Understanding ISO6 Cleanroom Standards & Applications

What is ISO 6 Cleanroom Requirement and Application

ISO 6 Cleanroom/ Class 1000 Cleanroom:
  A clean room is a controlled environment that must maintain a specific level of air quality. According to the ISO 14644 standard, the cleanroom can be divided into nine clean levels based on the number of particles per cubic meter of air. ISO 6 cleanroom is within one of the classes.
     ISO 14644 Cleanliness of airborne particles in clean areas:

From the above table, it can be seen that for an ISO 6 cleanroom, the particle count per cubic meter of air must be as follows:
  •For particles ≥0.1µm，the maximum count is 1000000
  •For particles ≥0.2µm，the maximum count is 237000
  •For particles ≥0.3µm，the maximum count is 102000
  •For particles ≥0.5µm，the maximum count is 35200
  •For particles ≥1.0µm，the maximum count is 8320
  •For particles ≥5.0µm，the maximum count is 293

Cleanroom occupancy states:
There are three main occupancy states of cleanroom, as-built, at-rest and at-operation respectively.
â–ºAs-built: The facility is constructed, all utilities are connected and operational, but there is no production equipment, materials, or personal present.
â–ºAt-rest : The facility is constructed, production equipment is installed and operating as agreed by the user and supplier, but without personnel present.
â–ºAt-operation: The facility is operating as specified, with a specified number of personnel present and working as agreed.
The particle cleanliness of air in cleanrooms or clean areas are defined based on one or more of the three states.
"As-built" applies to newly built or newly released cleanrooms or clean areas. After the test is done at As-built state, further tests can be done at “At-rest” or “At-operation” states.
 

The number of air changes per hour required for ISO 6 cleanrooms/ Class 1000 Cleanroom:
  The air exchange rate in a cleanroom varies depending on its classification and intended use, as well as several other factors including room size, usage purpose, number of personnel, quantity of equipment, and production processes. Here are the corresponding air change rates for different cleanroom classification:
 

From the table, the air exchange rate for an ISO6 cleanroom is typicalluy 60-100 changes per hour, ensuring rapid particle dilution and minimizing contamination risk.

 ISO 6 cleanroom layout requirements:
1.The floor plan should be rational and compact. Only necessary process equipment and areas with air cleanliness requirements should be located in cleanrooms or clean area.
2.Under the premise of meeting the production process and noise requirements, Cleanrooms or clean areas with strict air cleanliness requirements should be close to the HVAC room, and processes and workspaces with the same cleanliness level should be centrally arranged,
3.Processes requiring strict air cleanliness should be located upwind, and equipment that generates pollution should be placed near return air.
4.Consider routes for large equipment installation and maintenance, and provide access panels and inspection opening as needed.
5.When there is frequent contact between rooms of different cleanliness levels, measures such as airlock room and pass box should be implemented to prevent contamination.
6 A separate material entrance should be established, and the material transfer route should be as short as possible. Materials should be cleaned before entering the cleanroom.

ISO6 Cleanroom/ Class 1000 Cleanroom Principles for personnel and material purification:
1.The entrance of the personnel purification room shall be provided with shoe cleaning measures.
2.The rooms for storing clothes and changing clean clothes should be set up separately.
3.The lockers should be provided at a ratio of one locker per person, and the cleanroom clothes should gathered in the laminar air flow cabinet.
4.Washing and drying facilities should be provided in the lavatory.
5.Air shower room should be located at the entrance to the clean area, adjacent to the changing room/ gowning room. One single-person air shower should be provided for every 30 people, and a bypass should be included if tthe clean area has more than 5 staff members
6.Toilets should not be located within the clean area. The toilet in the room for personnel purification should have a ante room.

ISO6 Cleanroom/Class 1000 Cleanroom requirements on partition walls:
Material choice: Walls and floors should be made of non-porous materials to minimize particulate matter            
generation and promote cleanliness.
Smooth surface: Walls and floors must have a smooth surface to prevent particulate accumulation and     improve cleaning efficiency.
Antimicrobial growth: Walls and floors may need to have antibacterial properties to reduce the growth of           
microorganisms.
The construction of the cleanroom wall and cleanroom ceiling should also meet the following requirements:
1.The surface of the walls and ceiling in the cleanroom should be smooth, dust-free, glare-free, easy dust removal, and free of concave and convex surfaces.
2. The kick plates should not protrude from the wall.
3. Masonry walls and plastered walls should not be used in clean rooms.

ISO6 Clean room /Class 1000 Cleanroom floor requirements:
Clean room floor design shall comply with the following requirements:
1.The clean room floor should meet the requirements of the production process.
2.The clean room floor should be smooth, wear-resistant, easy to clean, non-cracking, and not easy to accumulate static electricity.
3.The floor bedding should be equipped with reinforcement and moisture-proof measures should be taken for the bedding in humid areas.

ISO6 Cleanroom /Class 1000 Cleanroom requirements on doors and windows:
1.When the external window is set in the cleanroom and the personnel purification room, the double layer tempered glass window should be used to meet the good air tightness.
2.The window of the cleanroom should be flush with the inner wall, and no window sill should be set up.
3.The sealed door of the clean room should be opened towards the room with higher air cleanliness, and a door closer should be added. The sealed door of the windowless clean room should be equipped with an observation window.

Differential pressure control requirements for ISO6 cleanrooms/ Class 1000 Cleanroom:
1.A certain differential pressure must be maintained between the cleanrooms and the surrounding areas, and positive pressure cleanroom or negative pressure cleanroom differential pressure should be maintained according to the process requirements.
2.The differential pressure between different cleanliness class of cleanrooms should not be less than 5Pa, the differential pressure between the clean area and the unclean area should not be less than 5Pa, and the differential pressure between the clean area and the outside (non clean area) should not be less than 10Pa.

ISO6 clean room air flow pattern and air supply volume requirements:
The air flow type of ISO6 clean room is non-unidirectional flow, also known as turbulent clean room;
the airflow in the clean area should be as uniform as possible;
1.The air flow velocity in the clean area should meet the requirements of the production process, and the speed of the high efficient air supply outlet is usually controlled between 0.2 and 0.4m/s;
2.The supply air volume for the clean area should be determined based on whichever is higher: the air volume required to meet the cleanliness class level or the air volume needed to handle the thermal and humidity loads.
3.The number of air changes in the clean area is usually 15~20t/h;

ISO6 clean room purification system requirements:
1.ISO6 clean room purification system is usually equipped with three-stage filtration, including G4 prefilter, F8 middle filter which are generally installed inside air conditioning unit, as well as H14 high efficiency filter which is generally placed at the cleanroom ceilings.
2.Air filtration is the frontline defense against contaminants in cleanrooms. Filters act as gatekeepers, intercepting particles that could compromise the environment's purity. These filters capture both visible dust and microscopic impurities.

ISO 6 Cleanroom HVAC System:
1.Air conditioning (HVAC) systems are used to regulate temperature, humidity and airflow in cleanrooms.
2.HVAC system is a core component of cleanrooms, controlling and maintaining a highly precise environment. In these sterile havens, even the smallest particles can disrupt processes, and HVAC systems play a vital role in maintaining optimal conditions. HVAC systems do more than control temperature; they filter and regulate air quality, ensuring a continuous flow of clean air and eliminating contaminants.
3.It is of high importance that the HVAC design and construction adhere to strict standards. From controlling humidity to managing airflow patterns, HVAC systems protect the integrity of sensitive operations across industries such as pharmaceuticals, electronics and healthcare.

ISO6 Cleanroom/Class 1000 Cleanroom cleanliness test:
To determine if a cleanroom meets ISO 6 standards, we need to follow a specified testing procedure and provide documentation on testing conditions and results to certify compliance with ISO 6 air cleanliness requirements.
Discrete particle counting and photometer can be used to determine the concentration of suspended particles greater than or equal to the specified particle size at designated sampling points.
Prior to testing, verify that the cleanroom or clean area functions as a complete and normal operating unit according to technical performance requirements.
Pre-testing activities typically include:
â–ºAir flow or velocity test;
â–ºDifferential pressure testï¼›
â–ºEnclosure integrity (leak) testï¼›
â–ºFilter leakage test.
Determining sampling point locations：
The minimum number of sampling points can be calculated using the following formula:

Where，
NL —Minimum number of sampling points (rounded to an integer).
A —Area of clean room or clean area, counted in ㎡.
Note：
1)Ensure that the sampling points are evenly distributed throughout the cleanroom or clean area and located at the height of the work activity.
2)The sampling volume should be at least 2 liters per sampling point and the sampling time should be at least 1 minute.
3)The sampling probe should be inserted into the air stream. If the direction of the sampled temperament is uncontrolled or unpredictable (such as non-unidirectional flow), the inlet of the sampling head should point vertically upward.
4)When only one sampling point is required, at least three test samples are taken at that point.
Result records:
Record the results of each sampling measurement for the concentrations of considered particle sizes. When using a single sampling point, calculate and record the average values.
For 1 to 9 sampling points, calculate the average particle concentration, standard error, and 95% upper confidence limit.
For 1 or more than 9 sampling points, there is no need to calculate the 95% confidence upper limit.
If the average particle concentration and the 95% upper confidence limit at each sampling point do not exceed the ISO 6 limits, the cleanroom is considered to have achieved the ISO6 cleanliness level and can meet process production requirements.

ISO6 Cleanroom / Class 1000 Cleanroom cleanliness maintenance:
Established cleanrooms require ongoing monitoring of technical indicators and various measures to ensure normal operation, meeting product environmental requirements and ensuring product quality. Maintenance of an ISO6 cleanroom typically includes:
â–ºCheck the constant positive pressureï¼›
â–ºCheck the particle levels in the room regularlyï¼›
â–ºAll personnel must comply with the prescribed hygiene and dress codeï¼›
â–ºDevelop and adhere to strict material cleaning, access management and waste management proceduresï¼›
â–ºCheck the air filtration system regularlyï¼›
â–ºEstablish and strictly follow regular cleaning proceduresï¼›
â–ºTimely maintenance of cleanroom structure and production equipment.

ISO6 Cleanroom / Class 1000 Cleanroom applications:
ISO6 cleanrooms are suitable for applications with high particle control requirements, such as bio-pharmaceutical, semiconductors, precision mechanics, optics, etc. As technology advances, the range of applications and demand for ISO6 cleanrooms will continue to expand, Here are some common examples of ISO6 cleanrooms:
1）ISO 6 Semiconductor Cleanroom
In the semiconductor industry, ISO6 cleanrooms are typically used for tasks like photo-lithography and wafer processing. The specific allowable particle count provides a controlled environment that helps reduce defects and failure rates, ensuring a stable and controllable indoor environment that protects materials and processes from external influences, enhancing product quality and production efficiency.
2）ISO 6 Bio-pharmaceutical Cleanroom
A biotechnology cleanroom is a cleanroom where airborne micro-organisms are the primary concern of control. An ISO6 biotechnology pharmaceutical cleanroom achieve a certain level of clenliness and hygiene by implementing measures such as air purification and environment control, to meet the cleanliness requirements for pharmaceuticals production.
3) ISO 6 Optical and laser Cleanrooms
Optical and laser cleanrooms also called Photolithography Cleanroom are typically used for the production, testing, and calibration of precision lasers, lenses, and optical equipment, which have strict requirements for dust and bacteria. An ISO6 cleanroom provides a stable and contamination-free environment, enabling reliable operation of precision subatomic particle test devices.
4) ISO 6 Aerospace Cleanrooms
Due to the industry particularity of ISO6 aerospace cleanrooms, the control of temperature, humidity, pressure, air flow velocity, air flow distribution, noise and vibration, lighting, static electricity and other parameters is more strict to ensure that the manufacturing process of the device can meet the required cleanliness standards.