09. CHAPTER - 9 Lighting and Control

8/19/2019 09. CHAPTER - 9 Lighting and Control

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CHAPTER - 9

Lighting and Colour

1. Sight and Light 2. Benefts o Lighting :

2.1 Purpose and Advantages olighting

2.2 Eects o Bad Lighting.2.3 ood Lighting increases Saet!

and Productivit! 3. Principles o "llu#ination :

3.1 $efnitions and actors3.2 %e&uire#ents o good lighting

3.2.1 Ade&uate "llu#ination3.2.2 lare3.2.3 Shado'3.2.( )nior# Lighting3.2.* +ontrast 3.2., +olour +ontrast 3.2.- +olour Eect 3.2. /lic0er and Strooscopic

Eect (. %eco##ended Standards o

"llu#ination:(.1 Statutor! Provisions(.2 "ndian Standards

(.3 "L %eco##endation(.( A#erican Standards

*. !pes o Light4 Sources4 /ittingsand "nstallations:

*.1 !pes o Light :*.1.1 $a!4 5atural or eneral

Lighting*.1.2 Artifcial Lighting 6 !pes

*.2 !pes o Light Sources*.3 !pes o Lighting /ittings*.( !pes o Lighting "nstallations*.* +ost o Lighting

,. $esign o Lighting "nstallation :,.1 eneral considerations,.2 $a! lighting o /actor! uildings,.3 "nstallation or Artifcial Lighting,.( Plant Lighting $esign

-. Lighting and +olour :-.1 5eed o +olours-.2 %e7ection /actors 8L%9-.3 +olour +ode and Saet! :

-.3.1 "ndian Standards-.3.2 +olours to "denti!

;a


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distinctly at varying distances.Ada'tation a(ility of an eye is itssensitivity adustment eected aftersu1cient e#posure to light -light3adapted/or dar!ness -dar!3adapted/. a""lingconditions and fre'uent adaptation maycause visual fatigue and eye trou(les

conductive to accidents. Con)!rg!n(!means an a(ility to get the impression of a single o(ect through t$o images on theretinas of (oth eyes. D!'th P!r(!'tionor St!r!o'"i" is the impression of depthgained from the fact that (oth eyes seean o(ect from a slightly dierent angle.Sudden closure of eye3lids againste#cessive light is the saet! response.Colour )i"ion is due to the a(ility of theretina to distinguish (et$een light of dierent $ave lengths. It is not e'uallysensitive to all $ave lengths.

5ut the "ight (annot do an#thingithout light. %he eye can portray tothe (rain only such impressions as arecarried to it (y light $aves, and if theselight $aves are insu1cient (ecause of poor illumination, the eect is the defectin performance. Inade'uate visualperception is a direct or indirect cause of many accidents. 6isual perceptiondepends on many factors $hich must (e

studied to improve them. Some suchfactors are 7

. %he eyesight of a person.2. %he 'uantity and 'uality of light on the

o(ect to (e seen.9. %he si"e, shape, speed and distance of

the o(ect.4. %he degree of colour contrast (et$een

the o(ect and its (ac!ground.:. %he o(structions, transparent or non3

transparent, in the path of the light

rays (et$een the eye and the o(ect.. ;lare and shado$ if any.

%hus light, colour, their 'uantity and'uality are the important factors for anyvisual perception and $or! performancedepending on it.

%he light is most important, (ecause$ithout light the things have no colour, noshape and no perspective. Light andcolour aect human e1ciency, accident3

proneness and his general $ell3(eing,morale and fatigue.


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,+, E2!(t" o ad or PoorLighting

E2!(t" o *ad lighting are directand manifold, (ecause, it aects our sightor visual perception. 5ad light causesglare, shado$s, dar!ness, eye strain,restricted vision, fatigue, accidents andlo$er output. ?ccidents during night areo(vious due to (ad or insu1cient i.e. poorlighting. %herefore, need of light is (asicand essentially re'uired to $or! (etter, toavoid eye strain and to reduce accidents.

5ad light causes eye3strain, fatigue,slo$er reaction and greater suscepti(ilityto error and accident.

;loomy, dirty and poorly lighted$or!places cause depression. Poor

lighting causes great hardship e.g.di1culty in reading micrometer, ma!ing&ne adustment, passing a thread inneedle and the li!e. Conversely, $elllighted $or!place loo!s delightful andencourages to $or!.

Poor lighting re'uires more time tosee or distinguish o(ect. ;lare andshado$s cause eye3strain resulting inmore chances of accidents. %herefore toincrease safety, prescri(ed standard of illumination is the (asic -minimum/$or!ing condition. See part 4 forStandards.

,+3 Good Lighting in(r!a"!"Sa!t# and Produ(ti)it#

;ood lighting ultimately improvespro&ta(ility. ;ood lighting includes (oth,day lighting and arti&cial lighting andthey should (e in the re'uisite proportion.

%he spectral composition of light andcolour layout should (e appropriate togain their ma#imum advantages.

;ood light decreases accident andincreases $or! 'uality and 'uantity,productivity and promotes (etter healthand morale of all $or!3people. In industry,therefore, it is the duty of lightingengineer to consider this (asic need andto provide good seeing conditions to avoid

accidents due to visual disorder. Planningfrom the design stage $ill help much.

;ood lighting ma!es the $or!er morealert and ena(les him to concentrate anduse (etter discrimination $hich result inless spoilage, less reects, fast faultdetection, (etter $or! and ultimately in

safety.Nu$!rou" "tudi!" have sho$n a

close relation (et$een accidentfre'uency and lighting conditions. %he

%ravellers Insurance Company estimatedthat of @AAA accidents, 24B $ere due toimperfect lighting.

0ne 83days study sho$ed that theemployees $ith the greatest deviationfrom the visual standards had the largestaccumulation of accidents.

In another case study -lectrical %imes of 43A93@8A/, accidents decreasein three companies $as :AB, 49B and:2B as an eect of improved illumination.

In one factory $hen illumination $asincreased from :A to 2AA Lu#, thereduction in accident $as 92B. ?notherreduction of .:B $as noticed $hen the$alls $ere treated $ith high re>ectancepaint $hich increased the illuminationlevel to D 2:A Lu#.

In a machine tool factory $ith the rise

from 92 to 49A Lu# and machines paintedto reduce (rightness contrasts, theaccident rate $as decreased up to :AB.

In a te#tile mill $ith the prescri(edillumination level, a safety a$ard $as$on for its accident3free performance.

%his proves that good lighting increasessafety.

?n old study (y the *ationalIndustrial Eatigue 5oard -)S?/ indicatesthat $or! output -e1ciency/ decreases(ecause of poor lighting. %he change in

e1ciency as measured (y productionrecord and num(er of errors made(ecause of change in illumination $as thesu(ect of numerous studies.Improvements in lighting increaseproduction and decrease errors.

? fe$ e#amples from one reportpu(lished in lectrical %imes,


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T#'! o 4or& Illu$inan(! 5Lu67 P!ror-$an(!

In(r!a"! 5%7R!!(t"

D!(r!a"!5%7

/ld N!

Composing room-print/

AA AAA 9A 8

Cotton Spinning uence on the nervous system, pulserate, intensity of certain meta(olicreactions and the psychological state of man. /or a rational or an ade&uatelighting4 the &uantit! and &ualit! o illu#ination4 oth are essential. Some(asic concepts, units and sym(ols areas follo$s 7

5A7 Lu$inair! is a complete lightingunit including the lamp, glo(e, re>ector,refractor, housing and support that isintegral $ith the housing.

57 Lu$inou" 5or light7 ;u6 is the'uantity of light emitted per second (ya light source. It is the radiant po$er orluminous >u# i.e. rate of propagation of radiant energy evaluated (y the eye.Its unit is lumen -lm/ and the sym(ol E.

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5C7 Lu$inou" Int!n"it# is theluminous >u# emitted per unit of solidangle -the measure of spatial density of the light >u#/ in a given direction. Itsunit is candela -cd/ and the sym(ol land l G E$, $here $ is the solid angle.

5D7 Illu$inan(! or Illu$ination isthe luminous >u# that stri!es a unitarea i.e. it is the surface density of thelight >u# distri(uted uniformly over thesurface. Its unit is lu# -l#/ $hich ise'uivalent to lmm2 and the sym(ol , G ES, $here S is the surface area.When calculating arti&cial illuminationof industrial premises, the concept of mean illuminance usually applies to ahori"ontal plane A.8 m a(ove the >oorlevel, also !no$n as the $or!placeplane.

0ld unit of illuminance $as foot3candle $hich is the num(er of lumensft2 or lmft2. *e$ unit is lu#$hich is lmm2. %heir relation is 3 foot candle G lmft2 G A.F lu# orlmm2,i.e. roughly foot candle G Alu#

meter candle G 9A lu#Da#light .a(tor 5D.7 G lu# 8A

Illu$inan(! l!)!l is a prescri(edamount of illuminance.

Initial illu$inan(! is the amountof illuminance o(tained $hen theluminaries are neat and clean and $henthe lamps are &rst energi"ed.

S!r)i(! or $aintain!dillu$inan(! is the mean or averageilluminance throughout the life of alighting installation or over an e#tenedperiod of time. %his is lo$er than the

initial illuminance for several reasonsstated (elo$.

Light lo"" a(tor is a factor $hichrepresents the average3to3initialilluminance ratio of a lighting system. Itrepresents the depreciation anddeterioration of a lighting systemcaused (y follo$ing reasons7. Loss of lamp lumens due to agingeect.2. ecrease in lamp and luminaire

output resulting from dust, dirt,

insects and chemical changes in theluminaire re>ecting surface.

9. Increased a(sorption of the lightoutput of the luminaries (y dust,dirt and chemical changes in theroom re>ecting surfaces.

4. ierences (et$een actual and

design lamp voltages.

Standard illu$inan(! is theservice illuminance recommended forstandard conditions.

Co!ected (y the (ody to theincident light.

Co!u#received (y a surface divided (y thetotal >u# from the lamps illuminating it.

S!!ing or )i"ual ta"& is theo(ect (eing regarded and its(ac!ground.

:ounting h!ight is the distancefrom the (ottom of the luminaire to thesurface used as a reference.

5E7 Lu$inan(! 5rightn!""7 is theluminous >u# -directly seen (y the eye/re>ected (y a surface in a given

direction. Its unit is candela per s'. m.-cdm2/, and the sym(ol L. ?ll otherconditions (eing e'ual, the luminance isproportional to the illuminance i.e. L Glrs, $here r is the r!;!(tion a(tor of the surface, and is given (y r G ErefEfal$here Eref G luminous >u# re>ectedfrom a surface and Efal G luminous >u#falling on that surface. It is also !no$nas (o!ection factor is greaterthan A.4, semi3dar!, if it is A.43A.2 anddar!, if less than A.2.

5G7 Contra"t is the relative luminance(et$een an o(ect and its (ac!ground-e.g. a letter on paper/ and its sym(ol isC. Where the (ac!ground has a

luminance L and the o(ect aluminance L2 -LJL2/, it can (e

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e#pressed C G -L3L2/L. Contrast is adimensionless magnitude ranging(et$een A and . It may (e high, soft orlo$.

-5/ to -/ are 'uantitative and -E/ K-;/ are 'ualitative indices of

illumination.? poc!et type light $!t!r

5'hoto(!ll d!)i(!7 is availa(le tomeasure light directly in lu#.

3+, R!>uir!$!nt" o GoodLighting

*ecessary conditions for good lightingare 7. ?de'uate illumination.

2. ?voidance of glare.9. ?voidance of shado$.4. )niform lighting.:. ?ppropriate contrast.. ?ppropriate colour contrast.F. Colour eect and8. ?voidance of >ic!er and stro(oscopic

eect.

%hese are (rie>y e#plained (elo$ 7

3+,+1 Ad!>uat! Illu$ination

?de'uate, rational or goodillumination needs "uuantit#o illu$ination necessary for avoidingdiscomfort to the $or!er and unduestrain on eyes.

%he >uantit# or int!n"it# o illu$ination is given (y luminous >u#,luminous intensity, illuminance,luminance and re>ection factor ase#plained in the foregoing part 9.. Its

re'uirement varies from place to place,person to person and $ith the age of person also. %herefore (y e#periments,standards of illumination arerecommended for a variety of placesand o(s to have su1cient 'uantity of light for (etter $or! performance. Suchstatutory standards and Indianstandards are separately given in part 4of this Chapter.

6isual acuity increases $ith lightintensity and is a(out e'ual to daylight

acuity as AAA lu# is approached.

Ho$ever, this degree of acuity isseldom re'uired and it is apparent thatthe desired amount of lighting $ill vary$ith the amount of detail re'uired inthe $or!. Eor e#ample, for very &ne$or! li!e distinguishing (lac! thread on(lac! cloth, intensity of 2AAA lu# is

re'uired.?lthough individuals dier in

amount of light they &nd mostdesira(le, :B of the su(ects of onestudy udged intensity (et$een A to9A foot3candles or AA to 9AA lu#, themost comforta(le for reading.

%he >ualit# o illu$inationdepends on three factors 3 diusion,distri(ution and colour value.=egardless of the 'uantity of illumination, its eects may (e impaired(ecause of the unevenness, the glareor the faulty direction of the light.

Di2u"ion is the (rea!ing up of a(eam of light and the spreading of itsrays in many directions (y a surface. Itis the process of re>ection of light (y are>ecting surface or of transmission of light through a translucent material.

%hus ade'uate illumination re'uiressu1cient 'uantity and good 'uality of light necessary for the $or!.

See Part 9.2.4 for uniform lighting.

3+,+, Glar!

;lare is the condition in $hich(rightness or the contrast of (rightnessinterferes $ith vision.

;lare is produced (y e#cessive lightstimuli i.e. e#cessive luminance in the&eld of vision $hich distur(s theadaptation process of retina.

Sometimes glare impairs the visualfunction of the eye and reduces visualperformance.

;lare causes discomfort,annoyance, eye fatigue and impairmentof or interference $ith vision. It isproduced (y e#cessive light stimuli i.e.too much light $hich aects theadaptation process of the retina. It can(e considered at three levels -types/ 3-/ irect or disa(ility glare -2/iscomfort glare and -9/ Indirect or

re>ected glare.

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Dir!(t or di"a*ilit# glar! comesdirectly from the light source to the eyeand impairs the a(ility to see clearly-e.g. up$ard headlight of a car/. %his isdue to e#cessive light focused on theeye and scattering of light inside theeye. It depends for its eects upon the

position of the light source in the &eldof vie$ and on the contrast in(rightness (et$een the light source andits (ac!ground. It can (e avoided (y 7

. Provide diuser over the lamp orre>ector -screen/ $ith minimumre>ecting angle 2AA (elo$ thehori"ontal.

2. =educing the (rightness of the lightsource -e.g. (y enclosing the lamp in(o$l re>ector/.

9. =educing the area of high (rightness-e.g. (y installing louvers (elo$ thelight source/.

4. Increasing the angle (et$een thesource of glare and the line of visioni.e. (y increasing the mountingheight.

:. ecreasing the source of glare so asto lessen the contrast.

Di"(o$ort glar! is due to li(eral

-less/ or (right -more/ light. It causesvisual discomfort $ithout necessarilyimpairing the a(ility to see and mayoccur from unscreened $indo$s in(right sunlight or $hen over3(right orunshaded lamps in the $or!room aretoo strong in (rightness for the$or!room environment.

R!;!(t!d glar! is glare thatcomes to the eyes as glint or re>ectionof the light source from some polishedor shining surface. It is caused (y a

mirror image of the (right light sourcesre>ected from shiny or $et $or!placessuch as glass or plated metal. %hesere>ections distract or distort attention,ma!e important detail di1cult to seeand reduce contrast or cause acutediscomfort. It can (e avoided (y 7

. Changing the shining &nish (y matt&nish.

2. Changing the tas! position or its

surrounding.

9. )sing light source of lo$ (rightnessor providing lamp shade.

4. ?rranging the geometry of theinstallation so that there is no glintat the particular vie$ing direction,e.g. increasing the source height.

:. Providing supplementary lighting.

. Painting $alls and ceiling $ith lightcolour so that surrounding (ecomes(right.

F. Increasing (rightness to reducerelative (rightness of the glare.

=ule 92 of the ;uarat Eactories=ules prescri(es, for the purpose of prevention of glare, that $here anylighting source is less than : mt a(ove>oor level, no part of that light having(rightness greater than : lam(erts -.:candlescm2/ shall (e visi(le to personsnormally $or!ing $ithin 9A mt from thatsource, e#cept $here the angle of elevation from the eye to that sourcee#ceeds 2AA. It is also suggested thatlocal light -lamp on the o(/ shall (eprovided $ith opa'ue shade or eectivescreen to prevent glare in the eyes of $or!ers $or!ing near(y.

6alues of limiting glare inde# along$ith average illumination lu# value are

given in IS7: and ?ppendi# , Part 4of *ational lectrical Code.

3+,+3 Shado

Shado$ aects the amount of illumination and is caused not (y poorlighting (ut 3 (y ing light sources too$ide apart or in $rong positions so thatlight is o(structed (y some o(ect. Light-faint/ shado$ may (e allo$ed (ut dar!-dense/ shado$ that conceals ha"ard orindicates $rong thing is not desira(le,as it may cause accident.

Shado$ on staircase, near door forentry or e#it, near tool rac! or on the$or! -o(/ ta(le is not at all desira(leand must (e removed (y providinge#tra or local light or shifting the lightsource or the o(ect causing shado$.

3+,+? nior$ Lighting

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%he human eye can clearlyperceive dierences in luminance of over :AB. It ta!es time to adopt suddenvariation in the intensity of lighting,particularly from higher to lo$erintensity. )niform distri(ution of lightingis desira(le. istri(ution of light

re'uires t$o pro(lems to solve -/uniformity of illumination and -2/elimination of shado$s.

In unior$ lighting4 thedistri(ution of light $ith a ma#imumand minimum illumination at any pointshould not (e more than one3si#tha(ove or (elo$ the average level inthe area. Indir!(t lighting is the (estmethod for producing uniformillumination. Here all the usa(le light isre>ected light, high points of light fromthe (ul( stri!ing the eye directly are outof the visual &eld. %he disadvantage of indirect light is its cost, sinceconsidera(le light is lost througha(sorption. Ho$ever its (ene&t is more$orth than its e#tra cost.

Har"h "hado" should (eavoided, (ut some shado$ eect may(e desira(le from the general lightingsystem to accentuate the depth andform of o(ect. %here are fe$ speci&c

visual tas!s $here clearly de&nedshado$s improve visi(ility and sucheects should (e provided (ysupplementary lighting e'uipmentarranged for the particular tas!.

3+,+@ Contra"t

%he a(ility to see detail dependsupon the contrast (et$een the detailand its (ac!ground. %he greater thecontrast, dierence in luminance, themore readily the seeing tas! isperformed. %he eyes function mostcomforta(ly and e1ciently $hen theluminance $ithin the remainder of theenvironment is relatively uniform.

%herefore all luminance in the &eld of vie$ should (e carefully controlled.IS794 -Part I K II/ provide details forthis. =e>ectance should (e maintainedas near as practical to recommendedvalues -Eor ceiling 8A to @AB, for $alls

4A to AB, for des!s and (ench tops,machine and e'uipment 2: to 4:B and

for >oors not less than 2AB/. Highre>ectance surfaces are desira(le toprovide the recommended luminancerelationship and high utilisation of light.

%hey improve the appearance of the$or! place. It is also desira(le that the(ac!ground should (e slightly dar!er or

paler than the seeing tas!. %oo muchcontrast is not desira(le.

%he contrast recognises the o(ecteasily and increases visualperformance. If the dierence (et$eenthe o(ect -o( or seeing tas!/ and its(ac!ground is not noticea(le, it isdi1cult to $or!. ? (lac! machine in(lac! (ac!ground -dar!ness/ is di1cultto be detect. %here should (e aminimum contrast (et$een the visualtarget detail and its (ac!ground.

%he dierences in luminance(et$een visual tas! area, its immediate(ac!ground and environment shouldnot e#ceed certain ma#imum values i.e.a relationship of A 7 9 7 for normaltas!s and A 7 : 7 and A 7 A 7 forprecision $or!.

3+,+ Colour Contra"t

ye sees an o(ect (y the light it

re>ects and distinguishes its detailsmainly (y colour contrast. %hus, inaddition to luminance contrast, colourcontrast may (e in>uenced (y thechoice of the colour of light. %he choiceof the correct colour of light dependson the tas! to (e performed and there'uirements to (e met (y vision. Itmay (e noted that there must not only(e ade'uate illumination to see ano(ect clearly, (ut also the o(ect must(e visi(le in its surroundings. It musthave moderate colour contrast. %hecolour appro#imating to $hite $ill give(etter colour rendering and light yield.

%he colour appro#imating to red $illgive more mediocre colour rendering(ut the light $ill create an emotionalatmosphere.

? $ell painted machine inspires afeeling of personal pride and propermaintenance is encouraged.

3+,+B Colour E2!(t

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It refers to the appearance of colouredo(ects $hen illuminated (y a particularlight source. It is the property of light$hich facilitates the perception of surface colours and depends on thespectral composition of the light. Eor

e#ample, red surface $ill appear redonly, if the light falling on it containsred, (ut it $ill appear (ro$n under theyello$ of sodium 3 street lighting.

%he ma#imum value of the inde# isAA and at this value there is no shift,i.e. the colour rendering is perfect. Eore#ample, an incandescent tungsten&lament lamp has a colour renderinginde# of AA, >uorescent tu(es (et$een:: to @:, mercury vapour lampsappro#imately 4: and lo$3pressuresodium vapour lamps less than 2:.Where colour discrimination and colourmatching are a part of the $or!process, the light source selectedshould have the desired colourrendering properties.

3+,+8 .li(&!r and Stro*o"(o'i(E2!(t

?ll lamps $or!ing on alternating current

give light $hich pulsates at t$ice thesupply fre'uency. %his types of discontinuous light of almost anyfre'uency can produce stro(oscopiceect, in $hich a rotating orreciprocating o(ect can appear to (estationary, or moving slo$ly, or evenappear to (e rotating in the oppositedirection etc. %his illusion can causeaccidents in the industrial situation. It isa real ha"ard in the presence of movingmachinery. High intensity dischargelamps and >uorescent tu(es have some+>ic!er content in their light output att$ice mains fre'uency. %he steps todiminish the stro(oscopic eect are 7

. Light the moving o(ect $ith lampsfed from t$o dierent out of phasea.c. supplies, or from t$o or threephases of a three3phase supply orlead lag luminaries.

2. Select a lamp $ith a lo$ >ic!er

characteristic, e.g. a >uorescent

coated high3intensity dischargetungsten &lament -;LS/ lamp orordinary &lament lamp.

9. ?dd a local ;LS lamp to augment thegeneral lighting.

4. )se ;LS or tungsten halogen lampsfed from a direct current -d.c./

supply.:. )se the common t$in3tu(e circuit.

? REC/::ENDEDSTANDARDS /.ILL:INATI/N

It is not a simple matter to specifysuita(le intensity levels (ased uponsound reasoning. ?s there is no edthreshold level of illumination (elo$

$hich a visual tas! is greatly impeded,some compromise has to (e made(et$een an ideal level and ade'uatelevel. ;enerally a recommended level isarrived at after careful consideration of eyesight, the visual tas!, theenvironment and the economyinvolved. ?ny speci&cation is therefore,opens to controversy, therecommended level, ho$ever, serveschie>y as a guide to good practices.

Standard illu#ination enefts people'ith nor#al sight and helps to ault! vision. It can (e achieved through acom(ined usage of day lighting andarti&cial lighting and maintained (yproper cleaning and re3lamping etc.

I$'ortan(! o illu$ination l!)!l

Illumination, noise, temperatureand other environmental conditionssuch as chemical e#posure and

vi(ration play an important role in thea(ility of humans to interact eectively$ith e'uipment or a system.

Lighting is an important element inthe design of any system as improperlighting levels may cause systemelements to (e seen incorrectly or notseen at all. Improperly designed lightingsystems may result in the eyestrain,muscle fatigue, headaches oraccidents.

%he ade'uacy of lighting dependsupon the type of lighting provided, its

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'uality and 'uantity, the age of the$or!er and visual re'uirements of thetas! or system.

Illu$inan(! rang!"

Circumstances may (e signi&cantly

dierent for di1cult interiors used forthe same application or dierentconditions for the same !ind of activity,a range of illuminance is recommendedfor each type of interior or activity. achrange consists of three successivesteps of the recommended scale of illuminance. ected glare and shado$scausing eye strain or ris! of accident.=ules 9A to 94 of the ;uarat Eactories=ules prescri(e further details. ;enerallevel of 9A meters candles or more at

the hori"ontal level of @.4 cm a(ove

the >oor is prescri(ed. Where the lightsource is a(ove F. meter height fromthe >oor, at least A meters candleminimum illumination should (eavaila(le. It should (e at least 9Ameters candles $here the $or! isactually going on. Wal!$ays re'uire at

least : meter candles at >oor level.=ule 92 descri(es details to preventglare. -see Part 9.2.2/


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carding, dra$ing, spinning-ordinary/ counts of cottonM.

.

Where moderatediscrimination of details isessential -e.g. mediumassem(ling, rough (ench$or! and machine $or!,

inspection and testing ofproducts, canning, sa$ing,se$ing of light colouredte#tiles and leatherproducts, $eaving lightthread, $arping, spinning&ne counts/.

2AA

F.

Where close discriminationof detail is essential -e.g.medium (ench and machine$or!, &ne testing, >our

grading, leather &nishing,$eaving cotton goods orlight coloured $oollengoods, $elding su(3assem(ly, drilling, riveting,(oo!3(inding and folding/.

9AA

8.

Where discrimination of &nedetail is involved under afair degree of contrast forlong periods of time -e.g.&ne assem(ly, &ne (enchand machine $or!, &ne

inspection, &ne polishingand (evelling of glass, &ne$ood $or!ing, $eaving dar!coloured $oollen goods/.

:AA

@.

Where discrimination ofe#tremely &ne detail isinvolved under conditions of e#tremely poor contrast forlong periods of time. -e.g.e#tra &ne assem(ling, e#tra&ne inspection, e$ellery

and $atch manufacturing,grading and $or!ing ofto(acco products, dar! clothhand tailoring, &nalperching in dye $or!s,ma!e3up and proof3readingin printing plants/.

AAA

?+, Indian Standard"

SP 92 a Hand(oo! on functionalre'uirements of industrial (uildings-lighting K ventilation/ may (e referred.

Some useful IS are given in %a(le @.: 7

Ta*l! 9+@ Indian Standard" onLighting

Titl! IS No+

. Industrial lighting :2. aylighting of factory

(uildingsAA

9. aylighting of (uildings 244A4. Principles of good lighting

and aspects of design-Part I/

94

:. Schedule for values ofillumination and glareinde# -Part II/

94

. Calculation of coe1cient

of utilisation (y the 5Nmethod -Part III/

94

F. lectrotechnicalvoca(ulary Part

88:

8. Elameproof electriclighting &ttings

22A

@. ust3proof electric lighting&ttings

4A2

A. ust3tight electric lighting&ttings

4A9

.


12/31

a =ough $or!, fore#ample, frameassem(ly, assem(ly of heavy machinery

:A

(


13/31

po$er and (lo$erhouses.

d Sla( inspection andconditioning, cold stripmills, sheet and plate&nishing, tinning,galvanising, machine

and roll shops.

2AA

e Plate inspection. 9AA

f %inplate inspection. SpecialLighting

2 La*oratori!" and T!"t Roo$"

a ;eneral la(oratories,(alance rooms.

9AA

( lectrical andinstrumentla(oratories.

4:A

9 :a(hin! and .ittingSho'"

a =ough (ench andmachine $or!.

:A

(


14/31

fa(rication.

.

0rdinary

Chal!(oards Kcharts, pharma3stores, (ottling Kcanning plants,(oo! (inding,food preparation,

coo!ing,canteens.

9AA

F.

Simple

=ough (ench andmachine $or!,counting,chec!ing, halls,$aiting rooms,$arehouses,stores, par!ing,dispatch.

2AA

8

.

=ough

intermittenttas!s

Live storage,

rough (ul!ymaterial, loading(ays,changeloc!errooms.

AA

@.


15/31

meet the re'uired standard orparticular demand of any o(. Eor thispurpose supplementary luminaries areused to provide higher illuminationlevels for small or restricted areas. ?lsothey are used to furnish a certainluminance, colour or to permit special

aiming or positioning of light sources toproduce or avoid highlights or shado$sto (est portray the details of the tas!.?t the dar! spots, supplementarylighting is re'uired. Permanentsupplementary arti&cial lighting -PS?L/in (uildings is re'uired $here ade'uateday lighting over the $hole $or!ingarea is not availa(le and to createaccepta(le (rightness levels on thevarious surfaces in $or!ing interior.

Dir!(t Lighting means light fallingon o(ect directly from source O naturalor arti&cial. %hus direct light from Sun orelectric tu(e on the o( or (oo! is calleddirect lighting. Its &rst re>ection is tothe eye, therefore, it should not (ee#cessive, other$ise it may causere>ected glare or eye strain. Local light-lamp/ hanging on machine is a directlight. irect arti&cial light re'uires lesselectric po$er consumption than theindirect arti&cial light for the same

(rightness re'uired.Indir!(t lighting is re>ected or

diused light coming after re>ection of light from some surface or comingthrough some transparent surface. Its(ene&t is to avoid direct glare and toma!e the light of comforta(le(rightness.

S!$i-dir!(t or "!$i indir!(tlight is a com(ination of direct andindirect light. irect light from $indo$and simultaneously re>ected light form

a lamp is of this type of light. Wheredirect or indirect light is insu1cient,lighting level is increased (y this typeof com(ination.

Di2u"!d or reduced light throughsome surface should (e su1cientother$ise it may cause discomfort oreye3fatigue.

S!(urit# or Prot!(ti)! Lightingis re'uired in (ordering areas andsecurity points for night3time policing. It

$ill sho$ and restrict entry of intruders.It is of four types 3 >oodlights, street

lights, fresnel lens units andsearchlights. It may (e re'uired at thetime of evacuation of people in case of emergency. ?lternate po$er source-e.g. ; set/ should (e connected toemergency or protective lighting.

.loodlight" provide area lighting

at an economical cost. %hey must (elocated at suita(le mounting heightsand $ith uno(structed (eam paths.oodlight poles. Eloodlights are of lamptypes and $ith (eam spreads from Ato 8 degrees.

@+1+1 Da# Natural or G!n!ralLighting

In our country natural sun lightavaila(le during most of the days iscalled da#light or da# lighting. Itsvarying intensity from sunrise to sunsetprovides harmonious variation of thevisual environment inside or outside a(uilding and is normally $elcomed forthe visual tas!. It is the cheapest lightand should (e eectively utilised (yproper design of roof, doors, $indo$sand ventilators. ;enerally northlight

roof, also !no$n as sa$ toothed roof orpent roof, is a more e1cient $ay of getting daylight $ithout glare andheating (y direct sunlight. %he standardsi"e $indo$s should (e provided on(oth sides opposite to each other too(tain (etter and uniform illuminationthroughout the area.

Windo$s, monitor -louvers/ roof and the north light roof are generallypreferred for day lighting. In our country

mostly north3light -sa$ tooth type/roofs are preferred in the northernhemisphere. Such design !eeps o direct mid3day sun in latitudes north of 29A. %ransparent glass or plastic sheet-plain or corrugated/ is provided in roof at certain intervals. %ransmissioncoe1cients of some such materials aregiven in %a(le @.2.

Ta*l! 9+, Tran"$i""ionCo!


16/31

light7 or "o$! gla=ing$at!rial"

:at!rial Tran"+Co!2+

%ransparent $indo$glass

A.8A toA.8:

2 Clear acrylic plastic A.8A toA.8:

9 Patterned glass A.FA toA.8:

4 Clean rigid P6C A.FA toA.8A

: Wired rigid P6C A.FA toA.F:

Sand (lasted glass A.: toA.8A

F Wired &nish glass A.A to

A.8A8 Corrugated glass &(re

reinforced sheetA.:: toA.8A

Proper utilisation of day lighting toget appropriate illumination levels onthe $or!ing plane in factories $ill resultin considera(le economy consistent$ith e1ciency of production and$or!ers $ell3(eing. %he Central5uilding =esearch Institute, =oor!eecarried out research and measurementsof daylight re'uirements for factory(uilding and IS7AA is prepared on the(asis of its investigations.

0ne research has sho$n thatarti&cial lighting in the a(sence of natural -day/ light, aects theautonomous nervous system. %hereforearti&cial -electric/ lighting should (econtrolled in accordance $ith thevariations of daylight.

See also Part .2.

@+1+, Arti(ial Lighting andT#'!"

uring night time i.e. in thea(sence of daylight, arti&cial light is theonly remedy. ven during day time$here the day lighting is insu1cient toprovide prescri(ed illumination due too(structed locality or $eather eect, it$ill (e necessary to supplement the

natural lighting (y arti&cial lightingdesigned to operate permanently

during day time. It should (e properlyco3ordinated $ith natural lighting as perIS794 -Part I/. %he com(ination of daylighting and arti&cial lighting is !no$nas tilighting.

%ypes of arti&cial light depend ontypes of arti&cial -vi" electrical/ light

sources or its tures. Lighting fromelectric lamp or tu(e or from manytypes of their com(ination gives averity of arti&cial lighting. Eor detail seePart :.2 and :.9.

See Part .9 for installation of arti&cial lighting.

@+, T#'!" o Light Sour(!"

It is interesting to note that electric

lamps produce more heat than light asfollo$s7

T#'! o La$' H!at 5%7 Light5%7

Incandescent @F 9Eluorescent @A A

Sodium 6apour 8A 2A

0ther types and lamp data aregiven in %a(le @.9.

Ta*l! 9+3 Lamp ata

T#'! o La$'

Lu$inou"

E


17/31

LampsHighPressure-HPuorescence


18/31

lamps have more rapid lumendepreciation than do mercury vapourlamps and have high surface operatingtemperature $hich must (e considered(efore application in classi&edlocations. %he lamp life and lumenoutput are aected (y (urning position.

HI lighting may (e supplemented(y incandescent or >uorescent lighting$hich $ould provide illumination duringthe initial $arm3up time and during there3stri!e time after e#tinction caused (yvoltage dips in the A percent to Apercent range, depending on (allasttype.

Compared $ith incandescentlamps, mercury vapour lamps oer theadvantages of longer average life andhigher lumen outputQ ho$ever, $ith theadvent of metal halide and highpressure sodium lamps, the mercuryvapour lamp is considered (y many to(e o(solete, e#cept in e#isting plantshaving similar lamps. %he mercuryvapour lamp is considered o(solete(ecause of its rapid lumen depreciationand lo$ lumens3per3$attcharacteristics.

Erom a(ove types the mercuryvapour lamps ta!e up to minutes and

sodium vapour lamps ta!e up to 2Aminutes to reach their ma#imumoutput, the actual time $ill (edetermined (y the $attage of thelamps. In the event of a po$er failure,restoration of po$er $ill immediatelystart machinery $hile discharge lamps$ould ta!e +$arming time to relight.

%his time gap may cause accident. %oavoid such situation emergency lightingis a must $hich $ill glo$ during po$era(sence.

uorescent and sodiumvapour lamps are generally called!l!(tri( di"(harg! la$'" as electriccurrent is passed through certain gasesto produce emission of light.

S!l!(tion o th! t#'! o light"our(! depends on e1ciency,installation, running costs,maintenance, life characteristics, si"e,ro(ustness and heat K colour output.

%he e>cienc! of any lamp is the lightoutput per unit of electricity consumed

and is measured in lumens per $att. Eore#ample, it is as under7

T#'! o La$' Lu$!n" '!ratt 5a''ro6+7

Incandescent lamps : %ungsten halogen 22High pressuremercury

9:3::

Eluorescent lamps F:3@:High pressure sodium AA

Incandescent lamps are cheaper(ut they are more e#pensive than othertypes of lamps to run and they re'uirefre'uent replacement. ischarge and

>uorescent lamps cost more to install(ut their greater e1ciencies and longerlife ma!e them more suita(le forgeneral interior lighting.

Where colour performance isimportant, the tu(ular >uorescentlamps is more suita(le and not themercury or sodium vapour lamp. Wherelighting is re'uired at height -e.g.overhead crane in $or!shop/ the highpressure discharge lamps are oftenselected.

Where arti&cial lighting is supplied,ha=ard" o !l!(tri(it# must (eidenti&ed and removed. Loose $iring,faulty s$itches, fuses etc., un3insulated$ire or ca(le, open s$itch (o#, open$ire in plug, many oints in phase $ireetc. are sources of danger $ith electriclighting. Safe lighting is lo$ voltagelighting -allo$ing lo$ current at thesame resistance G I=/ or solarlighting.

Similar precautions are alsonecessary $hile providing lighting inha=ardou" ar!a". ust, dampness,>amma(lee#plosive atmosphere,corrosion etc. re'uire standard>ameproof electric lighting. lectrice'uipmenttool should also (e of theapproved type. See Chapter3 fordetails.

@+3 T#'!" o Lighting.itting"

18


19/31

Lu$inair! is a general term usedfor all the apparatus necessary toprovide a lighting eect. It includes allcomponents for the mounting andprotection of lamps and connectingthem to po$er supply i.e. the $holelighting &tting.

In selection of a luminaire -lighting&tting/, a separate study should (emade for each application. Eactorsin>uencing the selection areappearance, e1ciency, glare, density of e'uipment, fre'uency of operation,maintenance, re'uired colour renditionand area classi&cation.

%he lighting &ttings or tures areof many types, vi". (are, re>ector type-direct/, direct3indirect, louvereddiused, diused panels, local lightingunits, hand lamps and >ame proof anddust proof &ttings for ha"ardous areas.Hand lamps should (e of lo$ voltage ≤24 6 and >ameproof if it is to (e used in>amma(le area. It should have a lampguard and an insulated handle. Sometypical general lighting units are asfollo$s7

. Indu"trial t#'! trough" and"had!"7 %hese have small slots

$hich allo$ at least A3:B of thelight to escape in an up$arddirection. %his $ill (e su1cient todispel overhead gloom and alsoensure ade'uate ventilation of the&tting, thus helping to prevent dirtfrom collecting inside.

2. Totall#-!n(lo"!d di2u"ing unit" 7)nits of this type provide high'uality lighting and the incandescentvariety are (y far the (est type touse $hen an o1ce is to (e lit $ithincandescent lamps. %he >uorescentversion gives comparatively littleup$ard light and for this reason itshould (e ceiling3mounted ratherthan suspended.

9. Lou)!r" ;uor!"(!nt unit" 7 %hesemay have metal louvers, ortranslucent diusing ones. If suspended from the ceiling, at leastsome of the lamps should emituno(structed up$ard light. Such

units are generally less aected (y

air(orne dirt than totally enclosedtypes.

4. Dir!(t-Indir!(t unit" 7 %heessential features of this type of unitis the pair of large apparatus -some2 or 9 inches $ide/ a(ove the lamps.

%hese large slots allo$ some 4AB of

the availa(le light to escape to theceiling and for this reason it isconvenient to refer to them asR4AA &ttings -this (eing therelative proportions of up$ard anddo$n$ard light/. 5eing madeentirely of metal, such &ttings arefre'uently cheaper than theenclosed diusing type.

:. ar! ;uor!"(!nt la$' unit" 7 If the room is very small -so that alllamps are $ell up out of the &eld of vie$ of the occupants/ they can (esafely used. %hey can also (esometimes employed in long narro$room $here everyone vie$s theunits more or less on end.

. R!(!""!d unit" 7 In o1ces $ith lo$ceilings, it is often necessary torecess the lighting &ttings, leavingthe mouth >ush $ith the ceiling. Insuch cases light from the &ttings canonly reach the ceiling (y re>ection

and the system is most li!ely to (esatisfactory $hen the room is smallin si"e, $ith a light decorationscheme or $hen the generalillumination is reasona(ly high -atleast :A lms'. ft or :AA lu#/.

F. Lu$inou" and lou)!r!d (!iling" 7In general, a louvered ceiling gives(etter visual conditions than aluminous ceiling made of continuoussheets of diusing material. ?uniformly (right luminous ceiling

tends to produce e#cessivelydiused lighting $hich is apt to ma!ethe interior loo! dull unless theillumination level is particularly high.

8. In(and!"(!nt la$' unit"7 eepshades should (e used and a (lac!(and should prefera(ly (e paintedround the inner edge of adusta(leshades $hich may (e set at anangle.

Hand lamps should (e of a $ell

designed, strongly constructed type. %he lamp soc!et should (e properly

19


20/31

shrouded and insulated from the $ireguard. Lo$3voltage incandescentlamps are more e1cient and ro(ustthan e'uivalent mains voltage types.

%hey are safer to use, provided thatthe supply transformer is properlyinsulated and earthed, prefera(ly at

the centre point of the secondary$inding. In particularly dangeroussituations -e.g. inside a metal tan!or (oiler shell/ the lamp voltageshould prefera(ly not e#ceed 24volts, $ith centre3point earthing toreduce the ma#imum potential toearth to 2 volts.

@. .luor!"(!nt la$' unit"7 %roughsshould (e mounted either lo$enough to ensure that all (rightsurfaces are completely hidden, orhigh enough to ensure that they are$ell outside the normal &eld of vie$.

@+? T#'!" o LightingIn"tallation"

%he term lighting installationincludes types of lighting, light sourcesand &ttings ust mentioned in foregoingparts :. to :.9. It is a (road termdescri(ing overall arti&cial lighting

arrangement.;enerally lighting installation is

classi&ed as 7

. )niform general lighting.2. ;eneral plus local

supplementary lighting.9. Localised general lighting and4. Special purpose lighting

-ultraviolet lamp etc./.

nior$ g!n!ral lighting should(e -/ as high as possi(le to avoidglare -2/ spaced evenly proportional tomounting height and-9/ uniform and notless than 29 of average any$here. If mounting height is H, then distances of spacing of ro$s, close to $all andgang$ay along a $all should (e .: H,A.: H and A.F: H respectively. )niformgeneral lighting is suita(le in place$here the $or! points are not ed e.g.foundries, large assem(ly shops,

$arehouses etc.

In g!n!ral 'lu" lo(al"u''l!$!ntar# lighting, additionallocal units -usually mounted close tothe $or! point/ supplement the evenlydistri(uted general lighting provided (yoverhead units. %he system is re'uiredat a fe$ de&nite scattered locations

and $here light from overheadinstallation cannot reach the $or! pointe.g. inside the throat of a heavy po$erpress, inside hopper on point of operation etc. ;enerally the averageillumination should not (e less than thes'uare root of the illumination on thelocally lit tas!.

Lo(all# g!n!ral lighting isprovided (y overhead units onindividual $or! (enches or machinesre'uiring strong illumination. es!sta(les or machines should (e lightedfrom side rather than from directly infront.

@+@ Co"t o Lighting

0ld data of cost of lighting, in @:3, in 24 ;erman factories $as 2B of the $age (ill. It $as .4B in A 5ritishfactories. It may (e assumed around.:B of the $age (ill of a factory.

Lighting cost is the sum of ...

. Cost of &ttings # depreciation -DAB/.

2. Cost of lampstupes.9. Cost of electricity.4.


21/31

9. 0verall cost can (e reduced (yusing lamps having a high luminouse1cacy and suita(le lightdistri(ution.

DESIGN /. LIGHTINGINATALLATI/N

ight points discussed in foregoingpart 9.2 are most important to designeective lighting installations.Particularly principles of illuminationand utility of types of light, sources and&ttings must al$ays (e considered$hile designing factory (uilding andinteriore#terior lighting arrangement.Selection of lighting &ttings shouldconsider 3

. Luminance or (rightness.2. esign of luminaries -/ to avoid

glare and shado$ under normalseeing conditions -2/ to producehighest initial and sustained lightoutputs.

9. ameproofdustproof and non3corrosive light &tting $here they arespeci&cally needed.

F. Pay more attention on inspectionareas re'uiring continuous closeo(servation.

8. Select good lighting for (uilding sitesand internal road$ays. )se of

tungsten halogen >oodlights,(ecause of their small si"e and lo$cost, permits a temporaryinstallation to (e made 'uic!ly andeasily.

Eor good design, it is important tosee! co3operation (et$een architect,occupational hygienist and lightingengineer to avoid errors from (eginning.Erom the design stage, the planningshould include appropriate light

distri(ution and colour layout of the

21


22/31

$or! areas and for that purpose thetype of lamps, luminance distri(ution,luminous e1ciency and spectralcomposition of light should (econsidered.

Lighting installations should (edesigned to meet the conditions

peculiar to the tas!s of each area.Standard -recommended/ illuminationlevels serve only as a guide to goodlighting practice. 0(viously dependingon $or! re'uired, illumination should (eincreased on the tas!.

+, Da# lighting o .a(tor#uilding"

Some design factors are 7

. %he design of openings, gla"ing andsimilar sources of daylight should (eso positioned as to give illuminationlevels given in %a(le3 of IS7AA.

2. )sually north lights are employed toprovide re'uisite illumination on the$or!ing plane. Location of $or!should (e such as to avoid glarefrom the north light gla"ed openings.

9. Where $or! is carried out duringdus! hours, the day lighting should(e com(ined $ith arti&cial lighting in

such a manner that the diminution of daylight is unnoticea(le specially forthose engaged in precision $or!involving eye strain.

4. ? careful interpretation of da!light actor -divide lu# value (y 8A to getdaylight factor 3 E/ should (e made(efore designing the fenestration.*ormally factories should (edesigned to give atleast .2: E.

:. 0(structions li!e structural

mem(ers, overhead installations,vertical and hori"ontal machines andthe li!e should (e considered inrelation to the gla"ing. It is essentialto foresee the proposed layout of themachines, as ignorance of thisaspect is li!ely to cut do$n the lightreaching the $or! plane.

. %here should (e a good distri(utionof light over the $hole interior.)nilateral systems should (eavoided. Light colours should (e

preferred on the interior surfaces. In

case of north light roof truss,shado$s caused at $or!ing planes(y machines and operators can (eminimised (y providing openings inthe side $alls andor (y use of lightcoloured &nish for ceiling surfaces.

F. Wor! should (e so located as to

avoid glare from the north lightgla"ed openings.

8. %he uniformity of illumination on the$or!ing plane in a north light factorydepends on the $idth of the (ay-distance (et$een the north lightopenings/, the slope of the roof andthe re>ectance of the ceiling.

@. 0ther types of north lights such assa$tooth, cylindrical shell or foldedplate north light roofs should (edesigned properly.

A. Side3lighting is similar to vertical$indo$s.


23/31

maintenance costs, versus the'uantity and 'uality re'uirementsfor optimum visual performance.

:. Control the light to control glare,shado$, distri(ution and diusion.

. Luminaries $ith some up$ardcomponents of light are preferred

for most area (ecause anilluminated ceiling or upperstructure reduces luminance ratios(et$een luminaries and the(ac!ground. %he up$ard lightreduces the +dungeon eect andcreates cheerful environment.

F. Higher mounting heights -out of thenormal &eld of vie$/, (ettershielding of the light sources andtop openings in luminaries to allo$to move dirt particles up$ardshould also (e considered.

8. Where false ceiling is provided, thelighting &ttings may (e recessed inthe ceiling giving a morestreamlined appearance to the$hole installation

@. ;enerally a continuous mounting of tu(ular >uorescent tu(es &tting ispreferred to an arrangement of re>ectors at intervals.

A. %he &ttings should (e ed to the

e#isting mem(ers of the roof structure and should (e orientedaccording to the layout of themachinery to o(tain mostsatisfactory result. %he trenchingsystem -metal channels $ith coverplates at the (ottom, of standardlengths oined together/ runningacross the hall $ith suspensions atnecessary intervals is alsopreferred.

. Illumination values and (rightness

ratios must (e carefully controlledso that $or!ers in one part of thefactory are not su(ected to higher(rightness than they see in theirimmediate surroundings.

2. Contrasts (et$een the high(rightness of gla"ing and the dar!solid surface around it should (eminimised.

Cal(ulation o Arti(ial Lighting

Eollo$ing four methods are in use to

calculate arti&cial lighting installationsin industrial (uildings.

1. Th! Light Sour(! Point :!thod 7It is applied to calculate lightingtures $here light sources arelocalised. Illuminance of inclined

planes and uniformity of generalillumination -e#clusive of re>ected>u#/ are determined.

2. Th! 4attag! :!thod 7 It is simpleand uses the formula W G PS*,$here W is the $attage of a lightsource in $atts, P is the po$erdensity in $attsm2, S is the surface-room/ area in m2 and * is thenum(er of light sources -lamps/ inthe lighting ture. %he values of Pare availa(le from appropriateta(les.

3. Th! Gra'hi(al :!thod 7 %hismethod of Prof. %ru!hanov is mostuseful $hen light sources areproectors. It uses specialisednomograms.

4. Th! :!thod o Light .lu6tili"ation .a(tor 7 It is mostuseful to calculate general uniformlighting in industrial (uilding. It usesthe formula E G STN)* $here, E

G light >u# -l#/, G illuminance-l#/, S G area of enclosure -m 2/, T Gcorrection factor for the luminaryssoiling -from a ta(le/, N G thelighting non3uniformity coe1cient, )G the light >u# utilisation factor of alighting ture and * G the num(erof lighting sources -lamps/. %hemethod ta!es into account (oth thedirect light from the luminaries andthe light re>ected from the $allsand the ceiling.

+? Plant Lighting D!"ign

ntire plant lighting shall (e dividedinto follo$ing three categories.5a7 Nor$al AC lighting+

*ormal lighting panels shall (esupplied (y three phase and neutral4: 6 Po$er derived from


24/31

Critical lighting $ill (e providedon escape route $ithin the controlroom (uilding, su(station (uilding.

%hese lights $ill (e normally +0EEK %urn +0* automatically only oncomplete Po$er failure.

ssential light $ill remain

energised all the time.

5(7 Criti(al DC lighting+ %he critical lighting shall (e

supplied (y 22A 6 C systemhaving (attery (ac!3up.

ssential lighting panels shall(e supplied in the same manner asthe normal lighting panels (ut fromthe emergency (oard $hich has the(ac! up of a stand (y Po$er.

Porta*l! !$!rg!n(# light" $ith(uilt3in (attery and (attery chargershall (e provided at strategic locationsin (uilding li!e ?dministrative (uilding,uoreocent tures.Process area shall (e lighted (yHPS6HP


25/31

. Improve lighting conditions.2. ecorate the environment.9. Increase e1ciency and productivity.4. Improve 'uality of $or!manship and

normal s!ill.:. Improve la(our morale and interest

in $or!.. =educe accidents and increase

safety.F. =educe +reects.8. =educe a(senteeism.@. =aise standard of good

house!eeping.A. Improve (uilding and machinery

maintenance.. =educe hidden costs of dull and

gloomy atmosphere, and2. Improve overall psychological and

physiological eects on $or!ers for(etter $or! performance.

B+, R!;!(tion .a(tor"5LR7

? surface re>ects light. %he amountof light re>ected $ill depend on thecolour scheme of the surface. Pure$hite $ill re>ect AAB and pure (lac!AB of light falling on them and

re>ections factor of other colours $illfall in (et$een. %he recommendedre>ection factors, also !no$n as light re7ectance value 8L%94 for interiors are7

Part LR Colour

Ceiling 8A3@AB $hiteWalls :A3F:B light colour

Eurniture,'uipment,

machinery, des!etc.

9A3:AB mediumcolours

Eloors :39AB dar!colours

Light re>ectance values -L=6/ of some colours are as follo$s 7

Colour P!r(!ntag! o r!;!(t!dlight

White 8:

Vello$ lightF: medium:

;rey lightF:

medium::

dar! 9A

;reen light:

medium:2

dar! F

5lue light::

medium9:

dar! 8

=ed light

4A

cardinal

2A

dar! 9

Ivory lightFF

over green or $hitestippled 4A

Cream light

5u light:

5ro$n dar! A

?ppropriate colour should (eselected from a(ove t$o ta(les $hichconclude that ceilings and $alls shouldhave light colours for more re>ectionand >oors, furniture and e'uipmentshould have medium to dar! colours forless re>ection. Colour can (e used as afactor to re>ect light to increase it.

B+3 Colour Cod! and Sa!t#

B+3+1 Indian Standard"

IS to (e follo$ed are 7 Code of practice for safety colours and safetysigns @4:F, Pipelines, identi&cation,colour code 29F@, Standard colours for(uilding and decorative &nishes :A,pipelines in thermal po$er plants @4A4,Identi&cation for canisters andcartridges 898 and ;as cylinders andrelated medical e'uipment 9@99.

B+3+, Colour" to Id!nti#

Ha=ard"

Colour coding is most desira(le anduseful for safety purposes. Standardcolours are used to identify ha=ard" asfollo$s 7

=ed 3 Eire protection, prohi(ition,danger, emergency stops onmachines.

Vello$ 3 =is!, danger or caution,

ha"ards of slipping, falling,stri!ing etc., >amma(le

25


26/31

li'uid storage, (and on redsafety cans, materialhandling e'uipment vi". lifttruc!s, cranes, crane hoo!s,caution, transporte'uipment, o(structions,change in >oor level, stair

nosing etc.;reen 3 Eirst3aid, safety e'uipment

not identi&ed else$here,safety (oard, safe condition.

5lue 3 Warning and informationsigns, (ulletin (oards,railroad uses. It indicatessafety colour only if used$ith a circular sign.

0range

3 angerous parts of machines or energised

e'uipment such as e#posededges of cutting devices,inside of mova(le guards,enclosure doors,transmission guards, electricinstallations.

Purple 3 =adiation ha"ards.5lac!KWhite

3 House!eeping and tra1cmar!ings. ?lso used ascontrast colours.

White is a contrast colour for red,

green and (lue. 5lac! is a contrastcolour for yello$.

%he piping in a plant may carryharmless or ha"ardous contents.

%herefore it is highly desira(le toidentify them. Some standard colourcoding is as follo$s 7

Cont!nt in th! 'i'ing Colour

Elamma(le or $ater for &reprotection

=ed

angerous -ha"ardouschemical/

Vello$

Safe -$ater, air/ ;reenProtective material -inertgas/

5lue

%he proper colour may (e appliedto the entire length of the pipe or in(ands 2A32: cm $ide near valves,pumps and at repeated intervals alongthe line. %he name of the speci&c

material should (e stencilled in (lac! atreadily visi(le locations such as valves

and pumps. Piping less than 94 inchdiameter is identi&ed (y enamel onmetal tags. ?nti3resistant colours should(e used $here acids and otherchemicals may aect the paints.

Eollo$ing colour coding is alsouseful in identifying pipelines -IS729F@/ 7

Sr+ :at!rial Colour Water Sea green2 Steam ?luminium,

IS7299@9 ?ir S!y (lue4 ?cids ar! violet: ?l!alis Smo!e grey ;ases Canary yello$F Hydrocar(ons

organic compoundsar!admiralitygrey

8


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?ccident prevention signs are most$idely used safety measures inindustry. %heir uniformity in the colourand design of sign are essential.mployees may (e una(le to readnglish or may (e colour3(lind and yetreact correctly to standard sign.

Eollo$ing colours are normally used forsigns7

Dang!r 3 Immediate and gravedanger or peril. =ed oval in top panelQ(lac! or red lettering in lo$er panel.

Caution 3 ?gainst lesser ha"ards. Vello$ (ac!ground colourQ (lac!lettering.

G!n!ral Sa!t# 3 ;reen(ac!ground on upper panelQ (lac! orgreen lettering on lo$er panel.

.ir! and E$!rg!n(# 3 Whiteletters on red (ac!ground. 0ptional forlo$er panelQ red on $hite (ac!ground.

Inor$ation 3 5lue for (ulletin(oards.

In - Plant !hi(l! Traection of light, topaint the plant and everything (y $hitecolour is not advisa(le, (ecause +only$hite premises and e'uipment causefatigue and (oredom and are noincentive for active or creative $or! if there is no com(ination of other

colours. ?ny e#treme should also (eavoided.

Eor (!iling", the re>ection factorshould (e at least F:B $hich means$hite or near3$hite. ? matt &nish isprefera(le. ?luminium paint is not recommended.

4all" are (est &nished in lightpastel colours in the :A3F:B range,e#cept in the case of very (rightly lit$alls -e.g. those adacent to a large$indo$/ $hich may need toning do$nto 4AB or less to prevent them from(ecoming too glaring. Conversely, $allscontaining $indo$s -(ut $hich receiveno direct light themselves/ cannot often(e painted $hite $ith advantage.

.urnitur! should prefera(ly have are>ection factor of at least 2AB, andthe modern (lond $ood &nishes andlight grey paints for steel ca(inets arepreferred to the old3fashioned dar!stained $ood and dull olive green&nishes. 0n des! and ta(le tops $hichform a (ac!ground to the $or!, it isimportant to guard against distractingre>ections.

.loor" should (e reasona(ly lightin colour. Practical considerationsusually govern the nature of the >oor

&nish, (ut 2A32:B or so is generally asatisfactory &gure. Eloor &nishes $hichare very much lighter than this should(e treated $ith caution since they cansometimes cause glare -e.g.particularly $ell3lit o1ce interiors/.

A !ll 'aint!d $a(hin! inspiresfeeling of personal pride and propermaintenance is encouraged. )nder the;eneral Code of Practice for


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painted in RStatic colours -Cream,Stone ;rey, Pale ;reen, Pale 5lue/.+ontrol areas should (e painted insuita(le colour to provide a neutral(ac!ground for coloured indicatorplates.

Guard" should (e regarded as part

of the machine and should (e paintedin the same colour as the colour of themachine. +olouring recessed surace of machines $ith lighter shade than usedfor the outer surfaces help to minimisethe eect of shado$s on the innersurfaces -#ample 7 Static grey forouter surfaces, static stone for recessedsurfaces/.

Identi&cation colours on machinesshould (e reserved for things $hichreally matter, such as stop (uttons andother safety tripping devices $hichmust (e found 'uic!ly in an emergency.RSafety colours must also (e used $ithgreat restraint. angerous moving partsshould (e guarded, not coloured, and$hen guarding is impossi(le, colourshould (e used to highlight the actualha"ard and not merely as a general$arning.

Eor paints IS 7 : and for (uilding anddecorative &nishes IS 7 SP :A are

relevant.

B+? P"#(hologi(al E2!(t" o Colour

%hey are as follo$s 7

=ed 3 Stimulates, activates,energises

Vello$ 3 5right, ;ay, Eresh li!esunshine

0range 3 ? room painted in(rilliant orange $ill (etension producing

Light ;reenLight 5lue

3 =ela#ed feeling,improve morale

Purple 3 Eeeling of depression

White 3 Is stimulating if it isused $ith $arm colours

5lac! 3 Is not depressing if it isused $ith other colours

Si"e 3 ;reen and 5lue o(ects

loo! larger than Vello$and =ed

Space 3 ;reen and 5luesurfaces record. =edand Vello$ comefor$ard

%emperature

3 =ed and Vello$ give$arm feeling. 5lue and;reen give cool feeling

Weight 3 5right colours ma!eo(ects loo! lighter

=ed, orange and yello$ -light/ are'ar# colours. 5lue, tur'uoise K greenare cool colours. 03$hites and pasteltints are light colours. 5lac!, grey anddeep tones are dar0 colours and red,yello$, yello$3green, orange and red3orange are considered right colours.

Warm colours may (e used to

o(tain activation and rela#ation eectsi.e. energy input. Cool colours are aid toenergy output. 5right colours give animpression of amenity and lightnessand produce serenity. ar! colours mayhave a cheerless and depressing eect.

In "!l!(ting (olour" olloingguid!lin! i" u"!ul -

. *atural $hite or light colours aresafe and render all colour shades intrue proportions.

2. Cool colours on o(ects give goodeect. %herefore they are called safeo(ect colours.

9. 5right colours should (e preferred as(ac!ground colours.


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F. Colours can aect their (ac!groundalso -5e"olls eect/.

%hese rules emphasise importanceof and interaction (et$een light andcolour. %he appropriate light has to (echosen $ith colour and vice versa.

While designing colour schemes forplant K e'uipment these factors are to(e ta!en into consideration.

%his discussion concludes that the'uestion of colour may not ust (e leftto the painter, nor the 'uestion of lightto the electrician. Scienti&c !no$ledgeof com(ined eects of lighting andcolour should (e properly utilised.

Colour li!ing may change $ith timeand fashion (ut safety aspect shouldnot (e forgotten.

8 :AINTENANCE ./RLIGHTING AND C/L/R

)nless a lighting installation isproperly maintained, lamp depreciationand dirt accumulation on the &ttings$ill cause an increasing loss of lightQ insome circumstances this can cut theillumination level (y half in the periodof only a fe$ months.

4h!n (hoo"ing !>ui'$!nt,ma!e sure that it $ill (e easy to cleanand re3lamp, and also provide safe andready means of access to the units.

Cl!aning "(h!dul!" should (ecarefully planned. Eittings should (e

cleaned at regular intervals and not ust$hen a lamp fails. %he need for this isoften overloo!ed (ecause dirt collectsso slo$ly and evenly that a deposit$hich may (e a(sor(ing a largeproportion of the light is often di1cultto detect until it is distur(ed. Cleaning

should (e done often enough to preventthe illumination level from droppingmore than a(out 2A39AB during theinterval. ? systematic chec! $ith alight3meter at several ed points in aninstallation is one $ay of deciding ho$often to service it.

La$' R!'la(!$!nt should also(e done systematically, and it is notal$ays advisa(le to $ait until theyactually fail to light. %he output of anincandescent lamp does not drop agreat deal (efore it &nally (urns outQ(ut this is not necessarily true of the>uorescent type, $hich may continue tostri!e long after the light output hasdropped to a very lo$ &gure.

Grou' r!'la(!$!nt of all thelamps together at some predeterminedtime is often favoured for largeinstallation in $hich many units are inuse for appro#imately the same num(erof hours each day. %his group

replacement ta!es place after theinstallation has (urned for a ednum(er of hours, or after some edproportion -say 2AB/ of the lamps hasfailed.

E6!r(i"!

1. E6'lain Stat! :!ntion orDi"(u""

. *eed, purpose or (ene&ts oflighting.

2. ects of (ad or poor lighting.9. =e'uirements of good lighting.4. aylight factor, =e>ection factor

and )tili"ation factor for light.:. %he dierence (et$een

. Illuminance and Luminance.2. Initial and service illuminance.

9. ?de'uate and uniform lighting.4. Xuantify and 'uality of light.

:. Luminance contrast and colourcontrast.

. irect glare and isa(ility glare.F. iscomfort glare and =e>ected

glare.8. ;lare and Shado$@. ay lighting K ?rti&cial lighting.A.


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9. Porta(le emergency light KLocal light.

. %ypes of lighting.F. Eactors of selection of light sources

or lamps.8. ierent sources of lighting

commonly used in a factory and

discuss their merits and demerits.@. Eollo$ing terms7 -/ Luminous >u#

-2/ Luminous intensity -9/Illuminance -4/ 5rightness -:/5ac!ground and-/ Contrast.

A. ?dvantages of good lighting.. =ecommended standards of

illumination $ith fe$ e#amples.2. Importance of illuminance level.9. Criteria for selection of lighting

&ttings.4. 5asic or general considerations for

design of lighting installation.:. esign factors for ay lighting of

factory (uilding.. esign factors for arti&cial lighting

in factory (uilding.F. Categories of plant lighting.8. ects of colour on safety.@. Choice of colour for plant and

machinery.2A. Psychological eects of colour.

2. *eed of maintenance for lighting Kcolour.

22. Colours and signs for accidentprevention.

29. ierent methods to derivema#imum advantage of naturallighting in a factory (uilding.

,+ 4rit! "hort not!" on -. Sight and light.2. Studies and results of lighting

eect.

9. Light loss factors and reasons of light losses.

4. ?de'uate illumination.:. ;lare 0= Shado$.. )niform lightingF. Colour eect

8. Elic!er and stro(oscopic eect@. ay lightingA. ?rti&cial lighting and their types. %ypes of light sources or lamps

-tu(es/2. %ypes of lighting &ttings9. %ypes of lighting installations.

4. Colour rendering inde#.:. Illuminance ranges. ection

factors or Light =e>ectance6alues -L=6/

@. Colours for accident preventionsigns.

2A. Colour scheme for machines2. Cleaning scheme for lighting

&ttings22. Statutory provisions for lighting

in factories.29. *eed to allo$ up$ard light on

roof or ceiling

3+ Co$$!nt on olloing "tatingh!th!r it i" tru! or not -

. yes, sight and light areinterdependent.

2. ;ood lighting increases safetyand had lighting decreases it.

9. Contrast should (e appropriate.4. Illumination level -standard/

cannot (e ed for all personsand places.

:. Colour has no eect on lighting.. Lighting and colour are

complementary.F. ;uards should have dierent

colour than that of the machine.8. Ceiling, >oor and $all should

have dierent colours.@. Colours have no eect on mind.A. ;roup replacement of lamps has

advantages.. ;ood arti&cial lighting improves

$or! performance and safety.

R!!r!n(! and R!(o$$!nd!d R!ading

. %he Lighting of Eactories, Teyte and;loag, H


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9. Colour and Light at Wor!, Sevenoa!sPress, London.

4. Hand(oo! of Industrial Lighting,Stanley L. Lyons, 5utter$orths

:. Psychology for 5usiness and Industry,Her(ert

09. CHAPTER - 9 Lighting and Control

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Transcript of 09. CHAPTER - 9 Lighting and Control