postfile_23270 GH

7/21/2019 postfile_23270 GH

http://slidepdf.com/reader/full/postfile23270-gh 1/214

9. Cleanroom Testing9. Cleanroom Testing

and Monitoringand Monitoring

7/21/2019 postfile_23270 GH


Purposes for initial test:Purposes for initial test:

• Fulfill the design – working correctly and achieving the contamination

standards

• Bench-mark: – establish the initial performance of the room tocompare the results of routine check or contaminationproblem in the future.

•raining the staff: !most important" – initial testing is to familiari#e and train the staff. – $nly opportunity to understand how their cleanroom

works and learn the methods used to test.

7/21/2019 postfile_23270 GH


initial testinitial test

• ime – been built% going to hand over% reopen

• ested standards – &'$ ()*))-(.

• +onitoring

– to regularly check the room at the timeintervals set by &'$ ()*))-,

7/21/2019 postfile_23270 GH


Principles of leanroom estingPrinciples of leanroom esting

• uantity: – urbulently: dilute--air volume !supply and e/tract" – 0nidirectional: remove –air velocity

•1irection !flow direction": – from clean area less-clean areas to minimise the

movement of contaminated air.• uality:

– the air will not add significantly to the contamination

within the room• 1istribution inside cleanroom – the air movement has no areas with high

concentrations of contamination.

7/21/2019 postfile_23270 GH


leanroom estsleanroom ests

7/21/2019 postfile_23270 GH


• Air supply and extract quantities

– turbulently ventilated cleanrooms

the airsupply and e/tract volumes

– unidirectional airflow air velocity.

• Air movement control between areas: direction – he pressure differences between areas are

correct.

– he air direction through doorways2 hatches2etc. is from clean to less-clean.

7/21/2019 postfile_23270 GH


• Filter installation leak test

– a damaged filter – between the filter and its housing or – any other part of the filter installation.

• Containment leak testing

– ontamination is not entering the cleanroomthrough its construction materials.

7/21/2019 postfile_23270 GH


• Air movement control witin te room

– turbulently ventilated : check that there are no

areas within the room with insufficient airmovement.

– unidirectional airflow : check that the airvelocity and direction throughout the room isthat specified in the design.

• Airborne particles and microbialconcentrations

– final measurements of the concentration ofparticles and micro-organisms

7/21/2019 postfile_23270 GH


• Additional tests

– temperature

– relative humidity – heating and cooling capabilities of the room – sound levels

– lighting levels – vibration levels.

7/21/2019 postfile_23270 GH


re3uirementsre3uirements

• 4uides provided by – the 5merican 'ociety 6eating 7efrigeration

and 5irconditioning 8ngineers !5'6758" in

the 0'52 and – the hartered &nstitute of Building 'ervices

8ngineers !&B'8" in the 09.

7/21/2019 postfile_23270 GH


esting in 7elation to 7oom ypeesting in 7elation to 7oom ypeand $ccupation 'tateand $ccupation 'tate

• he type of tests to be carried out in acleanroom depends on whether the roomis unidirectional2 turbulent or mi/ed airflow: – as-built; ---in the empty room2 – at rest; --- the room fitted with machinery but

no personnel present or

– fully operational;---these occupancy statesare discussed more fully in 'ection <.) of thisbook.

7/21/2019 postfile_23270 GH


7e-testing to 1emonstrate7e-testing to 1emonstrateomplianceompliance

• he cleanroomcheckedintervals2 theseintervals being

more fre3uentin higherspecifiedrooms: &'$

()*))-,

7/21/2019 postfile_23270 GH


+onitoring of leanrooms+onitoring of leanrooms

• 0se risk assessment to decide what monitoringtests should be done and how often. hevariables that are most likely to be monitored

are: – air pressure difference• his might be necessary in high 3uality cleanrooms such as

&'$ lass )2 and better.

– airborne particle count• his might be necessary in high 3uality cleanrooms such as&'$ lass )2 and better.

– where appropriate2 microbiological counts.

7/21/2019 postfile_23270 GH


(=. +easurement of 5ir(=. +easurement of 5iruantities and Pressureuantities and Pressure

1ifferences1ifferences

7/21/2019 postfile_23270 GH


PurposePurpose

• 5 cleanroom must have sufficient clean airsupplied to dilute and remove the airbornecontamination generated within the room.

• 5ir leanliness: – urbulently ventilated cleanroom

• air supply> the more air supplied in a given time2 the cleanerthe room.

– unidirectional cleanroom• air supply velocity

• est: – &nitial testing of the design – 7egular intervals check

7/21/2019 postfile_23270 GH


5ir uantities 5ir uantities

• &nstruments: – 6oods: air supply

volumes – 5nemometers: air

velocities• urbulently ventilated

rooms – measured within the

air conditioningducts Pitot-statictube

7/21/2019 postfile_23270 GH


Measuring air quantities !romMeasuring air quantities !rom

witin a cleanroomwitin a cleanroom

• 5irair filter !no diffuser"anemometer at thefilter face average velocity air volume – 1ifficulty: the non-uniformity of the air velocity

inaccurate measurement• 5irair diffusers unevenness of air

velocities incorrect air volume• 6ood: air supply volume average velocity

measured at the e/it of the hood air volume

7/21/2019 postfile_23270 GH


AnemometersAnemometers

• 5nemometers: away from the filter ofabout <=cm !(, inches"

• "ane Anemometer

– Principle: 5ir supply turning a vane fre3uency velocity

– 5ccuracy: velocity is less than about =., m%s

!)= ft%min"2 the mechanical friction affects theturning of the vane

7/21/2019 postfile_23270 GH


"ane Anemometer

7/21/2019 postfile_23270 GH


Termal AnemometersTermal Anemometers

• Principle: 5ir passingthrough the head ofthe instrument

cooling effect theair velocity: Fig.(=.< :a bead thermistor ! 有

孔的電熱調節器 "

• ?ow velocities can bemeasured with thistype of apparatus

7/21/2019 postfile_23270 GH


1ifferential Pressure ests1ifferential Pressure ests

• he units: – Pascals2 inch water gauge are used !(,Pa @

=.=A inch water gauge".

• Pressure difference: (= or (A Pa betweenclean areas – (A Pa is commonly used between a

cleanroom and an unclassified room2 – (= Pa between two cleanrooms.

7/21/2019 postfile_23270 GH


• ?arge openings: – problems can occur when trying to achieve a

pressure difference between areas connectedby large openings2 such as a supply tunnel. oachieve the suggested pressure drop :

•ery large air 3uantities through the tunnel• o accept a lower pressure difference

7/21/2019 postfile_23270 GH


Apparatus !or measuringApparatus !or measuring

pressure di!!erencespressure di!!erences

• +anometer: – range of pressure

difference of =-*= Pa

!=-=.,A inch water" – inclined manometer>magnehelic gauge>electronic manometer

7/21/2019 postfile_23270 GH


&nclined manometer &nclined manometer

• works by pressurepushing a li3uid up aninclined tube. – small pressure

changes in the inclinedtube up to a pressureof about *= Pa.

– 5fter that pressure2 thetube moves round to

the vertical measuringpressure differencescan be in the (== toA== Pa range.

7/21/2019 postfile_23270 GH


Metods o! cecking pressureMetods o! cecking pressure

di!!erencesdi!!erences

• pressure differences between areas – adCusting the pressure differences :

• e/tract be reduced to increase the pressure2 and increased todecrease it.

• &f manometers are not permanently installed2 a tube froma pressure gauge is passed under the door2 or throughan open by-pass grille or damper into the adCacent area.

• &n some ventilation systems2 the pressures within roomsare measured with respect to one reference point. Dhen

this type of system is being checked2 the pressuredifference across a doorway can be calculated bysubtracting the two readings of the adCoining spaces.

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


((. 5ir +ovement ontrol((. 5ir +ovement ontrolBetween and DithinBetween and Dithin

leanroomsleanrooms

7/21/2019 postfile_23270 GH


PurposesPurposes

• o show that a cleanroom is workingcorrectly2 it is necessary to demonstratethat no contamination infiltrates into the

cleanroom from dirtier adCacent areas.• leanroom ontainment ?eak esting

– 5irborne contamination: doors and hatches2

holes and cracks in the walls2 ceilings andother parts of the cleanroom fabric

7/21/2019 postfile_23270 GH


ontamination can be pushed intoontamination can be pushed intothe cleanroom atthe cleanroom at

• ceiling-to-wall interface• filter and lighting housings-to-ceiling interfaces• ceiling-to-column interface

• the cladding of the ceiling support pillars• 'ervice plenums and the entry of services into

the cleanroom: electrical sockets and switches2

and other types of services providers.Particularly difficult to foresee and control in anegatively pressuri#ed containment room.

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


Metods o! cecking in!iltrationMetods o! cecking in!iltration

• 'moke test !dust test" – flow direction: open door2 or through the

cracks around a closed door2 cracks at the

walls2 ceiling2 floor and filter housings2 serviceducts or conduits.

• 1ifficulty

– where the containment originates from maybe unknown2 and it is often difficult to find theplaces to release test smoke.

7/21/2019 postfile_23270 GH


ontainment leak testingontainment leak testing

• iming – handing it over to the user – maCor reconstruction work has been carried

out – &'$ ()*))-, lists the containment leak; test

as an optional; test and suggest a re-testing

interval of two years

7/21/2019 postfile_23270 GH


5ir +ovement ontrol within a 5ir +ovement ontrol within aleanroomleanroom

• sufficient air movement – dilute2 or remove airborne contaminationprevent a build-up of

contamination• turbulently ventilated cleanroom:

– good mi/ing2 critical areas: where the product is e/posed to therisk of contamination

• unidirectional flow cleanroom – critical areas should be supplied with air coming directly from

the high efficiency filters. 6owever2 problems may beencountered because of:

• heat rising from the machinery and disrupting the airflow• obstructions preventing the supply air getting to the critical area• obstructions2 or the machinery shape2 turning the unidirectional flow

into turbulent flow• contamination being entrained into the clean air.

7/21/2019 postfile_23270 GH


Air movement visuali#ationAir movement visuali#ation

• $bCective: sufficient clean air gets to the criticalareas 3ualitative methods

• isuali#ation:

– 'treamers – smoke or particle streams

• 'treamers !threads or tapes": – high surface-area-to-weight ratio2 e/. recording tapes

– 5 hori#ontal flow: =.A m%s !(== ft%min" streamer )AEto the hori#ontal

• about (m%s !,== ft%min" almost hori#ontal.

7/21/2019 postfile_23270 GH


'treamers

7/21/2019 postfile_23270 GH


smoke or particle streamssmoke or particle streams

–oil smoke contamination

–Dater vapour :from solid =,!dry ice" or by

nebuli#ingwater

7/21/2019 postfile_23270 GH


putter and smoke tube:putter and smoke tube:

• itanium tetrachloride!il)"producesacid corrodes some

surfacesharmful tosensitive machinery orharm the operatorslungs.

7/21/2019 postfile_23270 GH


5ir +ovement in turbulently 5ir +ovement in turbulentlyventilated roomsventilated rooms

• working well: 3uickly dispersed• not working well 5reas: not disperse

3uickly contamination build up improved by adCusting the air supplydiffuser blades2 removing an obstruction2moving a machine.

7/21/2019 postfile_23270 GH


5ir +ovement in unidirectional flow 5ir +ovement in unidirectional flow

• air moves in lines – isualisation

techni3ues: smokestream

– 'till picture

7/21/2019 postfile_23270 GH


5ir velocity and 1irection 5ir velocity and 1irectionmeasurementmeasurement

• 5 permanent record: velocity and direction

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


7ecovery est +ethod7ecovery est +ethod

• 5 3uantitative approach• 5 burst of test particlesintroduced into

the area to be tested mi/ed with their

surroundingsthe airborne particle countshould be measured2

• 5 useful endpoint is one-hundredth of the

original concentration2 and the time takento reach there can be used as an inde/ ofefficiency.

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


h. (,h. (,Filter &nstallation ?eak estingFilter &nstallation ?eak esting

7/21/2019 postfile_23270 GH


68P5 test68P5 test

• +anufacturers factory and packed $9• 0npacked and fitted into the filter housings

maybe damage

• ?eakage problems – casing – housing

• esting : artificial test aerosol

7/21/2019 postfile_23270 GH


?eakage areas in a 68P5 filter

5 - filter paper-to-case cement area - gasket

1 - frame Coints. B - filter paper !often at the paper fold"

7/21/2019 postfile_23270 GH


4asket leaks from filters

inserted down from ceiling

4asket and casing leaks from

filter inserted up from cleanroom

7/21/2019 postfile_23270 GH


Figure $%.& Filter-housing gel seal method

7/21/2019 postfile_23270 GH


5rtificial 'moke and Particle est 5rtificial 'moke and Particle est

• Cold'generated oils

– 1i-octyl phthalate !1$P" 鄰苯二甲酸二辛酯

• oily li3uid2 potentially to/ic effects2 no longer used

– 1i-octylsebacate !1$'" 葵二酸二辛酯• 常用

– poly alpha olefin !P5$" 聚烯茎油

• 常用

7/21/2019 postfile_23270 GH


Cold'generated oil TestCold'generated oil Test

?askin no##leair!high pressure"

oil

5irGoil particle

=.A m

5ir pump

7/21/2019 postfile_23270 GH


(ot generated smokes(ot generated smokes

8vaporation chamber

inert gas: $,

oil

oil smoke

aerosol

condense

vaporize

=.< m

7/21/2019 postfile_23270 GH


6ot oil smoke generator

7/21/2019 postfile_23270 GH


'emiconductor manufacturing'emiconductor manufacturing

• outgassing• chemical products harmful to filter• 使用

Polystyrene ?ate/ 'pheres !P?'s"聚苯乙烯乳膠球 !=.( H (µm"

5 t f + i ' k5pparatus for +easuring 'moke

7/21/2019 postfile_23270 GH


5pparatus for +easuring 'moke 5pparatus for +easuring 'mokePenetrationPenetration

• )otometer 光度計 – ,I (%min !( ft<%min" of

airborne particles

– particles refract the light – electrical signal – concentration: between

=.===( Jg%( and (== Jg%(.

*ingle particle

7/21/2019 postfile_23270 GH


• *ingle particlecounters

– sample a volume o!

air and tis iscollected in a set time

+ethods of esting Filters and Filter+ethods of esting Filters and Filter

7/21/2019 postfile_23270 GH


+ethods of esting Filters and Filter+ethods of esting Filters and Filter6ousings6ousings

• *canning metods – a probe with a photometer2 or single particle

counter2

– 'can speed : not more than Acm%s – leaks : media2 filter case2 its housing – he most common leaks:

• around the periphery of the filter

• the casing-to-housing seal2• the casing Coints

7/21/2019 postfile_23270 GH


+epair o! leaks+epair o! leaks

• Filter media leak – at the fold of the paper – repaired on site with

silicon• replaced

7/21/2019 postfile_23270 GH


h. (<h. (< 5irborne Particle ounts 5irborne Particle ounts

7/21/2019 postfile_23270 GH


leanroom testleanroom test

• air supply volume2• pressure differences2• air movement within and between

cleanrooms2• filter integrity

• airborne particle concentration

7/21/2019 postfile_23270 GH


Particle counterParticle counter

• Particle counter : both counts and si#es

• Photometer : mass of particles

http://www.breathepureair.com/climet_ci-200.html

7/21/2019 postfile_23270 GH


principle of Particle ounter

7/21/2019 postfile_23270 GH


Particle ounter

5irborne particle counter:

7/21/2019 postfile_23270 GH


heck:

p-counter.pdf

$pc-I,)=.pdf

flow rate: ,I (%min !( ft<%min" of airsi#e range: regular =.< Jm or =.A Jm

high-sensitivity: =.( Jm but with a smaller airvolume.

7/21/2019 postfile_23270 GH


ontinuous +onitoring 5pparatusontinuous +onitoring 5pparatus

for 5irborne Particlesfor 5irborne Particles

• se3uential

• simultaneous

7/21/2019 postfile_23270 GH


'e3uential monitoring system'e3uential monitoring system

7/21/2019 postfile_23270 GH


'imultaneous monitoring system'imultaneous monitoring system

best but most e/pensive

Particle ounting in 1ifferentParticle ounting in 1ifferent

7/21/2019 postfile_23270 GH


Particle ounting in 1ifferentParticle ounting in 1ifferent$ccupancy 'tates$ccupancy 'tates

• $ccupancy state: as built2 at rest2operational.

• cleanroom contractor: as built• rule of thumb: as built; room will beabout one class of cleanliness cleaner

than when operational;.

+easurement of Particle+easurement of Particle

7/21/2019 postfile_23270 GH


+easurement of Particle+easurement of Particleoncentrations !&'$ ()*))-("oncentrations !&'$ ()*))-("

• Principles: he number of samplinglocations must reflect the si#e of the roomand its cleanliness.

• he methods: !a" number of samplinglocations and !b" the minimum air volume

*ample locations and number*ample locations and number

7/21/2019 postfile_23270 GH


*ample locations and number*ample locations and number

,,&'$ standard ()*))-(&'$ standard ()*))-(--

• +inimum number of locations: – Dhere N L rounded up to a whole

number

– A is the area of the cleanroom2or clean air controlled space2 inm,.

• evenly distributed and height

A N L =

7/21/2019 postfile_23270 GH


Airborne sampling volumeAirborne sampling volume

• +inimum volume at each location: the airvolume should be large enough to count,= particles of the largest particle si#e

specified• @ ,=% / (===

– where is the minimum single sample

volume per location2 e/pressed in litres. – is the class limit !number of particles%m<"

7/21/2019 postfile_23270 GH


• $ne or more samples : at each location

• he volume sampled at each location: atleast two liters

• he minimum sample time : at least one

minute

7/21/2019 postfile_23270 GH


Acceptance criteria, */ $&0&&'$-Acceptance criteria, */ $&0&&'$-

• the average particle concentration at each ofthe particle measuring locations falls belowthe class limit

• when the total number of locations sampled isless than (=2 the calculated KAL 0pperonfidence ?imit !0?" of the particleconcentrations is below the class limit.

7/21/2019 postfile_23270 GH


8/ample8/ample

• 4m x 5m size. ISO Class 3 in the 'as built'condition at a particle size o !" #.$ %m.

• 1umber o! locations

– 5@ )m / Am. M @ N)/A @ ).)OA – he minimum number of locations is A

• Minimum air sampling volume

– @ ,=% / (=== – : &'$ lass < room is (===%m<. – ∴+inimum volume @ ,=%(=== / (===@ ,= litres

7/21/2019 postfile_23270 GH


• particle counter flow rate of ,I.< liter%min2

i.e. ,=liter2 time @ ), s

• &'$ ()*))-( re3uires a minimum sample timeof ( minute ( minute

7/21/2019 postfile_23270 GH


• first part of the &'$ re3uirement istherefore satisfied!(===".$9

• 5s less than nine samples were taken

KAL 0? does not e/ceeded the classlimit. QQQ

l l ti f KAL0?

7/21/2019 postfile_23270 GH


alculation of KAL0?alculation of KAL0?

• the means of averages: ++ @ !AI=G*(,GO=*GA<=GAA<"%A @ AK*

• 'tandard deviation !s.d".

• 'tandard deviation s.d.@*K

• KAR0? @ +GS0? factor / !s.d%Nn"T

• 5s number of locations is A2 the t-factor is ,.(.• ∴ KAR 0? for particles U =.( Jm @ AK* G S ,.( /

*K%NA T@ **((===

1

)(

.1

2

−

−

=

∑ =

N

M X

d s

N

i i

7/21/2019 postfile_23270 GH


• he cleanroom is therefore within there3uired class limit.

• he way to avoid any KAL 0? problemsis to always test more than nine points inthe room

7/21/2019 postfile_23270 GH


h.() +icrobial ountsh.() +icrobial ounts

7/21/2019 postfile_23270 GH


• People are normally the only source ofmicro-organisms in a cleanroom

• as built% at rest little value

• $perational: micro-organisms arecontinually dispersed from people in theroom.

+i bi l ' li f th 5i+i bi l ' li f th 5i

7/21/2019 postfile_23270 GH


+icrobial 'ampling of the 5ir +icrobial 'ampling of the 5ir

• olumetric air sampler• 'ettle plate sampling

l t i i l l t i i l

7/21/2019 postfile_23270 GH


olumetric air samplersolumetric air samplers

• a given volume of air is sampled> alsoknown as active sampling.

• impact micro-organisms onto agarmedia>• remove micro-organisms by membrane

filtration.

7/21/2019 postfile_23270 GH


• 5gar: Celly-type material with nutrientsadded to support microbial growth.

• +icro-organisms landing

temperature2 time colony !millimetresdiameter"

' ttl l t li' ttl l t li

7/21/2019 postfile_23270 GH


'ettle plate sampling'ettle plate sampling

• where micro-organisms are deposited2mainly by gravity2 onto an agar plate.

• &mpaction onto agar:

– inertial impaction – centrifugal forces.

7/21/2019 postfile_23270 GH


• ime and emperature to grow• Bacteria : )I hours at <=E to <AE >• Fungi: O, hours at ,=E to ,AE

ti l i ti l ti l i ti l

7/21/2019 postfile_23270 GH


nertial impaction samplersnertial impaction samplers

• Flow rate: <= to (I= litres%min !( ft<%min to *ft<%min" of air

• 5ir&nertial impactors slit or hole accelerate !,=H<=m%s"

C t i! l i lC t i! l i l

7/21/2019 postfile_23270 GH


Centri!ugal air samplersCentri!ugal air samplers

• 5ir rotating vane centrifugal force agarsurface

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


• he impaction surface is in the form of aplastic strip with rectangular recesses intowhich agar is dispensed

M b !ilt tiMembrane !iltration

7/21/2019 postfile_23270 GH


Membrane !iltrationMembrane !iltration

• 5 membrane filter is mounted in aholder vacuum draw air microbe-carrying will be filtered out by membrane

he membrane placed an agar plate• 5 membrane filter with a grid printed on

the surface will assist in counting the

micro-organisms.

7/21/2019 postfile_23270 GH


Membrane holder with filter

+icrobial 1eposition onto 'urfaces+icrobial 1e

position onto 'urfaces

7/21/2019 postfile_23270 GH


+icrobial 1eposition onto 'urfaces+icrobial 1eposition onto 'urfaces

• &ndirect measurementvolumetricsampling

• direct method settle plate sampling

*ettle plate sampling*ettle plate sampling

7/21/2019 postfile_23270 GH


*ettle plate sampling*ettle plate sampling

• micro-organisms skin particles (= to<=Jm by gravity onto surfaces at anaverage rate of about ( cm%s

• 'ettle plate sampling: Petri dishes!diameter:K=mm" containing agar medium opened and e/posed time !)HAhours"particles to deposit Petri dishes

Calculation o! te likely airborneCalculation o! te likely airborne

7/21/2019 postfile_23270 GH


yy

contaminationcontamination

exposed platessettletime

exposed producttime x

dish petriof area

productof area x

count plateSettle

rateionContaminat

=

+icrobial 'urface 'ampling+icrobial 'urface '

ampling

7/21/2019 postfile_23270 GH


+icrobial 'urface 'ampling+icrobial 'urface 'ampling

• contact sampling• swabbing

Contact sur!ace samplingContact sur!ace sampling

7/21/2019 postfile_23270 GH


Contact sur!ace samplingContact sur!ace sampling

• surface !flat" 7$15!7eplicate $rganisms1etection and ounting"dishes Fig ().A areusedhe agar is rolledover the cleanroomsurface+icro-organisms stick to theagarincubated timeand temperature micro-organisms grow Vcounted.

7/21/2019 postfile_23270 GH


Contact SlidesContact Slides

*wabbing*wabbing

7/21/2019 postfile_23270 GH


*wabbing*wabbing

• uneven surfaces: budswab rubbed surfaceand then rubbed overan agar plate.

Copan *wab +inse 2itsCopan *wab +inse 2its

7/21/2019 postfile_23270 GH


Copan *wab +inse 2itsCopan *wab +inse 2its

Personnel samplingPersonnel s

ampling

7/21/2019 postfile_23270 GH


Personnel samplingPersonnel sampling

• Personnel are the primary source of micro-organisms in a cleanroom.

• he methods commonly used are: – Finger dabs.

– he persons fingers tips2 or their gloved hand2 is pressed or wipedon an agar plate and the number of micro-organisms ascertained.

– ontact plates or strips. – he persons garments are sampled by pressing the plate or strip

onto their clothing. his is best done as they come out of the

cleanroom. – Body bo/.

– &f a person wearing normal indoor clothing e/ercises within a bodybo/ their dispersion rate of airborne micro-organisms can beascertained.

7/21/2019 postfile_23270 GH


Dip SlideDip Slide

7/21/2019 postfile_23270 GH


(A.(A.$perating a leanroom:$perating a leanroom:

ontamination ontrolontamination ontrol

PurposePurpose

7/21/2019 postfile_23270 GH


PurposePurpose

• considering the sources and routes ofcontamination within a cleanroom and howto control these.

ontrol contaminationontrol contamination

7/21/2019 postfile_23270 GH


ontrol contaminationontrol contamination

• assessing risk during manufacturing: suchas Fault ree 5nalysis !F5" and Failure+ode and 8ffect 5nalysis !F+85".

!8lectrical and mechanical systems"

6a#ard 5nalysis and ritical6a#ard 5nalysis and ritical

7/21/2019 postfile_23270 GH


ontrol Point !65P" system.ontrol Point !65P" system.

• 65P has a seven-step approach: – &dentify the sources of contamination in the

cleanroom.

– 5ssess the importance of these sources – &dentify methods that can be used to control these

ha#ards. – 1etermine valid sampling methods to monitor

either the ha#ards2 or their control methods2 orboth.

7/21/2019 postfile_23270 GH


– 8stablish a monitoring schedule with alert andaction levels

– 8stablish a monitoring schedule with alert andaction levels

– erify that the contamination control system isworking effectively by reviewing the product reCectionrate2 sampling results and control methods and2where appropriate2 modifying them.

– 8stablish and maintain appropriate documentation.

– rain the staff.

&dentification of 'ources and&dentification of 'ources and

7/21/2019 postfile_23270 GH


7outes of ontamination7outes of ontamination

• 'ources of contamination – dirty areas adCacent to the cleanroom> – unfiltered air supply> – room air> – surfaces> – people> – machines2 as they work>

– raw materials> – containers> – packaging.

Airborne and contact routes o!Airborne and contact routes o!

7/21/2019 postfile_23270 GH


trans!er trans!er

– he two main routes of transfer are airborneand contact.

– 5irbone: particles are small> fibres2 chips or

cuttings fall directly on to the product. – ontact: machines2 containers2 packaging2raw materials2 gloves2 clothes2 etc.

Construction o! a risk diagramConstruction o! a risk diagram

7/21/2019 postfile_23270 GH


Construction o! a risk diagramConstruction o! a risk diagram

• 7isk diagram: possible sources ofcontamination> their main routes oftransfer> methods of controlling this

transfer.• Figure (A.( is an e/ample of a risk

diagram> the manufacturing process has

been shown

7/21/2019 postfile_23270 GH


'ources and routes of particle and microbialcontamination in a

cleanroom along with preventative measures

7/21/2019 postfile_23270 GH


'ources and routes of control associated with process machinery.

5ssessment of the &mportance of 5ssessment of the &mportance of

7/21/2019 postfile_23270 GH


6a#ards6a#ards

• Possible sources of contamination routes oftransmission risk assessment

• 7isk factors: – risk factor 5: the amount of contamination on2 or in2

the source that is available for transfer – risk factor B: the ease by which the contamination is

dispersed or transferred – risk factor : the pro/imity of the source to the critical

point where the product is e/posed – risk factor 1: how easily the contamination can passthrough the control method

7isk factors for assessing ha#ards7isk factors for assessing ha#ards

7/21/2019 postfile_23270 GH


• 7isk rating @ 5 / B / / 1

• ?ow: a risk rating of

less than )• +edium: between )and (,

• 6igh: higher than (,

&dentification of +ethods to ontrol&dentification of +ethods to ontrol6 d

7/21/2019 postfile_23270 GH


6a#ards6a#ards

• &dentify the contamination ha#ards theirdegree of risk assessed methodsavailable to control them.

• Figures (A.( and (A., show methods that can be used tocontrol the routes of spread of contamination hese are:

7/21/2019 postfile_23270 GH


control the routes of spread of contamination. hese are: – 68P5 or 0?P5 air filters supply air – 5irborne contamination from areas outside the cleanroom air

moves from the cleanroom outward – he contamination from the floors2 walls and ceiling cleaning – People;s mouth2 hair2 clothing and skin leanroom garments

and gloves – ontamination from machines design of the machine2 the use

of e/haust air systems to draw the contamination away.leaning dirt on the machine.

– 7aw materials2 containers and packaging made frommaterials that do not generate contamination> manufactured inan environment have minimal concentrations of contamination>

correctly wrapped to ensure that they are not contaminatedduring delivery

'ampling +ethods to +onitor'ampling +ethods to +onitor6 d d l + h d6 d d t l + th d

7/21/2019 postfile_23270 GH


6a#ards and ontrol +ethods6a#ards and ontrol +ethods

• +onitoring: – collection efficiency of sampling instruments> – calibration of the instruments>

– determination that the ha#ard is of sufficientimportance to need to be monitored>

– determination that the sampling method used

is the best available for directly measuring theha#ard2 or its control method.

8stablishing a +onitoring 'chedule8stablishing a +onitoring 'cheduleith 5l t d 5 ti ? lith 5l t d 5 ti ? l

7/21/2019 postfile_23270 GH


with 5lert and 5ction ?evelswith 5lert and 5ction ?evels

• alert and action conditions> warning and alarmlevels.• he alert level should be set to indicate that the

contamination concentrations are higher than

might be e/pected2 but are still under control.• he action level should be set such that when itis e/ceeded there should be an investigation.

• 5nalysing the monitoring results and setting alertand action levels is 3uite a complicated subCect ifa statistical approach is used. 9nowledge ofstatistical techni3ues2 especially the use of trendanalysis.

erification and 7eappraisal of theerification and 7eappraisal of the' t' t

7/21/2019 postfile_23270 GH


'ystem'ystem

• he method is correctly implemented reCectionrate of the product> measurement of the particle2or microbial2 levels in samples of the finalproduct. De can now reassess the following:

– the relative importance of the ha#ards – the necessity and the methods for controlling the

ha#ards – the effectiveness of the control methods

– the correctness of the monitoring schedule – whether the action and alert levels should belowered or raised.

1ocumentation1ocumentation

7/21/2019 postfile_23270 GH


1ocumentation1ocumentation

• 5n effective contamination control system willdocument

• !(" the methods described in the precedingsteps of this chapter2

• !," the monitoring procedures2 and• !<" results from the monitoring.• 7egular reports should be issued of an analysis

of the monitoring results and any deviations fromthe e/pected results.•

*ta!! Training*ta!! Training

7/21/2019 postfile_23270 GH


*ta!! Training*ta!! Training

• hey first arrive at the cleanroom• rain at regular intervals throughout their

careers.

7/21/2019 postfile_23270 GH


(*. leanroom 1isciplines(*. leanroom 1isciplines

PersonnelPersonnel

7/21/2019 postfile_23270 GH


PersonnelPersonnel

• source of contamination – micro-organisms

– particles and fibres

People 5llowed into leanroomsPeople 5llowed into leanrooms

7/21/2019 postfile_23270 GH


pp

• Dalking: – produce (2===2=== particles U@ =.A mm

– several thousand microbe-carrying particles

per minute

• 'uggestions contain criteria that can discriminate

7/21/2019 postfile_23270 GH


against some personnel

– 'kin conditions: skin cells2 dermatitis2 sunburn or baddandruff. – 7espiratory conditions: coughing2 snee#ing – Biocleanroom:

• allergic conditions2 which cause snee#ing2 itching2 scratching2or a running nose• allergic to materials used in the cleanroom2 !a" garments

!polyester" !b" plastic or late/ gloves2 !c" chemicals: acids2solvents2 cleaning agents and disinfectants2 and !d" products

manufactured in the room2 e.g. antibiotics and hormones.

Personal &tems Mot 5llowed into thePersonal &tems Mot 5llowed into thelleanroom

7/21/2019 postfile_23270 GH


leanroomleanroom

• 4eneral rule: nothing should be allowedinto the cleanroom that is not re3uired forproduction within the room.

Prohibited items:Prohibited items:

7/21/2019 postfile_23270 GH


• food2 drink2 sweets and chewing gum• cans or bottles2 smoking materials• radios2 1 players2 Dalkmans2 cell phones2

pagers2 etc.

• newspapers2 maga#ines2 books and paperhandkerchiefs

• pencils and erasers

• wallets2 purses and other similar items.

1isciplines within the leanroom1isciplines within the leanroom

7/21/2019 postfile_23270 GH


pp

• Dithin a cleanroom: rules-of-conduct:written procedures> does and dontsposted in the change or production area

• 5ir transfer: – come in and out through change areas: buffer#one> not use emergency e/it

– 1oors: not be left open> not be opened or

closed 3uickly: open inwards into theproduction room

Personnel behaviour Personnel behaviour

7/21/2019 postfile_23270 GH


• Mo 'illy behaviour: he generation ofcontamination is proportional to activity.

– motionless: (==2=== particles U@=.A Jm%min – head2 arms and body moving: (2===2=== particles U@ =.A

mm%min – walking: A2===2=== particles U@ =.A Jm%min

PersonnelPersonnel productproduct

7/21/2019 postfile_23270 GH


• position themselves correctly• not lean over the product>• working in unidirectional air: not between

the product and the source of the cleanair2 i.e. the air filter.

• Mo-touch techni3ues should be devised:

from gloved hand onto the product.

7/21/2019 postfile_23270 GH


• $il and skin particles would contaminatethe wafer with catastrophic results.

• not support material against their body

• Mo personal handkerchiefs• Dashing2 or disinfection when re3uired2 of

gloves during use should be considered.

6andling materials6andling materials

7/21/2019 postfile_23270 GH


gg

• he movement of materials between theinside and outside of a cleanroom shouldbe minimi#ed.

• Daste material: collected fre3uently intoeasily identified containers and removedfre3uently from the cleanroom.

+aintenance and 'ervice+aintenance and 'ervicePersonnelPersonnel

7/21/2019 postfile_23270 GH


PersonnelPersonnel

• 8nter a cleanroom with permission.• +aintenance be trained cleanroom

techni3ues2 or closely supervised when they arewithin the cleanroom.

• Dear the same cleanroom clothing ascleanroom personnel

• echnicians should ensure they remove dirtyboiler suits2 etc. and wash their hands beforechanging into cleanroom clothing.

• ools cleaned and sterili#ed> stored for sole used

7/21/2019 postfile_23270 GH


>within the cleanroom> ool;s materials not corrode.$nly the tools or instruments needed within the roomshould be selected2 decontaminated2 and put into acleanroom compatible bag or container.

• instructions or drawings can be photocopied ontocleanroom paper2 or laminated within plastic sheets2 or

placed in sealed plastic bags.• Particle generating operations such as drilling holes2 orrepairing ceilings and floors should be isolated from therest of the area. 5 locali#ed e/tract or vacuum can alsobe used to remove any dust generated.

7/21/2019 postfile_23270 GH


(O. 8ntry and 8/it of(O. 8ntry and 8/it ofPersonnelPersonnel

7/21/2019 postfile_23270 GH


• 'kin and clothing: millions of particles andthousands of microbe-carrying particles

• Features of cleanroom clothing:

– not break up and lint: disperse the minimumof fibres and particles

– filter: against particles dispersed from the

persons skin and their clothing.

7/21/2019 postfile_23270 GH


• he type of cleanroom clothing – contamination control is very important: a

coverall2 hood2 facemask2 knee-length boots

and gloves – contamination is not as important: lessenveloping clothing such as a smock2 cap andshoe covers

Prior to 5rriving at the leanroomPrior to 5rriving at the leanroom

7/21/2019 postfile_23270 GH


• Fre3uency of bathe or shower:• remove the natural skin oils>• dispersion of skin and skin bacteria>• dry skin may wish to use a skin lotion

• Dhat clothing is best worn below cleanroom garmentsQ• 5rtificial fibres: polyester are better than those made from wool and

cotton• lose-woven fabrics: more effective in filtering and controlling the

particles and microbe-carrying particles

• osmetics2 hair spray2 nail varnish removed rings2

watches and valuablesremoved and stored

hanging into leanroomhanging into leanroom4arments4arments

7/21/2019 postfile_23270 GH


4arments4arments

• he best method of changing intocleanroom garments is one that minimisescontamination getting onto the outside ofthe garments.

• he design of clothing change areas isdivided into #ones: – Pre-change #one

– hanging #one – leanroom entrance #one.

Approacing te pre'cange #oneApproacing te pre'cange #one

7/21/2019 postfile_23270 GH


• blow nose2 go to thetoilet

• shoe cleaner

– 'ticky cleanroom matsor flooring: two general

types

7/21/2019 postfile_23270 GH


)re'cange #one)re'cange #one

7/21/2019 postfile_23270 GH


• street or factory clothes removed

• Watches and ringsremoved. tems such as cigarettes andlighters! "allets and other valua#les should #e securely stored.

• $emove cosmetics and apply a suita#le s%in moisturizer (no

chemicals used in the formulation cause contamination pro#lems in the product #eing manufactured)

• &ut on a pair of disposa#le foot"ear coverings! or change intodedicated cleanroom shoes.

• "ash the hands! dry them and apply a suita#le hand lotion.

• Cross over from the pre'entry area into the change zone.

Canging #oneCanging #one

7/21/2019 postfile_23270 GH


•he garments to be worn areselected.

• 5 facemask and hood !or cap" isput on

• emporary gloves known asdonning gloves are sometimesused

• he coverall !or gown" should beremoved from its packaging andunfolded without touching the floor.

Cleanroom entrance #oneCleanroom entrance #one

7/21/2019 postfile_23270 GH


• rossover bench: allowscleanroom footwear!overshoes or overboots"to be correctly put on.

• Protective goggle can beput on. hese are usednot only for safetyreasons but to preventeyelashes and eyebrowhair falling onto theproduct.

gogglegoggle

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


• he garments should be checked in a full-lengthmirror to see that they are worn correctly.

• &f donning gloves have been used they can bedispensed with now. hey can2 however2 be kepton and a pair of clean working gloves put on top.wo pairs of gloves can be used as a precautionagainst punctures2 although sensitivity of touch

is lost.

7/21/2019 postfile_23270 GH


• ?ow particle !and if re3uired2 sterile"working gloves should now be put on. &nsome cleanrooms this task is left until the

personnel is within the productioncleanroom.

3xit Canging )rocedures3xit Canging )rocedures

7/21/2019 postfile_23270 GH


• Dhen leaving a cleanroom2 personnel will either• discard all their garments and on reentry use a newset of garments !this is normally only employed in anaseptic pharmaceutical cleanroom"

• discard their disposable items2 such as masks and

gloves2 but reuse their coverall2 smock2 etc. on re-entry. – clothing rolled up> footwear pigeon holes> – he hood !or cap" can be attached to the outside of the

coverall !or gown" hung up2 preferably in a cabinet.

– 4arment bags can be used.

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


(I. +aterials(I. +aterials 、、 83uipment83uipmentand +achineryand +achinery

+aterials used in a cleanroom+aterials used in a cleanroom

7/21/2019 postfile_23270 GH


• For manufacturing• Packaging for the product• Process machinery and e3uipment

• ools used for the maintenance2calibration or repair of e3uipment andmachinery>

• lothing for personnel2 such as suits2gloves and masks>

7/21/2019 postfile_23270 GH


– +aterials for cleaning2 such as wipers andmops>

– 1isposable items such as writing materials2labels and swabs.

+aterials used in a cleanroom for+aterials used in a cleanroom formanufacturingmanufacturing

7/21/2019 postfile_23270 GH


manufacturingmanufacturing

• pharmaceutical manufacturing:containers and ingredients

• microelectronics industry: silicon wafersand process chemicals>

ontamination on materials can be:ontamination on materials can be:

7/21/2019 postfile_23270 GH


– particles – micro-organisms – chemicals

– electrostatic charge – molecular outgassing.

Prohibited material:Prohibited material:

7/21/2019 postfile_23270 GH


– abrasives or powders> – aerosol-producing cans or bottles> – items made from wood2 rubber2 paper2 leather2

wool2 cotton and other naturally occurringmaterials that break up easily> – items made from mild steel2 or other materials

that rust2 corrode or o/idise>

– items that cause problems when machined orprocessed2 e.g. they may smoke or break up>

7/21/2019 postfile_23270 GH


p 2 g y y p> – paper not manufactured for use in

cleanrooms. – pencils and erasers> – paper correcting fluid>

– personal items listed in 'ection (*., shouldnot be brought in by cleanroom personnel> – disposable items such as swabs2 tapes and

labels that are not cleanroom compatible.

ransfer of &tems and 'mall Piecesransfer of &tems and 'mall Piecesof 83uipment through an 5irlockof 83uipment through an 5irlock

7/21/2019 postfile_23270 GH


of 83uipment through an 5irlock3 p g

– Trans!er area wit abenc

• door !uncontrolled area"opened and the personenters he package

should be placed on thewrapped receiving ordirtier part of the pass-over bench

7/21/2019 postfile_23270 GH


• he wrapping is thencleaned and removed

7/21/2019 postfile_23270 GH


• he outer packagingis now removed anddeposited into asuitable container.

he item is then beplaced on thewrapping removed orclean part of thebench

7/21/2019 postfile_23270 GH


• he personleave. heairlock may be left for afew minutes to allow theairborne contamination tocome down to aconcentration. leanroompersonnel now enter thecleanroom and pick upitems that have been left

!Figure (I.*".

7/21/2019 postfile_23270 GH


8ntry of +achinery8ntry of +achinery

7/21/2019 postfile_23270 GH


– +achines2 and other heavy and large bulkyitems of e3uipment2 are occasionally taken inor out of a cleanroom.

– he best solution to the movement of bulkyitems is to design the materials airlock to belarge enough to allow the entry and e/it ofevery piece of machine to be brought in or out

of the room.

7/21/2019 postfile_23270 GH


$9. Cleanroom Cloting$9. Cleanroom Cloting

7/21/2019 postfile_23270 GH


• ontamination source: people clothing product

• leanroom clothing: originated from

hospitals• Function: reducing inert particles and

microbe-carrying particles.

'ources and 7outes of &nert'ources and 7outes of &nertParticle 1ispersionParticle 1ispersion

7/21/2019 postfile_23270 GH


pp

• +ore activity more particles disperse1ispersion is dependent on the clothingworn2 but can be in the range of (=* to (=O per minute for particles U@ =.A Jm2 i.e. upto (=(= per day.

• People may disperse particles from:• 'kin> clothing they wear under cleanroom

garments> cleanroom clothing• mouth and nose.

*ources o! particles and*ources o! particles and

mecanisms o! releasemecanisms o! release

7/21/2019 postfile_23270 GH


• *kin: People shed appro/imately (=K skin cellsper day. 'kin cells are appro/imately <<Jm / ))Jm

• 'kin cells: – released onto clothing and laundered away> – others are washed away in the bathtub or shower.

– a large number are dispersed into the air.

7/21/2019 postfile_23270 GH


'ources and routes of particles and microbe containing particles from people

7/21/2019 postfile_23270 GH


'kin surface showing skin cells and beads of sweat

Cloting under cleanroomCloting under cleanroom

clotingcloting

7/21/2019 postfile_23270 GH


g

• natural fabrics: such as a cotton shirt2cotton Ceans and woollen Cerseylarge3uantities of particles. natural materials

have fibres that are both short and breakup easily.• synthetic fabric: the particle challenge can

be reduced by K=L or more.

7/21/2019 postfile_23270 GH


otton fabric photographed through a microscope. +agnification about (== times

Cleanroom clotingCleanroom cloting

7/21/2019 postfile_23270 GH


• synthetic plastic materials: such aspolyester or nylon.

+outes o! trans!er o! particles+outes o! trans!er o! particles

7/21/2019 postfile_23270 GH


• Pores: between I=Jm and (==Jm heparticles generated from the skin and the innerclothing therefore pass through easily.

• Personnel move: particles be pumped out ofclosures at the neck2 ankles2 wrists and #ips.'ecure closures tight

• tears or holes2 particles can easily pass through.

7/21/2019 postfile_23270 GH


+icrocolony of bacteria on surface of skin

+outes o! microbial dispersion+outes o! microbial dispersion

7/21/2019 postfile_23270 GH


• he routes of transferthe same as with inertparticles:• the pores in the fabric• poor closures at the neck2 sleeves and ankles

• damage to the fabric2 i.e. tears and holes.• e/pelled from the mouth: speaking2 coughing and snee#ing.

• Dhen males wear ordinary indoor clothing2 theaverage rate being closer to ,== per minute.

Females will generally disperse less.

ypes of leanroom lothingypes of leanroom lothing

7/21/2019 postfile_23270 GH


• Cloting designs – he most effective type:

• completely envelopes a person>• be made from a fabric that has effective filtration properties

• have secure closures at the wrist2 neck and ankle. – he choice of clothing will depend on what is being

produced in the cleanroom. 5 poorer standard ofcleanroom may use a cap2 #ip-up coat !smock" and

shoe covers

7/21/2019 postfile_23270 GH


• &n a higher standardof cleanroom a one-piece #ip-up coverall2knee-high overboots

and a hood that tucksunder the neck of thegarment will be typical

Cleanroom !abricsCleanroom !abrics

7/21/2019 postfile_23270 GH


• he most popular type of clothing is

made from woven synthetic fabrics.• Mon-woven fabrics2 such as yvek2 are

used as single2 or limited reuse2garments. hey are popular for visitorsand are used by builders whenconstructing the room. hey are alsopopular in pharmaceuticalmanufacturing facilities in the 0'5.+embrane barrier fabrics2 such as4oree/2 which use a breathablemembrane sandwiched onto2 orbetween2 synthetic woven fabrics2 arevery efficient> they are e/pensive2 andhence are used in the higher standardrooms.

4arment construction4arment construction

7/21/2019 postfile_23270 GH


• o prevent the raw edges• o minimise shedding2 the #ippers2

fasteners and shoe soles should not chip2

break up or corrode.• Coice o! garments

– &8' 7ecommended Practice 7P--==<.,.

7/21/2019 postfile_23270 GH


7 @ recommended M7 @@ not recommended 5' @ application specific !M7W" @ not recommended in nonunidirectional

flowTable $9.% 4arment systems !or aseptic cleanrooms ,3*T +) CC'

556.%-

Processing of leanroomProcessing of leanroom4arments and hange Fre3uency4arments and hange Fre3uency

7/21/2019 postfile_23270 GH


• )rocessing – to be reused cleanroom laundry antistatic

treatment and disinfection or sterilisation

• Frequency o! cange• semiconductor industry ! the highest specification"2

changed once or twice a week.• fresh garments are put on every time personnel

move into an aseptic pharmaceutical production

area.

7/21/2019 postfile_23270 GH


Body bo/: a2 metronome> b2 bacterial and particle sampler

Comparison o! cloting madeComparison o! cloting made

!rom di!!erent !abrics!rom di!!erent !abrics

7/21/2019 postfile_23270 GH


• Bacterial dispersion !counts%min" inrelation to fabrics

Particle dispersion rate per minuteParticle dispersion rate per minutein relation to fabricin relation to fabric

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


,=. leanroom +asks and,=. leanroom +asks and4loves4loves

7ispersion !rom te mont7ispersion !rom te mont

7/21/2019 postfile_23270 GH


• snee#ing2 coughing and talking> these dropletscontain salts and bacteria.• 'aliva particles and droplets : about ( to

,===Jm> KAL of them lie being between , and

(==Jm2 with an average si#e of about A=Jm>bacteria in saliva is normally over (=O bacteriaper ml.

• 5 (==Jm particle will drop ( metre in about <

seconds2 but a (=Jm particle takes about Aminutes.

7/21/2019 postfile_23270 GH


• 1rying time: Particles of water (===Jm indiameter will take about < minutes toevaporate2 a ,==Jm particle will take O

seconds2 a (==Jm particle about (.*seconds and a A= Jm particle about =.)seconds.

7/21/2019 postfile_23270 GH


• 8fficiencies of over KAL for particlese/pelled from the mouth are usuallyobtained by most masks. 5 loss in

efficiency is caused by particles passinground the side of the mask2 and much ofthis is due to small particles !reported tobe <Jm in the dry state".

Mumber of inert and microbe-carryingMumber of inert and microbe-carryingparticles emitted by a personparticles emitted by a person

7/21/2019 postfile_23270 GH


Particles emitted when pronouncingParticles emitted when pronouncingthe letter Xf;the letter Xf;

7/21/2019 postfile_23270 GH


Face masksFace masks

7/21/2019 postfile_23270 GH


• surgical-style withstraps and loops:disposable surgical-type

7/21/2019 postfile_23270 GH


• onsideration: pressure drop across the maskfabric> masks high filtration efficiency againstsmall particles give a high-pressure dropacross the mask that causes the generated

particles to be forced round the outside of themask. veil or yashmak type2 one of thesetypes being e/posed to show its shape in Figure,=.). he normal way it is worn is shown in

Figure ,=.A.

7/21/2019 postfile_23270 GH


)owered exaust eadgear )owered exaust eadgear

7/21/2019 postfile_23270 GH


• hese provide a barrier tocontamination comingfrom the head2 as well asthe mouth. he e/haustfrom the helmet and face-shield is provided with a

filtered e/haust systemso that contaminationdoes not escape into thecleanroom. 5n e/ample isshown in Figure ,=.*.

leanroom 4lovesleanroom 4loves

7/21/2019 postfile_23270 GH


• (and contamination and gloves – here are two types of gloves associated with

cleanrooms.• 9nitted or woven gloves are used for lower

classes2 i.e. &'$ lass O !lass (=2===" andpoorer areas2 as well as undergloves. he knit orweave should be tight and a number of loosethreads minimised.

• Barrier gloves2 which have a continuous thinmembrane covering the whole hand are used inthe maCority of cleanrooms.

7/21/2019 postfile_23270 GH


• leanroom gloves are not usually manufactured in acleanroom> they therefore re3uire cleaning before beingused.

• 4loves may be re3uired in some cleanrooms to preventdangerous chemicals2 usually acids or solvents2attacking the operators hands.

• 'ome operators skin is allergic to the materials thatgloves are made from.

• $ther glove properties: chemical resistance andcompatibility2 electrostatic discharge properties2 surfaceion contribution when wet2 contact transfer2 barrierintegrity2 permeability to li3uids2 heat resistance andoutgassing.

4love manu!acturing process4love manu!acturing process

7/21/2019 postfile_23270 GH


• 4loves are generally manufactured by dipping a former!porcelain or stainless steel"2 shape of a hand2 moltenor li3uid glove material removed from the molten orli3uid material a layer of material stripped by releaseagent 7elease agents are a problem in cleanrooms 7elease agents kept to a minimum.

• Dhen stripped from the formers2 late/ gloves are sticky.o correct this2 late/ gloves are washed in a chlorinebath. he free chlorine combines chemically with thelate/ chemical bonds and lead to a case-hardening ofthe surface of the glove2 which prevents them sticking to

each other. his washing also helps to clean to thegloves.

Types o! glovesTypes o! gloves

7/21/2019 postfile_23270 GH


• )olyvinyl cloride ,)"C- gloves• 8atex 4loves

• /ter )olymer 4loves

)olyvinyl cloride ,)"C- gloves)olyvinyl cloride ,)"C- gloves

7/21/2019 postfile_23270 GH


• hese plastic gloves are also known as vinylgloves and are popular in electronic cleanrooms>can not sterilised2 not used in bioclean rooms.

• hey are available in normal and long-sleevelength. onsideration should be made of the factthat plasticisers make up almost A=L of a vinylglove. Plasdcisers come from the same group ofchemicals used to test the integrity of air filters2i.e. phthalates2 antistatic properties2 outgassing

8atex 4loves8atex 4loves

7/21/2019 postfile_23270 GH


• his is the type used by surgeons2 and the particle-free type is nowused in cleanrooms. ?ate/ gloves can be produced powder-free2and those gloves that are washed further by use of filtered2deionised water are often used in &'$ lass ) !lass (=" or &'$lass < !lass (" cleanrooms.

• hey have good chemical resistance2 giving protection against mostweak acids and bases2 and alcohols2 as well as having a fairly good

resistance against aldehydes and ketones.• hey are slightly more e/pensive to buy than the P type2 butcheaper than any other polymer. hey can be sterilised. Because oftheir elasticity2 the glove can securely incorporate the cuff of agarment under the sleeve.

/ter )olymer 4loves/ter )olymer 4loves

7/21/2019 postfile_23270 GH


• Polythene gloves

– are used in cleanrooms and have the advantage of being free of oils and additives2 as wellas resistant to puncturing. hey are not resistant to aliphatic solvents. he main drawback ofthis glove type is that they are constructed from float sheets and the seams are welded.+anual de/terity is reduced with these gloves.

• Meoprene and nitrile gloves – are chemically similar to late/ gloves2 but have the advantage of having a better resistance

to solvents than late/ gloves. hey are slightly more e/pensive than late/.• Polyurethane gloves

– are strong2 very thin2 3uite infle/ible2 and e/pensive. hey may be manufactured withmicroporous material for better comfort2 or with carbon in the formulation which makes themconductive.

• P5 gloves – are resistant to strong acids and solvents2 but not water in which they are soluble. hey are

e/pensive.• 4ore-e/ gloves

– have welded seams and are hypoallergenic. hey are breathable because of their porousmembrane. hey are e/pensive.

7/21/2019 postfile_23270 GH


7/21/2019 postfile_23270 GH


,(. leaning a leanroom,(. leaning a leanroom

Dhy a leanroom +ust beDhy a leanroom +ust beleanedQleanedQ

7/21/2019 postfile_23270 GH


•Particles: – cleanroom clothing2 over (==2=== particles U@ =.A Jm and over

(=2=== particles U@ A.=Jm. – +achines also disperse millions of particles.

• +icrobe-carrying particles: People can also disperse

hundreds2 or thousands2 of microbe-carrying particlesper minute. Because these micro-organisms are carriedon skin cells2 or fragments of skin cells2 their averagee3uivalent diameter is between (= Jm and ,= Jm.

• ransfer: leanrooms surfaces get dirty be transferred

by personnel touching a cleanroom surface and then theproduct.

leaning +ethods and the Physicsleaning +ethods and the Physicsof leaning 'urfacesof leaning 'urfaces

7/21/2019 postfile_23270 GH


• Forces hold particles to cleanroomsurfaces: – he main force : the ?ondon-van der DaaP;s

force2 this being an inter-molecular force.

– 8lectrostatic forces can also attract particlesto a surface.

– 5 third force can arise after wet cleaning.Particles that are left behind will dry on thesurface2 and may adhere to it

7/21/2019 postfile_23270 GH


• he methods that are generally used forcleaning a cleanroom2 are: – acuuming !wet or dry": immersing the particle in a

li3uid2 as occurs in wet pick-up vacuuming – Det wiping !mopping or damp wiping": an a3ueous-

based detergent is used then the ?ondon-van derDaaFs force and electrostatic forces can be reducedor eliminated. he particle can then be pushed ordrawn off from a surface by wiping2 mopping or

vacuuming. – Picking-up with a tacky roller.

"acuuming"acuuming

7/21/2019 postfile_23270 GH


• 1ry vacuuming : – depends on a Cet of air moving towards the vacuumno##le and overcoming the adhesion forces ofparticles to the surface

– Figure ,(.( : efficiency of dry vacuuming againstdifferent si#es of sand particles on a glass surface.

• Det vacuum: Dater and solvents have muchhigher viscosity than air2 so that the drag forcese/erted by li3uids on a surface particle are very

much greater.

7/21/2019 postfile_23270 GH


8fficiency of dry vacuuming

7/21/2019 postfile_23270 GH


• et 'wiping – Det wiping2 with wipers or mops2 can

efficiently clean cleanroom surfaces. heli3uid used allows some of the particle-to-

surface bonds to be broken and particles tofloat off.

• Tacky rollers – he particle removal efficiency of tacky

rollers is dependent on the strength of theadhesive force of the rollers surface.

7/21/2019 postfile_23270 GH


• dry brush should never be used to sweepa cleanroom. they can produce over A=million particles U@ =.A Jm per minute.

• 'tring mops are not much better2 as theycan produce almost ,= million particles U@=.A Jm per minute.

7/21/2019 postfile_23270 GH


• 1ry vacuuming: popular method – relatively ine/pensive – no cleaning li3uids are needed

– Mote: unfiltered e/haust-air must not pass intothe cleanroom. his is achieved by usingeither an e/ternal central-vacuum source2 orproviding a portable vacuums e/haust air with

a 68P5 or 0?P5 filter.

7/21/2019 postfile_23270 GH


• Det vacuum or pick-up system: is moreefficient than dry vacuum – more efficient than a mopping method2 – less li3uid left to dry on the floor

– floor will also dry 3uicker. – Det pick-up systems are used on

conventionally ventilated cleanroom floors2

but may not be suitable for the pass-thoughtype of floor used in the vertical unidirectionalsystem.

• Mopping systems

7/21/2019 postfile_23270 GH


• Mopping systems – mops for cleanroom:

• materials that do not easilybreak up: P5 orpolyurethane open-porefoam2 or a fabric such as

polyester.• he compatibility of thematerial to sterili#ation2disinfectants and solventsshould be checked

• Buckets should be made

from plastic or stainlesssteel.

7/21/2019 postfile_23270 GH


wo and three bucket systems

7/21/2019 postfile_23270 GH


6ow to use a three-bucket mopping system

7/21/2019 postfile_23270 GH


• ipers – Purpose: wipe surfaces and remove contamination> towipe contamination from products produced> used dryto mop-up li3uids that may have been spilled.

– *orbency

• 'orbency is an important property of wipers. Dipers areoften used to mop up a spillage and other similar tasks.

• wipers sorbency: both its capacity !the amountof li3uid it can sorb" and its rate !how fast it can

sorb li3u

7/21/2019 postfile_23270 GH


• Tacky rollers – acky rollers aresimilar in si#e andshape to paint rollersused in the home2 but

they have a tackymaterial around theoutside of the roller. 5ne/ample of a tackyroller is shown in

postfile_23270 GH

Documents

Transcript of postfile_23270 GH