maintenance training to ensure customers can correctly use and maintain the air shower.
▶Acceptance and after-sales service: The customer inspects the air shower to ensure that it meets the design requirements and usage needs. Providing repair and maintenance services during the warranty period, as well as continuous technical support, to ensure the long-term stable operation of the air shower.‌‌