The principles, methods, and results of air filtration applications in pharmaceutical and medical device manufacturing systems. In this sector, air filtration is a core element in ensuring product quality, safety, and regulatory compliance, far exceeding the importance of general industrial or residential environments.

 Why Use Air Filtration? 

In pharmaceutical and medical device manufacturing, the core principle of air filtration systems is strict contamination control. The goal is to create and maintain a controlled environment that meets specific cleanliness levels to prevent product contamination from various airborne sources.

 Specific principles and motivations include: 

Preventing microbial contamination: This is a critical goal, especially in the production of sterile pharmaceuticals (such as injectables and eye drops) and implantable/sterile medical devices. Airborne microorganisms such as bacteria, fungal spores, and viruses can cause product failure, lead to patient infection, or even be life-threatening if they land on product or contact surfaces. Air filtration (particularly HEPA/ULPA grades) is the primary means of removing airborne microorganisms and their carriers (such as dust particles).

Preventing Particulate Contamination: Non-viable particles in the air, such as dust, fibers, metal shavings, and skin flakes, are also serious contaminants for pharmaceuticals (especially injectables, which can cause blood vessel blockage) and precision medical devices (which can affect performance or trigger foreign body reactions in the body). High-efficiency filtration can keep the number of airborne particles to extremely low levels.

Preventing Cross-Contamination: In workshops producing different types of pharmaceuticals or active ingredients, air filtration helps coordinate airflow design to prevent powder or active ingredients from previous batches from spreading through the air and contaminating subsequent products.

 II. How is Air Filtration Implemented? 

Air filtration in pharmaceutical and medical device production is a complex and sophisticated systems engineering process, primarily manifesting in the following aspects:

 Cleanroom HVAC System: 

Core Support: Air filtration functions are primarily integrated into HVAC systems designed specifically for cleanrooms.

Multi-stage Filtration Strategy: Air handling units (AHUs) typically have multiple stages of filtration:

Pre-filter: Typically rated G4/MERV 8/ISO Coarse, removes large particles and protects the medium-efficiency filter.

Medium/High-Medium Filter: Typically rated F7-F9/MERV 13-15/ePM1, ePM2.5, further purifies the air and reduces the burden on the final HEPA filter.

Terminal Filtration: This is the most critical step in ensuring cleanroom quality. These filters are installed at the very end of the air supply system, directly supplying air into the cleanroom.

Filter Type: HEPA (High-Efficiency Particulate Air) filters (H13, H14) or ULPA (Ultra-Low Penetration Air) filters (U15 or higher) are commonly used. The specific cleanliness level to choose depends on the required cleanliness level of the area (for example, an ISO 8/GMP Grade D area might use H13, an ISO 7/GMP Grade C area uses H14, and an ISO 5/GMP Grade A/B core area must use H14 or higher, combined with unidirectional airflow).

 Installation Type: 

High-efficiency air inlets: HEPA/ULPA filters are installed in a custom-designed air inlet housing, with air delivered through diffusers (often used in areas with non-unidirectional airflow).

Fan filter units (FFUs): Fans and HEPA/ULPA filters are integrated into a modular unit. These units are densely mounted in the ceiling to create vertical, unidirectional (laminar) airflow over a large area. They are the primary method for achieving an ISO 5/GMP Grade A environment.

Airflow pattern: This works closely with filtration to control the direction of air flow to remove contaminants.

Unidirectional Flow (Laminar Flow): In critical operating areas (such as aseptic filling and areas directly exposed to product, corresponding to GMP Grade A), HEPA/ULPA-filtered air flows through the work area in uniform, parallel streams (typically vertically downward) at a specific velocity (e.g., 0.36-0.54 m/s). This quickly "blows away" generated particles and prevents them from settling above the product or on critical surfaces.

Non-Unidirectional Flow (Turbulent Flow): In areas with lower cleanliness requirements (such as GMP Grades C and D), filtered air is introduced through supply vents, mixed with room air to dilute contaminants, and exhausted through return vents. Maintaining cleanliness relies on a sufficiently high air changes per hour (ACH).

 Localized Protection & Containment Systems: 

Laminar Flow Hoods / Biological Safety Cabinets (BSCs): These provide a small, unidirectional, clean environment to protect products or personnel.

Isolators / Restricted Access Barrier Systems (RABS): These provide highly enclosed physical barriers, maintaining a GMP Grade A environment and separating personnel from the core aseptic processing area. They are a key technology in modern aseptic production, relying on HEPA/ULPA filtration for both internal air circulation and exchange with the external environment.

Exhaust Air Filtration: For operating rooms or equipment generating hazardous dusts (such as highly active pharmaceutical powders), aerosols, or biohazardous materials, exhaust air must be filtered through HEPA filtration (sometimes even two stages of HEPA) before discharge to protect personnel and the environment. A bag-in/bag-out (BIBO) filter replacement system is often used to ensure that operators do not come into contact with contaminated filters when replacing used filters.

 III. Application Outcomes (What are the Outcomes?) 

The successful application of air filtration systems in the pharmaceutical and medical device sectors is crucial:

Major Pros (Pros):

Ensuring Product Safety and Quality: Minimizing the risk of microbial and particulate contamination ensures the safety and effectiveness of finished drugs and medical devices, which is directly related to patient health and life.

Meeting Regulatory Compliance: This is a prerequisite for companies to obtain production licenses and market their products. Compliance with standards such as GMP and ISO 14644 is mandatory. Failure to comply can result in serious consequences such as warning letters, product recalls, production suspension, and even license revocation.

Improving Production Reliability and Consistency: A stable, clean production environment reduces process fluctuations and deviations caused by environmental factors, helping to ensure consistent quality between product batches.

Reduce Batch Rejection Due to Contamination: Effective contamination control significantly reduces the risk of products failing quality inspection due to microbial or particulate contamination, thereby mitigating significant economic losses.

Ensure Operator Safety: Exhaust air filtration and isolation technologies protect employee health in processes handling highly active or toxic substances.

Improve Corporate Reputation and Market Competitiveness: Strict adherence to high-standard production practices is the cornerstone of the credibility of pharmaceutical and medical device companies.

 Summary: 

Air filtration plays an absolutely core role in pharmaceutical and medical device manufacturing. It is a cornerstone technology for ensuring product sterility and the absence of particulate contamination, thereby safeguarding patient safety and meeting regulatory requirements. Its application is highly systematic and sophisticated, closely integrated with HVAC systems, air flow management, and isolation technologies. While costly and maintenance-intensive, the resulting product safety, regulatory compliance, and production reliability are fundamental to the survival and growth of this industry.

The production environment for semiconductor devices is extremely sensitive to the presence of contaminants. Even small amounts of gaseous or particulate contaminants can reduce product quality. Therefore, cleanliness requirements in semiconductor device manufacturing are far higher than in other industries.

Throughout the entire chip and semiconductor device manufacturing process, process environment contamination control is crucial. The air cleanliness of core processes needs to meet ISO Class 1 standards, with gaseous molecular contaminant (AMC) concentrations below one part per billion. Substandard process environments can lead to a significant reduction in product yield.

Ordinary air contains a large number of particulate contaminants such as microparticles and dust, as well as gaseous contaminants such as sulfur dioxide, nitrogen oxides, and ammoniaaa. Only after treatment can it enter a cleanroom. Because cleanrooms used for producing semiconductors and other microelectronic devices must maintain standard cleanliness levels 24/7, the cleanroom air conditioning system (including the exhaust system), its associated heat and cold sources, and corresponding delivery systems must operate 24 hours a day, which is significantly different from other conventional air conditioning systems.

As the power source, the fan consumes most of its energy due to the combined resistance of its components. Furthermore, the air filter's resistance accounts for approximately 50% of the fan's total head. Therefore, reducing the energy consumption of air conditioning filters is crucial for lowering building energy consumption and carbon emissions. From the perspective of improving energy efficiency and reducing energy consumption, optimizing air filter performance without compromising filtration requirements is essential.

Filter energy consumption is directly determined by average resistance and is related to initial resistance and dust holding capacity. Reducing initial resistance, increasing dust holding capacity, and minimizing the increase in resistance during dust holding are effective ways to reduce energy consumption, thus lowering energy costs for customers and contributing to environmental protection.

Cleanrooms place stringent requirements on ventilation systems. They must provide sufficient airflow and pressure while precisely controlling temperature and humidity, ensuring consistent air quality. These requirements apply to various airflow patterns and room sizes.

Many production processes mandate cleanroom conditions because cleanrooms, and even ultra-cleanrooms, guarantee the environmental quality of products during rigorous manufacturing. Even minute impurities in the air can adversely affect production processes, leading to high scrap rates. For example, production environments in fields such as optics and lasers, aerospace, biosciences, medical research and treatment, food and pharmaceutical production, and nanotechnology require a near 100% dust-free and bacteria-free air supply.

However, air conditioning and ventilation systems in cleanrooms consume significant amounts of energy due to high air exchange rates, making energy efficiency and cost critical issues. Therefore, in addition to meeting aerodynamic performance requirements, fans must also meet key standards such as compact size, low noise, use cleanroom-compatible materials, proper control capabilities, networking capabilities, and energy-efficient operation.

FFU are designed specifically to address these needs. They effectively improve ventilation in cleanrooms, ensuring the stability of the production environment and product quality.

An FFU is a device that cleverly combines a filtration system with a fan. It features a ceiling-mounted design, is compact and efficient, and requires minimal installation space. The FFU contains pre-filters and high-efficiency filters. Air is drawn in from the top by the fan, finely filtered, and then uniformly delivered at a velocity of 0.45 m/s ± 20%.

FFU play a crucial role in cleanrooms, clean benches, clean production lines, modular cleanrooms, and localized Class 100 environments. These applications span semiconductor, electronics, flat panel display, and disk drive manufacturing, as well as optics, biomedicine, and precision manufacturing—industries with stringent requirements for air pollution control.

The flexibility and ease of use of FFU: The self-powered, modular design of the FFU makes replacement, installation, and relocation simple and easy. Its matching filters are easy to replace, not limited by location, and ideal for the zoned control needs of cleanrooms. FFU can be easily replaced or moved to adapt to different clean environments as needed. Furthermore, FFU can be used to easily create simple clean benches, clean booths, clean pass-through cabinets, and clean storage cabinets to meet various cleanliness requirements. Its ceiling-mounted installation method, especially in large cleanrooms, significantly reduces construction costs.

Negative Pressure Ventilation Technology: The unique negative pressure ventilation design of the FFU fan filter unit allows it to easily achieve high-level cleanliness in various environments. Its self-powered characteristic maintains positive pressure inside the cleanroom, effectively preventing the infiltration of external particles and ensuring a safe and convenient seal.

Quiet Operation: The FFU fan filter unit boasts excellent quiet operation, maintaining low noise even during prolonged use. Its vibration is very low, ensuring smooth stepless speed regulation and uniform airflow distribution, providing stable support for the clean environment.

 Cleanroom Air Supply Units 

* Rapid Construction: Utilizing FFU technology, there is no need for ductwork fabrication and installation, significantly shortening the construction cycle.

* Reduced Operating Costs: Supplying clean air to cleanrooms with FFU technology is not only economical but also remarkably energy-efficient. Although the initial investment for FFU may be slightly higher than ducted ventilation, their maintenance-free operation over the long term significantly reduces overall operating costs.

* Space Saving: Compared to other systems, FFU systems occupy less floor height within the plenum chamber and take up virtually no space within the cleanroom.

* Wide Applicability: FFU systems can adapt to cleanrooms and microenvironments of varying sizes and cleanliness requirements, providing high-quality clean air. During the construction or renovation of cleanrooms, it not only improves cleanliness but also effectively reduces noise and vibration.

FFU System Applications in Semiconductor Wafer Shops: FFU systems are widely used in cleanrooms requiring ISO 1-4 air purification levels, playing a crucial role, particularly in the vertical laminar flow operations of semiconductor wafer shops. In the technical mezzanine, air is efficiently delivered to the clean production layer via FFU. This airflow then passes through raised floors and waffle slab openings, reaching the clean lower technical mezzanine. Finally, after being processed by DCC (Dry Cooling Coils) in the return air duct, the air returns to the upper technical mezzanine, forming a cycle. This design effectively supports the wafer fabrication workshop's stringent control over the production environment, including temperature, humidity, cleanliness, and vibration damping.

Furthermore, the application of FFU systems in biological laboratories is also significant. When laboratory personnel handle pathogenic microorganisms, experimental materials containing pathogenic microorganisms, or parasites, FFU systems impose special requirements on laboratory design and construction to ensure experimental safety and a pollution-free environment.

Current laboratory purification systems typically consist of multiple parts, including a static pressure layer, a process layer, a process auxiliary layer, and a return air duct. This system primarily relies on FFU to process the air. Its working principle is: the FFU provide the necessary circulation power, mixing fresh air with recirculated air, which is then delivered to the process layer and process auxiliary layer after passing through ultra-high efficiency filters. At the same time, by maintaining a negative pressure state between the static pressure layer and the process layer, the leakage of harmful substances is effectively prevented, ensuring the cleanliness and safety of the laboratory environment.

The Battery Show and Electric & Hybrid Vehicle Technology Expo 2025, a highly anticipated annual event for the global new energy industry, was successfully held in the United States on October 9th. As a leading company in air filtration and cleanroom solutions, KLC participated in the exhibition, showcasing cutting-edge technology, professional solutions, and in-depth industry insights. We worked with global customers and partners to successfully demonstrate our key value in supporting the electric vehicle and battery manufacturing supply chain.

High-precision battery workshop air filters: We showcased HEPA/ULPA high-efficiency filters for controlling the battery production environment. These products effectively remove fine dust and metal particles from the air, ensuring extremely clean battery production, and guaranteeing consistent and safe battery performance from the source, attracting significant attention from battery manufacturers.

 Professional Exchanges, Insights into the Industry 

The KLC booth was bustling with visitors throughout the exhibition. We engaged in hundreds of high-quality, in-depth discussions with representatives from battery manufacturers, electric vehicle OEMs, component suppliers, and research institutions from North America and around the world.

This exhibition was not only a successful brand showcase, but also a valuable journey of learning and insight. We deeply feel that with the rapid development of the electric vehicle industry and the continuous iteration of battery technology, the requirements for "purity" and "precision control" in the production environment are becoming more stringent than ever before.

KLC will use this exhibition as a new starting point to continuously increase R&D investment and continuously optimize our products and technologies, striving to provide safer, more efficient, and more economical air filtration and cleanroom solutions for the global new energy industry chain. We look forward to transforming the sparks generated during the exhibition into fruitful future collaborations and working with industry colleagues to contribute the "pure power of KLC" to driving the future of green mobility.

Air filters are filtration-based air purifiers. The HEPA filter we often hear about stands for High-efficiency Particulate Air Filter.

Let's break down the five core principles of air filtration to help you understand its underlying logic.

1. Interception Effect: The fibers in a filter are intricately arranged. When airborne dust particles come into contact with the surface of the filter fibers, they are directly trapped if the particle is close enough to the filter material. This phenomenon is particularly evident in dense filter materials, such as the three-dimensional mesh structure formed by ultra-fine fibers in meltblown fabric for masks, which can firmly lock viral aerosols within the fiber gaps.

2. Inertial Effect: The complex arrangement of filter fibers in an air filter causes airflow to encounter obstacles and deflect as it passes through the filter material. Dust particles in the air, under the influence of inertial forces, break away from the streamline and collide with the surface of the filter fibers, depositing there. The larger the particle, the greater the inertial force, the greater the likelihood of it being blocked by the filter fibers, and the better the filtration efficiency.

3. Diffusion Effect: The diffusion effect targets ultrafine particles smaller than 0.1 micrometers. Particles smaller than 0.1 micrometers primarily undergo Brownian motion, exhibiting a disordered trajectory, significantly increasing the probability of contact with filter fibers; the smaller the particle, the easier it is to remove.

4. Gravity Effect: When the airflow velocity is lower than the particle settling velocity, larger particles naturally settle under gravity. Flue gas treatment towers in thermal power plants expand the space and reduce the flow velocity, allowing dust to fall into the dust collection hopper like sand settling to the bottom of water. This mechanism is economical and efficient for treating high concentrations of dust, but its effect on suspended particles is limited, and it is usually used as a pretreatment method.

5. Electrostatic Effect: Electrostatic electret technology charges the fibers, giving the filter material the ability to actively capture particles with opposite charges, much like a magnet attracts iron filings. This mechanism is particularly effective for charged particles in PM2.5, and industrial dust removal equipment performs electret treatment on the filter surface.

From September 11th to 13th, 2025, KLC participated in RHVAC & CLEANFACT 2025 in Vietnam. As a leading brand in China's air purification and cleanroom solutions sector, KLC showcased its cutting-edge high-efficiency filters and innovative cleanroom technologies. With its superior product performance and professional solutions, KLC served as a vital bridge between the Vietnamese and Southeast Asian markets, further strengthening exchanges and cooperation within the cleanroom technology industry.

The Vietnam HVAC & Refrigeration & Cleanroom & High-Tech Factory Facilities Exhibition, which has undergone multiple iterations, has attracted participants from countries including Japan, South Korea, the European Union, Singapore, China, and India, including investors, general contractors, engineers, and representatives from manufacturing, cleanroom, and HVAC/Refrigeration industry associations. Notably, this exhibition was held concurrently with the Vietnam International Industrial Exhibition 2025 (VIET INDUSTRY 2025), which encompassed sectors such as machinery manufacturing, automation, pharmaceutical technology, and the construction industry. Together, they fostered a diverse exhibition ecosystem, strengthened industry collaboration and cooperation in modern infrastructure development, and provided exhibitors, sponsors, and partners with an excellent opportunity to explore business prospects and establish connections within the industry.

 Technical Interaction and Exchange 

At the booth, KLC's team of technical experts engaged in in-depth and fruitful exchanges with visitors and industry experts from Vietnam, surrounding regions, and around the world. Through product sample dissections, performance demonstrations, and case studies, the KLC team thoroughly addressed specific questions regarding product compatibility, energy-saving optimization, and maintenance cycles.

 A Successful Ending: Fruitful Harvest, Looking Forward to the Future 

The KLC booth remained bustling with visitors and a lively atmosphere throughout the multi-day exhibition. This RHVAC & CLEANFACT 2025 journey was not only a successful brand showcase and product promotion, but also a platform for profound market insights and industry exchange. KLC will continue to deepen its presence in the Southeast Asian market, continuously increasing R&D investment, launching products that better meet regional needs, and continuously improving its sales and service network. KLC is committed to becoming a "Clean Air Gold Partner" that supports industrial upgrading in Vietnam and Southeast Asia, working with customers to build a clean, healthy, and efficient industrial environment for the future.

In modern industrial and commercial environments, air quality management has become a critical consideration for business operations. Chemical air filters, as a key component of air purification technology, have been used across multiple industries for decades. They effectively remove odors, corrosive gases, and harmful or toxic gases from the air, protecting personnel health and optimizing the production environment.

 The Development of Chemical Filtration Technology 

Activated carbon, one of the primary materials used in chemical filtration technology, has been used as far back as 3750 BC. Egyptians first used charcoal to smelt ore to create bronze. By 1500 BC, activated carbon's uses had expanded to treating intestinal ailments, absorbing odors, and for papyrus writing. By 400 BC, ancient Indian and Phoenician civilizations had discovered activated carbon's antiseptic properties and used it for water purification.

Today, activated carbon is widely used in air filtration technology. For more detailed information on the classification and filtration mechanisms of chemical filters, please refer to "AMC Pollutant Control - Filter Media."

In addition to activated carbon, chemical filtration materials also include coconut shell activated carbon, ion exchange resins, and other adsorbent media, providing highly effective purification in diverse environments.

 Wide Application of Chemical Filters 

With the acceleration of industrialization, air pollution, particularly chemical pollution in the industrial sector, has become increasingly prominent. Unlike conventional cleanroom methods for controlling particulate and microbial contamination, the molecular size of chemical pollutants is often too small to be effectively captured by traditional particle filters. Therefore, chemical filtration technology has become essential for air pollution control, with applications across a wide range of industries.

 Air Molecular Contamination Control (AMC) 

In high-tech industries such as semiconductor, microelectronics, and photovoltaic manufacturing, even the slightest change in air quality can impact product yield. Consequently, these industries place extremely high demands on chemical filters, requiring the removal of acids, alkalinity, volatile organic compounds (VOCs), refractory compounds (RCs), oxidants, dopants, and ozone to ensure a stable production environment.

Cleanroom are designed to meet varying cleanroom cleanliness requirements, such as Class 100, Class 1000, Class 10,000, Class 100,000, Class 300,000, and even higher. This is why FFU have emerged as a valuable solution to these challenges.

 FFU can effectively address challenges in cleanroom. The key advantages are as follows: 

1. Space Savings – FFU can save space and address the limited maintenance access above cleanroom ceilings.

Because high-quality cleanroom require Class 100 or even Class 10 laminar flow hoods to meet process requirements, large supply air plenums are installed above the cleanroom ceilings. These plenums, along with the supply and return air ducts, take up significant space, limiting maintenance access and sometimes even restricting access to fire escapes.

When using FFU, the cleanroom ceiling is divided into several modules, each of which serves as an FFU. This allows for adjustments to meet the pressure balance requirements of the supply air plenum above the ceiling, significantly reducing the required plenum height. This also eliminates the need for large supply and return air ducts, saving installation space. FFU are particularly effective when floor height restrictions are imposed during renovation projects. Furthermore, FFUs are available in a variety of sizes and can be customized to the exact size of the cleanroom. As a result, they occupy less floor height within the supply air plenum, or even virtually no space within the cleanroom, further conserving space.

2. FFU Flexibility – The FFU's independent design allows for immediate adjustments, compensating for the lack of cleanroom flexibility and addressing the inherent limitations of production process adjustments.

Cleanroom structures are typically constructed of metallic panels, and their layout cannot be altered after construction. However, due to constant changes in production processes, the existing cleanroom layout can no longer meet new process requirements. This leads to frequent cleanroom modifications for product upgrades, resulting in significant financial and material waste.

By increasing or decreasing the number of FFU, the cleanroom layout can be locally adjusted to accommodate process changes. Furthermore, FFU have their own power supply, air vents, and lighting, saving significant investment. This is virtually impossible to achieve with conventional centralized air purification systems.

Because FFU are self-powered, they are not restricted by location. Within a large cleanroom, they can be controlled in zones as needed. Furthermore, as semiconductor production processes evolve, the layout inevitably needs to be adjusted accordingly. The flexibility of FFU makes such adjustments easy and eliminates the need for secondary investment.

3. Reduced Operational Burden - FFU systems are energy-efficient, eliminating the drawbacks of centralized air supply systems, which often require bulky air conditioning rooms and high operating costs for air conditioning units.

If individual cleanroom within a larger cleanroom building require a higher cleanliness level, centralized air supply units with high air volumes and fan pressures are required to overcome resistance in the ductwork and the resistance of the primary, medium, and high-efficiency filters to meet the required cleanliness level. Furthermore, a single air conditioner failure in a centralized air supply system would halt operation in all cleanroom served by that unit.

Although the initial investment in FFU is higher than that of ducted ventilation, their outstanding energy-saving and maintenance-free features make FFU more popular.

Food safety is paramount. For a responsible food company, having a standard-compliant cleanroom is like donning a "golden armor" for its products.

However, this "armor" isn't a monolithic structure. Instead, it's scientifically divided into different zones based on production processes and hygiene requirements, with layers of protection to precisely filter risks.

 Core Principle: Why Zoning is Essential? 

The core purpose of cleanroom zoning is singular: to control contamination and prevent cross-contamination.

Contamination sources mainly come from three aspects: people, machines, materials, methods, and environment. By physically isolating areas with different cleanliness requirements and coordinating different pressure differentials, airflow organization, and personnel purification procedures, a unidirectional contamination control gradient can be formed from low-cleanliness to high-cleanliness areas, ensuring a high level of cleanliness in the core production areas.

 Four Core Functional Areas of a Cleanroom 

Typically, a standard food cleanroom is divided into the following four main areas from the inside out, with cleanliness requirements decreasing sequentially.

1. Core Production Area (Clean Zone)

Function: This is the area where products are directly exposed to the environment, including processes such as ingredient preparation, mixing, filling, inner packaging, cooling, final cooling of semi-finished products for perishable foods, and temporary storage after disinfection of inner packaging materials. This is the "heart" area with the highest hygiene requirements.

Cleanliness Level: Typically requires Class 10,000 or higher. For certain special foods, some processes even require localized purification down to Class 100.

Management Requirements: Personnel must undergo the strictest first and second changing procedures before entering. Materials are introduced through a pass-through window after disinfection. This area maintains positive pressure to prevent backflow of air from lower-level areas.

2. Semi-Clean Area (Buffer Zone)

Function: This is the "buffer zone" before entering the clean area, a purification preparation area for personnel and materials before entering the core area. It mainly includes: changing rooms, air showers, handwashing and disinfection rooms, material buffer rooms, and equipment cleaning and disinfection rooms.

Cleanliness Level: Cleanliness requirements are lower than the core area but higher than general areas, typically Class 100,000 or Class 300,000.

Management Requirements: In this area, personnel complete key steps such as changing shoes, putting on cleanroom garments, and washing and disinfecting hands. Materials undergo pre-treatment here, including removing outer packaging and wiping and disinfecting surfaces. This area serves as a crucial "filter."

3. General Work Area (Non-Clean Area)

Function: Areas where products are not directly exposed or only undergo simple primary processing. Examples include: raw material warehouses, outer packaging areas, finished product warehouses, testing laboratories (partial), equipment maintenance rooms, and office areas.

Cleanliness Level: No strict air cleanliness requirements, but good environmental hygiene must still be maintained, complying with basic food factory hygiene standards (e.g., GB 14881).

Management Requirements: Personnel do not need to undergo complex changing procedures, but must wear work clothes and maintain personal hygiene. Access control must be installed between this area and the semi-clean area for physical isolation.

4. Auxiliary Area

Function: Areas that provide power and support to the cleanroom. Although not directly involved in production, they are crucial. Includes: air conditioning room, water treatment system, changing rooms, restrooms, and sanitary ware rooms.

Management Requirements: These areas require regular maintenance to ensure stable operation. Restrooms and sanitary ware rooms, in particular, must be strictly managed; their doors must never open directly towards the clean area.

 Dynamic Defense Line: Intelligent Design of Personnel and Material Flow 

Static zoning alone is insufficient; dynamic personnel and material flow route design is the soul of zoning.

Personnel Flow Route: Must follow the unidirectional flow principle of "low clean area → high clean area".

Correct Route: General Area → Shoe Change → First Changing Room (Removing Outerwear) → Second Changing Room (Putting on Cleanroom Gown, Handwashing and Disinfecting) → Air Shower → Core Clean Area.

Absolutely Prohibited: When returning from a high clean area to a low clean area, the same route must not be used; a dedicated passage must be designed to avoid cross-contamination.

Material Flow Route: Raw Materials → Unpacking and Preliminary Processing (General Area) → Through Material Transfer Window (after Disinfection/Wiping) → Buffer Room → Core Clean Area.

Finished Products flow out in the opposite direction, but separately from the raw material flow to avoid cross-contamination.

The zoned management of cleanrooms in food factories is a comprehensive art that integrates architecture, aerodynamics, microbiology, and food processing. Every wall, every pass-through window, and every air shower represents a solemn commitment to food safety for consumers.

Understanding this knowledge not only helps food industry professionals better implement regulations but also gives every consumer greater peace of mind and confidence in the food we consume. Because true deliciousness stems from the utmost respect and protection for detail.