10. Clean Room Application

Clean room technology -> Aerosol-free environment

Applications:

1. Pharmaceutical industry 2 . Hospitals 3 . BBBBBBB BBBBBBBB

4. BBB BBBBBBBBBB BBBBBBBB 5 . Microelectronic industry

Examples

Sources of contamination

- 1. Aerosol > airborne particles 2. Hydrosol, e.g., control of deionized water and

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The Principles of a Clean Room

1. BBB BBB BBBBBBBB BB BBB BB BB BBBBBBBBBB BB BBBBBBBB BB BBBBBB BBB BBB BBB BBBBBBBBBBBBB BBBBBBBBB BB BBB BBBBB.

- 2. The air within the cleanroom moves from clean to less clean areas and moves BBB BBBBBBB BBBBBBBBB BBBBBBB BBBBBBBBB.

3. The air supplied to the room is of sufficient quality that it will not add to the BB BBB BBBBB.

4. The air movement in the room should insure that there are no areas in the room BBBB BBBBBBBBBBBBB BB BBBBBBBBBBBBBB.

5. If all other principles are met then the concentration of particles should be BB BBBB BB BBB BBBB BBBBB BBB BBBBBBBB BBBBBBBBB.

Design

1. Room is supplied with large quantities of highly filtered air. 2. This air dilutes and removes the particles and bacteria dispersed

BBBBBBBBB BBB BBBBBBBBB BB BBB BBBBB. 3. Also this holds positive pressure and ensures that air only flows

BB BBB BBBBB. 4. Room is built from materials that do not generate particles and can

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Positive Isolation Schematic

Blank supplies or Terminal HEPAs

3001X A/C

OptionalFloor A/C

Return

OptionalFilter Integratedto A/C

3001X

MakeUp Air

Negative Pressure (TB) Isolation Room Schematic

Exhaust

A/C

SupplyReturn

Supplies

Bathroom exhaust tied into the exhaust ducting. Pre filter should be accessible from room. Main filter housed in module that is removed and accessed above ceiling.

Annunciator

3 TOTAL

A/C

Term HEPA

5. Cleanroom personnel wear clothing which minimizes their dispersion BB BBBBBBBBB

6. Two major types of cleanrooms: BBB BBBBBBBBBBB BBBBBBBBBBB( ) .

7 . .Unidirectional uses much more air than turbulent

8 . Unidirectional CR air speed is typically about 0.4m/s. BB BBBBBBBBBBBB BB B BBBBB BBBBB BBBBBBB B BBB BBB B BBBBB BBB BBB9 . ,

BB BBBBBBBBBB. 10. Pencils cause graphite particles! - 11 210. % of total air supply is fresh air.

Class of clean room - U.S. standard

class >0.1 m#/ft3

>0.2 m#/ft3

>0.3 m#ft3

>5.0 m#/ft3

1 35 7.5 3 -10 350 75 30 -100 - 750 300 -

1,000 - - - 710,000 - - - 70

100,000 - - - 700

Class of Filter

Filter class Overall efficiency(%)H10 85H11 95H12 99.5H13 99.95H14 99.995H15 99.9995H16 99.999 95H17 99.999 995

1. B BBB FILTERS -High Efficiency Particulate Air filters are replaceable extended media BBB-BBBB BBBBBBB BB B BBBBB BBBBB BBBBBB B BBBBBBB BBBBBBBB BBBBBBBBBB BBBBBBBBBB BB - 9997 03. percent for a . micron particle (standard grade) - 9990 03. percent for a . micron particle (low grade) - 9999 03. percent for a . micron particle (high grade) and a maximum clean filter pressure drop of 2.54 cm (1") water gauge when tested BBBBB BBB BBBB BBBBBBBBB.

2. ULPA FILTER Ultra Low Penetration Air filters are extended media dry filters in a rigid frame BBBB BBBB B BBBBBBB BBBBBBBB BBBBBBBBBB BBBBBBBBBB BB 99999. percent for 012particles greater than or equal to . micron BB BBBB

Commercial HEPA filter module.

1. Average person in poor CR garments (coats) generates about 2 10x 6 05part/min greater than . 300000 50m and part/min > . .

2 6 1000. For cleanrooms of ISO class (class ) and poorer quality, HEPA filters BBBB BBBB BBBBBBBBB BBBBBBBBBBB BB BBBB BBB BBBBBBBBB BBBBBBBBBBBBBBB.

3 5 100. For cleanrooms of ISO class (class ), HEPA filters are used with BBBBBBBBBBB BB BBBB BBB BBBBBBBBB BBBBBBBBBBBBBBB .

4 4 10. For cleanrooms of ISO class (class ) or lower, ULPA filters are used with BBBBBBBBBBB BB BBBB BBB BBBBBBBBB BBBBBBBBBBBBBBB .

5. Pressure drop across a filter is obviously dependant on the velocity of air through the filter. The nominal air velocity is usually considered to be 0.5 m/s (100ft/min) and pressure drop at this velocity is likely to be between 120-170 Pa.

6. When the pressure drop reaches 2.5-3 times the original pressure, its time to replace the filters.

1. Diffusion: tiny particles which don’t have enough mass to leave the air stream on their own move randomly in the air stream. This random motion is due to collisions with BBBBB BBBBB BBBB BBBBBBBBB BBB BBBBBBBBBB BBBB BBB BBBBBBBBB BB BBB BBB BBBBB BBBB BBBBBBBBBB BB BBBBB BBBBBBBBB BBBBB B BBBBB BB BBBBBBBBBB BBBBBBBB BBBBBBBBB BBBB. will be held. (Brownian movement causes them to move randomly)

Filter Collection Mechanism - A Review

fibercross section

Streamlines

2. BBBBBBBBB BB BBBB BBBB BBBBBBB BBBBBBBBB BBBBB BBB BBB BBBBBB BBB BB BBBBB BBB inertia and collide with a fibre. This will cause them to be imbedded.

fibercross section

Streamlines

Particletrajectory

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fibercross section

Streamlines

Electrically Enhanced Filtration

Electrically Enhanced Filtration

Filter becomesbactericidal!

Flow enters first

high intensity

ionizing field.

Particles and bacteriaare charged due to ion

flux in this ionizing field- some of the bacteria

are killed here.

The charged particlesand bacteria are highlyefficiently filtered - up

to 1000 times lowerpenetration than

conventional filterswith the same pressure

drop and flow rate.

Bacteria caught onthe filter are subjectedto a continuous doseof ionizing radiationand are thus killed.

282Militarystandard - 1. Thermally generated particles of di octyl phthalate (DOP) with average size of

- 03. micron. Nowadays poly alpha olefin(PAO) or di octyl sebacate(DOS) have replaced DOP.

2. Oil mist is produced upon heating these oils. 3. Efficiency is then measured directly.

( 4 / 4 ) 1. An aerosol of sodium chloride is sprayed into the air then sucked through the filter 2. The efficiency is tested.

Filter Testing

Clean room limits: U.S. (209D) and Germany Standards (VDI 2083)

Clean Room Measurements

Recommended time intervals for regular particle measurements in various BBBBB BBBB BBBBBBB

German VDI 2083US 209D

6100,000

510,000

41,000

3100

210

11

Frequency Half-yearly

Monthly 14 days Weekly Daily Continuous

Minimize sampling loss

1. Short sampling tubes. - 2. Non conductive material for the tubings. Avoid polymeric materials. 3. Isokinetic sampling is not possible due to turbulence and it may not

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Sampling points

1. Distributed uniformly in clean room.2. Distance between points should not be larger than 2 m.3. Minimum number of sampling points from US Fed Std 209D: - Area of the entrance plane divided by 25 ft2, or - Area of the entrance plane divided by the square root of class designation.4. Height of the sampling should be at the working or product level.

Minimum volume per sampling in liter per minute: US Fed Std 209D

Measured particle size

Class 0.1 micron 0.2 micron 0.3 micron 0.5 micron 5 micron

1 17 85 198 566 -

10 2.83 8.5 19.8 56.6 -

100 - 2.83 2.83 5.6 -

1,000 - - - 2.83 85

10,000 - - - 2.83 8.5

100,000 - - - 2.83 8.5

Monotoring Systems

1. Monitor ambient air and within the equipment.2. Sensor system is needed to give a feedback to the control system to prevent deposition on the product.3 Aim of clean-room monitoring - To gain information about the process - To determine the interdependence of different parameter - To elucidate the cause of low product quality - To determine the effects of any actions on product yield.

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Commercial monitoring systems

Measurement Techniques

Optical Particle Counters (OPC)

Light scatteringScattering plane

Spherical particle

Incidentlight

Scatterredlight

Angular scattering forwater droplet (m = 1.33).Spectral scattering for water

droplet (m = 1.33).

Climet OPC.

Condensation Particle Counter (CPC)

- CPC uses the principle that supersaturated vapor condenses on small particles.

- An internal pump draws the aerosol sample into the CPC.

- A flowmeter controls the flow volumetrically.

- Upon entering the instrument, the sample passes through a heated saturator, where butanol evaporates into the air stream and saturates the flow.

- The aerosol sample then passes into a cooled condenser tube,where vapor supersaturates and condenses onto the airborne particles.

- This produces larger, easily detectable aerosol droplets.

- These droplets pass through an optical detector immediately after leaving the condenser.

Principle of CPC

Particle Flux Meter

- No sample is taken. Light is introduced to measurement volume.

- Otherwise functions like an OPC.

- Three types of PFM

1. Beam expansion: Laser beam is expanded by cylindrical lenses to form a rectangular beam.

2. Multiple reflection: Light sheet is produced by multiple reflection of a laser beam between two mirrors.

3. Scanner: Laser beam is deflected by a polygon mirror.

Principle of PFM