Cleanroom Classifications, Classes and ISO Standards
What is a Cleanroom?
A cleanroom is a room that has minimum pollutants such as airborne microbes, dust, aerosol particles and chemical vapors. The contamination level of the cleanroom is controlled and is specified by the number of particles per cubic meter (m³) at a specified size of the particle.
What is a Clean Zone?
A cleanroom is a defined area where the no. concentration of particles is classified and controlled. It is designed to disallow or eliminate contaminants.
Use of Cleanroom
Cleanrooms are used in the manufacturing industry. It is used to control small particles that can hamper the manufacturing process.
Is Cleanroom really clean?
Do you know your normal office room has between 500000 and 1000000 particles per cubic foot?
And class A cleanroom has 100 particles per cubic foot. The size and complexity of the cleanroom are different.
Clean room Air Flow Principles
Cleanrooms keep up without particulate air using either HEPA or ULPA filters employing laminar or turbulent airflow principles. Laminar, or unidirectional, air flow systems direct clean air horizontal or in a downward direction in a steady stream towards filters situated on walls close to the cleanroom floor or through raised punctured floorboards to be recirculated.
Laminar airflow systems are normally employed across 80 percent of a cleanroom roof to keep up steady air preparation. Stainless steel or other non-shedding products are used to make laminar airflow filters and hoods to forestall overabundance particles entering the air.
The harsh air tries to trap particles that might be noticeable all around and drive them towards the floor, where they enter channels and leave the cleanroom environment. US FDA and EU have set down rules and breaking point for microbial defilement which is tough to guarantee independence from microorganisms in drug items.
Requirement of a Cleanroom in Pharma Company
The cleanliness level of a pharmaceutical cleanroom depends on the product. Non-sterile product require only proper ventilation and filtered air
But there is always a requirement of a sterile environment to manufacture products. Cleanrooms fulfill this requirement by reducing the contamination level.
Corridors in Pharmaceutical Cleanroom
Basically, there are two corridors required to keep pharmaceutical products free from risk.
Clean Corridors: Drugs which are in powdered form need to be free from microorganisms. And there is always a risk of cross-contamination between products. So for the manufacturing of these drugs a negative (-ve) pressure is required to keep powdered drug free from contamination.
Dirty Corridors: There is a positive pressure in Cleanrooms for aspectics and biopharmaceuticals products manufacturing.
Notable Do’s and Don’ts in a Cleanroom
- Always keep the doors of the cleanroom closed
- Clean all surfaces regularly to remove contamination
- Cleanroom staff must wear the suits
- Don’t allow eatables and drinks inside the cleanroom
- Bring in dirty material and equipment
- Turn off the filters
- No Smoking
Cleanrooms are classified by the quality of the air. In FED STD 209 (A to D) of the United States of America, the no. of particles equal to and more than 0.5 μm is measured in one cubic foot of air and used for the cleanroom classification. This metric nomenclature is accepted in the latest 209E version of the Standard. And TC 209 is the latest standard from the International Standards Organization. Both standards classify a clean room by the no. of particles present in the lab air. The cleanroom classification standards FS 209 E and ISO 14644-1 require measurements of specific particle count and calculations for the classification of cleanroom cleanliness level.
Cleanrooms are classified according to the no. and particle size allowed per volume of air. Large numbers such as class 100 or class 1000 refer to US FED STD 209E and denote the no. of particles of size 0.5 microns or larger size allowed per cubic foot of air.
United States FED STD 209E
|Class||≥0.1μm||≥0.2 μm||≥0.3 μm||≥ 0.4 μm||≥0.5 μm||ISO equivalent|
ISO 14644-1 Cleanroom Standards
|ISO Class||≥0.1μm||≥0.2 μm||≥0.3 μm||≥ 0.5 μm||≥ 1 μm||≥ 5 μm||US FED STD 209E Equivalent|
|Criteria||Class 10/ISO Class 4||Class 100/ ISO Class 5||Class 1000/ ISO Class 6||Class 10000/ISO Class 7||Class 100000/ISO Class 8|
|Air Changes per hr/min||500 to 600/ 8 to 10||300 to 480/5 to 8||180/3||60/1||20/0.33|
|Filter Coverage percentage||90 to 100||60 to 70||20 to 30||7 to 15||4 to 5|
|CFM per sq. foot||85 to 90||36 to 65||18 to 32||9 to 16||4 to 8|
|Filter Efficiency||99.9997 percent ULPAs||99.997 percent HEPAs||99.997 percent HEPAs||99.997 percent HEPAs||99.997 percent HEPAs|
|Type of Ceiling||T-bar grid||T-bar grid||T-bar grid||Conventional T-bar grid||Conventional T-bar grid|
|Light Fixture||Tear drop or Flow Thru||Tear drop or 2’ x 4’ clean room fixture||2’ x 4’ clean room fixture||2’ x 4’ clean room fixture||2’x4’ standard fixture|
|Ceiling Panel||Fiberglass reinforced panels, Mylar or Vinyl Rock||Fiberglass reinforced panels , Vinyl Rock or Mylar||Mylar/ Vinyl Rock||Mylar /Vinyl Rock||Mylar/ Vinyl Rock|
|Wall Type||Modular /Standard Built||Modular/Standard Built||Modular/ Standard Built||Modular/Drywall||Modular/Drywall|
|Floor Cover||Epoxy or Welded sheet Vinyl||Epoxy or Welded sheet Vinyl||Epoxy or Welded sheet Vinyl||Sheet Vinyl/ Vinyl Composite Tile||Sheet Vinyl /Vinyl Composite Tile|
|Floor Base||2”- 6” Cove||Cove/Aluminium Base Channel||Cove/Aluminium Base Channel||Cove/Aluminium Base Channel||Cove/Aluminium Base Channel|
|Air Returns||Raised floor /Center returns||Low wall on long axis||Low wall at perimeter||Low wall||Low wall /ceiling|
British Standard 5295 Cleanroom Standards
|Class||≥0.5μm||≥1 μm||≥5 μm||≥ 10 μm||≥25 μm|
In the United Kingdom, BS 5295 is about to be replaced by British Standard EN ISO 14644-1
ISO Cleanrooms Specifications
ISO Class 1 is the cleanest cleanroom, mostly used in electronics and lifesciences industries that require nanotechnology or ultra-fine particulate processing. The recommended air changes per hour for an ISO Class 1 clean room are 500 to 700.
The recommended air changes for ISO Class 2 and ISO Class 3 are 500-750. And for ISO Class 4 it is 400-750 air changes per hour.
In Biotechnology and Pharma industry Cleanrooms are required for taking care of fluids, cells, organic substances, chemicals and compounds. Because outside sources can decrease the cell viability rates and lead to incorrect test results. So cleanrooms for these industries are mostly specified between ISO 5 and ISO 8
ISO 5 cleanroom has less than 3520 particles > 0.5 microns per cubic meter and 250-300 HEPA filtered air changes per hour. The equivalent Federal standard is class 100
ISO 6 cleanroom specification is quite similar to ISO 5 but it has 180 HEPA filtered air change per hour basis. The equivalent federal standard is class 1000
ISO 7 is a common cleanroom specification. A cleanroom must have less than 352000 particles > 0.5 micron per cubic meter and 60 HEPA filtered air changes per hour. The equivalent federal standard is class 10.000 or 10000 particles per cubic foot.
ISO 8 is the least clean cleanroom classification. A cleanroom must have less than 35200000 particles > 0.5 micron per cubic meter and 20 HEPA filtered air change rate. The equivalent federal standard is class 100000 or 100000 particles per cubic foot.
ISO Ceiling Fan Coverage Percentage Specifications
To achieve the optimal ACH (air change per hour) or ACR (air change rate) requires ceiling fan coverage. The cleanest cleanroom has FFUs (filter/fan units) in every 610-millimeter x 219-millimeter ceiling area. This is close to 100 percent coverage which provides a unidirectional flow of filtered air to eliminate contaminants.
This level of coverage not only leads to high energy consumption but also high construction and operation cost.
You may like to learn: Energy Saving in Cleanrooms
Below table represents the ceiling coverage percentage for each ISO class:
|ISO Class||Ceiling Coverage %|
|ISO 1 to 2||80 to 100 %|
|ISO 3||60 to 100 %|
|ISO 4||50 to 90 %|
|ISO 5||35 to 70 %|
|ISO 6||25 to 40 %|
|ISO 7||15 to 20 %|
|ISO 8||5 to 15 %|
ISO 5 depends on laminar or unidirectional airflow. This means that filtered air is supplied in a uniform direction at a constant velocity. Air is recirculated between base of the walls and the filtering system
ISO 6 or above ISO 6 cleanrooms rely on turbulent or non-unidirectional airflow. It gives a uniform environment and does not allow the formation of air pockets.