1. D e v e lo p m e n ts o f th e p a s t few y e a r s in s o u rc e s o f l ig h t a n d lig h tin g e q u ip m e n t m a k e it s tr o n g ly a d v is a b le to h a v e a su rv e y m a d e o f t h e e x is tin g lig h tin g s y s te m th r o u g h o u t y o u r p la n t.
A c o m p e te n t c h e m ic a l e n g in e e r , w o r k in g in d e p e n d e n tly o r in c o o p e r a tio n w ith a n e le c tr ic a l e n g in e e r o r l i g h t in g c o n s u lta n t, c a n h a n d le th is a s s ig n m e n t. I n a ll lik e lih o o d s u c h a n e x a m in a tio n w o u ld sh o w t h a t a p r o g r a m o f m o d e rn iz a tio n w o u ld b r in g a b o u t a r e d u c tio n in th e n u m b e r a n d in th e s e rio u s n e s s o f a c c id e n ts to e m p lo y e e s a n d p l a n t e q u ip m e n t. A s a r e s u l t th e efficiency o f th e o p e r a to r s w o u ld b e in c r e a s e d a n d fe w e r m is ta k e s w o u ld b e m a d e .
2 . M a k e c e r ta in t h a t th e la m p s a n d lig h tin g e q u ip m e n t d e s ig n e d fo r
a p a r t i c u l a r s e rv ic e a r e u s e d in t h a t se rv ic e a n d f o r n o o th e r p u r p o s e o r in n o o th e r lo c a tio n . F o r e x a m p le , v i b r a tio n la m p s a r e n o t s u ita b le f o r a ll ro u g h s e rv ic e s a n d r o u g h -s e rv ic e la m p s a r e n o t s u i t a b l e f o r v ib r a tio n se rv ic e . ( S e e p . 2 8 .)
3. L o s s o f h u m a n lif e a s w e ll a s lo s s o f p r o p e r t y b y e x p lo s io n s a n d fire s f u lly w a r r a n t th e a d d e d e x p e n s e i n c i d e n t to th e in s t a l l a t i o n o f d u s t- tig h t o r e x p lo s io n -p ro o f l ig h t i n g f ix tu re s in lo c a tio n s w h e r e d a n g e r o u s m a te r ia ls a r e p r o d u c e d , p r o c e s s e d o r o th e rw is e h a n d le d . S tu d y c a r e f u lly t h e d e ta ile d d a ta o n a p p lic a tio n s g iv e n in t h e f o l
lo w in g p a g e s fo r h a z a r d o u s c h e m ic a ls , p ro c e s s e s a n d i n d u s tr ie s .
4 . I n th e d e s ig n o f lig h tin g i n s t a l l a tio n s fo r h a z a r d o u s lo c a tio n s , e v e ry
e ffo rt m u s t b e m a d e to e lim in a te th e u s e o f p o r t a b l e la m p s .
5. T h e n e w e r f lu o re s c e n t, p o la r iz e d a n d u ltr a - v io le t l i g h t s o u r c e s a r e j u s t i fy in g t h e i r a c c e p ta n c e f o r s p e c ia l i n d u s t r i a l p u r p o s e s . I t is tim e to f a m il
ia r iz e y o u r s e lf w ith t h e i r p o te n tia litie s . 6. I n f r a - r e d la m p s w ill o f te n d r y s y n th e tic e n a m e ls a n d l a c q u e r s a n d o t h e r m a t e r i a ls in fro m 5 to 15 p e r c e n t o f th e tim e f o r m e r ly r e q u ir e d b y s t a n d a r d m e th o d s o f d r y in g a c c o r d in g to t h e c la im s o f t h e i r m a n u f a c t u r e r s . R e c e n t in s t a l l a t i o n s a r e r e p o r t e d
7 . I n d u s t r i a l s a b o ta g e a n d v a n d a l is m c a n b e g r e a tly r e d u c e d o r o f te n e lim in a te d e n tir e ly b y p r o p e r l y l i g h t in g p l a n t p r e m is e s t h a t h a v e b e e n a d e q u a te ly f e n c e d o r o th e r w is e p r o te c te d a g a in s t u n w e lc o m e i n tr u d e r s .
26 VOL. 47 • C H EM IC A L & M E T A L L U R G IC A L E N G IN E E R IN G • N o . 1 J A N U A R Y 1 9 4 0
G
o o d l i g h t i n g is a p a y in g in v e s t (These foot-candle values represent order of magnituderather than exact level)
(Based on data prepared by Illuminating Engineering Society) provided from a general lighting system. In other cases it will be found more economical to provide a combina
tion of general lighting plus supplementary. Direction of light, diffusion, eye protection, study of direct and reflected glare, as well as elimination of objectionable shadows are all vitally important and must be considered.
VOL. 47 • C H EM IC A L & M E T A L L U R G IC A L E N G IN E E R IN G • N o. 1 J A N U A R Y 1 9 4 0
27
w o rk a n d le s s w e ll- lig h te d s u r r o u n d in g s is a s u b j e c t s till u n d e r in v e s tig a tio n . I n g e n e r a l, h o w e v e r, a r a ti o o f 10 to 1 in b r ig h tn e s s b e tw e e n w o rk a n d s u r r o u n d in g s is a c c e p ta b le . T h e e r r o r o f in te r p r e t i n g t h is r a ti o in foot- c a n d le s o f illu m in a tio n is c o m m o n a n d r e s p o n s ib le fo r f a u lty in s ta lla tio n s . T h e r a tio o f 10 to 1 if i n te r p r e t e d in fo o t-c a n d le s m a y r e s u lt in a m u c h g r e a t e r c o n tr a s t r a ti o p a r ti c u l a r ly if th e w o rk b e o f a c o lo r o r fin is h w ith a h ig h re fle c tio n f a c to r . C o n tr a s t l im i ts a r c th e n e x c e e d e d w ith th e r e s u l t t h a t th e w o r k e r ’s ey es m a y b e c o m e t ir e d a n d efficien cy s u ffe rs.
N e iv lig h t s o u r c e s .— T h e r e a r e sev e r a l ty p e s o f l i g h t s o u r c e t h a t a r e p ro v in g to b e e x tr e m e ly im p o r t a n t to o ls fo r in s p e c tio n a n d o th e r p u r p o s e s in th e p ro c e s s in d u s tr ie s . F lu o r e s c e n t l a m p s o ffer d a y lig h t q u a lity a n d a n u m b e r o f c o lo rs a t h ig h effic ie n c ie s.
P e r h a p s th e m o s t s ig n if ic a n t f e a tu r e o f th is ty p e o f la m p is th e p r e c is e a n d efficien t m a n n e r in w h ic h l ig h t o f d a y l ig h t q u a lity a n d c o lo re d l i g h t c a n b e p r o d u c e d . T h is d a y lig h t s o u rc e m a k e s in s p e c tio n e a s ie r a n d m o re a c c u r a te w h e re c o lo r c o m p a r is o n s a r e im p o r ta n t.
S o u rc e s o f la r g e lu m in o u s a r e a a n d re la tiv e ly u n if o r m b r ig h tn e s s m a y b e o b ta in e d b y e m p lo y in g flu o re s c e n t la m p s in s u ita b ly d e s ig n e d s p e c u la r t r o u g h re fle c to rs . U n its o f th is ty p e p r o d u c e h ig h illu m in a tio n o f g o o d q u a lity . B e c a u s e th e r a d i a n t h e a t fro m th e s e la m p s is o n ly o n e - q u a r te r t h a t o f in c a n d e s c e n t la m p s fo r e q u a l foot- c a n d le s , a s o u rc e o f th is ty p e c a n f u r n is h s e v e ra l h u n d r e d fo o tc a n d le s w ith o u t th e d is c o m f o r t fro m h e a t f o r
m e rly a s s o c ia te d w ith h i g h f o o tc a n d le s . T h is f a c to r a ls o d e c r e a s e s th e lo a d o n c o o lin g a n d a ir c o n d itio n in g s y s te m s fo r e q u a l illu m in a tio n .
P o la r iz e d l i g h t is u s e d o c c a s io n a lly in m in im iz in g r e fle c te d g la r e f ro m s u c h s u r f a c e s a s g la s s , lin o le u m , v a r n is h e d w o o d , e tc . I t is o n ly e ffe c tiv e w h e n i n c id e n t l ig h t is a t p o l a n z m ^ a n g le a n d a n a n a ly z in g s c r e e n is u s e d a t th e e y e. T h is ty p e o f l i g h t is v e ry g o o d f o r d e te c tin g s t r a in s a n d d e te c ts in g la s s , m o u n te d le n s e s , r a d io tu b e s , t r a n s p a r e n t p la s tic s , e tc . A p o la r iz in g s c r e e n a n d a n a n a ly z in g s c r e e n m u s t b e u s e d . T h e s t r a in e d a r e a s a p p e a r a s c o lo r f r in g e s in t h e m a t e r i a l, I h i s te c h n ic h a s b e e n a p p li e d s u c c e s s f u lly w ith t r a n s p a r e n t w o r k in g m o d e ls o t s t r u c tu r e s a n d m a c h in e p a r t s to d e te c t s t r a in e d s e c tio n s u n d e r o p e r a t in g c o n d itio n s . P o l a r iz e d l i g h t is b e in g u s e d a ls o fo r th e i n s p e c tio n o f t r a n s l u c e n t in f la te d r u b b e r a r tic le s .
U l t r a v io le t l i g h t s o u r c e s m a k e it p o s s ib le to id e n tif y p r o d u c ts w ith m a r k s v is ib le o n ly u n d e r th e s e u n its , a n d n o t s e e n b y t h e c u s to m e r . I In s s a m e ty p e o f l ig h t s o u r c e is a ls o m a d e u s e o f in in s p e c tio n w h e r e i t is n e c e s s a r y to d e te r m in e t h e p r e s e n c e of flu o re s c e n t s u b s ta n c e s in o th e r m a te r ia ls .
S p e c ia l l a m p s fo r s p e c ia l p u r p o s e s .
— W h ile i t is n o t p o s s ib le to d is c u s s a ll o f t h e la m p s s p e c ific a lly d e s ig n e d fo r th e v a r io u s ty p e s o f s e rv ic e s , t h e fo llo w in g ty p e s o f la m p s d e s e rv e b r ie f d is c u s s io n .
B a k e-o v e n la m p s .— T h e s e _ s o u r c e s h a v e f o u r s p e c ia l f e a tu r e s n o t in c lu d e d in lo w -w a tta g e g e n e r a l s e rv ic e l a m p s :
( 1 ) a s p e c ia l b a s in g c e m e n t w ill w ith s ta n d t e m p e r a tu r e s u p to 550 d e g . F ., ( 2 ) th e l e a d w ir e s a r e w e ld e d to t h e b a s e , ( 3 ) a n a s b e s to s i n s u la tio n is p la c e d b e tw e e n th e l e a d s in th e b a s e so t h a t f a llin g o x id e w ill n o t c a u s e a s h o r t c ir c u it, a n d ( 4 ) b a k e -o v e n la m p s u n d e r g o a s p e c ia l h ig h - te m p e r a tu r e e x h a u s t, g iv in g im p r o v e d o p e r a tio n
E x p lo sio n -p ro o f lig h tin g of a sp ray b o o th ro o m
a n d lo n g e r lif e a t t h e h ig h e x te r n a l t e m p e r a t u r e in v o lv e d . T h e s e la m p s s h o u ld a ls o b e u s e d in a p p lic a tio n s w h e r e h i g h e x te r n a l t e m p e r a t u r e s
p r e v a il. , ,
V ib r a tio n - s e r v ic e la m p s . — M o s t la m p s h a v e c o ile d f ila m e n ts m a d e o t a s p e c ia lly p r e p a r e d tu n g s t e n h a v in g h ig h s a g r e s is ta n c e . H o w e v e r, v i b r a tio n la m p s , d e s ig n e d fo r u s e o n h i g h s p e e d m a c h in e r y , a n d th e l ik e w h e re c o n tin u o u s h ig h f r e q u e n c y v ib r a tio n s w o u ld c a u s e e a r ly f a il u r e o f g e n e r a l s e rv ic e la m p s , e m p lo y a m o r e fle x ib le t u n g s te n fila m e n t. T h e s a g g in g c h a r a c te r i s t i c o f t h e w ir e u s e d a llo w s th e c o ils to o p e n u p u n d e r v ib r a tio n , th u s p r e v e n tin g s h o r t c ir c u its b e tw e e n c o ils.
T h e s e la m p s a r e a v a ila b le m th e bU w a t t size. T h e y s h o u ld b e u s e d i n a v e r tic a l, n o t in a h o r iz o n ta l p o s itio n . V ib r a tio n la m p s s h o u ld n o t b e u s e d f o r g e n e r a l s e rv ic e lig h t i n g . I t s h o u ld b e r e m e m b e r e d t h a t v ib r a tio n la m p s a r e n o t s u ita b le f o r r o u g h s e rv ic e , a n d r o u g h - s e r v ic e l a m p s a r e n o t s u i t a b le f o r v ib r a tio n s e rv ic e . V ib r a tio n r e s i s t in g a d a p t e r s u tiliz in g a c o ile d s p r i n g to d a m p e n v ib r a tio n , a r e r e c o m m e n d e d w h e r e g e n e r a l s e rv ic e la m p s a r e u s e d u n d e r c o n d itio n s o f s e v e re
v ib r a tio n s . f
R o u g h - s e r v ic e l a m p s . —-F ila m e n ts o t la m p s d e s ig n e d to w i t h s t a n d s h o c k s a n d b u m p s a r e c o ile d o n a v e ry s m a ll m a n d r e l, r e s u l ti n g in a r e la tiv e ly lo n g c o il w h ic h is th e n c a r e f u lly m o u n te d a n d h e ld b y m a n y s u p p o r t s ( t h e 50- w a t t r o u g h s e rv ic e l a m p h a s 16 s u p p o r t s ) . B e c a u s e o f t h e n u m b e r o t s u p p o r ts , th e e n d lo g s w ill b e h i g h e r a n d t h e efficien cy lo w e r . T h e c e n t e r s u p p o r t s a c t u a l l y g r ip th e f ila m e n t a n d p r e v e n t s l i p p in g a n d t h u s p o s s ib le s h o r tin g b e c a u s e o f s u d d e n sh o c k . R o u g h s e rv ic e l a m p s fin d t h e i r p r i n c i p a l a p p li c a t io n in e x te n s io n c o r d s a n d s im ila r s e rv ic e w h e r e th e y m u s t w ith s t a n d s e v e re s h o c k s a n d b u m p s . 1 h ey a r e a v a ila b le in th e 50 a n d 100 w a tt siz es. T h is ty p e o f la m p is n o t r e c o m m e n d e d to s t a n d s te a d y v i b r a tio n o r g e n e r a l l ig h t i n g s e rv ic e . _
I n d i c a to r la m p s .— I n th is e r a o t m o d e r n c o n tr o l s y s te m s fo r te le m e te r - in g , r e m o te -c o n tr o l o p e r a tio n , e tc ., s m a ll i n d ic a to r l a m p s p la y a n im p o r t a n t r o le . S o m e o f t h e lo w -v o lta g e la m p s r e q u i r e fila m e n ts o f s u c h s m a ll d ia m e te r t h a t o r d i n a r y d r a w in g o f t h e tu n g s te n h a s to b e fo llo w e d b y a c id t r e a tm e n t to r e a liz e f u r t h e r r e d u c t io n o f th e f ila m e n t c ro s s -s e c tio n . S u c h s m a ll la m p s r e q u i r e a ll t h e m a n u f a c tu r in g p r e c is io n o f l a r g e r la m p s a n d b e c a u s e o f s p e c ia l tr e a tm e n ts o f te n c o s t m o r e t h a n h i g h e r w a tta g e la m p s .
D r y in g la m p s .— A n e w la m p p r o d u c in g r a d i a n t e n e r g y in t h e n e a r in f r a - r e d re g io n o f t h e s p e c tr u m is f in d in g m a n y u s e s in i n d u s tr y . S in c e th e la m p is a s o u r c e o f h e a t , o r d i n a r y la m p e c o n o m ic s d o n o t a p p ly in i ts d e s ig n a n d u s e . T h e 2 5 0 -w a tt, 1 1 5 v o lt
28 VOL. 47 • C H EM ICA L & M E T A L LU R G IC A L E N G IN E E R IN G • N o . 1 J A N U A R Y 1 9 4 0
E x p lo s io n -p ro o f lig h tin g fixtures in a cliu rn ro o m o f a ra y o n p la n t
A cistern ro o m of a d is tille ry p ro te c te d by explosion- p ro o f lig h tin g e q u ip m e n t
la m p lia s th e s a m e p h y s ic a l d im e n s io n s a s th e 2 0 0 -w a tt g e n e r a l se rv ic e la m p a n d a s p e c ia l fila m e n t w h ic h is o p e r a te d a t a m u c h lo w e r te m p e r a tu r e th a n th e fila m e n ts o f M a z d a la m p s . T h e lo w o p e r a tin g t e m p e r a t u r e r e s u lts in a v e ry lo n g life .
T h e r a d i a n t e n e rg y e m a n a tin g fro m th e fila m e n t s h o u ld b e r e d ir e c te d b y a p o lis h e d re fle c to r to th e o b je c t b e in g p r o c e s s e d . T h e re fle c to rs a r e m o u n te d in b a n k s s p a c e d fro m 9 to 18 in c h e s fro m th e w e t s u r f a c e . I t is r e p o r te d t h a t s y n th e tic e n a m e ls a n d l a c q u e r s a r e b e in g d r ie d in fro m 5 to 15 p e r c e n t o f th e tim e fo r m e r ly r e q u ir e d b y s t a n d a r d m e th o d s o f d r y in g . S a tis f a c to r y r e s u l ts h a v e a ls o b e e n e x p e r ie n c e d in th e d r y in g o f la te x , p a p e r , b l u e p r i n t s , r e s in s , a n d o th e r m a te ria ls .
S p e c ia l E q u ip m e n t fo r H a z a rd o u s L o c a tio n s .— L o ss o f h u m a n l if e a s w e ll a s lo s s o f p r o p e r ty b y e x p lo s io n s a n d fire s f u lly w a r r a n t th e a d d e d e x p e n s e i n c id e n t to th e in s ta lla tio n o f d u s t- tig h t o r e x p lo s io n -p ro o f lig h tin g f ix tu re s in lo c a tio n s w h e re d a n g e r o u s m a te r ia ls a r e p r o d u c e d , p ro c e s s e d o r o th e r w is e h a n d le d . S a fe ty is th e first
c o n s id e r a tio n w h e n p la n n in g th e l ig h t in g sy s te m fo r th e c h e m ic a l p la n t.
A s th e d iffe re n c e s in e x p lo s iv e e ffe c ts o f m a n y o f th e c o m m o n m a te r ia ls a r e su fficien t to c a ll fo r d iffe r
e n t fo rm s o f c o n s tr u c tio n o f e x p lo s io n - p ro o f e le c tr ic a l e q u ip m e n t, i t a p p e a r s t h a t th e m o s t p r a c tic a l a n d lo g ic a l c o u rs e is first to d iv id e c o m m o n m a te r ia ls in to g r o u p s in a c c o r d a n c e w ith th e e x p lo s io n h a z a r d s , a n d s e c o n d to b a s e th e t e s t r e q u ir e m e n ts o n th e g ro u p in w h ic h th e e q u ip m e n t is d e s ig n e d to o p e r a te .
T h e N a tio n a l E le c tr ic C o d e g r o u p s m a te r ia ls in to f o u r d iv is io n s : C la s s I c o v ers fla m m a b le v o la tile liq u id s a n d g a se s. C la s s I I in c lu d e s m e ta llic a n d n o n -m e ta llic d u s ts . C la s s I I I c o v ers lo c a tio n s w h e re fib e rs o r m a te r ia ls p r o d u c in g c o m b u s tib le fly in g s a r e h a n d le d , m a n u f a c tu r e d o r u s e d . C la s s I V d e a ls w ith lo c a tio n s w h e re fib e rs a r e s to re d .
A te n ta tiv e g r o u p in g o f c o m m o n g a s e s a n d v a p o rs in r e s p e c t to th e e x p lo s iv e h a z a r d h a s b e e n w o rk e d o u t w ith th e th o u g h t t h a t i t m ig h t b e e x p a n d e d o r lim ite d in th e l ig h t o f f u r t h e r e x p e rie n c e , a c c o r d in g to A . H .