seminar 1 - cleanroom hvac design - karachi

2/20/2011

1

Cleanrooms &

HVAC Systems Design Fundamentals(Karachi, Pakistan, February 22, 2011)

Wei Sun, P.E.

ASHRAE―Clean Spaces‖ Technical Committee (TC9.11) Chairman (07-10)

―Healthcare Facilities‖ Technical Committee (TC9.6) Member

―Laboratory Systems‖ Technical Committee (TC9.10) Member

IESTWorking Group CC012 (Cleanroom Design), Chairman

President

Engsysco, Inc.

Ann Arbor, Michigan, USAwww.engsysco.com

Engsysco

Contents

• Definition and classifications

• Standards

• Nonviable, viable particles (microbiological) and airborne molecular contamination (AMC)

• Particle sources

• Airflow quantity and pattern and floor arrangement

• Airlock and pressurization

• HVAC, plumbing, fire protection, and process systems

• Common devices and equipment

• Architectural construction materials, cleaning procedures, testing standards and construction cost

• CFD application

http://www.engsysco.com/

2/20/2011

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Introduction

Applications

• Semiconductor

• Microelectronic

• Pharmaceutical

• Biotechnology

• University

• Aerospace

• Automotive

• Hospital

• Miscellaneous

Cleanroom Definition

Definition - A specially constructed enclosed area, its environment has following controlled parameters:

• Temperature

• Humidity

• Sound and Vibration

Common Requirements

• Airflow Pattern

• Pressurization

• Particle Count

• Microbial Contamination

• Electrostatic Discharge (ESD)

• Gaseous Contamination

• Process Specific

Special & Unique Requirements

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Standards

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

Classifications

Air Cleanliness Class Definition Comparison Between FS 209 and ISO 14644

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

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ClassificationsOld Air Cleanliness Class Definition - FS 209

Air Cleanliness Class Definition - FS 209

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

FS-1

FS-100,000

FS-10,000

FS-1,000

FS-100

FS-10

ClassificationsCurrent Air Cleanliness Class Definition - ISO 14644

Air Cleanliness Class Definition - 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-3

ISO-6

ISO-9

ISO-8

ISO-7

ISO-5

ISO-4

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ClassificationsClassification Comparison Between FS 209 and ISO 14644

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

Airborne Particles

Airborne particulates can be:

1. Particles larger than 100 microns can be seen with naked eyes.

2. Next step particles ranging from 0.001 to 100 microns are main interest of contamination for years.

3. Atoms and molecules used to be considered too small as industrial contamination, but not any more after introduction of molecular contamination.

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Particle Sources & Control 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

Microbiological Contamination & Control

Control Methods

Physical:

• Heat

• Radiation

• Filtration

Chemical:

• Sterilization

• Disinfection

• Unlike non-viable particles, which can’t

reproduce, microorganisms could reproduce at a

rapid speed if nutrition and environment are

favorable.

• Microorganism can be classified as bacteria,

algae, fungi, protozoa and viruses. Some of

these are essential, useful and harmless, while

others are harmful and dangerous.

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Airborne Particle Physical Controls

Filtration Dilution Isolation

Utilizing HEPA &

ULPA filters to

remove particles

from supply air

• HEPA: 99.97%

([email protected]μm)

• ULPA: 99.9997%

([email protected]μm)

Diluting internally contaminated air with clean, filtered air

• Higher air

change

rate, better

dilution.

Containing or isolating particle generations with barriers

• Process exhaust

• Mini-environment

Typical Ceiling Filter Coverage

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

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Room Airflow Quantity(Traditional Methodology)

Classification

ISO Class FS-209 Class

Air Change Per Hour

Range

8 100,000 5 – 48

7 10,000 60 – 90

6 1,000 150 – 240

5 100 240 – 480

4 10 300 – 540

3 1 360 – 540

2 360 – 600

1

IEST Recommended (RP-12)

Air Change Rate For Cleanrooms

5

150

240

300

360360360

48

90

240

480

540540

600600

600

100

200

300

400

500

600

700

0 1 2 3 4 5 6 7 8 9

ISO Cleanliness Class

Air

Ch

an

ge P

er

Ho

ur

(AC

H)

Airflow Patterns

Non-Unidirectional

(Conventional) Flow

Unidirectional

Flow

Mixed

Flow

Mini-Environment

Flow

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Cleanroom Floor Arrangements

Ballroom Office and

Support

AreasCleanrooms

Service Area

Service Area

Mini-Environment

Service Chase

Office and

Support

AreasCleanrooms

Service Area

Service Area

C C C C

C C C C

Office and

Support

AreasCleanrooms

Service Area

Service Area

R R R R R

R R R R R

Example – Fan Tower Arrangement

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

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Example – Fan Filter Units Arrangement

Stair Case

Scrubbed Exhaust Air

Ret urn Air

SubmainsMake-Up Air Process Supply Submains

Basement

Scrubber

Cleanroom

Process Suppl y Syst emsGas Cabinets

4.8m

0.0m

3.6m

9.6m

4.8m

2.2m

3.5m

Control Airflows Between Rooms

Air Lock

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 LockAn intermediate room

between adjacent

areas with different

cleanliness to prevent

airborne cross

contamination

Type• Cascading

• Bubble

• Sink

• Dual Compartment

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Air LockType 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 releas ing 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 releas ing 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 substan ces

Containment needed

Personal protecti on needed

Dual Compart -ment

Prevent cleanroom being contaminated from dirty corridor air

Prevent cleanroom fume or bio agent releas ing to corridor

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

Cleanroom: -

Neg. Airlock: - -

Pos. Airlock: ++

Corridor: -

Notes:

1. EXCESSIVE NEGATIVE P RESSURE IN CLEANROOM IS NOT RECOMMENDED, SINCE IF IT IS NOT S URROUNDED BY OTHER C LEAN SPACES S, UNTREATED DIRTY AIR CAN INFILT RATE THROUGH CRACKS INTO CLEANROO M.

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

Application

• Positive or

Negative

Pressure?

• Has Fume or Bio

Contamination?

• Containment

Needed?

• Personal

Protection

Needed?


Pressurization

• Air should always flows from high pressure to low pressure

area. Normally the desired flow path should be from the area of

cleanest, to less-clean, to less-contaminated, and then to dirty

areas.

• Pressurization is defined as a technique that air pressure

differences are created mechanically between rooms to

introduce intentional air movement paths through room leakage

openings. These openings could be either designated, such as

doorways, or undesignated, such as air gaps around

doorframes or other cracks.

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Pressurization

• Room pressurization

Entering (SA) airflow rate is

higher than leaving (EA +

RA) airflow rate in the

room, room net (offset)

flow is positive.

• Room depressurization

Entering (SA) airflow rate is

lower than leaving (EA +

RA) airflow rate in the

room, room net (offset)

flow is negative.

Single Room Pressurization

0

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

1,600

1,700

1,800

1,900

2,000

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05 0.055 0.06 0.065 0.07 0.075 0.08

Pressure Differential Between Rooms (in.)

Le

aka

ge

Flo

wra

te (

cfm

)

Leakage Area

(Sq. in.)

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

Room Net Flow Rate vs. Pressure Differential


Pressurization

Single Room Pressurization Room Pressure Control Strategies

Room Airtightness is the key element in the

relationship between the room’s flow offset

value and the resulting pressure

differential, and each room airtightness is

unique and unknown unless tested.

The treatment of the room net flow ―offset‖

value defines a pressurization control

strategy. Typical pressurization control

techniques:

• Direct Pressure-Differential Control

• Differential Flow Tracking Control

• Hybrid Control

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Pressurization

Multiple Room (Suite) Pressurization

Room Pressure & Flow (P&F) diagram

(suite, zone or floor) – The basis of

continuous validation and qualification

of room pressure control:

• Indicate airflow design settings

(values) of all supply, return and

exhaust registers.

• Indicate the desired room

pressure value with an acceptable

tolerance.

• Indicate the resulting leakage flow

directions (due to room pressure

differentials) and their estimated

leakage values through doors at

closed-door condition.

Typical HVAC Systems

FS209 Class

10,000, 100,000

ISO Class

7, 8

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FS209 Class

100, 1,000

ISO Class

5, 6


FS209 Class

1, 10

ISO Class

3, 4

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Basic HVAC Flow Diagrams

Configuration-1: Conventional Primary loop

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


Configuration-2: Primary loop with supply bypass

RA

EA

SA1

Q

OAOA+RASA

Space Impurity

Concentration

Exhaust

AirLeakage

Air

Particle Generation

Deposition

Cs

Space

D

G

Efficiency Ea

Return

Air

Makeup

Air

Co

CeCs

Cs

H

C

FIL

TE

R

C

C

AHU Unit

SA1

SA2 SA2+RA

Supply

Air

HE

PA

Efficiency Eb

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Configuration-3: Primary loop with dual returns

RA

EA

SA

Q

OAOA+RA1

Space Impurity

Concentration

Exhaust

AirLeakage

Air

Particle Generation

Deposition

Cs

Space

D

G

Efficiency Ea

Return

Air

Makeup

Air

Co

CeCs

Cs

H

C

FIL

TE

R

C

C

AHU Unit

SA=OA+RA

RA2

FIL

TE

R

Efficiency EbRA1

Supply

Air

HE

PA

Efficiency Ec


Configuration-4: Primary loop plus secondary makeup unit

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

HE

PA

Efficiency Ea

Efficiency Ec

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Configuration-5: Primary loop plus secondary AHU unit with dual returns

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

FIL

TE

R

C

C

Secondary AHU Unit

OA

Makeup

Air

Co

SA

Supply

Air

HE

PA

Efficiency Ea

Efficiency EcRA2RA1


Configuration-6: Primary loop plus secondary AHU unit and tertiary

makeup unit with dual returns

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

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Building Section Schematic

Semiconductor Fabrication Facility

Process and Building Systems

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

• 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

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Typical Specified Cleanroom

Components, Devices & Equipment

Fan-Filter Ceiling Module

HEPA / ULPA Filter

Bag-in/Bag-out multiple filters

- Against biological, chemical

& radiological materials

Air

FiltrationHandhold

Particle

Counter

Pharmaceutical cGMP

Particle Monitoring & Validation

Microbial Air Sampler &

Agar Media

Portable Particle CounterAir Particle

Sensor

Air

Sampling

Typical Specified Cleanroom

Components, Devices & Equipment

Air Valve

Precision

Room

Pressure

Transducer

Floor Grate

& Perforated

Panel

Isolator (Glove Box) Small Mini-Environment

Product

Pass-

through

Soft

Wall

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Cleanroom Building Exterior and Interior

Building Finished

Exterior

Cleanrooms in Construction

Finished Cleanrooms

Window on

Exterior Wall

Window on

Interior Wall

Service Hallway

Enclosing Cleanrooms

Class 10,

Raised Floor

Gowning Area,

Raised Floor

Interior HallwaySmall Class 100,000

Cleanroom

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Cleanroom Utility and Support

Large DI Water

System

Steam-Hot Water

Exchange Unit

(Packaged)

AHU Unit for Office/

Administration Areas

Cleanrooms In Operation

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Cleanroom Construction Materials

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

ISO Construction Cleaning Procedures

Stage Purpose Responsible party Method Standard

Stage 1 — Clean during demolition or preliminary construction such as framing for wall installation.

Preventing unnecessary dust concentration in places that will be difficult to reach during later construction.

Contractor. If the construction contractor has no relevant experience in cleanroom cleaning, it is advisable to hire a professional cleaning contractor specializing in cleanroom cleaning.

Vacuum clean upon completion. Visual-clean.

Stage 2 — Clean during utility installation.

Removing local contaminants caused by installing electricity, gas, water, etc.

Installation engineer. Vacuum clean; wipe-down piping and fixtures with moistened wipers upon completion. The use of vacuum cleaning and/or other cleaning materials is necessary.

Visual-clean.

Stage 3 — Clean during early construction.

Cleaning all visible contamination from ceilings, walls, floors, (filter mountings), etc. after completion of construction and installation activities.

Cleaning contractor. Vacuum clean; wipe-down piping and fixtures with moistened wipers. Application of protective floor sealants is generally a particle generating activity. If this is necessary, it should be applied at this time.

Visual-clean.

Stage 4 — Prepare for air conditioning ductwork installation.

Cleaning any dust from ductwork sections before installing using a vacuum cleaner and wipers. Meanwhile, a positive pressure should be introduced to the cleanroom.

Installation engineer and cleaning contractor.

Vacuum clean; wipe down with moistened wipers.

Wiper-clean.

Stage 5 — Clean before mounting all air filters into the system.

Removing deposited or settled dust, or both, from ceilings, walls, and floors.

Cleaning contractor. Wipe down with moistened wipers. Wiper-clean.

Stage 6 — Mount the (HEPA/ULPA) filters into the air systems

Removing possible contamination caused by the mounting operation.

Cleanroom HVAC filter engineer/ technician.

Clean all surface edges on all sides.

Wiper-clean.

Stage 7 — Adjust the air conditioning equipment.

Removing suspended dust from the airflow and creating overpressure installation, including the filters.


Air conditioning air flushing operation.

Wiper-clean.

Stage 8 — Upgrade the room into prescribed classification.

Removing all deposited and clinging dust from every surface (in order: ceilings, walls, equipment, floors).

A professional cleanroom cleaning by personnel specially instructed on regulations, routing and behaviour.

Wipe down with moistened wipers. Wiper-clean.

Stage 9 — Approve installation.

Verifying the cleanroom to the prescribed design specifications. Customer acceptance.

Installation engineer and certification engineer.

Monitor airborne and surface particles, air velocities, temperature and humidity.

Wiper-clean. Results should conform to agreed design criteria.

Stage 10 — Clean daily and periodically

Maintaining the cleanroom in long-term compliance with designed classification. Microbiological cleaning and testing begins in biocleanrooms.

Cleanroom manager/cleaning contractor.

Listed in F.1 to F.8. A tailor-made cleaning programme for the cleanroom, accounting for the specific demands of the production process and the customer. Routine testing of critical operation parameters.

NOTE 1 During Stages 4 to 10, all high-efficiency and ultra-high-purity components, such as filters, ducts, etc., should arrive on site protected by plastic or foil covers on both ends. Covers should only be removed when ready for use. NOTE 2 During Stages 6 to 10, all activities should be done wearing prescribed cleanroom clothing.

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ISO Construction Cleaning Procedures









Visual-clean.




Visual-clean.





Wiper-clean.








Wiper-clean.





Wiper-clean.























Visual-clean.




Visual-clean.





Wiper-clean.








Wiper-clean.





Wiper-clean.























Visual-clean.




Visual-clean.





Wiper-clean.








Wiper-clean.





Wiper-clean.























Visual-clean.




Visual-clean.





Wiper-clean.








Wiper-clean.





Wiper-clean.















Cleanroom Testing

Required Testing (ISO 14644-2)

ISO 14644-1 Annex B412 MonthsAll ClassesAirflow

ISO 14644-1 Annex B512 MonthsAll ClassesAir Pressure Difference

12 Months> ISO 5ISO 14644-1 Annex A

6 Months<= ISO 5Particle Count Test

Test ProcedureMaximum Time

IntervalClassTest Parameter

Schedule of Tests to Demonstrate Continuing Compliance

Optional Testing (ISO 14644-2)

ISO 14644-3 Annex B724 MonthsAll ClassesAirflow Visualization

ISO 14644-3 Annex B1324 MonthsAll ClassesRecovery

ISO 14644-3 Annex B424 MonthsAll ClassesContainment Leakage

ISO 14644-3 Annex B624 MonthsAll ClassesInstalled Filter Leakage

Test ProcedureMaximum Time

IntervalClassTest Parameter

Schedule of Additional Optional Tests

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Cleanroom Design Problems & Validation

Common Design Problems

• Poor laminarity

• Fail to pressurize to specified pressure levels

• Local stagnation near point of service

• Ineffective chemical vapor exhaust

• Too high noise

• Temperature & humidity variations above specifications

How to Ensure Quality During Design Phase?

• Engineer’s design knowledge & experience

• Mock-up or scale-down model

• CFD validation

CFD Applications

A case study: Examination of flow laminarity of a cleanroom with a

subfab underneath

CFD model geometry

Floor

Ceiling

Slab

FAB

SUBFAB CHASE

Cleanroom

with 35% FA

Floor Panels

Narrower

Cleanroom with

35% FA Floor

Panels

Cleanroom

with 20% FA

Floor Panels

Cleanroom

with 10% FA

Floor Panels

2/20/2011

25

Technology Trend – Determination of Airflow

Rate Based on Particle Generation Rate

During Design Phase

Room Particle Concentration versus Air Change Rate

(Steady State)

- Effect of Internal Particle Generation Rate

0.1

1.0

10.0

100.0

1,000.0

10,000.0

100,000.0

1,000,000.0

0 100 200 300 400 500 600

Supply Air ACH (Air Change Per Hour)

Co

nc

en

tra

tio

n (

Nu

mb

er

of

Pa

rtic

les

Pe

r F

T3)

G=1

G=10

G=100

G=1000

G=10000

Condition:

OA/SA=5%

CO=1x106

EU=95%

EH=99.97%

η =1.0

Internal Particle

Generation Rate:

G = Rate of

impurity

generation unit

floor area,

averaged

throughout the

space

Unit:

Particals/FT3/Min.

Technology Trend – Provide Airflow Rate

Based on Particle Generation Rate

During Operating Phase

AC

H R

ate

Room Particle Generation Rate G

VFD Ventilation

Staged Ventilation

The goal is to stage the ventilation rate to maintain the same room cleanliness

level through particle sensing during all modes (occupied and unoccupied)

seminar 1 - cleanroom hvac design - karachi

Documents

iso document iso

compliance iso

molecular contamination

cleanroom operations

controlled environments

definitions units iso

enhanced clean devices

control general principles