Slide 1

Information

Clean Room Concept is the best solution for tackling indoor air pollution. Workplace/Room where particulate is kept within tightly controlled limits by forcing filtered air into the room.

Correct proportion of Fresh Air and Return Air pass through Pre Air Filter (Particle Filtration 10 or 20 micron) then air pass through Heater or Cooling coil where air either gain or lose temperature as per user’s process or personal requirement. Then Blower unit will increase velocity of air. Further air passes through Fine Air Filter (Particle Filtration 3 or 5 micron) then using Ductsystem filtered air enters into the Clean room through HEPA Filter (Particle Filtration 0.3 micron). This filtered air has greater internal air pressure than ambient pressure which helps to prevent intrusion of contaminants in the clean room. Generally used Air of clean room is re-circulate from wall venting near floor level exhausts (Riser Air Filter) and promotes laminar flow of incoming air. The advantage of laminar over turbulent airflow is that it provides a uniform environment and prevents air pockets where contaminants might congregate.

Clean rooms are designed to maintain positive pressure to ensure that filtered air always flows from cleanest to clean space. Controlling particulate is a process not an event thus sources (Particulate are generated continuously by people, processes, facilities and equipment.) must be eliminated whenever possible. In order to restrict or eliminate particulate into the room one must focus on air changes per hour (number of times each hour that filtered outside air replaces existing volume in a room), Air flow rate, Air flow direction, pressurization, temperature, humidity and level of filtration etc. Allowable level of particulate is dictated by specifications for operations being performed.

Air filter is a device composed of fibrous materials which removes solid particle such as dust, pollen, mold and bacteria from airstream.Filtration is done as particle come in contact with fibers. Smaller diameter of fibre better will be filtration. The mechanisms by which the particle come in contact with fibers are Straining (sieving), Interception, Diffusion, Inertial separation and Electrostatic attraction (brief description of each mechanism is given below).

Straining (Sieving)
Straining is a simple and convenient mechanism for filtration. It occurs when opening between media members is smaller than particle diameter thus particle captured between clearances of media member.

Interception

Particle adheres to fiber when comes in contact with fiber edge. Particle follows stream line until it comes in contact with fiber because inertia of particle is not strong enough to cause particle to continue again in stream line.


Diffusion

Special design of fiber provides random (Brownian) motion to particle which increase possibilty of capture.Two distinct phenomenon are used for improvement of capture zone. Either employ more square footage area of coarse media or employ less square footage area of fine media.


Inertial separation

Filtration is due to rapid change in air direction. Mechanism is applied when there is a high concentration of coarse particle in air stream.


Electrostatic attraction

Large diameter of fiber is charged electro statically as to increase efficiency of media for removal of particles. Such fiber is normally chosen due to lower cost and lower air flow resistance. However such charged fibers often lose their energy over a time because particle accumulates over the surface of charged fiber thereby neutralizing their electrostatic charge.

Every Air filters clogged over a time due to deposition of particle, thus drop is observed in collection efficiency eventually increased pressure drop significantly inhibits airflow.To check whether air filter is providing result as per design parameter or not, one can either monitor Pressure drop or count particle content from sample.
If pressure drop is higher than designed pressure drop or sample indicates particle content in incoming air is same as in outgoing air which led to either leak or chance of clogged. Hence replacement of Air filter is required in order to restore function.

The European Committee for Standardization (CEN) has established a Standard EN779 : 2012 and EN1822 : 2009for Testing and Classifying Air filter. Air filters having higher class which not only removes particle effectively but it removes smaller particles too.

Note: If one wants to go for Pre Air filter | Fine Air filter | HEPA filter than select the appropriate class out of G1 to G4 |  M5 to F9  | E10 to H14 respectively.


EN779 : 2012

Filter
Class

Final Pressure Drop
Pascal

ASHRAE 52.1

Average Arrestance (AM) of Synthetic Dust %

Average Efficiency (EM) for 0.4 µm Particles %

G1

250

50 ≤ Am < 65

G2

250

65 ≤ Am < 80

G3

250

80 ≤ Am < 90

G4

250

90 ≤ Am

M5

450

40 ≤ EM < 60

M6

450

60 ≤ EM < 80

F7

450

80 ≤ EM < 90

F8

450

90 ≤ EM < 95

F9

450

95 ≤ EM


EN1822 : 2009

Filter Class

Integral Value

Average Efficiency at MPPS*%

Penetration %

E10

< 85

15

E11

< 95

5

E12

< 99.5

0.5

H13

< 99.95

0.05

H14

< 99.995

0.005

MPPS* - Most Penetrating Particle Size

US Federal Standard 209E


CLASS

Maximum Particles allowed in one meter³ of Air

S.I.

English

0.1 µm

0.2 µm

0.3 µm

0.5 µm

5 µm

M 1.5

1

1000

237

102

35

-

M 2.5

10

10000

2370

1020

352

-

M 3.5

100

100000

23700

10200

3520

29

M 4.5

1000

1000000

237000

102000

35200

293

M 5.5

10000

-

-

-

352000

2930

M 6.5

100000

-

-

-

3520000

29300


ISO* 14644.1


ISO CLASS

Maximum Particles allowed in one meter³ of Air

0.1 µm

0.2 µm

0.3 µm

0.5 µm

1 µm

5 µm

CLASS 1

10

2

-

-

-

-

CLASS 2

100

24

10

4

-

-

CLASS 3

1000

237

102

35

8

-

CLASS 4

10000

2370

1020

352

83

-

CLASS 5

100000

23700

10200

3520

832

29

CLASS 6

1000000

237000

102000

35200

8320

293

CLASS 7

-

-

-

352000

83200

2930

CLASS 8

-

-

-

3520000

832000

29300

CLASS 9

-

-

-

35200000

8320000

293000

ISO* - International Organization for Standardization


European Pharmaceutical Industry GMP* 1997


CLASS

Maximum Particles allowed in one meter³ of Air

Maximum no of Micro -organism presents in one meter³ of Air

0.1 µm

0.2 µm

0.3 µm

0.5 µm

1 µm

5 µm

A

100000

23700

10200

3520

832

29

<1

B

100000

23700

10200

3520

832

29

10

C

-

-

-

352000

83200

2930

100

D

-

-

-

3520000

832000

29300

200

GMP* - Good Manufacturing Practice

 

US Federal Standard 209E

1

10

100

1000

10000

100000

Various Industries

 

 

 

 

 

 

 

 

 

 

 

 

 

Chemistry Lab

 

 

 

 

 

 

 

 

 

 

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Car Industries

 

 

 

 

 

 

 

 

 

Electronic Industries

 

 

 

 

 

 

 

 

 

Micro Mechanic Industries

 

 

 

 

 

 

 

 

 

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Video Recording Studio

 

 

 

 

 

 

 

Pharmaceutical Industries