ISO7 Cleanroom Requirements and Applications

What is ISO7 Cleanroom/Class 10,000 Cleanroom？
  Cleanroom is a room where the concentration of suspended particles in the air is controlled, ISO7 Cleanroom（also called Class 10,000 Cleanroom） means concentration of particles in the air of the room meets the definition of the ISO 14644-1 standard. 

ISO Class 1 is the highest level of cleanroom, with the least amount of particulate matter in the air, suitable for fields like microelectronics and bioengineering. ISO Class 9 is the lowest level, allowing more particulate matter, suitable for general industrial production or storage environments.

  ISO 14644-1 Standard for airborne particles in clean area: 

From the table above ISO7 cleanroom standard, for every cubic meter of air in ISO 7 cleanroom room:
The number of particles ≥0.5μm shall not exceed 352,000;
The number of particles ≥1.0μm shall not exceed 83,200;
The number of particles ≥5.0μm shall not exceed 2,930;
ISO7 Cleanroom have no prescribed limits for particles at 0.5μm or less, as this particle size has a little impact on the production activities in ISO7 Cleanroom.

Cleanroom State:
  There are three different states for a cleanroom, and the design of an ISO7 cleanroom requires to confirm which state to reach ISO 7 standard (this will affect the selection of purification system). The three states are as follows:
►As-built: the cleanroom has been constructed and powered on, but no production equipment, materials or personnel are present.
►At-rest: The cleanroom has been built, the production equipment has been installed and is operating in a manner agreed to by the user and supplier, but no personnel are present.
►Operational: The cleanroom is operating in a defined manner, with a defined number of personnel present and working in a mutually agreeable manner.

  The particle cleanliness of the air in a Cleanroom or Clean Area shall be defined in terms of one or three of the three states: "As-built", "At-rest" and "Operational".
"As-built" applies to newly constructed or released Cleanroom or Clean Areas. Once the testing on the "As-built" has been completed, the "At-rest" or "Operational" or both states should be further tested.

How to Build an ISO7 Cleanroom/Class 10,000 Cleanroom？
  To build an ISO7 Cleanroom that meets specifications and production quality requirements, the following points need to be met simultaneously: 
Cleanroom HVAC System need to be arranged with compliant three-stage filters (Pre, Medium and HEPA), and HEPA filters should be set at the terminal of the system.
►HVAC Systems need to be arranged with compliant three-stage filters (Pre, Medium and HEPA efficiency), and HEPA Filters should be set at the end of the system. 
►The clean room should have sufficient purified air supply (the ISO7 cleanroom air changes in an ISO7 Cleanroom should not be less than 30-70 times/hour.)

►ISO7 Cleanroom should maintain the necessary pressure gradient.
►ISO7 Cleanroom should have appropriate airflow.

ISO7 Cleanroom/Class 10,000 Cleanroom Entrance and Exit:
  Openings connecting the cleanroom to outside or adjacent areas should be minimized.
Effective measures should be taken to minimize contamination due to the entry and exit of people or materials or the airflow movement. Normal (non-emergency) entry into and exit from the cleanroom should pass through the airlock room for both people and materials.
Airlocks or transfer gates (channels) are often required to ensure differential pressure and integrity of the controlled space during entry and exit. Airlock entrance and exit should be interlocked and cannot be opened at the same time. Transparent windows may be installed at both sides for observation. Consideration should be given to the use of electrical or mechanical interlocking systems containing audio/visual indicators. Access for people and materials should be set up separately.

ISO7 Cleanroom/Class 10,000 Cleanroom Gowning Room:
  The gowning room is a dedicated airlock for personnel entering and leaving the Cleanroom. It should have enough functional space and facilities for changing clean clothes, subject to the clean level of the cleanroom. It may also include washing and sanitizing facilities, etc. Special controls, such as air showers and shoe cleaners, may also be installed for access to the cleanroom.

The gowning room should have three functional areas:
A) Gowning Room Entrance: Enter the changing room (either directly or through the airlock) from an auxiliary area suitable for the removal, storage, handling and/or re-dressing of garments that is not permitted in the Cleanroom;
B) Transition Area: An area for the storage, replacement or removal of undressed garments or equipment;
C) Inspection/entry and exit area: the area where the inspection is carried out after the dressing process is completed, and also the area where access to the cleanroom is gained either directly or through an airlock.

  These three functional areas can be separated by specific barriers (e.g., cross-over bench or air locks) in a manner appropriate to the operations and purposes of the changing room. The three areas should be defined so that the area closest to the Cleanroom has the highest level of protection and minimizes the adverse effects on that area from changing or accessing in adjacent areas.

  ISO7 Cleanroom gowning rooms should have the following conditions:
►Storage and handling of cleanroom suit.
►Storage and handling of expendable items and appurtenances (e.g., gloves, masks, protective goggles, shoe covers) prior to use.
►Storage of personal items.
►Hand washing and drying and other decontamination processes;
►Visible display and posting of changing order with clear instructions;
►Through-length mirrors for checking dress code compliance.

ISO7 Cleanroom/Class 10,000 Cleanroom Test:
  To determine whether a cleanroom meets the ISO7 cleanroom standard requires documentation about test conditions and results as per specified test procedures.
Cleanliness test can be performed by using discrete particle counting and light scattering instruments to determine the concentration of suspended particles higher than or equal to a specified particle size at a given sampling point. 
  A discrete particle counter is a light scattering device with the ability to display or record the number and size of discrete particles in the air and the ability to discriminate between particle sizes, to detect the total particle concentration within the appropriate size range for the level being measured, and the appropriate sampling system.
►Airflow or flow rate test;
►Differential air pressure test;
►Enclosing structure Leakage Test;
►Integrity Test of the installed filters.

  Determine the location of sampling points: The minimum number of sampling points in an ISO7 cleanroom can be calculated according to the following formula:
In the formula, 

NL —Minimum number of sampling points (rounded to the nearest whole number).
A - Area of clean room or clean area, measured in square meters.

Attention:
1) Ensure the sampling points are evenly distributed throughout the cleanroom or clean area and are located at the height of the working area.
2) Each sampling point should have at least 2 liters sampling volume and the minimum sampling time is 1 minute.
3) The sampling probe should be inserted into the airflow. If the direction of the air being sampled is uncontrolled or unpredictable (e.g., non-laminar flow), the inlet of the sampling probe should point vertically upwards.
4) When only one sampling point is required, samples should be taken at that point for at least three times.

Results Record:
  Record the concentration of each considered particle size in relation to the air cleanliness class as a result of each sampling measurement, and when only one sampling point is used, calculate and record the average of the sampling data for each considered particle size.
  When more than 1 and less than 10 points were sampled, the mean, standard error, and upper 95% confidence limit were calculated from the average particle concentration from all the points.
  When there is only one sampling point, or more than nine, the upper 95% confidence limit does not have to be calculated.
  If the average value of particle concentration measured at each sampling point and the calculated upper 95% confidence limit does not exceed the ISO7 cleanroom particle concentration limit, the cleanroom or clean area is considered to have achieved the ISO Class7 air cleanliness level, and can meet the corresponding process and production requirements.

ISO7 Cleanroom/Class 10,000 Cleanroom Applications:
ISO7 Cleanroom are widely used in many industries and play an important role in production safety! Industries that typically use these kind of cleanroom are: 
► Electronics Industry（electronic cleanroom）
► Optical Manufacturing （optical cleanroom）
► Pharmaceutical Industry （pharmacy clean room）
► Food/Cosmetic Industry (food processing clean room)
► Aerospace (aerospace cleanroom)
► Medical Device Industry (medical clean room)
► Biological Product Industry (biotech cleanroom)