What is a Class 1 Cleanroom?

A CleanRoom is an environment designed to control particulate matter, microorganisms, and other contaminants in the air. It is widely used in industries such as Semiconductors, pharmaceuticals, and aerospace. According to international standards, the classification of cleanrooms is very important, and Class 1 cleanrooms are one of the highest levels. This article will analyze in detail the standards, implementation methods, and industry applications of Class 1 cleanrooms.

I. Classification standards for cleanrooms

The grades of cleanrooms are usually divided according to the maximum number of particles allowed per cubic meter in the air. Common standards include ISO 14644-1. According to this standard, the grades of cleanrooms range from ISO1 to ISO9. The smaller the number, the higher the cleanliness. The maximum number of particles with a diameter greater than 0.3 microns allowed in ISO1 is no more than 1 per cubic meter.

1. Application of ISO standards

The ISO 14644-1 standard defines the classification of cleanrooms and specifies the specific requirements for each level. Taking ISO Class 1 as an example, the standard requires that the maximum number of particles in 1 cubic meter of air must be less than 1, which is applicable to extremely strict environmental requirements. This standard is widely used in industries such as pharmaceuticals, semiconductors, and optoElectronics.

2. Basic design principles of clean rooms

The design of clean rooms must follow specific air flow patterns and filtration systems to ensure the cleanliness of the internal environment. Factors such as air flow rate, temperature, and humidity must be considered during design, and computational fluid dynamics (CFD) models are usually used to predict air flow and particle distribution. These design factors directly affect the performance and efficiency of clean rooms.

3. Particle monitoring and control

In clean rooms, particle monitoring systems are crucial. Through equipment such as laser particle counters, the concentration of particles in the air can be monitored in real time to ensure that it meets the corresponding cleanliness standards. Monitoring data needs to be analyzed regularly to identify potential sources of contamination and take corresponding control measures to maintain the grade of the clean room.

II. Class 1 cleanliness level standard

Class 1 clean rooms are the most stringent standards in clean rooms, and their cleanliness requirements are extremely high. According to iso 14644-1, Class 1 cleanrooms only allow one particle larger than 0.3 microns per cubic meter of air. This standard reflects the stringent requirements for cleanroom environments.

1. Classification and characteristics of particles

Particles are usually divided into inhalable particles and non-inhalable particles. Inhalable particles (PM10, PM2.5) have a significant impact on human health, and in Class 1 cleanrooms, the concentration of such particles must be strictly controlled. Cleanrooms can effectively remove these particles through high-efficiency filters (HEPA or ULPA) to ensure air quality.

2. The importance of temperature and humidity control

Temperature and humidity control in Class 1 cleanrooms is equally important. It is usually required that the temperature be maintained at 20℃±2℃ and the relative humidity be controlled between 30%-60%. Fluctuations in temperature and humidity will not only affect product quality, but may also lead to the aggregation of particles. Therefore, stable environmental conditions are a prerequisite for achieving high cleanliness.

3. Air flow design and management

Effective air flow design is the key to ensuring the cleanliness of Class 1 modular cleanrooms. Generally, laminar flow design is required. After passing through the filter, the air flows at a uniform speed to reduce dead corners and short-circuit flow, thereby ensuring uniform distribution of Clean air. The flow rate is usually designed between 0.45-0.5 m/s, which can save energy while ensuring cleanliness.

III. How to achieve class 1 cleanrooms

Achieving the cleanliness of class 1 cleanrooms requires a series of efficient technologies and equipment. The following are the key factors to achieve Class 1 cleanrooms.

1. The highest level of ultra-high efficiency filters

Class 1 cleanrooms must use ultra-high efficiency filters (such as HEPA and ULPA filters) with a filtration efficiency of 99.97% (HEPA) or 99.999% (ULPA) or above. The choice of filter directly determines the cleanliness of the cleanroom, so its specifications and design should be carefully considered. 

In actual applications, the performance test of the filter usually adopts the DOP (diphenylthiophene) test method to verify its filtration efficiency. According to ISO 29463 standard, HEPA and ULPA filters must be able to effectively capture more than 99.97% of 0.3 micron particles at a specific flow rate. This standard ensures that the filter can maintain effective air purification capabilities even under high cleanliness requirements.

In addition, the replacement cycle and maintenance of the filter are also crucial. The service life of the filter is usually between 2-5 years, but under extremely high cleanliness requirements, its pressure difference needs to be monitored regularly to ensure that the air circulation is not blocked due to filter clogging. Therefore, the maintenance plan includes regular inspection and replacement of filters to maintain the cleanliness level of the cleanroom.

2. Air circulation frequency requirements

The air circulation frequency of Class 1 cleanrooms is another key factor, which is usually required to reach 360-540 times per hour. This means that the air in the entire room must be replaced several times per hour to ensure that the particle concentration is always kept at an extremely low level. According to the Clean room design standard, the actual number of air circulations can be calculated by the following formula:

Wherein, (N) is the number of air circulations, (Q) is the air flow rate (cubic meters per hour), and (V) is the volume of the clean room (cubic meters). For example, for a Class 1 clean room with a volume of 100 cubic meters, if the air flow rate is 60,000 cubic meters per hour, the number of cycles is:

This calculation shows that appropriate air flow design can effectively improve the cleanliness of the air.

3. Temperature and humidity control and monitoring system

In a Class 1 clean room, strict control of temperature and humidity is not only a requirement for environmental comfort, but also the key to ensuring product quality and cleanliness. Usually, the temperature is controlled at 20±2℃, while the relative humidity is controlled between 30%-60%. To achieve this goal, high-precision temperature and humidity sensors need to be installed to monitor and feedback data in real time.

In the design of temperature and humidity control systems, the use of PID controllers (proportional-integral-differential controllers) can effectively adjust the output of the air conditioning system to maintain the set environmental conditions. When calculating the response time and stability of the system, transfer functions and control theory can be used for analysis to optimize the control strategy and ensure a rapid response of temperature and humidity.

IV. Class 1 clean room industry applications

Class 1 clean rooms are widely used in many high-tech and pharmaceutical industries due to their extremely high cleanliness requirements. The products of these industries often have strict environmental requirements, so Class 1 clean rooms have become necessary facilities for their production and research and development.

1. Application in the semiconductor manufacturing industry

In the semiconductor manufacturing process, any tiny contaminants may cause product defects, so wafer manufacturing, etching, and photolithography processes need to be carried out in Class 1 clean rooms. According to the regulations of the Semiconductor Equipment and Materials International (SEMI), the design and supervision of clean rooms in semiconductor manufacturing processes must meet Class 1 standards to ensure product quality and yield.

In addition, air quality monitoring systems in the semiconductor industry usually need to monitor particles and chemicals in real time to ensure compliance with strict environmental control standards. By adopting highly sensitive monitoring equipment, the industry can promptly detect and deal with potential sources of contamination.

2. Applications in the pharmaceutical and medical industries

Class 1 clean rooms also play an important role in the pharmaceutical and medical industries, especially in the production and packaging of sterile drugs. According to the FDA's GMP (Good Manufacturing Practice) standards, sterile preparations must be produced in a Class 1 or higher clean environment to prevent contamination by microorganisms and particulate matter.

During the production of drugs, the air quality in the modular clean room must meet the ISO 14644-1 standard to ensure the sterility and stability of the production environment. The use of advanced microbial monitoring and air quality control systems can effectively prevent and control contamination.

3. Applications in the aerospace field

The aerospace field has extremely strict requirements on the cleanliness of equipment and materials. Class 1 clean rooms provide guarantees for the development and production of high-precision components. In this field, any tiny particles In the aerospace field, the use of Class 1 clean rooms ensures the performance and reliability of components. Whether it is the manufacture of satellites, spacecraft or other high-precision equipment, the clean room environment can effectively prevent the impact of particles and contaminants on materials and electronic components. Because the space environment is extremely harsh, any minor defects in the manufacturing process on the ground may lead to major failures in space. Therefore, the use of Class 1 clean rooms has become a standard practice in this field.

In addition, in aerospace manufacturing, clean rooms are also used for the assembly of high-precision optical and sensor components, which are extremely sensitive to particulate matter. In this environment, strictly controlled air flow and cleanliness monitoring systems can ensure that the quality of products meets the standards before delivery.

4. Applications in the optoelectronics industry

The optoelectronics industry also relies on Class 1 clean rooms to ensure the production of high-performance optical components. During the manufacturing process of optical fibers, lasers, and other optoelectronic devices, tiny particles directly affect the transmission of light and the overall performance of the equipment. Therefore, the use of Class 1 clean rooms has become the standard during the production and assembly of these products.

In optoelectronic manufacturing, airflow uniformity and particle removal efficiency in clean rooms are critical. By optimizing air flow design and implementing efficient filtration measures, the optoelectronics industry can produce high-quality products and meet the market's requirements for technological innovation.

V. Future Development Direction

With the continuous advancement of science and technology, the requirements for clean rooms are also constantly increasing. In the future, Class 1 clean rooms may develop in the following aspects:

1. Intelligent management system

With the development of Internet of Things technology, clean room management in the future will be more intelligent. By integrating sensors and monitoring equipment, real-time data monitoring and analysis will become the norm. This intelligent management system can automatically adjust parameters such as air flow, temperature and humidity, and respond to any abnormal conditions in a timely manner to ensure that the clean room is always maintained in the best condition.

2. Energy-saving and environmental protection technology

In the design and operation of clean rooms, energy saving and environmental protection will become an important consideration. In the future, it will become a trend to adopt more efficient filtration technology and air conditioning systems to reduce energy consumption. At the same time, the use of renewable energy to power clean rooms, combined with the concept of green building design, will promote clean rooms to move towards sustainable development.

3. Application of new materials and new technologies

The emergence of new materials will promote the development of clean room technology. For example, filters made using nanotechnology may have higher filtration efficiency and longer service life. In addition, the development of new antistatic materials and antibacterial coatings will further improve the cleanliness and safety of clean rooms and meet higher industry needs.

4. Wider application areas

With the advancement of technology, the application areas of Class 1 clean rooms will gradually expand. For example, emerging fields such as biotechnology and nanotechnology have also begun to put forward demands for clean rooms, which will promote the diversification and specialization of clean room technology. Especially in the fields of biomedicine and high-tech materials, Class 1 clean rooms will play an increasingly important role.

As the highest standard in clean rooms, Class 1 clean rooms are used in high-tech industries such as semiconductors, pharmaceuticals, aerospace, and optoelectronics, demonstrating their importance and necessity. Through strict air quality control, temperature and humidity management, and efficient filtration systems, Class 1 clean rooms can effectively prevent pollution and ensure product quality and performance.

In the future, with the application of intelligent, energy-saving and environmentally friendly technologies and the continuous research and development of new materials, Class 1 clean rooms will continue to develop to meet higher standards of industrial needs and provide support for technological progress and innovation in various industries.