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Clean room classification

 Clean room classification

 To understand clean room classifications, we should learn what made clean room

Clean room is a room in which the concentration of airborne is controlled, and which is constructed and used in a manner to minimise the introduction, generation and retention of particles inside the room and in which other relevant enviroment parameters, e.g. temperature, humidity, and pressure, are controlled as neccessary.

What is a clean room classification?


Clean room classification is a system of standard or specification in which each clean room is classified by the cleanliness of their air. The method most easily understood and most universally applied is the one suggested in the earlier versions (A to D) of Federal Standard 209 of the USA. In this old standard the number of particles equal to and greater than 0.5 m m is measured in one cubic foot of air and this count used to classify the room. The most recent 209E version has also accepted a metric nomenclature. In the UK the British Standard 5295, published in 1989, is also used to classify clean rooms. This standard is about to be superseded by BS EN ISO 14644-1.

Clean room classification


There are many International specification of Clean Room and many Specification for clean room in Biology, Pharmaceutical, Micro-electronics and Aerospace, but in this post I will introduce only some important international specifications for clean room and clean room classification here:


US Federal Standard 209E 1992

EEC cGMP 1989

France AFNOR 1989

German VDI 2083 1990

British BS 5295 1989

Japan JIS B 9920 1989 

ISO EN 14611-1 1999

Australia AS 1386 – 1989

clean room classification comparison chart

How can we determine the classification of clean room

We all think clean room means there no rubbish, dust in room or house. At the beggining, me too. And the concept of cleaning is so relatively if we haven't got any measurement tool for classify them. For example: When I scan my room (collect rubbish, sweep the floor), it can be called clean room. OK? But I continue to wipe the wall, the floor and equipment in room. It still be called clean room. OK? So, we need a measurement system which can be determine exactly how is clean room.

clean room corridor
Clean room corridor. PS panel wall and ceiling, PS door and stainless steel accessories, epoxy paint for floor and air filter on the ceiling.


To solve this, we need to quantify the cleanliness of the room, it means measure the cleanliness of the room. The measurement of the cleanliness of the room refers to the purity of the air in the room. Usually it will be calculated by measuring / counting the number of particles with a given size range per unit air volume given to the cleanliness of the room. This is the first factor for define the clean room
clean room classification iso 14644

clean room classification ppt

For example: I think you are all agree with me:
In a Clean room A (A) with 1000 particles (size less than or equal to 0.5μm) per one cubic meter of air
and Clean room B (B) with 10.000 particles (size less than or equal to 0.5μm) per one cubic meter of air.

We can say that: Clean room A is cleanner than Clean room B. Are you OK with me?


When you read this sentence, I'm sure 99% for you beginners all agree with me, and myself last time is the same you. I think it is correct. This is our mis-understanding (you and me).

We can say that: Clean room A is cleanner than Clean room B at the time of taking sample only. For example: Clean room A is filetered by Air filter system continuously for 3 days, but the clean room B is only filtered for 1 day. Now you can understand the second factor for define the clean room.

clean room corridoor epoxy paint
clean room classification standards

I would like to extend my example a few lines to you to figure out the third factor related to clean room standards. In one clean room, I take the air sample A at HEPA filter then I take another air sample B at production line. It means that the air sample A is cleanner than the air sample B.



clean room classification for medical device

With the above example, we synthesized 3 basic factors to determine the clean elements of the room:

  1. Cleanliness level shown by quantifying the number and size of particle on a volume of air.
  2. Operating conditions of the sampling time.
  3. Sampling location in determining the level of cleanliness.

Clean room classification by International specifications:


The clean room standard I will continue to analyze in the next article.In this article, I would like to introduce of 2 most common clean room classification is US Federal Standard 209E - 1992 and ISO 14644-1-1999 as follows:

US Federal Standard 209E - 1992 for clean room classfification:

The air quality of a clean rooms are described in Federal Standard 209 "Airborne Particulate Cleanliness Classes in Clean Rooms and Clean Zones" (A through D) where the classes are named after the maximum number of particles of 0.5 micrometers or more in diameter which is acceptable in air.



Federal Standard 209D Class Limits

Maximum Number of Particles in Air
Particles per cubic foot air
Class
Measured particle Size (micrometers)
0.1 μm
0.2 μm
0.3 μm
0.5 μm
5.0 μm
1
35
7.5
3
1

10
350
75
30
10

100

750
300
100

1,000



1,000
7
10,000



10,000
70
100,000



100,000
700

Application of this clean room classification: This class is the ground for pre-design when the customer want to build a factory, we can consult them which class of clean room they need to be.


Class 1 & 10 - Production laboratories for electronic integrated circuits ..
Class 100 - Production areas for photo labs, medical implants ..
Class 10,000 - Production locales for TV tubes, hospital operating theaters ...
Class 100,000 - Production of ball bearings


ISO 14644-1-1999 for clean room classification:

Small numbers refer to ISO 14644-1 standards, which specify the decimal logarithm of the number of particles 0.1 µm or larger permitted per cubic metre of air. So, for example, an ISO class 5 cleanroom has at most 105 = 100,000 particles per cubic metre.

ISO 14644-1-1999 Class


Class
Maximum particles/m³
≥0.1 µm
≥0.2 µm
≥0.3 µm
≥0.5 µm
≥1 µm
≥5 µm
ISO 1
10
2.37
1.02
0.35
0.083
0.0029
ISO 2
100
23.7
10.2
3.5
0.83
0.029
ISO 3
1,000
237
102
35
8.3
0.29
ISO 4
10,000
2,370
1,020
352
83
2.9
ISO 5
100,000
23,700
10,200
3,520
832
29
ISO 6
1.0×106
237,000
102,000
35,200
8,320
293
ISO 7
1.0×107
2.37×106
1,020,000
352,000
83,200
2,930
ISO 8
1.0×108
2.37×107
1.02×107
3,520,000
832,000
29,300
ISO 9
1.0×109
2.37×108
1.02×108
35,200,000
8,320,000
293,000

You can download the ISO standard 14644-1-1999 for clean room classification here:

The equivalent classification between ISO 14644-1-1999 and FED Standard 209E


COMPARISION ISO 14644-1-1999 vs FED STD 209E
ISO 14644-1-1999
FED STD 209E
ISO 1

ISO 2

ISO 3
Class 1
ISO 4
Class 10
ISO 5
Class 100
ISO 6
Class 1,000
ISO 7
Class 10,000
ISO 8
Class 100,000
ISO 9
Room air

Images of clean room class 100

One of clean room photo which I took on Internet. I think this photo has a copyright, but I forgot the address to refer here. You notice about this photo, you see the worker is cleaning the floor and the floor is perforated panel. This clean room is so high, may be class of 100 because to build a clean room class of 100 like that, the air in this room need to be exchanged continously, make clean by filter (HEPA) and then return into the air. If the do not use the perforated floor like that, the speed of wind in this room is so high, morever, too much volume of air exchange at the same time, they need an air collected system enough capacity. So this perforated floor is the best choice.

iso 7, iso clean room classification, clean room standards

clean room class 100
Clean room class 100
You can find out 10 resource for study clean room classification here. Click here

Reference:


1. Definition of a clean space adapted from AS 1386.1 : 1989
2. Farquharson G., “Cleanrooms and Associated Controlled Environments – The New CEN and ISO Containment Control Standards” Pharmaceutical Engineering Vol. 19, No 5.
3. Table 1 Air Cleanness Classes – AS 1386.1 : 1989
4. Adapted from Figure 5 Particle Size Distribution – AS 1386.1 : 1989
5. Reinhardt Dr. H “Inlet Air Filtration in Hospitals” : Presentation Notes from Seminar - Carl
Freudenburg, West Germany & IPSCO Sales & Manufacturing Ltd.
6. 1996 ASHRAE Handbook, HVAC Systems and Equipment, Chapter 24
7. 1996 ASHRAE Handbook, HVAC Systems and Equipment, Chapter 24
8. Refer information from internet. Thank you for owner information and photos.