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Hazardous Airborne Pollutant Reduction Textbook Version: 10.2 © 2008 - 2014 Inter-Industry Conference On Auto Collision Repair HAP01e-STMAN1-E

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Page 1: Hazardous Airborne Textbook Pollutant Reduction

HazardousAirbornePollutant

Reduction

Textbo

ok

Version:�10.2

©�2008�-�2014�Inter-Industry�Conference�On�Auto�Collision�Repair

HAP01e-STMAN1-E

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Table�of�Contents 3

Contents

Module�1�-�Environmental�Compliance................................................................................... 7Program�Description............................................................................................................. 7NESHAP................................................................................................................................8HAP...................................................................................................................................... 8EPA�Final�Rule�For�PSMSC................................................................................................. 10Training�Requirements........................................................................................................ 11VOC....................................................................................................................................11SDS.....................................................................................................................................12Product� Information�Sheets.................................................................................................13HAP�Reduction...................................................................................................................14Developing�A�Compliance�Program................................................................................... 16Module�Wrap�Up............................................................................................................... 18

Module�2�-�Refinish�Application............................................................................................ 21Finish�Removal�With�MeCl.................................................................................................21Sanding...............................................................................................................................22Refinishing�Materials...........................................................................................................23Product�Mixing................................................................................................................... 27Spray�Environment..............................................................................................................28Spraybooth�Operation.........................................................................................................30Filter�Replacement.............................................................................................................. 30Spray�Gun�Types.................................................................................................................31Gun�Adjustments................................................................................................................ 33Operation�Techniques.........................................................................................................35Spray�Gun�Cleaning............................................................................................................37Module�Wrap�Up............................................................................................................... 38

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Module�1�-Environmental

Compliance

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Program�Description

Learning�objectives�for�this�moduleinclude:

• explaining�the�requirements�of�theenvironmental�protection�agency(EPA)�regulations.

• evaluating�the�EPA�regulations�andhow�they�may�apply�to�a�specificbusiness.

• identifying�hazardous�airpollutants�(HAPs)�and�how�theycan�affect�public�health�and�theenvironment.

• using�the�appropriate�personalprotection�equipment�(PPE).

• identifying�equipment�that�reducesthe�amount�of�HAP.

• evaluating�the�EPA�final�rule�in-house�training�program.

• describing�the�owners�or�managersresponsibility�for�implementingthe�EPA�final�rule�in-house�trainingprogram.

These�technicians�are�learning�about�spray�gunsettings�to�help�reduce�the�amount�of�HAP�emittedduring�refinishing.

Hazardous�materials�are�commonly�usedin�collision�repair�facilities�and�otherfacilities�that�apply�finishes�to�metalsand�plastics.�Many�of�these�materials�areapplied�using�a�spray�gun.�When�thesematerials�are�atomized�or�allowed�to�ventinto�the�atmosphere�through�evaporation,hazardous�air�pollutants�are�released�intothe�environment.�These�pollutants�havebeen�identified�by�the�EPA�as�HAPs.

This�online course�discusses�methods�thatmay�be�used�to�reduce�the�amount�ofHAPs�that�are�generated�through�severaldifferent�application�techniques,�usingproper�equipment,�and�the�proper�usageand�maintenance�of�the�equipment.

This course�also�provides�compliancefor�the�Final�Rule�from�the�EPA�NationalEmission�Standard�for�Hazardous�AirPollutants�(NESHAP):�Paint�Stripping�andMiscellaneous�Surface�Coatings�(PSMSC)Area�Sources.

There�are�several�benefits�for�reductionof�HAPs,�including�the�safety�and�healthof�workers�in�the�facility�and�surroundingareas,�and�a�potential�economic�benefitfrom�the�overall�reduction�of�the�amountof�materials�that�are�used.

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NESHAP

The�EPA�has�established�emission�standards�fornearly�every�manufacturing�facility�to�reducehazardous�air�pollutants.

The�Clean�Air�Act�(CAA)�requires�theEPA to�develop�emission�standards�andto�identify�the�source�of�HAPs.�Withinthe�refinishing�process,�hazardous�airpollutants�are�emitted�when�the�refinishmaterials�are�atomized�during�sprayapplication�and�during�the�evaporativecuring�process.�The�CAA�also�requires�theEPA�to�regulate�the�sources�that�pose�thegreatest�potential�health�threat�from�thesepollutants�in�urban�areas.�On�September6,�2007,�the�EPA�issued�proposed�air�toxicstandards�for�smaller�emitting�sources.These�are�called�area�sources.�An�areasource�is�a�manufacturing�or�servicefacility�that�has�the�potential�to�emit�lessthan�10�tons�per�year�of�a�single�toxic�airpollutant�or�less�than�25�tons�per�year�ofany�combination�of�toxic�air�pollutants.

Any�producer�of�toxic�air�pollutants�overthese�thresholds�is�considered�a�majorsource�and�is�covered�under�a�differentNational�Emission�Standard�for�HazardousAir�Pollutants�(NESHAP).�Most�collisionrepair�facilities�are�considered�an�areasource.

The�EPA�has�identified�paint�strippingoperations�and�product�surface�coatingas�an�area�source�of�HAPs�with�thestandard�being�NESHAP�Paint�Strippingand�Miscellaneous�Surface�Coatings.Collision�repair�facilities�are�included�inthis�category.�The�focus�of�the�standardis�to�reduce�the�amount�of�hazardous�airpollutants�by:

• implementation�of�managementpractices.

• choosing�alternative�methods�andmaterials.

• an�overall�reduction�of�the�amountof�hazardous�materials�releasedinto�the�environment.

HAP

Air�pollution�in�the�form�of�smog�is�apparent�in�thisurban�area.

The�EPA�defines�an�air�pollutant�asany�substance�in�the�air�that�can�causeharm�to�humans�or�the�environment.�Airpollution�can�lead�to�smog,�groundwatercontamination,�acid�rain,�or�otherenvironmental�damage.�HAPs�arepollutants�known�or�suspected�to�causecancer�or�other�serious�health�effects,

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such�as�reproductive�effects,�birth�defects,or�other�adverse�environmental�effects.

HAPs�are�emitted�when�the�refinishmaterials�are�atomized�during�sprayapplication�and�during�the�evaporativecuring�process.

This�is�the�symbol�that�appears�on�materials�withvaried�levels�of�health�hazards.

Refinish�materials have�been�associatedwith�both�chronic�and�acute�adversehealth�disorders.�Acute�health�disordersassociated�with�exposure�during�sprayapplication�of�coating�materials�includeirritation�of�eyes,�throat,�and�nose.There�can�be long-term�lung�functionimpairment�after�high�acute�exposure.Chronic�health�disorders�include�adverseeffects�on�the�central�nervous�system,blood�disorders,�and�cancer.

For�purposes�of�the�final�rule,�coatingsare�considered�to�contain�HAP�ifthe�Occupational�Safety�and�HealthAdministration�(OSHA)�has�identified�thesubstance�as�a�carcinogen,�which�is�acancer-�causing�agent,�at�a�concentrationof�0.1�percent�by�mass,�or�a�combinationof�the�target�HAP�is�greater�than�1.0percent�by�mass.

The�EPA�has�a�website�that�identifes�188�materialsand�compounds�classified�as�HAP.

The�EPA�has�identified�a�list�of�188materials�and�compounds�that�areclassified�as�hazardous�air�pollutants,some�of�which�are�commonly�used�inrefinishing�materials.�The�list�includesrelatively�common�pollutants�suchas�benzene,�chlorine,�methanol,�andasbestos,�as�well�as�numerous�lesscommon�substances.

Select�the�link�to�view�a�complete�listof�the�188�different�materials�the�EPAhas�determined�to�be�hazardous�airpollutants.

http://www.epa.gov/ttn/atw/188polls.html

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During�the�refinishing�and�coating�process,refinishing�materials�may�include�compoundscontaining�heavy�metals.

Refinishing�and�coating�products�mayinclude�compounds�containing�heavymetals.�The�heavy�metals,�also�referred�toas�the�target�HAP,�include:

• chromium�(Cr).• lead�(Pb).• manganese�(Mn).• nickel�(Ni).• cadmium�(Cd).

Other�hazardous�air�pollutants�associatedwith�refinishing�materials�include:

• trivalent�chromium�(Cr-III).• hexavalent�chromium�(Cr-VI).

EPA�Final�Rule�For�PSMSC

The�final�rule�for�Paint�Stripping�and�MiscellaneousSurface�Coating�(PSMSC)�defines�the�specificpractices�that�are�required�by�facilities�that�applycoatings�through�the�spray�application�process.

The�EPA�Final�Rule�for�PSMSC�waspublished�on�January�9,�2008.�The�goal�ofthis�EPA�final�rule�is�to�reduce�the�amountof�hazardous�air�pollutants�emitted�intothe�atmosphere�by�several�methods,including:

• a�reduction�of�the�amount�ofoverspray�created�when�refinishingmaterials�are�applied.

• effectively�cleaning�spray�gunswithout�atomization�of�thecleaning�solvent.

• applying�coatings�in�a�spraybooth,reducing�the�amount�of�hazardousair�pollutants�from�being�releasedinto�the�environment.

Collision�repair�facilities�and�otherindustries�that�apply�surface�coatingsare�required�to comply�to�this�rule.Exemptions�from�the�final�rule�include:

• individuals�who�use�paint�stripperor�apply�surface�coatings�to�their

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personal�vehicles,�possessions,�orproperty�without�compensation.

• hobbyists�who�may�apply�coatingsthrough�spray�applicationtechnique�to�no�more�than�twovehicles�per�year,�regardlessof�whether�compensation�wasreceived�for�the�application�of�thecoating.

The�final�rule�for�PSMSC�is�availableonline�by�selecting:

http://www.epa.gov/ttn/atw/area/fr09ja08.pdf

Training�Requirements

The�requirements�of�the�final�rule�include�bothclassroom�and�hands-on�training�for�persons�whoapply�coatings�with�a�spray�gun.

The�EPA�final�rule�for�PSMSC�requires�thatany�person�who�applies�coatings�witha�spray�gun�receive�training�on�how�toreduce�HAPs.�The�training�must�includetechniques�used�to�increase�transferefficiency,�reduce�overspray,�and�properspray�gun�cleaning.�The�initial�painttraining�is�valid�for�a�five-year�period�andrefresher�training�must�be�repeated�at�leastonce�every�five�years.

VOC

The�areas�in�the�USA�highlighted�in�blue�wereregulated�for�VOC�emissions�by�the�National�Rule�of1998.

Many�of�the�products�used�in�coatingapplications�and�refinishing�processescontain�hydrocarbons,�meaning�they�aremade�using�petroleum-based�chemicals.Many�of�these�products�contain�volatileorganic�compounds,�or�VOCs.�TheEPA�defines�a�VOC�as�any�organiccompound�that�evaporates�readily�intothe�atmosphere.�The�VOCs�in�refinishingand�paint�stripping�products�are�releasedinto�the�environment�when�the�solvents�inthe�product�evaporate�during�the�curingprocess.�EPA�studies�have�shown�thatthese�VOCs�contribute�to�depletion�ofthe�ozone�layer,�smog�production,�andadverse�health�effects.

Several�geographic�locations�acrossthe�United�States�have�been�regulatedfor�product�and�equipment�type�whenrefinishing�vehicles�since�1998.�Thesegeographic�locations�of�VOC-regulatedareas�are�primarily�in�coastal�regions,including�the�Atlantic�and�Pacific�Oceansand�around�the�Great�Lakes.�The�NationalRule�of�1998�deals�mainly�with�reducingVOCs�by�regulating�the�amount�ofsolvents�that�are�used�to�atomize�the

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products�and�requiring�a�higher�amountof�solids.�There�are�also�regulations�onthe�type�of�cleaning�solvents�that�areused�to�prepare�a�part�for�refinishing.�Thespray�equipment�that�is�used�to�apply�theproducts�to�meet�the�National�Rule�of1998�includes�the�use�of�high-volume,low-pressure�(HVLP)�spray�guns.�Thefinal�rule�on�hazardous�air�pollutantreduction�also�includes�the�HVLP�spraygun�requirement�on�a�nationwide�basis.

SDS

The�safety�data�sheet�(SDS)�must�be�easilyaccessible�by�employees.

It�is�important�for�workers�to�be�informedof�dangerous�materials�that�they�maybe�exposed�to�in�the�workplace.�OSHAdeveloped�the�employee�“Right-To-Know”law�that�requires�employers�to�informemployees�of�hazardous�chemicals.Employers�must�inform�employeesabout�hazardous�materials�stored�andused�within�the�facility.�According�toOSHA,�the�number�one�safety�andhealth�violation�for�collision�repairfacilities�is�the�failure�to�communicatehazardous�materials�that�are�used�in�theworkplace.

Penalties�should�not�be�the�reasonfor�being�compliant�with�health

and�environmental�regulations.�Theregulations�are�there�to�protect�the�worker.Health�and�safety�of�a�worker�should�bethe�reason�for�being�compliant�with�therules.

An�SDS�document�must�accompany�everypotentially�hazardous�product�that�is�used�in�afacility.

A�safety�data�sheet�(SDS)�must�accompanyevery�hazardous�material�that�is�usedin�a�workplace.�The�SDS�is�a�technicaldocument�that�provides�detailedinformation�for�handling,�storing,disposing�of,�and�using�the�material.Also�included�on�the�SDS�is�informationon�the�effects�of�overexposure�to�thematerial,�steps�to�avoid�overexposure,�andinformation�on�what�to�do�in�the�eventof�an�emergency.�A�good�way�to�find�outwhich�pollutants�may�be�released�whenapplying�coatings�is�to�refer�to�the�SDS.

Employers�are�allowed�to�add�to�ormodify�an�SDS�for�the�specific�use�of�thematerial�at�the�workplace.�The�revisedSDS�must�not�contain�less�informationthan�the�original�SDS.�The�revision�mayinclude�information�on�hazards�relatingto�the�specific�workplace,�including�locallaws,�waste�disposal�laws,�and�additionalexposure�limits.�The�original�SDS�must�be

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kept�on�file�at�the�workplace.�If�a�productis�no�longer�used�at�a�facility,�it�is�requiredthat�the�SDS�or�a�product�inventory�sheetbe�kept�on�file�for�30�years�for�medicalevaluation�purposes.�This�is�to�ensure�theinformation�is�available�for�employeeswho�may�be�affected�by�long-term�healthproblems�from�exposure�to�a�chemicalseveral�years�after�the�exposure�tookplace.�Product�inventory�sheets�mustinclude�information�on�where�and�whenthe�product�was�used�in�the�workplace.

Personal�protection�for�refinishers�typically�includesskin,�eye,�and�respiratory�protection.

OSHA�regulations�require�employers�toprovide�the�proper�personal�protectiveequipment�(PPE)�to�protect�the�workersfrom�hazards.�PPE�for�painters�andtechnicians�that�apply�coatings�andfinishes,�including�automotive�finishes,typically�includes�respiratory�protection,eye�protection,�chemical-resistantgloves,�and�a�full�body�refinishing�suit.Product�information�sheets�are�a�goodsource�to�find�out�which�proper�PPE�isrequired�when�using�materials�that�may�behazardous.

Section�8:�Exposure�Controls�/�PersonalProtection

This�section�indicates�the�exposurelimits,�engineering�controls,�and�personalprotective�measures�that�can�be�used�tominimize�worker�exposure.�The�requiredinformation�consists�of�OSHA�PermissibleExposure�Limits�(PELs),�exposure�limitused�or�recommended�by�the�chemicalmanufacturer,�importer,�or�employerpreparing�the�safety�data�sheet,�whereavailable.

Product�Information�Sheets

Product�information�sheets�provide�directions�onhow�to�use�a�product.

Not�to�be�confused�with�an�SDS,product�information�sheets�providespecific�directions�on�the�correct�usageof�the�product.�Product�informationsheets�do�not�provide�compliancewith�the�OSHA�Right-To-Know�law,although�most�product�informationsheets�provide�recommendations�on�theappropriate�PPE�that�should�be�used.Some�of�the�items�that�are�includedon�a�product�information�sheet�forrefinishing�products�include�mixinginstructions,�recommended�spray�gunsettings,�dry�and�cure�times,�applicationinstructions,�and�pot�life�of�the�product.The�product�information�sheets�willinclude�the�amount�of�VOCs�that�the

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product�contains�when�mixed�accordingto�the�directions.

HAP�Reduction

Many�collision�repair�facilities�are�choosing�productsbased�on�their�environmental�impact.

The�reduction�of�HAPs�has�manybenefits�to�the�environment�and�to�thecollision�repair�or�coating�applicationfacility.�Refinishing�product�makershave�made�many�of�the�products�moreenvironmentally�friendly.

Some�environmental�benefits�of�HAPreduction�include:

• better�air�quality�both�in�andaround�the�area�of�the�facility.

• less�chance�of�exposure�toworkers.

• reduced�potential�for�smog.• less�airborne�pollutants�that�could

end�up�polluting�groundwater.

An�advantage�of�HAP�reduction�is�spraybooth�filterswill�last�longer,�as�there�may�be�less�overspray�fromthe�spray�process.

Some�benefits�to�the�facility�of�HAPreduction�include:

• better�health�and�safety�for�theemployees�and�residents�in�thesurrounding�area.

• a�reduced�amount�of�overallmaterials�required�to�refinish�apart,�thus�resulting�in�an�economicsavings.

• extended�spraybooth�filter�life.• reduced�gun�cleaning�solvent

consumption.

Applying�a�polyester�glazing�putty�may�reduce�theamount�of�primer-surfacer�that�is�required�to�fillsome�imperfections.

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HAP�reduction�starts�in�the�beginningof�the�refinishing�process.�One�of�theeasiest�ways�to�reduce�the�amount�of�HAPis�to�reduce�the�amount�of�material�thatis�mixed.�Since�many�of�the�productscontain�a�catalyst�or�hardener,�they�willsolidify�after�a�specified�period�of�time.Therefore,�most�painters�try�to�spray�theproduct�until�the�gun�is�empty.

It�is�a�good�practice�to�mix�only�whatis�needed.�There�is�no�simple�way�tomeasure�how�much�of�a�product�shouldbe�mixed,�but�past�experience�may�behelpful�when�making�this�determination.Reducing�the�amount�of�product�that�ismixed�not�only�reduces�the�amount�ofHAP,�it�also�reduces�the�amount�of�solidwaste�that�a�facility�generates.

A�few�methods�that�could�reduce�theamount�of�HAP�is�to�reduce�the�amount�ofprimer-surfacer�that�is�required�by�using�afiner�grit�sandpaper�for�finish-sanding�thebody�filler�in�the�repair�area,�or�by�usinga�polyester-based�glazing�putty�to�fillimperfections�and�sandscratches.�Primer-surfacers�are�typically�spray-applied�withthin,�wet�coats.�Applying�the�primer-surfacer�heavier�than�recommended�mayprevent�the�solvents�in�the�primer�fromevaporating�during�the�cure.�This�couldlead�to�shrinkage,�incomplete�cure,�orsandscratch�swelling�after�the�part�istopcoated.

Applying�primer-surfacer�with�a�roller�reducesthe�amount�of�hazardous�air�pollutants�that�aregenerated.

There�are�several�ways�that�the�applicationprocess�of�primer-surfacer�can�reducethe�amount�of�HAPs�emitted.�Someproduct�makers�have�roll-on�or�brushableproducts�that�eliminate�the�need�for�sprayapplication.�A�thinner�is�not�requiredto�make�the�product�thin�enough�tospray�through�a�spray�gun.�Since�theeffectiveness�of�a�primer-surfacer�isdependent�upon�the�complete�cure�of�theprimer,�brushing�or�rolling�for�applicationmay�require�a�heat�source�to�bake�theprimer.�Infrared�heat�lamps�are�commonlyused�to�bake�the�primer�until�a�completecure�has�been�achieved.

Another�current�trend�is�to�use�a�UV-cure�primer-surfacer.�UV-cure�productis�increasing�in�popularity�as�low-VOCmaterials�are�mandated�by�local,�state,and�federal�governments.�The�reason�UV-cure�products�are�low-VOC�is�becausethey�use�ultraviolet�light�to�cure�a�productrather�than�evaporation�of�solvents.�TheUV-cure�process�also�takes�less�timecompared�to�curing�of�conventionaltwo-part�refinish�products.�The�resinsin�the�primer�change�from�a�liquid�to�a

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solid�through�a�chemical�reaction�whenexposed�to�UV�light.

Primer-sealer�application�serves�severalpurposes�that�can�reduce�HAPs.�Theuniform�color�that�some�primer-sealersprovide�may�reduce�the�amount�ofbasecoat�that�must�be�applied�until�hidingis�achieved.�Some�refinish�product�makersmake�a�primer-sealer�that�can�be�tintedor�mixed�to�closely�match�the�basecoat.This�also�reduces�the�amount�of�basecoatthat�must�be�applied.�To�reduce�theamount�of�VOC�emitted�when�applyingtopcoats,�a�higher�percentage�of�solidsis�used�than�with�traditional�topcoats.Traditional�topcoats�typically�require�areducer�that�evaporated�from�the�paintfilm�as�it�dried.�The�reducer�allows�thematerial�to�atomize�when�it�is�being�spray-applied�and�to�flow�out�as�the�coatingdries.

Some�refinishing�product�makers�havedeveloped�clearcoats�and�single-stagefinishes�that�require�little�or�no�reducerduring�spray�application.�The�higherconcentration�of�solids�may�relate�tobetter�coverage�and�increased�filmbuild.�Some�of�these�products�mayhave�a�speed�rating�for�the�type�ofhardener�that�is�added�to�the�clearcoat.With�the�development�of�higher�solidtopcoats,�different�application�and�dryingtechniques�may�be�required.�Higher-solidproducts�reduce�the�amount�of�VOC�thatis�released.�HAPs�are�also�reduced,�as�ahigher�film�build�and�better�coverage�maybe�possible�when�using�high-solid�contentrefinish�materials.

Developing�A�Compliance�Program

The�EPA�final�rule�allows�facilities�to�develop�an�in-house�training�program�that�includes�hands-on�andclassroom�training.

The�EPA�final�rule�allows�facilities�todevelop�an�in-house�training�programtailored�specifically�to�the�productsand�equipment�that�the�facility�uses.Some�key�points�that�must�be�includedin�the�training�include�a�hands-on�andclassroom�training�on�spray�gun�selection,setup,�and�operation�to�reduce�theamount�of�overspray.�This�should�includeinformation�on:

• spray�gun�air�pressure,�fluid,�andpattern�adjustments.

• selection�of�the�correct�needleand�fluid�tip�for�the�coating�that�isbeing�applied.

• various�application�techniques�toimprove�the�transfer�efficiency,including�spray�gun�distanceand�angle,�application�speed,and�correct�overlap�during�theapplication�process.

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A�manager�is�observing�a�technician�demonstratean�increase�in�transfer�efficiency�through�spray�gunoperation�techniques.

If�the�in-house�training�program�is�used,the�training�must�include�observation�ofthe�hands-on�requirements,�including:

• the�painter�verifies�that�theair�pressure�at�the�spray�gunis�adjusted�to�the�equipmentmanufacturer’s�recommendations.

• the�painter�demonstrates�anincrease�in�transfer�efficiencythrough�spray�gun�operationtechniques.�An�observer�or�trainermust�document�that�the�travelspeed�and�gun�distance�reducethe�amount�of�overspray�overtraditional�spray�applicationprocesses.

• the�pressure�in�the�sprayboothis�adjusted�to�efficiently�trapoverspray�in�the�filtration�system.Spraybooth�filter�change�intervalsshould�correspond�with�thepressures�of�the�sprayboothto�ensure�that�the�sprayboothis�filtering�the�overspray�withmaximum�efficiency.�The�requiredspraybooth�filters�with�at�least98%�efficiency�must�be�used.

• properly�cleaning�spray�gunsand�equipment�without�theatomization�of�solvents�outside�ofan�enclosed�gun�cleaner.

To�ensure�compliance,�the�manager�should�reviewthe�training�for�each�person�who�applies�coatings�attheir�facility.

The�manager�or�owner�of�the�facility�mustprovide:

• a�description�of�the�methods�usedto�complete�the�classroom�portionof�the�training�and�to�observe�andcertify�the�hands-on�elements�havebeen�successfully�completed.

• training�for�each�person�whoapplies�coatings using�sprayapplication.�The�painter�mustcomplete�the�initial�training�withinthe deadline�for�a facility�andrefresher�training�every�5�years.

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Refer�to�“Video:�Hands-On�TrainingRequirements”�in�the�presentation.�Thisvideo�demonstrates�the�observation�of�thehands-on�training�requirements.

Module�Wrap�Up

Topics�discussed�in�this�moduleincluded:

• the�requirements�of�the�EPAregulations.

• the�EPA�regulations�and�how�theymay�apply�to�a�specific�business.

• HAPs�and�how�they�canaffect�public�health�and�theenvironment.

• the�appropriate�personalprotection�equipment.

• equipment�that�reduces�theamount�of�HAP.

• the�EPA�final�rule�in-house�trainingprogram.

• the�owners�or�managersresponsibility�for�implementingthe�EPA�final�rule�in-house�trainingprogram.

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Module�2�-�RefinishApplication

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Finish�Removal�With�MeCl

Learning�objectives�for�this�moduleinclude:

• identifying�how�to�reduce�theamount�of�methylene�chloride(MeCl)�paint�stripper�that�is�used.

• identifying�sprayboothrequirements�and�filtermaintenance�schedules.

• identifying�spray�applicationtechniques�and�gun�adjustmentsthat�reduce�the�amount�of�HAPsreleased�into�the�environment.

• identifying�spray�gun�cleaningrequirements.

Many�paint�strippers�or�removers�contain�methylenechloride,�a�hazardous�air�pollutant.

Also�covered�under�the�final�rule�isthe�use�of�paint�strippers�containingmethylene�chloride�(MeCl).�MeCl,�theactive�ingredient�in�some�commercialpaint�strippers�or�removers,�is�ahazardous�air�pollutant�as�identifiedby�the�EPA.�Another�name�for�MeCl�isdichloromethane.�MeCl�is�a�colorlessliquid�with�a�mild,�sweet�odor.

The�primary�means�of�exposure�to�MeClis�through�inhalation�of�vapors�as�thesolvent�evaporates,�although�exposurecould�also�occur�from�skin�contactor�drinking�contaminated�water.�TheEPA�has�determined�that�MeCl�is�aprobable�cancer-causing�agent�in�humans.Symptoms�of�exposure�from�breathingfumes�containing�MeCl�include�feelingunsteady�and�dizzy,�nausea,�and�a�tinglingsensation�of�the�fingers�and�toes.�Insmaller�amounts,�exposure�to�MeCl�maycause�a�person�to�become�inattentive�andless�accurate�in�tasks�that�require�hand-eye�coordination.�Skin�contact�may�causeburning�and�redness.

The�proper�safety�equipment�when�usingpaint�strippers�includes�skin,�eye,�andrespiratory�protection.�When�using�anMeCl-based�paint�stripper,�OSHA�has�setlimits�of�exposure�for�breathing�air�thatmay�be�contaminated�with�MeCl.�Theappropriate�safety�equipment�should�beused�when�working�with�paint�strippers�orremovers.

The�proper�safety�equipment�when�using�paintstrippers�includes�skin,�eye,�and�respiratoryprotection.

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The�MeCl�portion�of�the�standard�willaffect�very�few�collision�repair�facilities,as�the�threshold�that�will�require�a�writtenreduction�plan�is�using�over�2000�lb.�peryear�of�MeCl-based�paint�remover.�If�MeClpaint�stripper�is�used�in�any�amount,�thefacility�must�notify�the�EPA�of�being�asource.�If�the�minimum�threshold�is�notmet,�there�are�no�reduction�requirements.If�the�threshold�amount�is�exceeded,�thestandard�requires�the�facility�to�developa�written�reduction�plan�that�includesidentifying�the�criteria�to�evaluate�thenecessity�of�using�an�MeCl-based�paintstripper,�using�alternative�methods�forfinish�removal�where�applicable,�andmaintaining�records�of�the�amountof�MeCl�stripper�that�has�been�used.It�is,�however,�a�good�practice�toreduce�the�amount�of�MeCl�used�eventhough�the�regulation�does�not�requirereduction.�Some�alternative�finish�removaltechniques�and�processes�include:

• using�a�non-MeCl�or�low-MeClcontent�paint�remover.

• mechanical�finish�removalprocesses.�Sanding�or�grindingthe�finish�is�an�alternative�to�usingpaint�strippers.

• blasting�with�water,�sand,�andother�media.

When�using�a�paint�stripper�containingMeCl,�placing�a�sheet�of�plastic�film�overthe�finish�can�reduce�the�overall�amountof�vapors�that�are�emitted.�This�reducesthe�amount�of�evaporative�loss�of�the�paintstripper,�equating�to�less�total�amount�ofstripper�required�to�remove�a�finish.

Refer�to�“Video:�MeCl�Paint�Stripper”�inthe�presentation.�This�video�discussesconcepts�on�how�to�reduce�the�amount�ofMeCl-based�paint�stripper�used.

Sanding

This�is�a�common�vacuum�sander�with�HVLVventilation.

Dust�created�during�the�sanding�processmay�contain�toxic�materials�such�asisocyanates,�lead,�chromium,�and�silicathat�are�harmful�to�the�lungs�and�nervoussystem.�Use�of�a�High�Velocity�LowVolume�(HVLV)�vacuum�sanding�systemcan�protect�workers�and�others�nearbyfrom�harmful�dust.

When�used�and�maintained�properly,vacuum�sanders�can�control�93�-�98%�of

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the�dust�generated�from�the�disc�sandingoperation.

Central�vacuum�sander�systems�produce�sufficientsuction�to�handle�up�to�twenty�technicians�sandingat�the�same�time.

Central�vacuum�systems�consistof�multiple�vacuum�sanding�dropsconnected�to�a�central�vacuum�systemby�means�of�retractable,�flexible�hosing.Such�systems�produce�sufficient�suctionto�handle�up�to�four�to�twenty�technicianssanding�at�the�same�time.

A�portable�unit�can�be�easily�moved�to�where�thesanding�has�to�be�performed.

Self-contained�(portable)�units�aredesigned�for�operation�by�one�to�threetechnicians�at�the�same�time.�The�unitcomes�with�attached�wheels�and�can�beeasily�moved�from�one�location�to�another

in�the�shop,�depending�on�where�thesanding�has�to�be�performed.

Refinishing�Materials

This�pie�chart�indicates�that�solvents�make�up�about60%�of�the�total�refinishing�material�formulation.

Solvents�traditionally�make�up�about60%�of�the�total�formulation.�Solvents�areadded�to�coatings�to�disperse�the�otherparts�of�the�formulation�and�to�reduceviscosity,�thereby�enabling�application�ofthe�coating.

Solvents�are�a�major�source�ofenvironmental�concern�because�at�normaltemperatures�and�pressures�they�canvolatilize�(i.e.,�the�liquid�solvent�becomesa�vapor).

This�pie�chart�indicates�that�binders�account�for30%�of�the�total�refinishing�material�formulation.

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Binders�account�for�30%�of�materialformulation.�Binders�are�liquid�polymericor�resinous�materials�that�are�used�incoatings�to�hold�the�pigment�and�additivestogether,�to�provide�adhesion,�and�toenable�the�coating�to�cure�into�a�thinplastic�film.

The�binder�provides�the�workingproperties�of�the�coating�and�determinesthe�performance�of�the�film,�includingflexibility,�durability,�and�chemicalresistance.

This�pie�chart�indicates�that�pigments�account�for�7�-8%�of�the�total�refinishing�material�formulation.

Pigments�account�for�7�to�8%�of�materialformulation.�Pigments�are�insolubleparticles�of�organic�or�inorganic�materials,either�natural�or�synthetic,�that�aredispersed�in�a�coating�to�provide�colorand�opacity�to�a�substrate,�or�to�improvethe�substrate's�environmental�resistanceand�the�flow�properties�of�the�paint.

The�type�of�pigment�in�the�paintdetermines�the�color�and�color�stabilityof�the�paint�or�coating,�while�the�amountof�pigment�determines�the�gloss,�hidingpower,�and�permeability�of�the�coating.

Many�pigments�still�contain�lead,chromium,�cadmium,�or�other�heavymetals.�These�paints�cannot�be�disposedof�in�a�landfill�and�must�be�handled�asa�hazardous�waste�because�the�heavymetals�can�leach�out�of�landfills�andcontaminate�groundwater.�The�fourcommonly�recognized�classes�of�pigmentsare:

• colored�pigments�such�as�red,yellow,�black�iron�oxide,�blue,�andgreen.

• white�pigments.• metallic�pigments�including

texture,�flake�aluminum�(sparkle /metallic�appearance),�andpearlescence.

• functional�pigments�such�aslimestone�and�clay�(fillers),preservatives�against�mold,mildew�or�bacteria,�and�UVstabilizers.

This�pie�chart�indicates�that�additives�make�upthe�last�2�to�3%�of�the�total�refinishing�materialformulation.

Additives�make�up�the�last�2�to�3%�of�thepaint�components.�Additives�are�materials

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that�improve�the�physical�and�chemicalproperties�of�the�coating.

Self-etching�primer�products�have�applicationmethods�that�do�not�require�spray�atomization�of�theproduct.

When�bare�metal�is�exposed,�it�isnecessary�to�apply�a�primer�that�willadhere�to�bare�metal�and�providecorrosion�resistance.�Primers�are�thefoundation�for�the�outer�finish.�There�areseveral�different�types�of�products�thataccomplish�this.

Self-etching�primers�and�epoxy-basedprimers�are�two�common�types�of�primersthat�provide�adhesion�of�the�topcoatsand�corrosion�resistance.�Self-etchingprimers,�also�called�wash�primers,generally�contain�an�additive�or�acid�thatchemically�etches�the�metal,�allowingexcellent�adhesion�to�the�bare�metal.Epoxy�primers�generally�consist�of�anepoxy�resin�and�a�catalyst�or�hardener.One�benefit�of�an�epoxy�primer�is�that�thecatalyzed�product�dries�in�a�permanentsolid�state.�Some�epoxy�primers�require�ametal�etching�or�conditioning�product�tobe�applied�before�the�application�of�theepoxy�primer.

These�products�typically�contain�aphosphate�coating�or�an�acid�to�cleanand�etch�the�bare�metal.�Within�the�lastseveral�years,�refinish�product�makershave�reduced�the�amount�of�heavy�metalsthat�were�typically�used�for�priming�andcorrosion-resistance�treatment�to�baremetals.�Lead-free�or�chromate-free�primershave�been�introduced�that�reduce�theamount�of�heavy�metals�that�are�releasedinto�the�environment.

Primer-surfacer�that�was�not�allowed�to�completelycure�typically�causes�a�condition�called�sandscratchswelling.

The�purpose�of�a�primer-surfacer�is�tofill�minor�surface�imperfections�that�maybe�present�in�an�area�where�damageto�a�finish�has�been�repaired.�Primer-surfacers�may�also�be�called�primer�fillers.Most�primer-surfacers�are�made�fromtalc�and�urethane�resins.�The�talc�is�usedto�fill�imperfections,�including�sandingscratches,�pinholes,�and�broken�paintedges.�The�urethane�resins�cure�througha�chemical�reaction�with�a�hardener�orcatalyst.�This�may�be�referred�to�as�a�2-part�or�2K�product.

Primer-surfacers�are�generally�appliedthrough�a�spray�gun.�Some�primer-

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surfacers�are�mixed�with�a�thinner�orreducer�that�makes�the�material�thinnerand�easier�to�atomize�during�sprayapplication.�The�thinner�evaporates�outof�the�sprayed�product.�After�the�primer-surfacer�has�cured,�the�surface�is�sandedwith�a�fine�sandpaper�to�make�the�finishsmooth,�and�the�sandscratches�or�otherimperfections�are�filled�in.

Variance�decks�can�be�used�to�help�identify�anacceptable�color�formula�to�match�the�original�color.

The�chemical�makeup�of�most�primer-sealers�is�very�similar�to�a�primer-surfacer.The�major�difference�is�that�there�istypically�a�higher�concentration�ofresins�to�talc�than�a�primer-surfacer.�Thepurpose�of�a�primer-sealer�is�to�providea�smooth�foundation�and�uniform�colorfor�the�new�topcoats.�Due�to�the�lowerconcentration�of�talc,�there�are�lessfilling�characteristics.�Primer-sealer�is�notintended�to�fill�imperfections.�Primer-sealers�are�generally�not�sanded�unlessthere�is�debris�in�the�sealer�coat.�Primer-sealers�typically�require�a�reducer�tomake�the�primer-sealer�thinner�and�moreviscous.�This�helps�with�the�atomizationduring�spraying�applications.

Some�undercoats�can�be�applied�directly�to�cleanbare�metal.

Some�refinishing�product�makers�havedeveloped�undercoats�that�can�beapplied�directly�to�clean�bare�metal.These�products�typically�provide�fillingcharacteristics�as�well�as�resistance�tocorrosion.

Single-stage�finishes�are�still�common�in�the�truckingindustry�and�for�fleet�vehicles.

The�color�and�final�appearance�of�thevehicle�is�dependent�on�the�topcoats.Nearly�all�vehicles�are�finished�with�abasecoat�that�provides�the�vehicle�colorand�a�clearcoat.�Single-stage�topcoats�orfinishes�provide�the�color�and�protectionfrom�the�environment.�Single-stagefinishes�are�still�common�in�the�truckingindustry�and�for�fleet�vehicles.�Mostvehicle�finishes�are�multi-stage,�meaning

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a�basecoat�and�a�clearcoat�are�applied�atthe�factory.

There�is�a�trend�toward�the�use�of�waterbornebasecoats.

Basecoat�consists�of�pigment�that�providesthe�color.�Basecoats�traditionally�area�solvent-based�product�where�thepigments,�additives,�and�resins�arecombined�to�match�the�desired�color.�Thebasecoat�is�typically�combined�with�areducer�to�allow�it�to�be�atomized�duringspray�application.�Basecoats�are�appliedto�a�prepared�substrate.�The�basecoat�mayrequire�blending�techniques�or�tinting�tomatch�the�original�vehicle�color.

Today�there�is�an�ever�increasing�use�ofwaterborne�basecoats.�Instead�of�usingpetroleum-based�resins�and�solvents�inthe�basecoat,�water�soluble�solutionsand�resins�are�used.�Waterborne�refinishproducts�still�contain�hazardous�airpollutants,�although�the�solid�content�ishigher�than�a�solvent-based�product.�Thisequates�to�less�VOCs�emitted�during�thespray�application�process.�The�applicationof�clearcoat�is�required�to�protect�thebasecoat�from�ultraviolet�(UV)�radiationfrom�the�sun.

Clearcoat�is�typically�a�petroleum-based�product,although�there�has�been�some�advancement�recentlyin�the�development�of�a�waterborne�clearcoat�that�iseffective�for�automotive�use.

Clearcoat�is�a�non-pigmented�coating�thatprovides�chemical�and�scratch�resistanceto�the�finish.�Clearcoat�also�provides�thefinish�with�resistance�to�deteriorationfrom�the�sun’s�UV�radiation.�Clearcoat�istypically�a�two-part�product�that�cures�bychemical�crosslinking�using�a�hardeneror�activator.�To�assist�in�the�atomizationof�the�clearcoat,�there�may�be�a�reduceror�thinner�added�to�the�clearcoat.�Likebasecoats,�there�are�both�solvent-borneand�waterborne�clearcoats�available�forrefinishing.

Product�Mixing

Some�refinishing�product�makers�provide�formulasfor�mixing�and�reducing�products�with�a�digital�scale.

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One�of�the�most�important�considerationswhen�applying�coatings�is�to�ensure�thatthe�products�are�mixed�correctly.�It�isalso�important�to�mix�only�the�requiredamount�of�material.�This�keeps�theamount�of�hazardous�air�pollutants�andhazardous�solid�waste�to�a�minimum.�Pastexperience�may�be�helpful�when�makingthe�determination�of�how�much�productto�mix.

Refinish�product�makers�provide�mixinginstructions�on�the�product�informationsheets.�Most�products�are�requiredto�achieve�a�specific�amount�of�VOCreduction.�This�means�that�the�amountof�solvents�that�evaporate�during�use�canonly�be�a�certain�amount�or�percentageof�the�product.�Therefore,�it�is�crucial�thatproducts�be�mixed�correctly�using�therecommended�products�and�procedures.Exceeding�the�amount�of�reducersor�solvents�that�the�product�makerrecommends�will�make�the�product�non-compliant.

Mixing�ratios�can�be�referenced�todetermine�how�much�reducer�or�hardenershould�be�added�to�the�product.�Thiswill�ensure�that�the�product�will�be�thinenough�to�be�spray-applied,�yet�notexceed�the�amount�of�VOCs�that�arepermitted.

Some�mixing�methods�include�using�adigital�scale�to�mix�the�product�accordingto�the�manufacturer’s�recommendations,measuring�in�a�calibrated�mixingcup,�or�measuring�the�viscosity�of�theproduct�with�a�viscosity�cup.�Mostrefinishing�product�makers�have�weight

measurements�for�mixing�a�product�sothat�the�correct�amount�of�reducers�andhardeners�are�added�when�mixing�on�thedigital�scale.

Spray�Environment

Spray-applied�coating�application�should�take�placein�an�enclosed�environment.

The�final�rule�requires�that�refinishingand�coating�products�be�applied�in�anapproved�prep�station�or�an�enclosedspraybooth.�The�spray�environment�isrequired�to�have�at�least�three�completewalls�or�curtains�and�a�ceiling�coveringthe�entire�spray�area.

The�spray�area�must�have�filters�made�offiberglass�or�other�media�that�is�at�least98%�efficient.�This�means�that�98%�of�theoverspray�from�the�spray�application�iscaptured�in�the�filters.

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In�a�downdraft�spray�booth,�air�flows�from�the�ceilingdownward�to�the�filters�in�the�floor.

There�are�several�types�of�sprayboothsused�in�a�collision�repair�facility.�Oneof�the�more�common�is�a�downdraftspraybooth.�A�downdraft�sprayboothoperates�by�drawing�air�in�from�the�ceilingand�exhausting�out�through�the�floor.There�are�typically�intake�filters�in�theceiling�that�filter�the�air�coming�into�thespraybooth�and�filters�in�the�floor�to�trapoverspray.

A�crossdraft�spraybooth�typically�has�intake�filters�inone�end�of�the�spraybooth�and�overspray�filters�inthe�other�end.

Another�type�of�spraybooth�is�a�crossdraftspraybooth.�A�crossdraft�sprayboothtypically�has�intake�filters�in�one�end�ofthe�spraybooth�and�overspray�filters�in�theother�end.

Consult�your�local�fire�code�to�see�if�sprayapplication�of�coatings�is�allowed�in�a�prep�station.

Prep�stations�are�another�type�of�sprayenvironment�that�is�often�used�in�acollision�repair�facility.�These�typicallyhave�the�same�type�of�makeup�as�adowndraft�spraybooth,�with�the�exceptionof�the�walls.�Prep�stations�typically�havecurtains�on�two�or�three�sides,�instead�of�asolid�wall.�Most�prep�stations�will�qualifyfor�a�spray�environment�under�the�EPAFinal�Rule�as�long�as�the�curtains�reach�allthe�way�to�the�floor�and�there�is�a�filtrationsystem�to�trap�overspray.

Some�local�or�state�regulations�prohibitthe�application�of�coatings�in�a�prepstation.�Before�using�a�prep�stationfor�coating�application,�always�checkthe�local�or�state�regulations�to�verifyif�coatings�may�be�applied�in�thisenvironment.

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Spraybooth�Operation

This�magnahelic�measures�the�amount�of�pressureinside�the�spraybooth.

Spraybooth�pressure�may�be�determinedwith�a�measuring�device�called�amanometer�or�a�magnahelic.�Both�devicesmeasure�the�air�pressure�inside�thespraybooth�as�opposed�to�the�pressureoutside�the�spraybooth.�Nearly�everyspraybooth�will�have�some�type�ofpressure�measuring�device.�The�final�rulerequires�that�positive�pressure�be�no�morethan�0.05"�of�water.

This�image�shows�the�magnahelic�indicating�therange�of�air�pressure�readings�found�in�a�spraybooth.

Spraybooths�typically�have�adjustmentsfor�the�amount�of�air�pressure�that�is�inthe�spray�environment.�The�adjustmentsmay�increase�or�decrease�the�amount�ofair�entering�and�exiting�the�spraybooth.When�more�air�is�entering�the�spraybooththan�is�removed,�it�is�considered�to�havepositive�pressure.�Negative�pressure�will

draw�out�more�air�than�what�is�supplied.The�final�rule�suggests�that�negativepressure�should�be�used,�as�this�methoddraws�the�most�overspray�through�thefilters.

Most�downdraft�spraybooth�manufacturersrecommend�a�slight�amount�of�positivepressure�to�reduce�the�amount�of�debristhat�could�enter�the�spray�environment.As�long�as�the�spraybooth�has�doorsand�other�openings�that�are�completelysealed�and�the�spraybooth�is�equippedwith�a�pressure�balancing�system,�aslight�amount�of�positive�pressure�can�becreated.

Filter�Replacement

Considerable�positive�pressure�is�a�indication�thatthe�filters�should�be�inspected�and�replaced�ifnecessary.

High�positive�pressure�is�an�indicatorof�when�the�spraybooth�filters�requirereplacement.�When�there�are�increasedpositive�pressure�readings,�less�materialis�able�to�flow�through�the�filters.The�positive�pressure�will�push�theoverspray�outside�of�the�spray�area.When�the�pressure�indicates�that�thereis�considerable�positive�pressure�thatcannot�be�adjusted�through�the�ventilation

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system,�the�filters�should�be�inspected�andreplaced�if�necessary.

Some�local�regulations�may�require�spraybooth�filtersto�be�handled�as�hazardous�waste.

When�replacing�the�filters,�the�used�filtersshould�be�disposed�of�following�state�orlocal�regulations.�The�residue�from�thefilters�may�contain�hazardous�materials.The�replacement�filters�should�be�at�least98%�efficient.

Refer�to�“Video:�Replace�Filters”�inthe�presentation.�This�video�discussesconcepts�on�how�to�replace�filters�in�aspraybooth.

Spray�Gun�Types

Being�familiar�with�the�spray�gun�settings�andadjustments�will�help�ensure�a�quality�finish�andreduce�the�amount�of�overspray�that�is�created.

The�EPA�final�rule�requires�that�spray�gunsthat�are�used�in�the�automotive�refinishingprocess�exhibit�a�transfer�efficiency�of�atleast�65%.�This�means�that�65%�of�theproduct�that�is�applied�is�transferred�tothe�part�or�object�that�is�being�coated.It�is�the�responsibility�of�the�spray�gunequipment�manufacturer�to�test�the�gunto�be�certain�that�this�transfer�efficiency�isachieved.�If�65%�of�the�refinish�materialis�applied�to�the�part,�the�remaining�35%ends�up�being�overspray.�High-volume,low-pressure�(HVLP)�spray�guns�arerecommended�by�the�EPA�final�rule.�Someother�guns�that�may�meet�the�65%�transferefficiency�include�reduced�pressure�(RP)spray�guns,�or�low-volume,�low-pressure(LVLP)�spray�guns.

One�important�consideration�when�usingHVLP�spray�guns�is�that�the�gun�mayrequire�a�larger�volume�of�air�as�opposedto�a�traditional�spray�gun.�A�typicalHVLP�spray�gun�will�require�around�15cubic�feet�per�minute�(cfm)�of�airflow,although�the�amount�of�air�pressure�isreduced.�Traditional�high�pressure�sprayguns�typically�require�around�10�cfm.�To

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meet�the�air�supply�demands�of�HVLPequipment,�a�larger�compressor�may�berequired.

The�advantage�of�using�HVLP,�RP,�orLVLP�spray�guns�is�a�reduction�in�refinishproduct�costs.�Because�HVLP�gunshave�increased�transfer�efficiency�overa�traditional�high-pressure�spray�gun,more�material�is�applied�to�the�objectbeing�coated.�This�creates�less�oversprayand�reduces�the�amount�of�total�materialrequired�to�achieve�the�proper�coverageand�film�thickness.�Although�a�spray�gunis�considered�to�be�HVLP,�the�spray�gunadjustments�must�be�made�accordingto�the�instructions�provided�by�the�gunmanufacturer.�An�HVLP�gun�with�an�inputair�pressure�exceeding�the�recommendedpressure�will�produce�excessive�oversprayand�will�not�meet�the�transfer�efficienciesrequired�by�the�EPA�final�rule.

This�spray�gun�is�a�gravity�feed�spray�gun.

Gravity�feed�spray�guns�are�commonlyused�in�a�collision�repair�facility.�Witha�gravity�feed�spray�gun,�the�refinishmaterial�flows�down�to�the�gun�head.A�needle�and�seat�regulate�the�amountof�refinish�material�that�is�provided�tothe�fluid�tip�and�air�cap.�Air�pressureis�routed�through�the�gun�body�and�is

directed�out�of�the�air�cap.�Holes�in�theair�cap�direct�the�airflow,�which�makes�thepattern.�This�airflow�atomizes�the�refinishmaterial,�breaking�it�into�tiny�droplets.HVLP�spray�guns�use�a�large�volume�of�airat�a�reduced�air�pressure�to�atomize�therefinish�material.

This�spray�gun�is�a�siphon�feed�spray�gun.

Siphon�feed�guns�are�also�common�ina�collision�repair�facility.�With�a�siphonfeed�gun,�the�refinish�material�is�drawnup�through�a�tube�by�a�vacuum�that�iscreated�through�a�venturi�in�the�air�cap.As�air�pressure�flows�through�the�gun,�therefinish�material�is�drawn�up�to�the�gunhead.�The�needle�and�seat�regulate�theamount�of�refinish�material�provided�tothe�fluid�tip�and�air�cap.�The�holes�on�theair�cap�direct�the�airflow�across�the�fluidtip,�atomizing�the�refinish�material�intosmall�droplets.

A�variation�of�a�siphon�feed�gun�is�apressure�feed�gun.�With�this�type�of�gun,regulated�air�pressure�is�applied�to�the�topof�the�gun�cup.�The�pressure�causes�thefluid�to�be�pushed�up�through�the�pickuptube�and�into�the�gun�head.

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Air�brushes�that�can�hold�no�more�than�3�fluidounces�of�refinishing�material�are�exempt�from�theHVLP�requirement.

Exemptions�from�the�EPA�final�ruleinclude�airless�sprayers�and�guns�that�havea�cup�that�holds�no�more�than�3.0�fluidounces�of�refinish�material.

Gun�Adjustments

Use�proper�gun�adjustments,�techniques,�and�airpressure�to�eliminate�orange�peel�finish.

Spraying�too�fast�or�using�air�pressure�that�is�too�highcan�cause�dry�spray.

Applying�a�finish�with�a�spray�gunrequires�a�great�deal�of�technique�andgun�adjustments.�The�overall�appearanceof�the�finish�depends�greatly�on�theatomization�of�the�material.�If�the�paintdroplets�are�not�properly�atomized,�theywill�land�on�the�surface,�giving�an�orangepeel�appearance.�Having�too�muchatomization�may�produce�a�dry-sprayeffect.

Most�refinishing�product�makers�havespecific�recommendations�on�gun�setupand�adjustments�for�specific�productsand�types�of�guns.�Following�the�refinishproduct�maker’s�recommendations�for�gunsetup�is�a�good�starting�point�for�properlyapplying�a�finish.

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Spray�gun�needles�and�fluid�tips�are�generallymachined�together�and�are�not�interchangeable.

Most�spray�guns�have�different�fluidneedle�and�fluid�tip�sizes�for�a�specifictype�of�product.�The�size�regulates�howmuch�material�is�released�at�the�air�cap.Larger�size�fluid�needles�and�fluid�tipsare�generally�used�for�products�that�arethicker�or�more�viscous�than�are�used�forbasecoats�that�are�generally�thinner.

The�needle�and�fluid�tips�are�generallymachined�as�a�matched�pair.�Somecommon�sizes�are�1.3�-�1.8�mm�needleand�fluid�tips.

This�pressure�regulator�allows�air�pressureadjustments�at�the�spray�gun�air�inlet.

A�spray�gun�has�three�main�adjustments.

The�air�input�adjustment�regulates�theamount�of�air�that�passes�through�the�gunbody.�Excessive�air�pressure�will�result�in�adry�finish�and�excessive�overspray.

The�fluid�flow�adjustment�regulates�howmuch�paint�is�allowed�to�pass�through�thefluid�needle�and�seat.

The�fan�adjustment�regulates�how�muchair�passes�through�the�air�horn�passagesof�the�air�cap.�Increasing�the�amount�ofair�creates�an�oval-shaped�pattern,�anddecreasing�the�amount�of�air�creates�around�pattern.

Most�HVLP�spray�guns�have�the�maximum�airpressure�identified�on�the�spray�gun�body.

The�amount�of�air�pressure�at�the�air�capis�what�provides�the�atomization�to�therefinish�material.

If�there�is�too�much�air�cap�pressure,�therewill�be�excessive�overspray�as�there�is�alarge�amount�of�atomization.�Generally,the�cap�pressure�should�not�exceed�10psi.�Some�gun�manufacturers�have�amaximum�input�pressure�stamped�orengraved�on�the�gun�body.�This�pressureshould�not�be�exceeded�as�it�will�produce

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excessive�air�cap�pressure.�As�the�inputpressure�increases,�the�air�cap�pressureincreases.�Also,�the�air�cap�pressurewill�change�as�the�fan�adjustment�ischanged.

Refer�to�“Video:�Spray�Gun�Adjustments”in�the�presentation.�This�video�discussesconcepts�on�how�a�spray�gun�is�adjustedfor�input�air�pressure,�air�cap�pressure,fluid�adjustment,�and�fan�adjustment.

Operation�Techniques

Transfer�efficiency�variables�must�be�mastered�toreduce�the�amount�of�HAPs�generated.

When�applying�a�finish�with�a�spray�gun,there�are�several�different�variables�thatwill�affect�the�transfer�efficiency.�Thegun�travel�speed�and�gun�distance�to�theobject�are�variables�that�will�affect�theamount�of�HAPs�generated�during�the

spray�application.�These�variables�can�alsoaffect�the�final�appearance�of�the�finish.Most�refinishing�product�makers�haverecommendations�for�gun�distance�whenapplying�a�specific�product.

The�final�appearance�of�the�finish�is�dependent�onthe�proper�atomization�of�the�material.

The�final�appearance�of�the�finish�isdependent�on�the�proper�atomization�ofthe�material.�The�finer�the�atomization,the�smoother�the�finish�will�be.Atomization�is�dependent�on�severalvariables,�including�the�viscosity�of�thematerial,�the�speed�of�the�reducer,�theamount�of�air�pressure�that�is�used,�andspray�gun�technique.

Since�the�final�rule�and�VOC�regulationsprohibit�over-reduction�of�refinishmaterials,�and�HVLP�spray�guns�limitthe�amount�of�pressure�that�is�used�toatomize�the�product,�spray�gun�operationtechnique�is�often�used�to�influence�thefinal�appearance�of�the�finish.

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Refer�to�“Video:�Atomization”�in�thepresentation.�This�video�discusses�howimportant�atomization�is�to�the�finalappearance�of�the�finish.

Spray�gun�travel�speed�that�is�too�slow�can�causesags�in�the�finish�material.

The�travel�speed�of�a�spray�gun�shouldbe�consistent.�If�the�travel�speed�is�tooslow,�the�material�may�sag�and�run.�Thistype�of�finish�is�unacceptable�and�willneed�to�be�sanded�down�and�possiblyreapplied.�If�the�travel�speed�is�too�fast,the�material�lays�down�dry�with�a�roughtexture.�This�finish�will�not�present�anacceptable�topcoat�appearance.

Inconsistent�spray�gun�overlap�can�result�in�a�stripingeffect.

When�spraying�refinish�materials,�anadequate�and�sufficient�overlapping�of�thematerial�is�required.�Typically,�an�overlapof�75%�is�recommended�to�get�completecoverage�and�hiding�of�the�materialbeing�sprayed.�When�applying�metallicor�special�effect�finishes,�keeping�theoverlap�consistent�is�crucial.�If�the�overlapis�inconsistent,�striping�and�mottling�of�thefinish�may�occur.

Spray�gun�setback�can�have�effects�similar�to�that�oftravel�speed.

Spray�gun�setback�can�have�effects�similarto�that�of�travel�speed.�A�spray�gun�thatis�too�close�will�have�a�heavy�materialdeposition.�This�will�result�in�runs�andsags.�These�defects�will�require�removal.If�the�spray�gun�distance�is�too�far�away

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from�the�surface,�the�result�is�a�dry,�roughtexture,�or�poor�coverage.

The�spray�gun�angle�is�typically�held�at�90º�to�thepanel�being�refinished.

When�applying�a�finish�with�a�spraygun,�it�is�important�to�hold�the�spray�gunperpendicular,�or�at�90�degrees,�to�theobject.�An�exception�to�this�may�be�whenthe�finish�is�being�blended�to�achieve�acolor�match.�In�this�case,�a�techniquecalled�“fanning”�the�spray�gun�is�usedto�taper�off�the�amount�of�finish�that�isapplied.

All�of�the�variables�in�spray�gun�techniquecan�be�used�to�reduce�HAP.�By�movingthe�spray�gun�closer�and�moving�at�afaster�travel�speed,�less�overspray�isgenerated�than�if�the�gun�is�held�furtheraway�and�the�travel�speed�is�reduced.

Spray�Gun�Cleaning

Special�equipment�is�available�for�cleaning�sprayguns�without�atomizing�the�cleaning�solvent.

Atomization�of�solvents�and�remainingrefinish�materials�when�cleaning�a�spraygun�is�a�source�of�air�pollution.

A�traditional�method�of�cleaning�a�spraygun�included�spraying�solvent�throughthe�spray�gun.�Traditional�siphon-feedguns�required�this,�as�it�was�difficult�toget�solvents�into�the�gun�head.�Othertechnologies,�including�gravity�feed�sprayguns�and�enclosed�gun�cleaners,�havemade�it�possible�for�cleaning�to�be�donewithout�atomization�of�the�solvent.

The�final�rule�requires�that�all�spray�guncleaning�be�done�in�an�enclosed�guncleaner�that�pumps�a�cleaning�solventthrough�the�gun.�If�a�facility�does�nothave�a�spray�gun�cleaner,�the�gun�can�bemanually�cleaned�as�long�as�the�solvent�isnot�atomized�through�the�gun.

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Refer�to�“Video:�Spray�Gun�Cleaning”�inthe�presentation.�This�video�discusses�howa�spray�gun�is�cleaned�in�several�types�ofautomated�spray�gun�cleaners.

Some�refinishing�product�makers�may�have�a�specificcleaning�solvent�for�waterborne�finishes.

Waterborne�refinishing�products�maypose�some�additional�challenges�whencleaning�spray�guns.�Since�a�specialcleaning�solvent,�water,�or�a�combinationof�water�and�denatured�alcohol,�is�usedto�clean�the�spray�guns,�the�same�spraygun�cleaning�equipment�cannot�be�usedto�clean�a�gun�that�is�used�to�spray�asolvent-based�product.�Water�may�causecorrosion�to�the�parts�of�a�spray�gun.Therefore,�the�spray�gun�may�have�fluidpassages�and�internal�parts�made�ofstainless�or�coated�steel,�specificallydesigned�for�applying�a�waterborne

product.�Some�paint�gun�manufacturersmay�specify�de-ionized�water,�a�specialcleaning�solvent,�or�isopropyl�alcoholto�clean�up�equipment�used�to�mix�andapply�waterborne�products.

Waste�that�is�generated�from�waterborneproducts�does�contain�hazardousmaterials.�The�water�or�solvents�usedto�clean�spray�equipment�should�bedisposed�of�as�hazardous�waste.�Aseparate�waste�disposal�containershould�be�used�so�that�solvent-basedand�waterborne�waste�do�not�get�mixedtogether.�The�waterborne�waste�should�notbe�washed�down�a�drain.

When�disposing�of�liquid�or�solidhazardous�waste,�check�with�local�or�stateregulations�concerning�the�requirementsof�disposal.

Module�Wrap�Up

Topics�discussed�in�this�moduleincluded:

• how�to�reduce�the�amount�ofmethylene�chloride�(MeCl)�paintstripper�that�is�used.

• spraybooth�requirements�and�filtermaintenance�schedules.

• spray�application�techniques�andgun�adjustments�that�reduce�theamount�of�HAP�released�into�theenvironment.

• spray�gun�cleaning�requirements.