cleanrooms and hvac systems design...

Engsysco

Wei Sun, P.E.

ASHRAE Distinguished Lecturer

Society Technology Transfer Committee Chair (12-13)

“Clean Spaces” Technical Committee (TC9.11) Chair (07-10)

“Healthcare Facilities” Technical Committee (TC9.6) Member

“Laboratory Systems” Technical Committee (TC9.10) Member

IEST (Institute of Environmental Sciences and Technology) Society President

ISO 14644 Cleanroom Standards USA Delegate

Engsysco, Inc. President

Ann Arbor, Michigan, USA

Web: www.engsysco.com Email: [email protected]

Cleanrooms and HVAC Systems

– Design Fundamentals Belgrade, Serbia April 28, 2017

http://www.engsysco.com/

mailto:[email protected]

Cleanroom Design Considerations (Applications)

Semiconductor

Microelectronic

Pharmaceutical

Biotechnology

Aerospace

Automotive

Medical Devices

Optical Devices

Hospital

University Labs

Food Processing

Miscellaneous

Cleanroom - A special enclosed area, its environment typically has the following controlled parameters:

Temperature

Humidity

Sound and Vibration

Lighting

etc.

Common Requirements

Airflow Pattern

Room Pressure

Particle Contamination

(Airborne, Surface & Liquid-borne)

Microbial Contamination

(Airborne, Surface & Liquid-borne)

Electrostatic Discharge

Gaseous Contamination

Process Specifics

Special Requirements

Cleanroom Design Considerations (Controlled Parameters)

U.S. Federal Standard 209E

Airborne particulate cleanliness classes in cleanrooms and clean zones (former US standard, canceled in November 2001)

ISO Document

ISO-14644: Cleanrooms and Associated Controlled Environments

ISO-14644-1 Classification of Air Cleanliness

ISO-14644-2 Cleanroom Testing for Compliance

ISO-14644-3 Methods for Evaluating & Measuring Cleanrooms & Associated Controlled Environments

ISO-14644-4 Cleanroom Design & Construction

ISO-14644-5 Cleanroom Operations

ISO-14644-6 Terms, Definitions & Units

ISO-14644-7 Enhanced Clean Devices

ISO-14644-8 Molecular Contamination

ISO-14698-1 Biocontamination: Control General Principles

ISO-14698-2 Biocontamination: Evaluation & Interpretation of Data

ISO-14698-3 Biocontamination: Methodology for Measuring Efficiency of Cleaning Inert Surfaces

Cleanroom Standards in US (Previous US Federal Standard and Current ISO Standards)

FS 209 ISO 14644 FS 209 ISO 14644 FS 209 ISO 14644 FS 209 ISO 14644 FS 209 ISO 14644 FS 209 ISO 14644

Particles/ft3

Particles/m3

Particles/ft3

Particles/m3

Particles/ft3

Particles/m3

Particles/ft3

Particles/m3

Particles/ft3

Particles/m3

Particles/ft3

Particles/m3

1 10 2

2 100 24 10 4

1 3 35 1,000 7.5 237 3 102 1 35 8

10 4 350 10,000 75 2,370 30 1,020 10 352 83

100 5 100,000 750 23,700 300 10,200 100 3,520 832 29

1000 6 1,000,000 237,000 102,000 1,000 35,200 8,320 7 293

10,000 7 10,000 352,000 83,200 70 2,930

100,000 8 100,000 3,520,000 832,000 700 29,300

9 35,200,000 8,320,000 293,000

0.1 µm 0.5 µm 5.0 µm0.3 µm 1 µm

FS 209

Class

ISO

14644

Class

0.2 µm

These Two Standards Similar? (Comparison of FS-209E and ISO-14644 in Combined Table)

Air Cleanliness Class Definition Comparison

Between FS 209 and ISO 14644

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

0.01 0.1 1 10

PARTICLE SIZE, μm

PA

RT

ICL

ES

PE

R C

UB

IC M

ET

ER

S

ISO-1

ISO-2

ISO-5

ISO-4

ISO-3

ISO-6

ISO-9

ISO-8

ISO-7

FS-1

FS-100,000

FS-10,000

FS-1,000

FS-100

FS-10

These Two Standards Similar? (Comparison of FS-209E and ISO-14644 in Overlapping Chart)

They are NOT identical, but roughly equivalent under certain classes and particle sizes.

0.1

µm 0.2

µm 0.3

µm 0.5

µm 1

µm 5.0

µm

Cla

ss 1

Cla

ss 2

Cla

ss 3

Cla

ss 4

Cla

ss 5

Cla

ss 6

Cla

ss 7

Cla

ss 8

Cla

ss 9

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

Particle C

ount / m3

Particle Size (Channel)Cleanlin

ess Class

Cleanroom Particle Counts Per ISO Classification

Class 1

Class 2

Class 3

Class 4

Class 5

Class 6

Class 7

Class 8

Class 9

ISO 14644 Classification (Airborne Particle Sizes, Counts and Classifications in 3D Illustration)

Sources of Contamination

Description Control Methods

Infiltration through doors, and cracks at windows, and walls

Tighter exterior wall construction, exterior zone pressurization, vestibules at main entrances, and seal space penetrations.

Outdoor air

Makeup air entering through the air conditioning systems

Multiple level filtrations External

Indoor transfer air between rooms

Infiltration through doors, windows, and wall penetrations for pipes, ducts, etc.

Seal wall penetrations, multiple level pressurizations & depressurizations to obtain proper airflow directions

People

Largest source of internal particles: skin scales, hair, textile fibers

Garments, proper gowning procedures, air shower before entry

Work surface shedding

Rubbing one item against another

Use cleanroom suitable or rated furniture

Process equipment

Spray, painting, welding, grinding

Local filtration and exhaust

Raw and semi-finished material

During transport

Equipment washing, cleaning and sterilization before entry, use airlock & pass-through

Liquids, pressurized gases used in process

During preparation, processing and packaging

Local exhaust

Chemicals used for cleaning

Out-gassing to room Use cleanroom suitable or rated cleaners

Internal

Room construction materials

Dust generated from wall, floor, ceiling, door, fibrous insulation

Constructed with special building materials

Particle Sources & Control

Filtration Dilution Isolation

Utilizing HEPA & ULPA

filters to remove

particles from supply

air

• HEPA: >99.97%

(@ 0.3μm MMD)

• ULPA: >99.999%

(@ 0.12μm MMD)

Diluting internally contaminated air with filtered clean air

• Higher air change

rate, better dilution

Isolating particle generations with barriers, or removing directly from major sources

• Process exhaust

• Mini-environment

Airborne Particle Physical Controls

Control Methods

Physical:

• Heat

• Radiation

• Filtration

Chemical:

• Sterilization

• Disinfection

Unlike non-viable particles which can’t

reproduce, microorganisms could

reproduce at a rapid rate if nutrition and

environment are favorable.

Microorganism can be classified as

bacteria, algae, fungi, protozoa and

viruses. Some of these are essential,

and harmless, while others are harmful

and dangerous.

Microbiological Contamination & Control

As Built: Installation is complete with all services connected and functioning, but with no production equipment materials and no personnel present.

At Rest: Installation is complete with equipment installed and operating in a manner agreed between the customer and supplier, but with no personnel present.

Operational: Installation is functioning in the specified manner, with specified number of personnel present and working in the manner agreed upon.

ISO 14644 Standard Classifications –

Occupancy States

Pharmaceutical Grade

vs. Classification

Maximum P ermitted N umber of P articles P er m 3 ( equal to or above )

EU Pharmaceutical Cleanliness Grade

Cleanliness Classification

Grade At Rest In Operation FS 209 ISO

14644

0.5 µ m 5 .0 µ m 0.5 µ m 5 .0 µ m 0.5 µ m 5 .0 µ m

A 3 , 500

0 3 , 500

0

100 5 3,520 29

B 3 , 500

0

350,000

2,000

1 , 000 6 35,200 293

C 350,000

2,000

3,500,000

20,000

10 , 000 7 3 52 , 000 2 , 930

D 3,500,000

20,000

Not defined

Not defined

100 , 000 8 3 , 520,000 29 , 300

Recommended limits for microbial contamination in the operation state (average values)

Microbial Contamination Limits

In Operation

Operation

Design Requirements

USA FDA EU

Non-sterilized product or container

Particle cleanliness ISO 8 (Controlled Area)

Grade C

Maximum viable Organisms (cfu)

2.5/ft3 100/m3

Room Airflow 20 ACH or higher 15-20 minute clean-up time

Room Pressure 12.5 Pa Positive

Sterilized product or container

Particle cleanliness ISO 5 in ISO 7 Background (Critical Area)

Grade A in Grade B Background

Maximum viable Organisms (cfu)

ISO 5: 0.1/ft3 ISO 7: 2.5/ft3

A: 1/m3 B: 5/m3

Room Airflow 90±20 fpm 0.36 - 0.54 m/s

Room Pressure 12.5 Pa Positive

Control of Particles and Microbial Sterilized

and Non-sterilized Product

Class

US 209 ISO

Ceiling Filter Coverage

HEPA or

ULPA

9 5% - 15%

100,000 8 5% - 15%

10,000 7 15% - 20%

1,000 6 25% - 40%

100 5 35% - 70%

HEPA

10 4 60% - 90%

1 3 60% - 100%

2 80% - 100%

1 80% - 100%

ULPA

Typical Ceiling Filter Coverage

IEST RP-12.1 (Before 2007)

Room Airflow Volume/Quantity (Traditional Approaches: Table Methods)

Classification

ISO Class FS - 209 Class

Air Change Per Hour (ACH)

Range

8 100,000 5 – 48

7 1 0,000 6 0 – 90

6 1 , 00 0 150 – 240

5 100 240 – 480

4 10 300 – 540

3 1 360 – 540

2 360 – 600

1

Non-Unidirectional

(Conventional) Flow

Unidirectional

Flow

Mixed

Flow

Mini-Environment

Flow

Room Airflow Patterns

Ballroom Office and

Support

Areas

One Big

Cleanroom

Service Area

Service Area

Mini-Environment

Service Chase

Office and

Support

Areas Cleanrooms

Service Area

Service Area

C C C C

C C C C

Office and

Support

Areas Cleanrooms

Service Area

Service Area

R

R

R

R

R

Small

rooms

Multiple

Clean

R

R

R

R

R

Shared Return Air

Chase (TYP)

Mini-Cleanrooms

Less-clean

Cleanroom

Cleanroom Floor Arrangements

Raised Floor

Cleanroom

Submains

Chemical Supply Systems Process Supply Systems

Gas Cabinets

Basement

Perforated Slab Process Exhaust

Waff le Slab

Ceili ng + Filter

Pump

Scrubbed Exhaust Air

Fan Tow er

Return Air

Stair Case

Visitors Corr idor

Maint. Corr idor

Pressurized Plenum

Silencer

Cooling CoilMake-Up Air

Process Corr idor

ITRI

Pressurized Plenum (Fan Tower) Arrangement

Stair Case

Scrubbed Exhaust Air

Ret urn Air

SubmainsMake-Up Air Process Supply Submains

Basement

Scrubber

Cleanroom

Process Supply Syst emsGas Cabinets

4.8m

0.0m

3.6m

9.6m

4.8m

2.2m

3.5m

ITRI

Fan Filter Units (FFU) Arrangement

Scennario 1: Room Prerssurized

SA - (EA+RA) = ΔV = ΣQ > 0

Total Room

Supply Airflow

(SA)

Total Room

Exhaust and/or

Return Airflow

(EA+RA)

Room

Positively

Pressurized

+ To

tal

Ro

om

Su

pp

ly A

irfl

ow

(S

A)

To

tal

Ro

om

Exh

au

st

an

d/o

r R

etu

rn A

irfl

ow

(EA

+R

A)

Offset

Flow

ΔV

Total Leakage

Airflows

ΣQ

Particle Migration Control (Room Pressure Control)

Scennario 2: Room Non-Prerssurized

SA - (EA+RA) = ΔV = ΣQ = 0

Total Room

Supply Airflow

(SA)

Total Room

Exhaust and/or

Return Airflow

(EA+RA)

Room

Non-Pressurized

To

tal

Ro

om

Su

pp

ly A

irfl

ow

(S

A)

To

tal

Ro

om

Exh

au

st

an

d/o

r

Retu

rn A

irfl

ow

(E

A+

RA

)

Offset

Flow

ΔV = 0

Total Leakage

Airflows

ΣQ = 0


Scennario 3: Room De-prerssurized

SA - (EA+RA) = ΔV = ΣQ < 0

Total Room

Supply Airflow

(SA)

Total Room

Exhaust and/or

Return Airflow

(EA+RA)

Room

Negatively

De-pressurized-

To

tal

Ro

om

Su

pp

ly A

irfl

ow

(S

A)

To

tal

Ro

om

Exh

au

st

an

d/o

r R

etu

rn

Air

flo

w

(E

A+

RA

)

Offset

Flow

ΔV

Total Leakage

Airflows

ΣQ


Pressure differential can force particles to migrate

(in or out) through cracks on cleanroom enclosure.

Particles can migrate through cracks, such as minor leaks on walls,

ceiling, joints, duct/pipe penetrations, etc. and air gap between door

and frame, when a pressure differential exists across the cleanroom

enclosure.

CleanroomCorridor

ΔP=0Neutral

CleanroomCorridor

ΔP>0Pressurized

CleanroomCorridor

ΔP<0De-Pressurized

Why Do Particles Migrate (Exchange) Between

Cleanroom and Adjacent Area(s)? (1)

Particle concentration difference can force particles to

migrate (in or out) through cracks on cleanroom

enclosure.

Particles can also migrate through these cracks when a particle

concentration difference exists across the cleanroom enclosure due

to mass diffusion until an equilibrium is reached.

CleanroomCorridor

ΔP=0Neutral

ΔC= One-Class Difference

CleanroomCorridor

ΔP=0Neutral

ΔC= Two-Class Difference

CleanroomCorridor

ΔP=0Neutral

ΔC= Three-Class Difference

Why Do Particles Migrate (Exchange) Between

Cleanroom and Adjacent Area(s)? (2)

By two forces:

Under pressure difference (air movement by force)

Under particle concentration difference (mass diffusion)

Based on the combination of conditions, these two forces

could work in the same or opposite directions.

What is the combined effect?

The prevailing force determines the particle net gain or

loss through migration into cleanroom.

Particle Net Gain/Loss through Migration

CLEANROOM

AIRLOCK

+CORRIDOR

++

+++

AIRFLOW

CASCADING AIRLOCK

AIRFLOW CLEANROOM

AIRLOCK

+CORRIDOR

++

-

AIRFLOW

BUBBLE AIRLOCK

AIRFLOW

CLEANROOM

AIRLOCK

+CORRIDOR

- -

-

AIRFLOW

SINK AIRLOCK

AIRFLOWCLEANROOM

AIRLOCK

-CORRIDOR

++

-

AIRFLOW

AIRFLOW

- -AIRLOCK

DUAL COMPARTMENT AIRLOCK

Air Lock An intermediate room

between adjacent

areas with different

cleanliness to

minimize particles,

microbial and/or fume

migrations.

Type Cascading

Bubble

Sink

Dual Compartment

Particle Migration Control (Airlock)

Type of Cleanroom Selection of Airlock

Functionality of Airlock Relative Pressure Relationship

Positive pressure

No fume or bio agent

No containment needed

Cascading Prevent cleanroom being contaminated from dirty corridor air

Prevent cleanroom being contaminated from surrounding spaces through cracks

Cleanroom: +++

Airlock: ++

Corridor: +

Negative pressure

Has fume or bio agent contamination

Containment needed

Bubble Prevent cleanroom being contaminated from dirty corridor air

Prevent cleanroom fume or bio agent releasing to corridor

Cleanroom: -

Airlock: ++

Corridor: +

Negative pressure

Has fume or bio agent contamination

Containment needed

Sink Prevent cleanroom being contaminated from dirty corridor air

Allow cleanroom fume or bio agent releasing to airlock. No personal protective equipment is needed

Cleanroom: -

Airlock: - -

Corridor: +

Negative pressure

Has toxic fume or hazardous bio agent contamination, or has potent compound substances

Containment needed

Personal protection needed

Dual Compart-ment

Prevent cleanroom being contaminated from dirty corridor air

Prevent cleanroom fume or bio agent releasing to corridor

Personal protective equipment (such as pressurized suit and respirator) is required

Cleanroom: -

Neg. Airlock: - -

Pos. Airlock: ++

Corridor: -

Notes:

1. EXCESSIVE NEGATIVE PRESSURE IN CLEANROOM IS NOT RECOMMENDED, SINCE IF IT IS NOT SURROUNDED BY OTHER CLEAN SPACESS, UNTREATED DIRTY AIR CAN INFILTRATE THROUGH CRACKS INTO CLEANROOM.

2. COMMONLY A CLEANROOM SERVICE CORRIDOR NEEDS TO BE DESIGNED SLIGHTLY POSITIVE OR NEUTRAL PRESSURE, DO NOT DESIGN IT IN NEGATIVE PRESSURE UNLESS A DUAL-COMPARTMENT LOCK IS UTILIZED.

How To Select

An Airlock?

Answer questions

below:

Is the room in

positive or

negative pressure?

Has fume or bio

contamination?

If containment

is needed?

If personal

protection

is needed?

Particle Migration Control (Airlock Selection)

Pressure Stabilizer

A dynamic control

approach: Use an

pressure-adjustable

automatic relief damper

as a leakage regulator

to maintain a minimum

room pressure when a

door is opened.

Particle Migration Control (Pressure Stabilizer)

Flow Percentage Method (Example: VA Hospital Std.)

• Neutral: SA – (RA+EA) = 0

• Positive (+): SA - (RA+EA) = 15% of SA

• Positive (++): SA - (RA+EA) = 30% of SA

• Negative (-): (RA+EA) – SA = 15% of SA

• Negative (- -): (RA+EA) – SA = 30% of SA

Flow Differential Method (Example: CDC Guideline)

• Neutral: SA – (RA+EA) = 0

• Positive : SA - (RA+EA) = Min. 60 L/s (125 CFM)

• Negative : (RA+EA) – SA = Min. 60 L/s (125 CFM)

Problem with these rule-of-thumb approaches: Each room may

have different air-tightness on enclosure, a fixed offset value ΔV

without field adjustment capability could cause problem in

control.

Traditional Rules-of-Thumb Design Methods

Cleanroom often requires higher airflow rate to dilute room

contaminated air in order to lower particle concentration, so its

“airflow rate over cooling load” ratio is typically higher, or

much higher than a normal ratio range for commercial spaces

(CFM/Ton=300-500, or L/s/Ton=150-250).

Mismatch design (higher airflow rate to a relative smaller cooling

load) could cause a cooling coil to have a sensible cooling only

without latent heat removal which may result poor humidity

control inside cleanrooms.

For ISO Class 6 or cleaner cleanrooms, the flow rate/cooling

ratio may be beyond the reach of a single AHU unit can handle to

avoid mismatch, multiple air-handing systems (loops) are often

utilized to ensure performance and save energy.

Load Characteristic and Air Loop Selections (For Energy Conservation and Performance)

HVAC Schematic and Diagram (Primary Loop Alone Air-Handling System)

For ISO Class 7, 8, 9 (FS-209 Class 10,000, 100,000)

Typical Application:

CFM/Ton ratio: 300-500 (L/s/Ton ratio: 150-250)

RA

EA

SA

Q

OAOA+RASA

Space Impurity

Concentration

Exhaust

AirLeakage

Air

Particle Generation

Deposition

Cs

Space

D

G

Efficiency Ea

Supply

Air

Return

Air

Makeup

Air

Co

CeCs

Cs

H

C

FIL

TE

R

C

C

AHU Unit

HE

PA

Efficiency Eb

HVAC Schematic and Diagram (Primary-Secondary Loops Air-Handling Systems)

For ISO Class 4, 5, 6, 7 (FS-209 Class 10, 100, 1,000, 10,000)


CFM/Ton ratio: 800-5,000 (L/s/Ton ratio: 400-2,500)

Primary flow/Secondary flow ratio: 2-10

RA

EAQ

OAOA+RASA

Space Impurity

Concentration

Exhaust

AirLeakage

Air

Particle Generation

Deposition

Cs

Space

D

G

Efficiency Eb

Return

Air

Treated

Makeup

Air

C1

CeCs

Cs

FIL

TE

R

Primary Fan Unit

H

C

FIL

TE

R

C

C

Secondary Makeup Unit

OA

Makeup

Air

Co

SA

Supply

Air H

EP

A

Efficiency Ea

Efficiency Ec

HVAC Schematic and Diagram (Primary-Secondary-Tertiary Loops Air-Handling Systems)

For ISO Class 1, 2, 3, 4 (FS-209 Class 1, 10)


CFM/Ton ratio: 2,500-25,000 (L/s/Ton ratio: 1,250-12,500)

Primary flow/Secondary flow ratio: 2-10

Secondary flow/Tertiary flow ratio: 2-5

RA

EAQ

OA+RA2OA+RASA

Space Impurity

Concentration

Exhaust

AirLeakage

Air

Particle Generation

Deposition

Cs

Space

D

G

Efficiency Eb

Return

Air

Treated

Makeup

Air

C1

CeCs

Cs

FIL

TE

R

Primary Fan Unit

H

C

C

C

Secondary AHU Unit

OA

SA

Supply

Air

HE

PA

Efficiency Ea

Efficiency EcRA2RA1

H

C

FIL

TE

R

C

C

Tertiary Makeup Unit

OA

Makeup

Air

Co

Efficiency Ea

Treated

Makeup

Air

C1

Configuration-7: Fan-Filter Units For Primary Recirculation


CFM/Ton ratio: 800-25,000

(L/s/Ton ratio: 400-12,500)

FFU flow/AHU flow ratio: 2-50

Room sensible ratio: high to very high

Air Handling Configuration Strategies 8 (ISO Class 1, 2, 3, 4, 5, 6, 7)

(FS-209 Class 1, 10, 100, 1,000, 10,000, 100,000)

Building Systems

City water & gas services

Cold/hot water distributions

Gas distributions

Storm, sanitary & vent

Fire pump & automatic sprinkler systems

Emergency power generator

HVAC & Indoor comfort

Building

management

Cleanroom HVAC&R

Make-up system

Recirculation system

Return air system

Temperature & humidity controls

Room pressure control

Airlock

Noise and vibration control

Hydronic heating

Comfort chilled water

Cooling tower water

Particle counting

Cleanroom Process

Gas detection

Static control

RO and DI waters

Process chilled water

Chemical gases and storages

Solvent drain and collection

Solvent gas exhaust

Process vacuum

Scrubbed exhaust

House vacuum

Acid drain and waste neutralization

Clean dry air

Instrumentation air & control

Process and Building Systems

FS Class 1

FS Class 10

FS Class 100

FS Class 1,000

FS Class 10,000

FS Class 100,000

Classification

ISO Class 1, 2 & 3

ISO Class 4

ISO Class 5

ISO Class 6

ISO Class 7

ISO Class 8 & 9

Wall System Aluminum Component

Aluminum Component or Metal Stud

Wall Panel Honeycomb Aluminum Conductive Finish Aluminum Polystyrene Core or Epoxy Coated Steel Laminated over Drywall

Vinyl or Epoxy Coated Drywall

Paint Epoxy

Epoxy / Latex Latex

Ceiling Grid 2” Aluminum Gel Seal Ceiling System

1½” Steel Gasketed

Grid Support All thread with Strut & Turn buckles

12 ga wire to grid, 10 ga wire to filter @ Corner of Grid Intersection Only

Floor Raised Floor with Perforated / Grated Access

Concrete Covered with Epoxy Solids or Sheet Vinyl

Air Return Floor Low Sidewall Low Sidewall or Ceiling

Typical Cleanroom Construction Materials

Selective Cleanroom Design Ideas (1)

ISO-5 raised-floor large ballroom design to meet processing requirements

Perforated concrete floor allows return air down to sub-floor area below.

Sub-floor area (below cleanroom) houses large process/utility equipment, ducts and piping.

Critical process located in a mini-environment (ISO-5) which is in an ISO-7 large cleanroom


Return air floor panels’ arrangement to accommodate equipment footprints (ISO-7)

Shared return air chase could house some process piping and small equipment.

Small pass-through on door allows small items transport while minimize door operations.

Sliding doors have shorter cycle than swing doors to reduce contamination from corridor.


CFD analysis of “velocity vector” around a moving door (second door of an airlock)

CFD to visualize particle migration from gowning room to airlock and to cleanroom

Roof storm drains collected for irrigation of landscaping

Solar panels on roof to supplement electricity usage

Unidirectional flow inside RAB Mixed flow in Room

Lower concentration inside RAB, higher

concentration near person due to recirculation air

Higher concentration near face

By K. Khankari 2013


Selective Cleanroom Renovation Ideas (1)

Changed from open ballroom to multiple narrower rooms to improve

airstream parallelism.

Used exhaust canopies to remove high-concentration particles generated

from process equipment. Room ACH reduced from 385 to 280.

Before After

Retrofits

Changed from general-purpose chemical lab to ISO Class-3 Nano research

lab in various aspects: Airflow rate, 100% HEPA ceiling with FFUs, tear-

drop lighting, and raised floor, etc.

Before After

Retrofits


ISO-4 cleanroom (358 ACH) converted to ISO-3 cleanroom (400 ACH) with

lighting-integrated ceiling (yellow light area after filtered spectrum).

Replaced “primary-alone” AHU with “primary-secondary” AHU systems,

reduced energy consumption about 65%.

Before After

Retrofits


Retrofitted a 22-ft height shop/storage area into a high-bay ISO-3 cleanroom

for aerodynamic research.

The cleanroom (280 ACH) has 2-ft wide return air chases on both sides, and

3-ft raised floor.

Before After

Retrofits


cleanrooms and hvac systems design...

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