Controlling microbiological contamination from personnel is a critical issue in factories that adhere to good manufacturing practices. According to cleanroom audit studies, humans release approximately 100,000 microscopic particles containing bacteria every minute. Improperly handled protective clothing can become dangerous disease vectors.

For QA/QC and Production Managers, finding the optimal solution for full-body disinfection is always a top priority. We need a thorough mechanical contamination removal process that doesn’t disrupt the workflow of the production shift.

This article is based on the international HACCP Codex 2022 standard, translated by SGS Vietnam. We will analyze the scientific aspects to optimize personnel cleaning before entering sterile areas.

1. International Standards for Personnel Control

1.1 Production Area Buffer Zone Regulations

The architectural design of factory zoning plays a core role in preventing cross-contamination. According to the guidelines in Section 13.2.4 of the international standard CXC 1-1969, access to high-risk processing areas must be through a suitably designed changing room. This regulation mandates that businesses establish physical boundaries isolating the contaminated buffer zone from the clean production zone.

This separation helps control pressure differentials and prevent the movement of airborne particles. You need to ensure that airflow does not flow backward from the heavily contaminated area to the microbiologically controlled area. This is a fundamental step in maintaining the integrity of the food hygiene system.

1.2 Personal Protective Equipment and Hygiene Requirements

Direct operators are required to strictly adhere to protective clothing regulations before their shift. Codex standards clearly stipulate that employees must wear clean protective clothing, and be equipped with a hair cap and beard cover. Additionally, you must use a handwashing sink with a hygienically designed faucet, ideally one that is not manually operated.
The cleaning process must thoroughly remove dirt and potential allergens from the body surface. Furthermore, personal items such as jewelry, watches, and artificial nails are strictly prohibited as they directly threaten product safety. Compliance with these regulations minimizes the amount of microbial contamination before performing advanced mechanical separation steps.

2. Principles of Dust Removal in Air Showers

2.1 Fluid Dynamics Through Nozzles

Air showers operate on the principle of circulating fluid mechanics to remove physical contaminants adhering to protective clothing. A high-powered motor forces a stream of sterile air through directional nozzles. This process creates high-velocity, swirling jets of air that powerfully impact the surface of the personnel’s clothing.

To achieve optimal mechanical removal efficiency, the air velocity at the nozzle opening must reach a standard range of 20 m/s to 25 m/s. The automatic cycle’s air blowing time is set to range from 10 to 20 seconds. These parameters ensure the breaking of the electrostatic bonds of fine dust without causing biological harm to the personnel inside.

2.2 Optimal Air Performance Operation Procedure

The mechanical cleaning efficiency of the equipment largely depends on the posture and behavior of the personnel inside the shower. When the air blowing cycle is activated, workers need to raise both hands and actively rotate their bodies 360 degrees. This action helps the high-velocity airflow directly reach hidden areas such as armpits, clothing folds, and trouser legs.

We need to establish standard operating procedures (SOPs) and provide regular training for factory personnel. If employees stand still, dust particles trapped in hidden corners will not be removed and risk entering the cleanroom. Proper movement optimizes cleaning efficiency and saves energy for the system.

Full-body disinfection is one of the factors in ensuring compliance with GMP standards

3. Standard Air Filtration System

3.1 Pre-filter and HEPA Filter Structure

To ensure the circulating air always achieves sterile purity, the device must have a multi-stage filtration structure. Dirty air carrying impurities first passes through the pre-filter to retain large dust particles larger than 10 µm, protecting the lifespan of the subsequent filter layers. Next, the air is forced through a HEPA H13 or H14 fine filter system.
The HEPA filter has an ultra-fine interwoven fiberglass mesh structure, providing a retention efficiency of 99.97% to 99.99% for particles as small as 0.3 µm in diameter, including bacterial and mold spores. Thanks to this continuous closed filtration cycle, the air inside the chamber is always regenerated to an ultra-clean state, completely preventing secondary pollution.

3.2 Frequency of filter maintenance and replacement

The performance of air filtration layers will decrease linearly over time due to dust accumulation. Based on technical data from industrial plants, the coarse filter needs to be cleaned or replaced every 2 to 3 months. Meanwhile, the HEPA fine filter needs to be checked for differential pressure and replaced periodically every 12 to 24 months.
If you ignore the maintenance schedule, the increased resistance of the filter will reduce the wind speed to below 20 m/s. At that point, the kinetic energy of the airflow is no longer strong enough to overcome the electrostatic bonding force of dust clinging to clothing. The expired filter itself also risks becoming a source of harmful microorganisms.
Businesses requiring on-site surveys and design of sterile air filtration systems for cleanroom entrances, please submit your request via the Duc Duong Contact Form so our cleanroom engineers can assist in calculating the appropriate filtration capacity.

4. Interlock System for Preventing Cross-Contamination

4.1 Principle of Electronic Interlock

The electronic interlock system is a mandatory technical solution for controlling pressure and preventing cross-contamination. This mechanism operates on the principle of exclusion: when one door opens, the other is immediately locked by an electromagnetic magnet. The system ensures that the two doors of the air chamber never open at the same time.

This structure completely eliminates the spontaneous convection tendency of untreated air from the protective corridor into the clean production area. When workers enter, the front door closes, and the air blowing cycle begins. The rear door is only released when the chamber finishes its mechanical cleaning time and the room pressure reaches equilibrium.

4.2 Emergency Door Release Button Design

In parallel with maintaining pressure security, workplace safety for personnel inside the cleanroom is always a top priority. Standard cleanroom equipment must integrate a red emergency power cut-off button on both sides of the cleanroom walls. This component helps personnel quickly handle unforeseen situations.

When the operator activates this button, the electrical circuit supplying the electromagnetic locking system is immediately completely cut off. The mechanical mechanism automatically releases the lock, allowing the door to be pushed freely in both directions for personnel to escape. This design provides maximum safety for workers in the event of a fire or sudden power outage.

5. High-Capacity Air Shower Solutions for Large Factories

5.1 Breakthrough Capacity of the 8-Person Model

In large-scale processing plants, the use of single-person (1-2 person) full-body disinfection booths often creates serious bottlenecks during shift changes. Workers have to queue for long periods waiting to be air-treated, wasting time and reducing the efficiency of shift management by Production Managers.
To thoroughly address this issue, Duc Duong Company offers a superior technological solution from Korea: the Sunkyung SK-2020CL8 automatic door air shower booth for 8 people. This device allows a group of 8 personnel to simultaneously air-treat to remove dirt and dust, accelerating the circulation through the clean buffer zone by 4 times compared to conventional configurations.

Sunkyung’s full-body air disinfection shower for 8 people saves time and maximizes efficiency

5.2 Advantages of Infrared Sensor Automatic Sliding Doors

The automatic sliding door system is a valuable mechanical improvement on Sunkyung’s high-end equipment lines. The integrated infrared sensor allows the door to automatically open when it detects people approaching. This mechanism eliminates the need for employees to directly touch the door handle, removing the risk of microbial contamination through contact surfaces.

Furthermore, the chamber walls are made of high-strength tempered glass, providing a wide and unobstructed view for personnel inside. The digital control system visually displays the air blowing progress, facilitating easy coordination among workers. You can refer to the basic operating parameters of the SK-2020CL8 model below:

Technical Specifications	Value / Configuration Characteristics
Integrated Door Type	Automatic sliding door with infrared sensor
Maximum Capacity	8 personnel / cycle
Control System	Digital LED display, fully automatic

6. Durable Mechanical Design and Equipment Cleaning Process

6.1 Durability of SUS 304 Stainless Steel Material

The structural material of the body directly determines the lifespan and chemical inertness of the system in an industrial environment. High-quality full-body disinfection chambers must have inner walls made of high-grade SUS 304 stainless steel. This alloy has excellent oxidation resistance and will not rust even when exposed to high concentrations of cleanroom cleaning chemicals.
The floor of the equipment uses a precisely perforated, high-strength stainless steel plate. This perforated design allows all dust particles and microorganisms, after being detached from clothing, to fall directly into the dust collection trough below under the pressure of gravity and downward airflow. This mechanism prevents dust from adhering back into the drying chamber.

6.2 Regular Air Shower Cleaning Procedure

The air filtration system itself, if not cleaned and maintained properly, will become a source of harmful mold growth. The QA/QC department needs to create a weekly cleaning checklist for factory maintenance staff. You should use 70% alcohol or specialized disinfectant solutions to clean the glass walls, air nozzles, and handrails.
The dust collection chute located under the perforated steel floor also needs to be removed and vacuumed regularly. Maintaining equipment hygiene ensures that the circulating air always achieves the highest sterile efficiency. This helps businesses pass the rigorous assessments of competent authorities regarding food and pharmaceutical safety.

Conclusion

In short, establishing a comprehensive personnel cleaning solution is an inseparable link in the GMP quality control chain. Businesses need to strictly adhere to Codex standards for zoning changing rooms, apply mechanical dust removal technology using high-velocity air streams of 20 to 25 m/s, and prioritize the selection of high-capacity air shower chamber configurations like Sunkyung to optimize staff flow. Duc Duong Company is proud to be a strategic partner supplying modern full-body air shower chamber disinfection machines from Korea, accompanying businesses in enhancing their biosafety capabilities.

To receive detailed technical specifications, cleanroom layout drawings, and a price list for Sunkyung automatic air shower chambers, please fill out the information at Contact Duc Duong Company or contact the project department hotline for the most comprehensive support.

 

DUC DUONG SCIENCE AND TECHNOLOGY COMPANY

Address: 1014/67 Tan Ky Tan Quy, Binh Hung Hoa Ward, Binh Tan District, Ho Chi Minh City

Tel: (028) 3762 8042 – 3762 8043 – 3750 8514 – 3750 8793

Fax: 028 37628043

Email: ducduong@ducduongco.com

Website: ducduongco.com

ZALO OA: DUC DUONG SCI

 

FAQ

1. What is the core difference between an Air Shower and a Disinfection Spray Chamber?

Air Shower systems use pure mechanical power from a high-velocity (20-25 m/s) circulating sterile air stream through a HEPA filter to blow away and detach dust particles and microorganisms adhering to protective clothing. In contrast, disinfection spray chambers or medical full-body disinfection chambers typically use a mechanism that sprays disinfectant chemicals directly onto the body. For industrial cleanroom standards (GMP), mechanical Air Shower equipment is a mandatory solution to prevent foreign particles from entering the production environment without causing wetness or chemical residue on clothing.

2. How does the Air Shower Interlock system work during shift changes?

The Interlock mechanism operates based on a system of position sensors and independent electromagnetic locks mounted on the two chamber doors. When an employee opens the door from the protective corridor to enter the cleanroom, the production cleanroom door will automatically lock securely. The cleanroom door is only released after the system completes the sterile air blowing cycle to remove dust (usually 10-20 seconds) and the corridor door is completely closed, absolutely preventing the convection of dirty air from flowing back inside.

3. Why should Production Managers prioritize automatic sliding door air showers over hinged doors?

The device integrates an automatic sliding door system combined with infrared motion sensors to automatically detect movement. This solution eliminates the need for employees to physically touch the door handle, completely eliminating the risk of cross-contamination to the auditory or tactile surfaces. In addition, the sliding door structure allows for quick flow of people, saving space for opening the door, helping Production Managers solve the problem of staff congestion during shift changes in large work shifts.

4. Can full-body chemical disinfectant sprayers replace air showers in cleanrooms?

The answer is No. Full-body disinfectant sprayers, chemical mist sprayers, or chemical mist sprayers only disinfect surfaces but cannot remove fine dust particles, lint, and stubborn physical contaminants that adhere to static electricity. Furthermore, continuous chemical misting in industrial environments can easily dampen protective clothing and affect the respiratory health of workers. Therefore, GMP cleanrooms must use mechanical air showers with circulating fluid through HEPA filters to ensure safety.

5. What is the recommended frequency for checking the accuracy and maintaining the electromechanical system of the air shower?

The infrared sensor system, digital controller with LED display, and electromagnetic locking circuit should be checked by factory engineers at least once a month. You need to periodically measure the wind velocity at the nozzle using a specialized measuring device to ensure that the dust removal pressure does not drop below 20 m/s. If signs of excessive pressure difference are detected on the gauge, the maintenance department must immediately replace the coarse or fine HEPA filter to maintain optimal sterilization performance in the air chamber.