Cleanroom: Ultimate Guide

With the rapid development of modern industry and production, tackling pollution has become more urgent than ever. Cleanrooms play a crucial role in tightly controlling environmental conditions and minimizing airborne contaminants within a specific area. There’s no doubt that in the future, cleanrooms will become increasingly favored across various industries. By the time you finish reading this guide, I believe you’ll have a much better understanding of cleanrooms, which will undoubtedly assist you in making informed decisions regarding their selection.

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What is a Cleanroom?

What Is a Cleanroom


A cleanroom, also known as a dust-free room, is an environment where the level of contamination approaches zero. While it’s impossible for the particle content in the air to be completely zero, the closer it gets to zero, the higher the cleanliness level of the area, demanding higher standards for equipment and procedures within it. Sources of contamination include airborne particles that we’re familiar with, as well as volatile gases from chemical experiments and microorganisms spread through the air. Additionally, factors such as temperature, humidity, airflow distribution, and velocity are strictly controlled within the cleanroom.


The Working Principle of Cleanrooms

The Working Principle of Cleanrooms

Filtering Air

Air is filtered and purified through a series of different-grade filters to remove dust, bacteria, viruses, and other pollutants, ensuring that the air meets the cleanliness requirements of the cleanroom level.

Controlling Airflow

Each cleanroom is equipped with its own proprietary airflow system to ensure uniform airflow within the cleanroom area. This also helps prevent the spread of contaminants.

Environmental Monitoring and Control

Cleanrooms are equipped with a comprehensive environmental monitoring and control system to ensure optimal conditions at all times. This system continuously monitors and regulates factors such as temperature, humidity, and pressure to maintain them within the required ranges. Additionally, it can be adjusted according to specific needs.

Preventing Contamination and Cross-Contamination

To prevent the entry of contaminants and minimize the risk of cross-contamination, each entry and exit position can be equipped with air showers for personnel and goods. These air showers effectively remove external pollutants from personnel or items before they enter the cleanroom, thus safeguarding the cleanliness of the controlled environment.

The Classification of Cleanrooms and its Reference Standards

Cleanrooms are classified mainly according to international ISO standards and Federal Standard 209. The classification is based on the calculation of the number of particles per cubic meter of air.

Cleanrooms are divided into nine levels, from low to high: ISO 9, ISO 8 (Class 100,000), ISO 7 (Class 10,000), ISO 6 (Class 1,000), ISO 5 (Class 100), ISO 4 (Class 10), ISO 3 (Class 1), ISO 2, ISO 1. The most common obese currently used across industries are ISO 3, ISO 4, ISO 5, ISO 6, ISO 7, and ISO 8.




ISO 1 is one of the highest cleanliness requirements for internal environments. It stipulates that there should be no more than 1 particle larger than 0.1 micrometers in diameter per cubic meter of air. This standard is typically applied in specialized industries such as semiconductor manufacturing.


ISO 2 requires that there be no more than 100 particles per cubic meter of air in the environment. It is commonly utilized in pharmaceutical cleanrooms, biological laboratories, and microelectronics manufacturing.

ISO 3 & Class 1

The standard ISO 3 set by the International Organization for Standardization (ISO) is also referred to as Class 1 in the United States. ISO 3 mandates that there be no more than 1000 particles per cubic meter of air. It finds applications in pharmaceutical production, food processing, and other industries.

ISO 4 & Class 10

ISO 4, also known as Class 10 according to the U.S. standard. ISO 4 requires that there be no more than 10,000 particles per cubic meter of air. It is commonly referred to as a Class 10 cleanroom and is used in laboratories, medical device manufacturing, precision instrument production, and similar industries. 

ISO 5 & Class 100

ISO 5, also known as Class 100 in the United States. It requires that the number of particles per cubic meter of air in the environment does not exceed 100,000. This level of cleanliness, often referred to as a “Class 100 cleanroom,” is typically used in industries such as pharmaceuticals and biotechnology. 

ISO 6 & Class 1,000

ISO 6, also referred to as Class 1,000 in the United States. It mandates that the number of particles per cubic meter of air does not exceed 1,000,000. This level, commonly known as a “Class 1,000 cleanroom,” is typically utilized in general production workshops and laboratories. 

ISO 7 & Class 10,000

ISO 7, also referred to as Class 10,000 in the United States. It dictates that the number of particles per cubic meter of air should not exceed 10,000,000. This level, often called a “Class 10,000 cleanroom,” is typically employed in general production workshops and assembly areas. 

ISO 8 & Class 100,000

ISO 8, also known as Class 100,000 in the United States. It requires that the number of particles per cubic meter of air does not exceed 100,000,000. This level, commonly referred to as a “Class 100,000 cleanroom,” is usually used in general offices and storage areas. 


ISO 9 mandates that the number of particles per cubic meter of air should not exceed 1,000,000,000. This level, often called a “million-level cleanroom,” is slightly better than a non-clean area but has minimal differences. It is typically used in areas where environmental cleanliness requirements are not strict.


Advantages of Cleanrooms:

Advantages of Cleanrooms

Ensuring Product Quality:

The cleanroom effectively controls the particles, viruses, bacteria, microorganisms, and other pollutants in the air within the area, maintaining the cleanliness of the air in the purified zone and thereby ensuring product quality.

Maintaining Environmental Stability during Production:

The cleanroom maintains stability in the production process by controlling environmental factors such as temperature, humidity, and pressure, thus reducing their impact on the quality of the products.

Reducing Product Loss:

Cleanrooms effectively minimize product contamination and damage, thus lowering the rate of defective products.

Protecting the Health of Frontline Workers:

By controlling toxic gasses and pollutants in the environment, cleanrooms reduce the likelihood of employees inhaling toxic gasses or coming into contact with pollutants, thereby ensuring the health and safety of workers.

Compliance with Legal Regulations:

Industries must adhere to strict regulatory standards to ensure product quality and safety.

Pollution Reduction and Environmental Protection:

Cleanrooms help reduce pollution sources and waste generated during the production process, thereby playing a positive role in environmental protection.

Enhancing Competitiveness:

Having compliant cleanrooms and clean, safe production environments will greatly enhance competitiveness among industry peers.

The Components of a Cleanroom


The Main Structure of Cleanrooms

Wall panels, ceiling: It’s ideal to use materials with smooth surfaces, good sealing properties, and resistance to dust accumulation, and also to undergo special treatment. Common options include PVC wall panels, aluminum-plastic panels, stainless steel wall panels, metal composite panels, etc.

Flooring: Common considerations for flooring include anti-static, anti-slip, easy-to-clean, corrosion-resistant, wear-resistant, and antibacterial materials. Popular choices include PVC flooring, epoxy flooring, ceramic tiles, and resin flooring. The choice of materials can be tailored to the specific requirements of the cleanroom. 

The Main Structure of Cleanrooms



The door is an essential component of a cleanroom, and a qualified cleanroom door should possess the following characteristics: excellent sealing, outstanding cleanliness function, anti-static properties, easy of cleaning, and more.

Cleanroom doors are typically made of stainless steel or aluminum alloy materials, with smooth and corrosion-resistant surfaces. Common types of cleanroom doors include swing doors, sliding doors, rapid roll-up doors, fire-rated doors, and water-resistant doors.


Cleanroom windows are specially designed for cleanrooms and are typically installed on the walls or doors of cleanrooms.

The window frame is usually made of aluminum alloy or stainless steel to ensure the stability and sealing of the window structure. The window glass is made of glass material that meets cleanroom standards, ensuring good transparency and cleanliness. Seals, typically made of silicone or rubber, are placed between the window frame and the window glass to provide sealing.

Considering the temperature difference between the inside and outside of the cleanroom window, the interior of the cleanroom window may be filled with ammonia or desiccant.

Filter System & Ventilation System

The filter system and ventilation system of the cleanroom are the most crucial components, and selecting the appropriate systems ensures that the air cleanliness of the cleanroom meets the requirements more effectively.


The primary efficiency filter serves as the first line of defense in a filtration system and is also the most fundamental. Its main purpose is to filter out large particles and dust from the air. Typically, the filter media is made of materials such as fiberglass, synthetic fibers, or cotton fibers. Its filtration efficiency typically ranges from 20% to 40%.

Medium-efficiency Filter

The medium-efficiency filter serves as the second line of defense in the filtration system, positioned after the initial-efficiency filter. Its primary function is to filter out smaller particles and dust in the air. The filter media typically consists of materials such as fiberglass, synthetic fibers, or activated carbon. Its filtration efficiency ranges from 60% to 90%.

High-efficiency filter (HEPA filter)

High-efficiency filters, also known as HEPA filters, are primarily designed to filter tiny particles and microorganisms from the air. The filter media typically consists of materials like glass fibers or synthetic fibers, achieving a filtration efficiency of over 99.97%. Because of this high efficiency, HEPA filters are essential components in cleanrooms.

Ultra-Low Penetration Air (ULPA) Filter

ULPA filters are typically used in cleanrooms where extremely high cleanliness is required. With a filtration efficiency of over 99.9995%, ULPA filters can capture even smaller particles and microorganisms.


FFU, short for Fan Filter Unit, is an air-handling device that integrates a fan and a filter. It is typically installed in the ceiling but can also be used as a standalone unit to form a complete clean air conditioning system. FFUs are designed to filter particles and microorganisms from the air and deliver purified air. The main components of an FFU include a fan, a filter, an airflow regulator, and a control system.

Air Handling Unit (AHU)

The Air Handling Unit (AHU), commonly referred to as HVAC, is an air-handling device used to centrally regulate parameters such as temperature, humidity, and cleanliness in clean rooms. Internally, an AHU system usually consists of one or more fans, heating elements, cooling components, filters, humidification/dehumidification elements, and a control system. In general, clean rooms do not require AHU systems, but specific places such as those dealing with flammable, toxic, or hazardous substances may need them. You can choose configurations based on the requirements of different clean rooms.

Supply Air Outlet

The air supply outlet in a cleanroom is a crucial component of the ventilation system, responsible for evenly distributing purified air throughout the cleanroom area. A standard high-efficiency air supply outlet typically consists of a static pressure box, diffuser plate, high-efficiency filter, and air valve. These outlets are primarily constructed using corrosion-resistant materials such as aluminum alloy or stainless steel. By adjusting the size and number of air supply outlets, control over airflow velocity can be achieved to meet specific requirements.

Exhaust Air Outlet

The exhaust air outlet in a clean room is primarily used to expel pollutants and exhaust gases from the indoor environment to maintain air cleanliness. These outlets are typically located on the walls or ceilings of clean rooms. The design of exhaust outlets should be based on the air treatment requirements of the clean room, and materials such as stainless steel or aluminum alloy, which are resistant to high temperatures, and corrosion, and easy to clean, are commonly used.

Air Shower System

The air shower system is a common air purification device equipped in cleanrooms. It is mainly divided into air shower rooms and cargo shower rooms due to differences in design and functionality. The air shower shell is mainly made of galvanized steel or stainless steel.

The air shower room is typically installed at the entrance area of the cleanroom to disinfect personnel, preventing external sources of contamination or pollutants from entering the cleanroom.

The cargo shower room is usually installed at the entrance of production areas to clean and disinfect materials and items, thereby preventing contamination of the production environment and affecting product quality.

Transfer System

Pass boxes play the role of transfer agents in cleanrooms without affecting changes in cleanliness. They are mainly classified into three categories: electronic interlocking pass boxes, mechanical interlocking pass boxes, and self-cleaning pass boxes. Pass boxes are primarily made of either 201 or 304 stainless steel. Comparatively, 304 stainless steel offers better corrosion resistance and is suitable for environments with high corrosion resistance requirements. On the other hand, 201 stainless steel is commonly used in general areas due to its cost-effectiveness. 

Lighting System

When designing and selecting the appropriate lighting system for cleanrooms, it’s essential to consider various factors such as color temperature, corrosion resistance, energy efficiency, waterproofing, and more.

LED Lighting:

LED lighting fixtures are the most commonly used in cleanrooms due to their energy efficiency, high efficiency, and long lifespan.

Dustproof Lighting:

For cleanrooms with higher cleanliness levels, dust-proof lighting fixtures are often chosen. These fixtures are dustproof, waterproof, easy to clean and maintain, and can effectively prevent dust and microorganisms from entering the lighting fixtures.

Medical Lighting:

Medical-grade cleanrooms use medical-grade lighting systems. These lighting systems must comply with medical hygiene standards and provide appropriate illumination and color temperature for medical operations.

Emergency Lighting:

Emergency lighting systems, such as emergency lights, ensure adequate illumination even in the event of a power outage.

Cleanroom Accessories

Aluminum profile accessories for cleanrooms are primarily used for supporting, connecting, installing, and decorating the structures within the cleanroom. Some common aluminum profiles include U-channel aluminum, outer cylinder, inner arc, inner tee, outer tee, I-beam aluminum, T-shaped aluminum, angle aluminum, door material, window material, wine glass suspension beam, R-channel aluminum, etc. The commonly used sealing adhesive is silicone sealant.


Application Fields of Cleanrooms

Automotive Manufacturing Industry:

Automotive Manufacturing Industry


Processes such as painting, coating, and assembly in the automotive manufacturing industry require cleanroom environments to ensure the cleanliness of the vehicle surface and the quality of the coating.

Pharmaceutical and Biotechnology Industry:

Pharmaceutical and Biotechnology Industry


Used for the production of drugs, biologics, and medical devices, where it is necessary to ensure that the products meet regulatory requirements.

Healthcare Industry:

Healthcare Industry


Operating rooms and laboratories in hospitals require sterile operating areas to maintain aseptic conditions.

Aerospace and Defense Industry:

Aerospace and Defense Industry


For the production, assembly, and testing of aerospace and aircraft components, ensuring compliance with aerospace standards is crucial.

Electronics Manufacturing Industry:

Electronics Manufacturing Industry


Production of semiconductors, integrated circuits, and display devices requires cleanrooms to prevent dust and static electricity from affecting product quality.

Food and Beverage Processing:

Food and Beverage Processing


Food and beverage processing plants require cleanrooms to ensure products meet hygiene standards, such as dairy products, alcoholic beverages, canned foods, etc.

These industries utilize cleanrooms to maintain controlled environments that meet specific cleanliness and quality standards essential for their operations.


Designing Cleanrooms

Designing Cleanrooms


Define the Purpose:

The first step in designing a cleanroom is to clearly understand which industry it will serve and what specific tasks it will be used for. This helps determine the appropriate cleanliness level for constructing the cleanroom.

Layout Design:

Design the layout of the cleanroom to maximize space utilization effectively, ensuring it meets the operational requirements.

Material Selection:

Choose materials that match the required cleanliness level for constructing the cleanroom. Consider materials that are easy to clean, corrosion-resistant, and anti-static.

Ventilation and Filtration System Design:

Select appropriate air filtration and ventilation systems and design suitable airflow patterns. Choose suitable environmental monitoring and control equipment to maintain the comfort level and meet the cleanliness requirements of the designated cleanroom class.

Safety Facility Design:

Include safety features such as fire alarm systems, emergency lighting systems, and fault alarms in the design to ensure the safety of personnel and equipment.

Establish Maintenance and Cleaning Procedures:

Cleanrooms require regular cleaning and maintenance. Therefore, in the design process, consider equipment layout and pathway arrangements to facilitate future cleaning and maintenance tasks.


Cleaning and Maintaining Cleanrooms 

Cleaning and Maintaining Cleanrooms


While cleanrooms are equipped with various devices to maintain good air quality, dust and dirt accumulation may still occur over time due to prolonged use. Therefore, cleanrooms should be equipped with common cleaning tools and equipment, including wiping cloths, gloves, masks, vacuum cleaners, disinfectants, cleaning agents, brooms, mops, ladders, and more.


In addition, cleaning cleanrooms requires following specific steps to achieve the best cleaning results. The specific steps are as follows: 

  1. Use a vacuum cleaner to remove dust and dirt.
  2. Use a wiping cloth to clean surfaces such as walls, ceilings, doors, windows, light fixtures, return air vents, and filters. Additionally, replace filter components regularly according to requirements.
  3. Disinfect areas that require disinfection using disinfectants.
  4. Use specialized floor cleaning agents and mops to clean the floor.
  5. Check if the equipment in the cleanroom is functioning properly and promptly repair any issues that arise.


The Future Development Trends and Prospects of Cleanrooms

The Future Development Trends and Prospects of Cleanrooms



With the advancement of artificial intelligence and the Internet of Things, the future of cleanrooms is trending toward intelligence and automation. Smart sensors and control systems can detect and adjust air quality, temperature, humidity, and other parameters in real time, thereby enhancing purification efficiency.


Green Environmental Protection:

There may be a greater emphasis on environmental protection and sustainable development in the future, with the adoption of environmentally friendly materials, energy-saving facilities, and reductions in energy consumption and pollution emissions, achieving the environmentalization of purification.



Cleanrooms may evolve towards multifunctionality, not only providing environmental purification functions but also potentially being used for remote diagnostics and healthcare services.



In the future, cleanrooms may leverage digitalization and virtualization technologies to achieve remote control and management, thereby improving operational efficiency and enhancing management capabilities.



In conclusion, cleanrooms play a crucial and indispensable role in modern industry and production. I believe that they will continue to evolve and innovate in response to market demands and technological advancements, providing more advanced and efficient purification solutions for various industries in the future.





Can the floor of the cleanroom be made of PVC flooring?

Certainly! PVC flooring offers easy cleaning, slip resistance, and durability.


Do the filters need to be replaced, and how often?

Yes, filters need to be replaced regularly. The frequency of replacement depends on the filter grade and the environmental conditions of the cleanroom, as well as usage frequency. Typically, the replacement frequency for pre-filters ranges from every few months to once a year, while for HEPA filters, it could be once every few years.


Can the voltage of the facilities in the cleanroom be customized?

Yes, the voltage can be customized to meet different country standards. However, customization may lead to longer lead times.


Design and application of the suspended ceiling system in the cleanroom

Suspended ceiling systems typically use aluminum alloy or galvanized steel. The design should consider equipment installation positions and connection methods, ensuring the structure meets load-bearing requirements.


Do we need to install cleanrooms by ourselves?

Generally, we provide installation drawings. If on-site installation assistance is required, expenses such as travel, accommodation, and labor costs for workers need to be covered.


How often does the cleanroom need cleaning?

Typically, once a week.

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