In industries with extremely high requirements on the production environment, clean rooms are a core part. It is also a guarantee for product safety production. I can say that only by maintaining the cleanliness of the room well can the smooth operation of the entire factory be ensured. This has been thoroughly proven in the pharmaceutical, electronic, semiconductor, and pharmaceutical industries.
As a leading manufacturer of cleanroom components and filters, I have participated in and completed many cleanroom projects. Whether it is new construction or renovation, I can advise customers professionally. In this article, I will discuss 5 tips for cleanroom contamination control. I will start from five aspects: personnel, equipment, materials, management methods, and environment.
1. Personnel: Best Practices for Clean Room Staff
Human body metabolism will produce pollutants, and people’s activities in clean rooms will produce and emit large amounts of contaminants. Human beings are the largest source of pollution and the primary media of transmission in production. Production personnel are always in direct or indirect contact with products, which will affect product quality. Therefore, personnel pollution control measures mainly focus on the following aspects:
Control personnel permissions and numbers in clean rooms
To control the pollution emitted by personnel, the first step is to manage the number of people entering the clean room and monitor the information and number of people entering and exiting the clean room in real-time.
Manual recording is prone to data deviation. The use of an Iris RFID dual-module access control machine, combined with smart clean clothing, can realize the management of personnel access rights in the clean area, real-time display of information on personnel in the clean area, real-time monitoring of the number of personnel in the clean area, and query of personnel entry and exit records in the clean area. And other functions and full life cycle management of cleaning and sterilization of clean clothing.
The dual authentication mode of iris recognition and RFID chip ensures that only qualified personnel and clean clothing can enter the clean area of the corresponding level, significantly reducing the risk of contamination.
Adherence to strict hygiene practices
Clean room staff should develop hygienic habits of washing hands and bathing frequently. They should not use cosmetics, wear watches or jewelry, and are prohibited from bringing personal items inside.
Proper attire, including gowns, gloves, and masks
Personnel entering the clean room must follow the clean room work rules, wear clean clothes neatly, wear gloves, masks, hats, and clean shoes, and enter through clean channels.
Clean clothing is an essential tool for isolating particles emitted by the human body. The performance of clean clothing affects the environmental quality of the clean room. Choosing professional and suitable clean clothes is the focus that pharmaceutical companies need to pay attention to.
Training and Education
Factories should carry out relevant hygiene training for staff, focusing on clean room work requirements, such as changing procedures, hygiene requirements, behavioral habits, precautions, etc.
2. Clean room equipment maintenance and isolation
The production equipment in the clean room should be made of fine, smooth, and wear-resistant materials, especially rotating and sliding parts, to reduce wear and dust production as much as possible.
Those processes that generate dust should be closed or enclosed as much as possible and supplemented with exhaust to form a local negative pressure relative to the clean room to limit the spread of pollutants to other areas of the clean room.
Regular cleaning and wiping of indoor machinery and equipment are also effective measures to reduce the secondary flying of dust.
3. Material control for in and out cleanroom
I will discuss it from the perspective of production materials, tools, and widgets.
Production materials
Material purification measures
The materials entering the clean room must use materials that do not produce pollution and must be made in an environment with relatively little pollution.
Before materials enter the clean room, particles and microorganisms contaminating the outer surface must be effectively eliminated. For this purpose, the material clean room should include a clean room, airlock, or transfer window.
The outer packaging of materials is removed in the outer packaging cleaning room and put into clean containers for later use.
In addition, materials should enter the clean room through an airlock or pass box.
The pass box is used to transfer items indoors and outdoors or between clean rooms of different cleanliness levels. It is a device that temporarily blocks the airflow to prevent damage to the cleanliness.
The conveyor belt that transfers materials must not be transported from an area with a low cleanliness level to a high one. Generally, it can only be conveyed in sections on both sides of the pass box.
Material channel
The materials’ and people’s purification paths are set up independently. The entrance and flow direction of materials must also be separated from the flow of people and try not to cross each other.
Multiple material inlets can be considered for sizeable comprehensive production plants, but they must not affect each other.
The production operation area must not be used as a channel for material transfer, and the space in the production site should minimize opening doors to ensure the air tightness and cleanliness of the cleanroom.
Handling of tools and widgets
All parts and tools entering the clean room should undergo strict cleaning procedures and can only be entered into the clean room after meeting the cleaning standards.
At the same time, the packaging of these parts and tools must also meet the requirements and ensure that these parts will not be contaminated when unpacking outside the clean room.
Components and tools must be processed and produced using non-polluting materials. These materials must also be processed or made in a relatively clean environment.
4. Pollution control in production processes
The amount of process dust mainly depends on the characteristics of the product production process, the status of the equipment selected and the technical measures taken, the raw materials and auxiliary materials selected, the purity of the process medium and its transportation system, etc.
In recent years, various technical measures have been taken to reduce the amount of dust produced, such as the use of closed partitions and local exhaust measures, so that the dust-producing area has a certain negative pressure relative to the surrounding space to prevent the dust from spreading and even endangering the cleanliness of other processes.
Take measures such as exhaust hoods to discharge process dust and minimize the dust that spreads to the production workshop.
What I would like to emphasize particularly is that during the working process of bearings, gears, transmission belts, and other moving parts of workshop machinery and equipment, the dust emitted into the air due to heating of lubricating oil, carbonization, and mechanical wear has attracted more and more attention.
5. Air Filtration and Contamination Control for Clean Room Environments
This part is also a relatively important one among these five aspects. I will discuss it from the following points.
Filtration of cleanroom air supply
The HEPA air filter or ULPA filter, the terminal device of the clean room air conditioning supply system, can effectively filter particulate pollutants in the fresh air and return air processed by the air conditioning unit under normal circumstances.
Clean air processed by HEPA and ULPA air filters is sent indoors, which can effectively displace and dilute indoor pollutants to maintain indoor cleanliness.
However, suppose the final filter is damaged, or there are cracks in the seal between the filter and the support frame, and the air tightness fails. In that case, the air that the high-efficiency air filter has not filtered may carry many pollutant particles into the room and spread with the airflow, causing harmful effects.
Therefore, it is essential to detect, plug, or replace the final filter before the clean room is put into use.
It is also crucial to prevent damage to the final filter during operation. Attention should also be paid to timely replacement of HEPA filters after reaching the end of their service life.
clean room surface
With the advancement of building materials technology, the dust produced on the walls, floors, and ceilings of clean rooms is decreasing daily.
During the design and construction of the clean room’s walls, floors, ceilings, and other enclosure structures, materials that meet quality requirements such as smooth surface, solid texture, no dust production, low dust accumulation, and resistance to cleaning must be selected.
Under the conditions of frequent cleaning and disinfection, such as wiping and washing, the surface will not become rough or porous. Otherwise, particles and chemical pollutants will remain, which can easily lead to microbial contamination.
During design and construction, it should be ensured that the walls, floors, ceilings, doors, air diffusion panels, and floor drains in the clean room are easy to clean.
Details of joints such as walls, floors, and ceilings should also be considered, and areas or surfaces where moisture may accumulate should be especially avoided.
Adjacent contaminated areas
The areas adjacent to the clean room can also be regarded as pollution sources, including lower cleanliness areas and non-clean areas. The polluted air carried in and out by workers and the production raw materials is another important source of pollution affecting the clean room.
To eliminate the influence of this factor, it is necessary to design a reasonable positive pressure difference to reduce the entry of polluted air from holes such as windows, doors, and conveyor belt openings. Alternatively, you can install airlocks, air showers, and buffers at the door. Setting a positive pressure difference in the room can also play a good role in preventing pollution.
It is challenging to contain the pollution caused by adjacent areas completely. Key processes should be set up as far away from the outer door as possible to minimize the negative impact of pollution on product quality.
Last thought
The pollution control management of clean rooms is a complex system project. I have only listed some management measures. I suggest combining the actual production conditions with continuous improvement in the practice process, drawing inferences from one example, and improving the management level to ensure safe production and product quality.
