Fremont 's

Severa l f a c t o r s a r e involved i n choosing a s t r i p p i n g method: Type of p a i n t , base ma te r i a l of p a r t , t i m e r equ i r ed t o s t r i p , shape o f p a r t , and a v a i l a b l e equipment'.

For s t r i p p i n g smaller p a r t s , e i t h e r s i n g l y o r i n volume, tank immersion i s recommended. If the p a r t t o b e s t r i p p e d i s r e l a t i v e l y f l a t , wi th unbroken su r faces , e i t h e r t he h o t o r co ld method can be used w i t h good r e s u l t s . I n case's where t h e p a r t s have a number of turns and recessed a r e a s , t h e p a r t s should b e p r e - t e s t e d t o determine whether c o l d o r h o t s t r i p p i n g would be more e f f e c t i v e .

For p a r t s t h a t a r e too l a rge o r cumbersome t o be immersed i n a tank , o r f o r v e r t i c a l s u r f a c e s , a brush-on s t r i p p e r i s recom- mended. A s w i t h p a r t s s t r i p p e d i n a tank , brush-on s t r i p p e r s a r e r i n s e d with cold water from a nozzled hose. Do not use ho t water t o r i n s e ; hot water c r e a t e s more so lven t vapors and tends t o r e -depos i t ma te r i a l onto the s t r i p p e d s u r f a c e .

\

The type o f ma te r i a l t o be s t r i p p e d a l s o he lps determine t h e s t r i p p i n g method. Most non-ferrous metals w i l l r e a c t with t h e c a u s t i c m a t e r i a l s i n hot a l k a l i n e s t r i p p e r s . The a c t i v e m a t e r i a l i n c a u s t i c s t r i p p e r s i s quickly consumed with each non-ferrous p a r t , thus k i l l i n g the tank.

Oftent imes, s t r i p p e r s a r e chosen t o be compatible with e x i s t i n g equipment. I f you have an unheated tank , bu t do not wish t o go t o t h e expense o f i n s t a l l i n g an immersion h e a t e r , co ld so lven t s t r i p p e r s a r e the only a l t e r n a t i v e . However, co ld s t r i p p e r s r e q u i r e more v e n t i l a t i o n . If present equipment i s not adequate t o handle so lvent vapors , t he cos t of i n s t a l l i n g a d d i t i o n a l equipment must be taken i n t o cons idera t ion . F i n a l l y , i f i t i s undes i rab le t o i n s t a l l any kind of tank, cold so lven t brush-on s t r i p p e r s a r e t h e only a l t e r n a t i v e .

COMPARING HOT AND COLD S T R I P P E R S

The p e r f e c t s t r i p p e r has y e t t o be formulated. which w i l l remove a l l f i n i s h e s from a l l s u r f a c e s . And because o f t h e development o f i n c r e a s i n g l y complex and durable coa t ings and f i n i s h e s , new s t r i p p e r s a r e becoming more s p e c i a l i z e d than be fo re .

There a r e four b a s i c types o f s t r i p p e r s : Hot o r co ld , a c i d o r a l k a l i n e . Hot s t r i p p e r s a r e used i n d ip tanks . They a r e s t r o n g l y a lka l i l i e ma te r i a l s t h a t a r e nixed with water and heated t o , o r n e a r , the b o i l i n g po in t . The high a l k a l i n i t y d i s so lves the p a i n t , and i s u s e d up i n t h e process . becomes a l i t t l e more contaminated and a l i t t l e weaker.

There i s no product

A s each p iece i s s t r i p p e d , t h e s o l u t i o n

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S T R I P P I N G ACTION - HOT ALKALINE PROCESS

Hot s t r i p p i n g r equ i r e s h e a t and a g i t a t i o n t o be most e f f e c t i v e . Agi ta t ion may be produced e i t h e r mechanica l ly , by a i r , o r through the b o i l i n g a c t i o n o f t h e so lu t&on. A s a gene ra l r u l e , s t r i p p i n g e f f i c i e n c y doubles for every 10 F . i n c r e a s e i n temperature , no t i ce - ably a f t e r 200UF. Ag i t a t ion s i g n i f i c a n t l y reduces s t r i p p i n g t ime.

An advantage of t he h o t s t r i p p i n g system i s t h a t t h e i n i t i a l cos t p e r ga l lon i n s o l u t i o n i s usua l ly lower than wi th co ld s t r i p p e r s . I n use , however, t h e o v e r a l l c o s t s can go up o r down, depending on: Type of f i n i s h removed; s t r i p p i n g t i m e ; and type o f p a r t . Heating t h e tank a l s o r e s u l t s i n h ighe r energy c o s t .

Cold s t r i p p e r s conta in s o l v e n t s . They work by f i r s t p e n e t r a t i n g the f i n i s h , then breaking t h e bond between t h e f i n i s h and t h e sur face of t h e p a r t . They do n o t need t o b e heated i n o rde r t o work, and they do not have t o be mixed o r d i s s o l v e d ; they normally come ready-to-use.

\-Metal Surface

STR I PP I NG

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ACTION - COLD SOLVENT PROCESS

2

When cold s t r i p p e r s a r e , p e d f o r immersion, the p a i n t f a l l s t o the bottom of t he tank; p a i n t does , ,not "use up" o r contaminate the s t r i p p e r . Only cold s t r i p p e r s w i l l s t r i p c e r t a i n non-ferrous p a r t s without a t t a c k i n g the base meta l . And o n l y cold s t r i p p e r s can remove the toughest of t o d a y ' s p a i n t s and f i n i s h e s .

The so lven t used i n co ld s t r i p p e r s does evapora te , causing t h e s t r i p p e r t o l o s e s t r e n g t h . Evap- o r a t i o n can be lessened by us ing w a t e r . o r o t h e r s e a l s and by keeping t h e tank covered when no t i n use . To form a water s e a l , one t o two inches of water i s simply f l o a t e d on top of t h e s t r i p p e r tank. Solvent fumes do not e a s i l y pene- t r a t e t h e water .

Frerront I n d u s t r i e s does no t r ec - ommend us ing a water s e a l . Water tends t o absorb t h e a c c e l e r a t o r s i n t h e s t r i p p e r , causing i t t o l o s e s t r e n g t h . You can check

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A l l Fremont co ld so lven t s t r i p - pers con ta in a b u i l t - i n s e a l t o minimize evapora t ion l o s s . On l a r g e r t anks , covers may be con- s t r u c t e d w i t h hinged s e c t i o n s ( s e e i l l u s t r a t i o n ) . When p a r t s of small bulk a r e being s t r i p - ped, p a r t o f t h e cover can be l i f t e d t o expose a smaller s u r f a c e a r e a t o t h e a i r .

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254 B P Soda 1 - 2 l b s l g a l 180-225 NA

-

3060 B P Soda 4-8 o z l g a l 90-100 NA

3030 A L MC AS 1 0 : 4 0 X X

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1 - 2 l b s / g a l w f 105 - B L G l y c o l s l i q u i d c a u s t i c 200-222 8 . 7 6

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F o r S t r i p p i n g P a i n t From T h e s e Base M a t e r i a l s Tank

A l l Fremont powdered s t r i p p e r s are d e - d u s t e d .

Paint Stripper To Strip These Finishes

Special Features Cleans hot melt residue I

Patented! Leaves wood grain and char.

natural color. -----I ~

Evaporation retarded, Low odor.

Long tank life

Strips Scotchlite f rom roadsigns. Highly acce1erated.Heavy duty.Designed to strip insul. from electric wire. Designed for printed circuit industry. 3030 and 3030M remove tough finishes like photo-resist coatings. Vacuum metalized racks and Darts.

Do Not Use On: / I / / / / , I J

Economical, concentrated.Accepts water seal.Strips automotive hooks & grates. x x x X 3 7 I No flash rusting.

Stable. Removes decals. 5 7 No flash rusting. x x x

DO Not Use On:

For hot or cold stripping. No x x x x x x x phenols or chromates.Removes rust

All Fremont strippers contain built-in detergents for easy rinsing

I

Comparing Hot and Cold Strippers HOT ALKALINE STRIPPERS

1.

2.

3 .

4 .

5 .

6 .

7.

ADVANTAGES

Lower cost per gallon in solution.

Vapors pose less health hazard.

Requires less ventilation.

Can be less expensive for stripping parts in volume.

Needs no evaporation retard- ant; does not lose strength from evaporation.

Introducing water does not kill solution.

Removes rust.

1.

2.

3 .

4 .

5.

6 .

7.

8.

DISADVANTAGES

Active ingredient consumed with each part stripped.

More difficult to rinse.

Usually requires heat and agitation.

Not recommended for most non- ferrous metals.

Requires longer stripping time.

Not as effective on tough, modern finishes . Must be diluted with water before use.

Can raise grain and discolor -

COLD SOLVENT STRIPPERS

1.

2.

3 .

4 .

5 .

6 .

7 .

8.

9.

Usually do not need to be diluted.

Active ingredient not con- sumed by dead paint.

Faster stripping action.

Removes all finishes; more effective on tough finishes than hot, solutions.

Needs no heat.

Strips ferrous and non- ferrous metals.

Needs no agitation.

Easier rinsing.

Cold strippers compatible with wood, do not discolor surface or raise grain.

1.

2.

3 .

4 .

5.

Higher cost per gallon.

Solvent evaporates rapidly; causes solution to lose strength

Fumes can pose health hazard.

Easily killed by introducing water.

Vapors can be corrosive to nearby equipment.

6

WHAT SHOULD A GOOD PAINT STRIPPER CONTAIN? e Cold Solvent Type

Solvent Base (Methylene Chloride) Neutral or minimal; no attack on base metal.

Evaporation Retardant

Accelerator Allows faster stripping. Prolongs tank life

Detergent Emulsifier

Corrosion Inhibitor

Minimizes loss of solvent due to evaporation.

by providing more uniform stripping action.

For easier rinsing of stripped parts.

Protects stripped parts and tank against attack. Also prevents consumption of accel- erator.

H o t Alkaline Type

Base Caustic Soda, Caustic Potash

Accelerator Allows faster stripping. Prolongs tank life by providing stripping action even as tank becomes contaminated.

For easier rinsing of stripped parts.

Hot alkaline strippers are diluted in water.

Surface Active Agent

Water

7

TANK LIFE

I REMOVING SLUDGE FROMTANK 1

Regular s ludge removal and f i l - t e r i n g o f t he s t r i p p e r s o l u t i o n w i l l g r e a t l y extend tank l i f e . I n s t a l l i n g removable screens o r w i r e baske ts ( p r e f e r r a b l y s t a i n - less s t e e l ) a t t h e bottom of a co ld s t r i p p e r tank makes i t easy t o s ieve ou t dislodged p a i n t p a r t i c l e s . The pe r fo r - a t i o n s should be 1 / 4 " i n diameter and spaced 1" a p a r t . This i s a very econorr.ica1 system. A l t e r n a t e l y , f i l t e r systems can be i n s t a l l e d which au tomat ica l ly remove p a i n t p a r t i c l e s , bu t they a re d i f f i c u l t t o design and in- s t a l l . They a re economically f e a s i b l e only f o r very l a r g e o p e r a t i o n s .

F i l t e r i n g and removal o f p a i n t s ludge i n h o t tanks is u s u a l l y accomplished by f i r s t a l lowing t h e suspended p a i n t t o s e t t l e . The top th ree - fou r ths o f t h e s o l u t i o n a r e pumped i n t o a hold ing tank . Then t h e s ludge remaining on the bottom i s dumped. This i s t h e l ea s t expensive method, i n terms c f equipment. The e n t i r e con ten t s of t h e tank can a l s o be pumped i n t o cone-shaped s e t t l i n g r ecep tac l e s . . The s ludge accumulates a t t he bottom of t h e cone where i t i s dra ined i n t o b a r r e l s , a f t e r t h e c l a r i f i e d s t r i p p i n g s o l u t i o n has been pump- ed o u t . Automatic f i l t e r i n g s y s t e m s can a l s o be used i n h o t s t r i p - i n g tanks .

EXTENDING TANK LIFE

Hot and Cold Tanks

1. Regular f i l t e r i n g and s ludge removal. 2 . 3 . flake r e g u l a r add i t ions o f s t r i p p e r a s s o l u t i o n i s consumed,

4 . S t r i p p a i n t hooks r e g u l a r l y , be fo re p a i n t becomes too t h i c k .

--

Do not allow s o l i d s l e v e l i n a tank t o go t o o h igh .

evaporated, draggcd out by p a r t s .

Cold Tanks Only

1. 2 . Do no t a l low water t o ge t i n t o tank . 3 . Do no t in t roduce a l k a l i n e chemicals i n t o a c i d s t r i p p e r tanks

Hot Tanks OnQ

1. Maintain proper chemical/water r a t i o . 2 .

3 - D o no t i n t roduce ac.id chemicals i n t o a l k a l i n e s t r i p p e r tanks

Keep tank covered when not i n use t o minimize evapora t ion ,

o r v i sa -ve r sa . --

S t r i p O n l y t hose p a r t s made from a m a t e r i a l f o r which s t r i p p e r w a s des igned , ,normal lv s t e e l o r s t e e l a l l o y s .

o r visa-versa . 8

L - - t -

. I

WHEN TO DUMP

With every p a r t s t r i p p e d , t h e s t r i p p i n g s o l u t i o n lo ses some of i t s s t r e n g t h . Deciding when t o dump t h e tank i n s t e a d of adding f r e s h chemcial i s o f t e n a mat ter of judgement.

For hot a l k a l i n e tanks , t i t r a t i o n w i l l show how much a l k a l i n e m a t e r i a l i s i n s o l u t i o n . This method i s only accu ra t e f o r a s h o r t t i m e a f t e r a f r e s h charge, because a s t h e s t r i p p e r becomes contaminated, with o l d p a i n t , e t c . , t h e f o r e i g n m a t e r i a l i n s o l u t i o n w i l l push the a l k a l i n i t y reading up. Thus, even though t i t r a t i o n shows a high a l k a l i n i t y l e v e l , t h e chemical may be near ly s p e n t , and p a r t s cannot be s t r i p p e d .

The most common method t o judge when t o add more chemical i s when t h e p a r t s take longer t o s t r i p and a r e more d i f f i c u l t t o r i n s e . Remove p a i n t sludge f rom tank. I f performance i s s t i l l u n s a t i s - f a c t o r y , make an add i t ion of s t r i p p e r . I f t h i s d o e s n ' t work, t h e a c t i v e s t r i p p i n t ; ma te r i a l has been consumed, and no amount of a d d i t i o n a l chemical w i l l make a s i g n i f i c a n c e d i f f e r e n c e . Dump t h e tank and re-charge with f r e s h s t r i p p e r .

(When proper ly maintained and by making a d d i t i o n s as r e q u i r e d , co ld so lven t s t r i p p i n g tanks can run f o r y e a r s without dumping.)

6 HOW TO KILL A STRIPPING TANK

1. Process non-ferrous metals i n a h o t a l k a l i n e s t r i p p e r . Caust ic ma te r i a l s r e a c t wi th non-ferrous metals. consuming t h e a c t i v e ing red ien t i n t h e s t r i p p e r . tank i n a mat te r of hours.

This can k i l l t h e u

2. A l l o w too much spent p a i n t t o accumulate i n t h e tank. S t r i p p e r may cont inue t o work on p rev ious ly - s t r ipped p a i n t , consuming a c t i v e i n g r e d i e n t s . Ce r t a in p a i n t r e s i n s and veh ic l e s w i l l a l s o r e a c t with and consume a l k a l i n i t y i n a ho t s y s t e m . i s c a l l e d sapon i f i ca t ion - making soap.

This

3 .

4 . Introduce chrome i n t o t h e s t r i p p i n g tank. Few th ings w i l l contaminate a s t r i p p i n g s o l u t i o n as quick ly a s chrome.

5 . A l l o w t o o much water t o accumulate i n a cold so lven t tank. I f 20 7 water by volume i s mixed i n t h e s t r i p p e r , t h e s o l u t i o n w i l l be de-ac t iva ted .

9

GENERAL HINTS ON PAINT STRIPPING

1.

2 .

3 .

4 .

5 .

6.

Hot s t r i p p i n g i s easier when p a r t s have been r e c e n t l y pa in ted . Af te r p a i n t has been baked, o r aged more than 24 hours , cold s t r i p p l n g i s more effective.

Heating p a i n t hooks r i g h t be fo re h o t a l k a l i n e s t r i p p i n g w i l l o f t e n make it easier t o remove heavy p a i n t accumulation.

Thorough r i n s i n g wi th w a t e r under p r e s s u r e may be necessary t o remove t h e l a s t remaining t r a c e s of p a i n t .

Acid based s t r i p p e r s can make p a r t s more vulnerable t o f l a s h r u s t . recommended immediately a f t e r s t r i p p i n g .

Some form of n e u t r a l i z a t i o n o r co r ros ion p r o t e c t i o n i s

Tanks should be deep enough s o t h a t p a r t s do no t touch t h e s ludge l a y e r on t h e bottom.

When us ing co ld s o l v e n t s t i r i ppe r s , p a r t s can be pul led ou t of t he s o l u t i o n so t h e a i r can evaporate some of t h e so lven t and then r ep laced i n t h e tank . This evapora t ion breaks the p a i n t bond and can speed up s t r i p p i n g t i m e .

10

All persons involved w i t h p a i n t s t r i p p e r s should understand how t o

maximum s a f e t y , people need thorough t r a i n i n g i n how t o proper ly handle p a i n t s t r i p p e r s and the s t r i p p i n g procedure. They a l s o need t o know and understand t h e hazards a s s o c i a t e d wi th p a i n t s t r i p p e r s , t h e f i r s t a i d t rea tment p re sc r ibed i n case of acc iden t s , and t h e proper use of p r o t e c t i v e equipment.

e - work wi th them s a f e l y . To p r o t e c t t h e i r h e a l t h and promote

Basic Sa fe ty Rules:

1. S t o r e o r use s t r i p p e r i n a coo l , dry a r e a .

2 . Keep s t r i p p i n g tanks covered when no t i n use .

3 . C l e a r l y i d e n t i f y s t r i p p i n g tanks by l a b e l i n g them "ACID STRIPPER" o r "ALKALINE STRIPPER".

4 . Dispose of d i r t y o r contaminated s t r i p p e r by p l ac ing i t i n a s u i t a b l e c o n t a i n e r . Local h e a l t h r egu la t ions should be observed i n waste d i s p o s a l of s t r i p p e r s .

5 . Wear p r o t e c t i v e garments and use p r o t e c t i v e equipment.

6 . Avoid any body c o n t a c t wi th s t r i p p e r s . S t r i p p e r s can cause

7. Do n o t take i n t e r n a l l y . S t r i p p e r s may be f a t a l i f swallowed.

s eve re burns t o eyes and s k i n .

@ 8. Use s t r i p p e r s on ly i n we l l v e n t i l a t e d a r e a s .

9 . Do n o t u se open c o n t a i n e r s o r open tanks unless adequate v e n t i - l a t i o n i s provided t o draw vapors away from working a r e a .

10 . A cont inuing s t r o n g o r o b j e c t i o n a b l e odor should n o t be t o l e r a t e d . It i n d i c a t e s excess ive vapor i n t h e a i r . A person who becomes l i f h t headed o r d izzy i n a s t r i p p e r a r e a should leave the a r e a immediately and g e t t o o u t s i d e f r e s h a i r .

Addi t iona l Sa fe ty Rules f o r Caus t ic Soda Based Powders:

1. Powdered s t r i p p e r s w i l l gene ra t e h e a t when added t o water . Add powdered s t r i p p e r s t o cold water slowly while mixing t o avoid v i o l e n t b o i l i n g o r s p a t t e r i n g . Always add ac ids t o water ; never add water t o a c i d concen t r a t e s .

Addi t iona l Sa fe ty Rules f o r Methylene Chloride Based S t r i p p e r s :

1.

2. Wear f a c e s h i e l d .

Do n o t s t o r e under d i r e c t s u n l i g h t .

slowly because of p r e s s u r e bui ld-up i n drums. Cover vent plug wi th c lean rag and remove very

-~

I 1

- .

Addi t iona l Safe ty Rules f o r Methylene Chloride Based S t r i p p e r s Cont 'd:

3 . Avoid the p o s s i b i l i t y of exposing s t r i p p e r s o r t h e i r vapors t o excess ive hea t such as welding, fu rnace , o r space h e a t .

4 . D o no t smoke while handl ing s t r i p p e r .

5 . Do no t hea t o r use heated water f o r r i n s i n g .

6 . Do n o t use through sprayers o r o t h e r means which atomize t h e m a t e r i a l . Th ixo t rop ic , viscous material (such as 57 o r 553) I 1 may be appl ied wi th s p e c i a l a i r l e s s , p o t type sp raye r when they a r e used ou t s ide . I1

Hazards and F i r s t Aid Treatment

S K I N : Use so lven t r e s i s t a n t g loves , rubber b o o t s , rubber ap ron , f ace s h i e l d and hard h a t . Discard when evidence of d e t e r i o r a t i o n appea r s . Contact can cause severe burns t o s k i n . i a t e l y remove a l l soaked c l o t h i n g . immediately. washed and d r i e d .

I f s k i n i s exposed, immed- Wash s k i n wi th running water

Do n o t wear soaked c l o t h i n g u n t i l i t i s thoroughly

EYES: Use goggles ( a c i d type sp la sh proof) and p r e f e r a b l y a f ace - s h i e l d t o p r o t e c t from eye i n j u r y . eyes , s e r i o u s i n j u r y t o eyes may r e s u l t . eyes , immediately f l u s h eyes thoroughly w i t h l a r g e amounts of water. Obtain medical a t t e n t i o n immediately.

SAFETY EQUIPMEHT: Sa fe ty garments and p r o t e c t i v e equipment should be provided t o safeguard t h e h e a l t h and s a f e t y of o p e r a t o r s , maint- enance men, and a l l o t h e r people working wi th p a i n t s t r i p p e r s . S a f e t y garments and p r o t e c t i v e equipment a r e n o t intended t o s u b s t i t u t e f o r proper ope ra t ion and maintenance p r a c t i c e s . The manufac turer ' s i n s t r u c t i o n s should be followed a t a l l t imes.

SUGGESTED GARMENTS AND EQUIPMENT

Gloves: polyvinyl a lcohol p l a s t i c

Apron : polyvinyl a lcohol p l a s t i c

Goggles: ac id type sp lash-proof . Shoes : rubber boo t s .

Note: PVA p l a s t i c , though

When s t r i p p e r i s s p a t t e r e d i n t o I n c a s e of c o n t a c t w i t h

Safety Goggles

Apron

o r neoprene.

o r neoprene.

Protective Shoes so lvent r e s i s t a n t , i s soruble i n water .

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ORAL: Do no t take i n t e r n a l l y . Never s t o r e i n unlabe led o r improperly l abe led conta iner . Keep out of reach of c h i l d r e n .

Swallowing s t r i p p e r may cause severe burns, i l l n e s s , o r dea th , depend- ing upon the quan t i ty swallowed. I f swallowed, c a l l a phys ic ian immediately. Drink l a r g e q u a n t i t i e s o f wa te r . I n case o f uncon- sc iousness , follow t he procedures shown below.

INHALATION: Use s t r i p p e r s only wi th adequate v e n t i l a t i o n . I n h a l a t i o n of excessive amounts of vapor may produce l i g h t headedness, d i z z i n e s s , nausea, o r unconsciousness. I n case of excess ive i n h a l a t i o n , remove t o f r e s h a i r . Obtain medical a t t e n t i o n a t once. If brea th ing s t o p s , a r t i f i c a l r e s p i r a t i o n should be used. Mouth t o mouth i s the most e f f e c t i v e and e a s i e s t method. When b rea th ing s t a r t s , oxygen should be adminis tered. I f t h e h e a r t has s topped, g i v e c l o s e d ches t c a r d i a massage, but only i f properly t r a i n e d t o recognize and t r e a t t h i s cond i t ion .

Decomposition, - Hazards with Methylene Chloride - Solvent Based S t r i p p e r s :

Poor v e n t i l a t i o n may cause cor ros iveness due t o fumes, vapor , and degraded gas due t o hea t o r flame sources . Never weld i n a reas where these type s t r i p p e r s a r e used o r s t o r e d . Avoid open flames and space h e a t e r s . When exposed t o high tempera tures , t hese type s t r i p p e r s may decompose and produce hydrochlor ic a c i d and harmful vapors . A s t rong i n d i c a t i o n of so lven t reaching an open flame i s cor ros ion of exhaust f l u e s .

Ven t i l a t ion :

The amount and type of v e n t i l a t i o n r equ i r ed f o r a s t r i p p i n g ope ra t ion depends on i t s l e v e l of vapor concen t r a t ion i n t h e a i r . The legal al lowable concent ra t ion of a i r -vapor mixture i s c a l l e d the th re sho ld l i m i t value (TLV).

TLV i s a r e g i s t e r e d trademark of t h e American Conference of Goverh- mental I n d u s t r i a l Hygenists. TLV i s the th re sho ld l i m i t value o r occupat ional exposure l i m i t . This i s def ined a s t h e time weighted average concent ra t ion f o r a normal 8 hour workday, 40 hour weekweek, t o which nea r ly a l l workers may be exposed r epea ted ly without adverse e f f e c t .

General ly , the longer your s t r i p p i n g tank i s completely covered, t h e l e s s v e n t i l a t i o n i s requi red t o i n s u r e meeting t h e TLV. Some type

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of mechanical exhaust system is usually required to maintain proper ventilation. that the vapor concentration for open surface tanks does not exceed the eight-hour, time weighted average (TLV).

The potential effects from overexposure through inhalation of strippers are: light headedness, dizziness, drunkeness, nausea, and unconsciousness. If the TLV cannot be met, workers should be supplied with NIOSH approved respirators for organic vapors.

Mechanical exhaust systems help insure meeting the TLV. This is accomplished with blowers and ductwork necessary t o maintain the proper air-vapor mixture, o r TLV. vapors away from the stripping tank, and also draw vapors away from the tank or area where parts are rinsed. system is placed by the tank sides, by the top and by the bottom of the tank.

The purpose of mechanical ventilation is to insure

Mechanical exhaust systems draw

Normally, the exhaust

Open surface stripping tanks and open surface rinse tanks

For specific recommendations on the type and amount of ventilation equipment your operation requires, contact an industrial hygenist or a firm specializing in ventilation engineering.

TLV (threshold limit value) is expressed in parts per million (ppm) or milligrams per cubic meter (mg/m3). produced, a minimum of 10,000 cubic meters of fresh air is needed to maintain a vapor concentra,tion of 100 ppm.

Refer to the most recent Material Safety Data Sheet for the latest recommended maximum exposure limit (TLV) f o r each stripper used.

For each cubic meter of vapor

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