CLASS 100 CLEANROOM DESIGN -...

CLASS 100 CLEANROOM DESIGN By Group I Ryan Zellars , Jeremy Zetterberg , Simon Weber , Bret Tollgaard , Sumedha Weerasuriya ,Amanda Willis , Abraham Buenrostro and Jonathan Zander .

PRESENTATION OUTLINE• Introduction to cleanrooms - what? why? how?

• Project definition - Requirements, standards and design approach

• Fluid dynamic considerations - ACR, CFM and FFUs

• Cleanroom type, material and equipment selection- Room configuration , doors, walls, ceilings, windows, lighting.

• Air recirculation system and sensors - what is measured and controlled

• Possible shortcomings and further work - pressure drops, contamination and FEA modeling

• Conclusion - Summary.

INTRODUCTION • ISO 14644-1 definition of a cleanroom

“[A] room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation and retention of particles inside the room, and in which other relevant parameters, e.g. temperature, humidity, and pressure, are controlled as necessary" [ISO-1, p. 1]

INTRODUCTION Contamination free environment needed in

• Semi-conductor industry -Integrated circuit manufacturing

• Hospitals-operating theaters -prevent infection

• Biotechnology - Genetic engineering, antibiotic production.

INTRODUCTION Basic idea behind a cleanroom.

• Isolate area from external environment.

• Continuous monitoring and control of air supply to cleanroom (pressure, temperature, humidity and airborne particle size)

• Identify sources of contamination and take measures to eliminate or reduce it- Follow strict protocol.

• High velocity airflow for quick removal of contaminants.

PROJECT DEFINITION

Given Information

• ISO class 5 or FS 209 Class 100

• Unidirectional ( laminar ) & positive pressure

• 500 sq. ft

Note- Budget not specified

ISO 14644 CLEANROOMS AND ASSOCIATED CONTROLLED ENVIRONMENTS

- 8 part document drafted by a committee of experts !- Provides

- Air borne particle limits for different ISO standard cleanrooms - Specifications for testing cleanrooms for compliance with ISO standards - Various testing methods - Guidelines on how to design, construct and start up cleanrooms - Guidelines on how the room should be run - Guidelines on isolators and mini environments

ISO 14644-Part 1: Classification of air cleanliness by particle concentration

CALCULATING MAXIMUM PERMITTED CONCENTRATION OF AIR BORNE PARTICLES

DESIGN APPROACH Fluid dynamic considerations

- Calculate needed air change rate ( ACR) - Needed air flow rate in cfm - Determine number of filter fan units needed !

Cleanroom type ,material and equipment selection - Perform a trade study to determine most suitable cleanroom type. - Material selection for

Doors Walls Ceilings Windows

- Equipment selection for Circulating and filtering air. Air conditioning ( temperature and humidity control ) Air borne particle monitoring

FLUID DYNAMIC CONSIDERATIONS

Air Change Rate - ACR - This refers to the number of times the air in the room is replaced. !

If too high - Increased power consumption. Induced turbulence may effect cleanliness of room Increased fan size- increased initial investment and construction costs

If too low - Ineffective contaminant removal

Compromise cleanroom standard. !- Documented large ranges of ACR and Air flow velocities for varying classes of cleanrooms.

Main reason for large ranges is the three stages of occupancy defined in ISO 14661-1 !As built - no equipment, materials or personnel At-rest - equipment installed, but no personnel present Operational - specified number of personnel is present and working

FLUID DYNAMIC CONSIDERATIONS

Class Iso 146144-1

(Standard 209E)

Average Airflow Velocity

m/s (ft/min)

Air Changes Per Hour

ISO 8 (Class 100,000) 0.005 - 0.041 (1 - 8) 5 - 48

ISO 7 (Class 10,000) 0.051 - 0.076 (10 - 15) 60 - 90

ISO 6 (Class 1,000) 0.127 - 0.203 (25 - 40) 150 - 240

ISO 5 (Class 100) 0.203 - 0.406 (40 - 80) 240 - 480

ISO 4 (Class 10) 0.254 - 0.457 (50 - 90) 300 - 540

ISO 3 (Class 1) 0.305 - 0.457 (60 - 90) 360 - 540

ISO 1-2 0.305 - 0.508 (60 - 100) 360 - 600

• Recommended airflow velocities and air change rates ( obtained from IEST)

FLUID DYNAMIC CONSIDERATIONS Calculating required air flow rate CFM

• Room dimensions

Total Volume = 4000 cubic feet

FLUID DYNAMIC CONSIDERATIONS Calculating required CFM

@ low end - ACR 240

@ high end - ACR 480 VSD- Variable speed drive fan

FLUID DYNAMIC CONSIDERATIONS Calculating number of Filter-Fan Units ( HEPA filters )

Terra Universal - Room side replaceable FFUs

• Variable speed fans • Connects to Power distribution module • 99.99% efficient HEPA filter pre-installed • Comes in 3 different sizes

• 2’ X 2’ • 2’ X 3’ • 2’ X 4’

FLUID DYNAMIC CONSIDERATIONS Calculating number of Filter-Fan Units ( HEPA filters )

Size (ft) Average CFM

# of FFUs needed

% ceiling coverage

Price per unit

Total equipment

cost

Average Power

Consumption (Watts)

Replaement filter cost

2 X 2 558 58 46% $1,040.00 $60,320.00 290 $466.00

2 X 3 602 54 65% $1,040.00 $56,160.00 329 $537.00

2 X 4 717 45 72% $1,040.00 $46,800.00 393 $545.00

• FFU selection based on a simple cost- benefit analysis

FLUID DYNAMIC CONSIDERATIONS Calculating number of Filter-Fan Units ( HEPA filters ) • 2 X 4 FFU proposed layout ( 9 by 5 array with 0.7 ft spacing for lighting )

20 ft.

25 ft.

0.7 ft.

2 X 4 FFU

THERMODYNAMIC CONSIDERATIONS

• BTU requirement*

* Calculated using information obtained from energystar.gov

Base BTU requirement for a well ventilated 500 sq. ft room is approximately 12,000 BTU/hr

Add 600 BTU/hr for every additional person in room after 2 occupants. Therefore, assuming 3 teams of two members. There is an addition of 2400 BTU/hr.

This gives a total cooling requirement requirement of 14,000 BTUs/hr. ( Current spot cooler is 9000 BTUs )

• BTU requirement*

* Calculated using information obtained from energystar.gov

Heavy insulation eliminating external environmental influences, is said to warrant a decrease in the BTU/hr requirement by 10 %.

18,000 BTU Cleanroom Air Conditioning Module with AC/Dehumidifier/RH Control is available at Terra Universal for $ 7430.00

This single unit should take care of the rooms cooling requirement.

THERMODYNAMIC CONSIDERATIONS

• Other factors influencing BTU requirement

* Calculated using information obtained from energystar.gov

Equipment used inside the cleanroom, such as hot plates and plasma etches generate a lot of heat. Therefore, once the the equipment to be placed inside the room is decided on, the BTU requirement must be marked up.

THERMODYNAMIC CONSIDERATIONS

CLEANROOM TYPE, MATERIALS & EQUIPMENT SELECTION

• Cleanroom Type Selection

CLEANROOM TYPE, MATERIALS & EQUIPMENT SELECTION

• Cleanroom Type Selection

Vertical unidirectional CR with exhausts in wall

Vertical unidirectional, raised floor CR

Horizontal unidirectional flow CR

Poor unidirectional flow High manufacturing and running costs Not suitable for a multipurpose CR

Poor contamination control in center

Not recommended for high width rooms *

*Cleanroom Technology: Fundamentals of Design, Testing and Operation by William Whyte

LIGHTING Terra Universal tear drop lights

• 0.2 X 4 Lighting fixtures • Total of 20 units needed • ( $ 240.00 per unit ) • 160 watts per unit • Total cost $ 4800 Proposed scattered

lighting array layout

CEILING T bar grid

• 2 X 4 ft. heavy duty steel T bar grid • Neoprene sealing to prevent out gassing • Available at AmericanCleanroom Systems • Cost available at request

DOORS Aluminum Frame Sliding Door

• 40” W x 82” H • Static-Dissipative PVC • $ 2,200.00 per unit • Available at terrauniversal.com

WINDOWS Nicomac double glazed window

• Rounded edges and safety film • UV and IR filtering films • Silicon sealed • Available at nicomac.com

WALLS Honeycomb core hardboard walls

• Standard panel is a double faced Kraft Honeycomb core with 1/8" White Melamine covered Hardboard both sides.

• Panel sizes: 4-feet wide by 8-feet high • Available at abtech.net

AIR RECIRCULATION SYSTEM AND SENSORS

Proposed Air recirculation system Key Description

1 Perforated floor

2 Air borne particle counter

3 Fresh air inlet

4 First Stage Filter

5 Flow guide vanes

6 Air conditioning unit

7 Insulated ducting

8 Second stage filtering

9 HEPA FFUs

AIR RECIRCULATION SYSTEM AND SENSORS

Air recirculation system sensors

Location Sensor Controlling

variable Actuation

Inside Cleanroom Pressure transducer Regulate room pressure regulate air input and air

exhaust in room to maintain positive

pressure Exhaust inlet / Other critical clean zones

Air borne particle counter

Active particle count monitoring and control

VSD in FFUs to increase air flow

Inside cleanroom Thermocouple Room Temperature Regulates cooling in A/C unit

Inside cleanroom Humidity sensor Room Humidity level Regulates humidity control in A/C unit

POSSIBLE SHORTCOMINGS AND FURTHER WORK

Shortcoming Possible solution

Induced turbulent flow due to equipment

FEA modeling of heat generation and fluid flow around equipment

Outgassing and excessive pressure drops due to leaks

Excessive testing and sealing prior to cleanroom operation

High maintenance cost due to HEPA filter clogging ( depends on usage )

Add better first and second stage filtering

Insuffiencent insualtion leading to external environment influence

Find average external environmental conditions and determine required insulation

DESIGN SUMMARY

• Double walled - raised floor CR

• High end 480 ACR requires 32,000 CFM

• 45 2x4 filter fan units with HEPA filters

• Preliminary equipment and material costs approximately 75,000 USD • Preliminary cleanroom design layout

DESIGN SUMMARY

• Double walled - raised floor CR

• High end 480 ACR requires 32,000 CFM

• 45 2x4 filter fan units with HEPA filters

• Preliminary equipment and material costs approximately 75,000 USD • Preliminary cleanroom design layout

Questions?

Additional Slides