developed Thi ef pr in too ls schemes Th ing Council as da fu re ae de hu 1960 no hu I Suport li By P Ta Their rovid fic p N O C n e B we l • in • • Af a e L to od nc s Offi Tod B ght t si ma n ma n is i ed fle th or t, s st s Kar pa de t Ident Re over E ter n g u iency, t u r far e ex i fam s val w io et i r t umber ne rs uc t t i f e move su g of x ct s cogniz te ch n i n pe si ay ce I T as a re ed ibi as na al ing uat fa c sk cs nd i in gn ify ma st cr on s f .s t (US ading N r ’s ili g that g ac he m f l l n in g ed it , l e b li G N I U To Te or it no lo gy ight Use Ta es t d e of O to rs the w wh with 1970s a arit w o ny y off or e to rs ghti o d y o nd toward t c e j b m t r it GBC) k s tlo the ed ea r or of Hum cum ne w s woul li e ice for e so i g an a ile this h th ng li y ode rn nvi o s gh t rou nd kp l is su es, de e o n h g i L w th e ng gh t e sw er im the D E ff wi to employers Lightn sm light wne m pl re se svi e o pr l ron the a ea si t ar pr ent s, by ne ic portance a in g to of co ac ans Econmi d any th in g oviding n. C U gn er r de LEED® ar n i t ient in i mental, ovi th n AI ,icle env ns nt eg r fi c typi crital ng e il l r ar c use r. in offi e li te r corporatio s si cale t tr g AT A/ C t c su c g he ght q human ha n um in a yea rs ded e uc design pl a dem and gn tha t al l S office ue ironme s h ob you cal ce, O I o co ns t ti o so lu t of ES at i st h : s n o i t u l bel je ing s The econmi a ns , an d io n N ly i nd h c mo c i should fo r a mprove ncor .c on tive Le su seek li ns on c ow for s ago , ief o te er ght u sp li i an d ar m/ C ru ct ey e ch re res o on s. nt tin se s fl c gh por tifi en ha nce eff n of n ni wo r en e on su lt belo i t compnet ex ib l all ing , c r i e h T t li p cif hat ng o ue ul as j be E/ ti ect p st ra whe at ag i erg us and ca gh fu nc f f mo r th e ng on . rod y ment t ing w U ic ks pa ces . a s e Ye ive a actor ta mo t tio nd was t ble mor n XX y ati in to r huma e a l sk is it , n t th es i an t ta u c i m o n o c E t, mb work o e se le c ti n ke f effi cien cy li focus nit ol ctivit on d sk to: an d em b X, i an on s s po lig nc gh t for m ap pr e wa eco lo w mo s fo n ient li ors s lu di te ot th e n an y plo ye i the ht ght envi fa pa s in g Sol r s and ti on s he a ste your c thei her f ming th e ve Mo r n ct i i y w hn ol ogi es or ng op r bet ter. bl ing ng and y or f or res ronme job ol lo d or measure r sy st ems e of da on d n a r ep em pl oye e LEED study toward b bui lding int m es int ene r overhead of ia ke eo ve r, enf bui or desi f e w or ch e incre n a r ic or o te of h o e wor r ti n nts. ote g r E th e th e ou r a US es quir Worksp a ldi it e comfort arch a gy workplace n g s. li gh tin g Educat utions: gn nd s s r boo k asingly in st n o of ngs, you a of ep or req ked efficent co nt inu e Si nc e li gh tin g s, mo st a Gre en th a t e ha ve greater te nt ion can task i m o nd he d ru c sys t s. uirements. light t re ti al t he w mos tly ng and a t a su pp ort c c t and i lightn. h d and ith on s. ional ce be omp u th en , e v a cr so l sa pr ov ide d n Bu m Ergonmic dv an ced ari s s light a eed fe ty ex pe rts itica l ources en further s, ittle to to safety. ut io ns of grow il ety wit h din er Ad ne ter driven wa us e l— ing th e the the fo gy of or and w s. g ver s r - . ti re C 2004, P t Addi spac t W t P re r re sing hei hat he en ov h.D. l effectiv ons t duc i movi duct at a n O Re sh buil r by i es num i t ce l e S ing at e ncorporat i ruc t i ng i onal and ght on sponsor ng ect nt provi di r d deman ton , e ef ng i cer r exc c on, sp ac i sourc i ly, esear Je on n fec n e owne des ti nni D wat ess t i c ts f t ed e, C, i i ont r ca ng es c workplace fe provi x e of h w t m l s-per- ight wh t r r by most i a . hi ch i any ol j on. posi nt Vei m ob- r i de o i c p ove r for t ng Ben he h t e l One squar t ti bene ch, i s el com he nc lu a onabl fi indi at c C s i xt h phy si use enrgy P ed ana ie f fort benefi de d ures, e h.D. i vi t t ve e s st h foot of dual dia e abl r cal d wi l in light ess or i i whi ta ght a n n t U di . t y. h sk wor king LE t HSW EA G S workers v Designers a hat f NR Moreove ch id regar s. sour prese l saving, E i its ua l R ’C B i ght D-C omm re C accrued ng N su RN LEA ces d i ta Inst nt ng s OE N lted con diti ons sk to the a solu r, n tion has into itute ac w e li e r in epor n gh ts , freedom out complish erc ial / IA A e pr energy Courtesy at r G IN ind task tions. gy d a e h side for ovided ts Science w ividua CES con trib utes Kate consumptio Int a Resea ITN U of q s the sa to t r a u e e Humanscle a d rio evidence vings dr 70 . 1 1 Charles, p r l this ecently Insight osition s r e r am rch w s (CI ) or at i 17 f b k or i n. in t n o y c 3 -

CONTINUING EDUCATION t - - - - n n t i e r o t o t e h e l l a h e h t e h t e h t n e t u o , P A h d a h e n o i t i r a v imitro e h T d n s ’ g n s n o i e h b n i a t , n g i s c m o r f n o D m y r a n i g i l , P L L w g n i e b a e – – s t n i w r o f d s e v r r , e t D t r a s u s t a h w e d i c n r t n e i c i f f e i t a c o o p a t s k r o w ylight e s ilyana y l n o a w t s e u q t o n , 6 0 0 2 e s o h c i f i d l i u b p e B s p m a l e d i a l u g n s a r t a e l , h c i h - ® D E E h d d n a by f o x c l e l b i s i e r L w Da d e p e e h t y l u . g n i t h g i l s a h l v y r t r e c s t c e t i h c r A . s w o d n i w c u s a c J . s e i c n e i c i f f e e k s a t i t h g i y r e v e d n a y t i l a u q e t h g i l P L L e w t , C A V H ) e g n i t h g i l p u s d e h D E E L u x h d n a L n o y g r e n E s a w — s t e l i o t c o t e n i e h t x o F u m u e c e n i o t f o n l n o e h t e o s n n i y b + l i g i h s m k s a t u d o y t i l t n e i b m a a d . g n i t h g i d e n c r u o s t t a a p s , o i d u t s l ith W l y a/photograph v y g r e n e s a w i b , h g r p s n o i t i t o e t s n c a p s l a o g P d e d d , z e n i t r a M n d e d g n s t c e t i h c d n a t r A - f - 9 e c a d e t n u o r a e k o o C d e t e l p i h i e h a s ’ n o s r r e e l b a e h t d r e t e d , y l t h g t x l t a r a p imitr . s r o s n e s l p g n i v a s - r m e s e v e v e n r A i i l B e h t a r u d i e f o i D e p r e h e p o m o f o k s a t e t f o c i C l a l o r t a h s l o r s p t c e i v o r p t d n a , e t a t S C f o x o f o e h f o e h l l - 8 4 t u a e B t h g i h c a n a - w o a w t i e c e r F h g i s e g d i l s r u o t o n a l e s e r e w . e t a N m a t 2 Bilyana y d e , t n o c l o e r u t a i h a w t n o c + t . Y . N y c n e r t t © 0 t s a w a n o e k i k r o Y t e l e d o t n e t n y r u i . g n e p 9 c e l i n i l y a d a r l n o s i e d l l 1 l Lighting m e e e B i , s n o t n i f t c e i e k e h T s p m m m e i a p r e n g r k o o i t t h g e l e h e a a o r t a e f e n o z i t f - 4 1 f e t l e t c r h t n l l e e e r a o C l a h s w e N e p m e g n f s i l o n o i t a n i b m o c j o r p T t t r e m r c a p s k r o w a u d i v i i s e d e t l a a t s k a i h t n e h C n o d e ® y g r e i g i u q e t . s n o i i e t k s a y n a h r t t o f t e r t , f o o r t u p m t i s n o i s t r o . e t y h w i d n ask T t e d n e p e d e i b s a h a m t n i n m n o i t a c i f i t r e c c e r o w t a e h e n e o c a r s i w t n m r h g u o r h ” . n o l a c i m o c l o c e l b t . e c a p s o t y r e v e t s n a t l t o r a p C O V - w o m a i f i a p l e h D E E L r o f n i s y t i C t c e n n o d n e l b . t i j o r p , d e e r g o g n c a x: o a e D - 3 l a d l e w e h n o s a e i v o t g n g n e h i n h c a e u n e v A t , s e h e h i ’ d a b ‘ r i t s r t t n g n i k t y t t a m F a e on u s n o i ( e c a p s : n i t s k r o w t t e s u t i s n i f l a m u n i t a l P k r o Y o i h c r o y t n e e c i f t i t h g e c s e r o u d e e n l m S e r a m f i f t o n i r i a o n d n a f o e l t 6 + l f t h g i l o r a e h e o r o w m o c e h e h t n i i d m r l s t ect t g n t h g c t t m e e h e g a t a i i b a a q s s m t a t w e N l e r s r o s t e t S s i e v o b t s n e h T d e d u i i D E E L n o a l p x e i l y e s u e h n o i a g n m k r o Y t n e “ t t h g r c i s i r p e e a e e c n t c a p i l o r , d e t a w i k e c i c a d g n o e m u e r ” , e h s t a h w m t n e l c n I l p p u S i S i t h g i L i V , . c v o i f d e g n i f t s r i F . n o ising t n t e e r e h i o t l y a d i 1 2 1 , 2 1 o t s w e N Cook e h T l f o t l a w m a l b a m t n o c l o c f e m o c t l a c c e b “ r o t n e e s g n i l g n a i h s a n I w o h r Adve l e e e d n y n s i s i c i o t d e n a b h t v i o r t c , s r o l i w t - y g r t n e c t n t r e v o h c s r i s m o r f t i r o e h w . s n o i t . ) t o o f t n e u q t c e r e h w e r e m u l ional i h e m e d i v o l o , t e k c u b e d . t e k c u b i o p e r h g e n e l f e s w s e u d e c f e r r e s o l c y l l a c i p y t n o — d e d e i l t h g i l r p d e u n r e t h g i r c e l f e r l e h t a e h t c e r i d d e h t n a s e h t : g n i w o l l o f t o n r t n o y e k c e e n e t tions. e b t duca , x u l s i f o n o a u q s n i t t a p s i , r e t t e b l l a 500 r e k r o t s o m 50 10 , a e E d n v i e c e 100 n e h e h t n i h c u m - - r - a t w r e r u t - l l i n i r a r e k r o w e h T a c o l 5 t n e i b m s i h t n i m u l l n i a g r e p y r t s u d n i 20 o t w c a 50 e h t d e i a e e e b w o l f t s o m , d , t c a f 200 s a w e r a l g s i r o f r e t a w c n d y a r p s Values b l u g n i t h g i l i applica w o h . e m l l i , e r i a n i m u l s i f n i r u s f u n b a c f a e h a e l o f o e h t i t d n a l e c r u o s w w o l . d e t e l p m o s u a o & d n a t i n a h t e h t e h t c a m c a f r u s t r e a e m d n a t c e n a o t g n i t h g i l s n e m u l y b e e h t r e b m e m s r e k c g n e h t s l l e nce ) r t n o c f f f o g n i t h g i l t . s k s a t t i f o r t e r y l g n i t h g i l h g i l e r a r n e v i g , t n r e t a w . y t i c i l p m e c a f r w o h b l u b e c n a n i m u l e h t y l l a c f f o s u a o n o i r o t d s r e a n i l a r f g n i e b e r e h w r o w f i s c t h g l i h c e s s t n u o m a y l o t u s i d n a k s a t a o t a l , r e t t e b t y t d e d n e m m o c e r n e e w n a e n t a r e c i f f o e b t u b f o h t i g n a h c h t a e n o k r u m t e m e r o m w n e v i k s a l l a t i d d a o t r , t o f e g i n o m t t e i t t e b , e h c u g r e r u l t r o f t o n r g e r p e r r e h c u w r e t y b n o l f i m o n o c s i o w 5000 s l a u d i v m i a k c i e r 100 500 Categories h t a p 1000 i e m o t a h h e k a s m e s u a c n e r e f f i Lumina - y t e i c o S - - e h t e F o h t - o f o r o d u b n a c s n o i m o c . n i n o m m o c l d n a c e m a t h g i l e b i c e p s e h t g n c s i e c n 50 e h i d n i , e r a u q s e o o a n i m u , s u a a e r o t 200 e h t l d u t x i f f 500 e r o r o f n o e v t 2000 w o h y c n i r o f f o l l o l i n t o o m r a p t c u r e u c i h w ( t a r e t u p m o e i i g y t i l t r o f l a and i t h g i d e , n o c t h g i , t e k c e t f r t i r e p e g n i n o e i c s l a n i m t a y f l , c i m e d e h r t p m s r e e n i g n E n a h t e c a f r u s t a h s i u b t d e t g n i d i t s b o l a u q t i f f n u o c t i d u l l s l e v e l m — s t ce , n g i s e d i r p e n o s e l d e h t 0 . 0 n o i t a I e i t h g i : s i x a c k s a u s s 1 s e v e , d a i l c e l e h n e s u t i c e p s n i n a v o r s y h p m a , e c n a a k r o low t n e i b t g n a g n i an i v o r p s i h T , x over n P a u l f s n e m u o t g n i y g r w time of n I l book l o c m u i t p o Illuminance n o r p p a u l m a e . g n e l b x u l w o h . d t h g screen n i m of f r o r e n e h t d n a document, l a t size , s t i i t h g i l a t o t r e e h c t o o f r o newspaper i l a c r a n i m u l l i e l l task l a c i s y h p t a e t s a f . e c a f r u s o t min g n i t a n i m u l l I c o d h c u s ( s n e m u l RT l a 6 7 e h i v o w o h s r t a . s r e k t c a d a n o or o t u l l I phone y w o l l o g n i l w t o n f e d e e l a n f o t ’ n s e o d f d e o t p m t o e h t IES m w n i small t o t lu e p n s a r o o . 0 1 y n a periods , i t i s s e c visual g n i t g n i e d x h r i e c y p r o w o c o d or standard g n i t h o r f o Il a e v o r g b m r o f e m a s o d e s a b n e v i g o i t o e h t View C s i h t t e c r f Activity LUX Footcandles x u g 7 o p n a s ’ t i e r a u l f f o g n i b h g i s n a i l .0 t s a r t n l f s i g r e n . d e d e e l t n e r u s o s h c r e p m reference x, e w o t e h u o g b - r n i g p m s a e r c n s d i e l t n e l a v Read i s t t r o t photocopy n e a m E E I I e r 11 s r i e y l p n n n o c m , t u p f t n u o u h c c i Perform l a t a t s k s a I • • • • s u contrast 4 h s e s i i s a h prolonged e m u e h View photo in moderate detail; y p a i r c s e a u q f f u o n e a e s n e e h d a e i e h t t a h c t h c m i s o T t r a m a r e h w l e i T r L t u o d Fl o T b I r U l w a T e p t 17

CONTINUING EDUCATION Educational Advertising Section N O I T A

For lighting designs, we should not assume that two lamps with the CPE, Director of the Human Factors and Ergonomics Laboratory at C same lumen rating will each give the same amount of light where needed. the Cornell University Department of Design and Environmental U D

Thirty years ago, standards of the Illuminating Engineers Society of Analysis. The majority of work that most office workers perform E North America (IESNA) called for general office lighting in the range today is a combination of viewing a monitor and reading documents G

of 100–150 footcandles (1,000–1,500 lux). Huge, increasingly cubicled or other printed material. Yet these two tasks require significantly N floorplates, often without any natural, outside illumination, were lighted, different levels of light because monitors are a source of light where - I U

for the most part, by banks of 4-ft, ceiling-mounted fluorescent troffers as paper reflects light. In fact, reading documents requires four to five N I

(recessed fluorescent fixtures) that, in too many cases, resembled times the amount of light needed for viewing a monitor. T stadium floodlights in their intensity. If the ambient lighting level is set at the appropriate level for reading N By 2002, nearly all office tasks were being performed on desktop printed documents (20–50 footcandles), the lighting intensity will O C computers and average ambient light levels in the American workplace be much too high for proper monitor viewing (5–10 footcandles declined to one-third of 1970s levels. Today, ambient office lighting is required). This leads to glare on the surface of the monitor, substantial likely to be in the range of 25–45 footcandles (250–450 lux), which is energy waste and a variety of worker productivity issues. However, if still far more light than is necessary for getting around the office or the ambient lighting level is brought down to a point which is appro - viewing a computer screen. According to IES, computers are best viewed priate for monitor viewing and movement throughout the workspace, in an environment where the ambient lighting is 5–10 footcandles then there won’t be nearly enough light to read documents and other (50–100 lux), whereas most reading of documents requires 20–50 paper-based reading material. footcandles (200–500 lux). The only solution to this conflict is to lower the overall ambient lighting levels and provide individuals with positionable task lights to The Monitor—Document Conflict properly illuminate the reading material on the desktop. In this way, “The demands of differing tasks within the workplace create an obvious both the monitor and documents can be lit to appropriate levels for the conflict in lighting requirements,” says researcher Alan Hedge, PhD, tasks being performed. SmithGroup: Task Lighting Essentials

For Detroit-based SmithGroup, Inc., an A/E firm with its own in- 2006, workers have personal control over lighting within individual house lighting design group, according to James Luckey, AIA, Senior workstations; individual controls allow them to control floor- Design Architect, a main goal with creating a nine-building campus distributed heating and cooling as well. in Van Buren Township, Michigan, for auto parts supplier, Visteon “Overall, lighting consumption,” Luckey says, “is one watt per sq Corporation, was to attain “the absolute minimization” of energy ft; lighting and miscellaneous power consumption, 2.25 watts per sq ft costs. The first consideration was natural light. To allow as much light —the figure excludes air-handling. as possible into interiors, Luckey designed all of the 100,000- to Perhaps more importantly,” Luckey says, “ASHRAE 90.1 sets a 150,000-sq-ft buildings to be “…extremely narrow, 64 feet in width. standard of 94,842 BTUs (British thermal units) per square foot per We wanted this project to conform to the European standard, in which year. Visteon Village consumes about 59,000 BTUs per square foot workers are never more than 10 meters from a window,” he said. per year—a 37 percent energy reduction from the code allowance. Exposures are large: sills of 15-ft-wide windows are only 2 feet off That number includes under-floor heating and cooling consumption.” floors; headers are 10 feet above floor height; ceilings at 1-ft 6-in. We like, whenever possible, to push ceiling height,” says Luckey. Photo courtesy of Justin Maconochie Photography Ambient lighting, via indirect pendants (95 percent upward, 5 percent downward), centered in 20-ft ceiling bays, 30 inches beneath ceilings, is at 25 to 30 footcandles and blends perfectly with the distribution of natural light. The uniformly illuminated ceiling plane increases the sense of openness and maximizes the impact of the high ceilings. For “sparkle,” SmithGroup used café and track lights. Each 50-sq-ft workstation has one adjustable compact fluorescent task light and one furniture-mounted fluorescent light capable of providing 50 footcandles where it is needed. “The use of task lighting allows higher intensities only where that level of light is needed, while also providing the benefit of personal - ized control,” says Luckey. “In a computer environment, the goal is to minimize glare. This project,” he says, “is in keeping with what we try to do with every project. If ceilings are shallower, we have no choice but to put lights in the ceiling plane, but we prefer not to.” The SmithGroup delivered 25 to 30 footcandles of ambient lighting for the At Visteon’s new corporate campus, which opened in January Visteon Corporation Michigan campus.

11.07 175 C Educational Advertising Section O N T I N

U Relative Contrast Required as a Function of Age I N 400 G

d 350 E e r D i

u 300 q U e C R 250 t A s

a 200 T r t I n 150 O o C N

e 100 v i t

a 50 l e

R 0 20-30 31-40 41-50 51-60 61-70 Age Lower ambient lighting plus task lamp provides appropriate lighting for viewing computer screens and reading documents. Lighting Needs Change As We Age providing the same amount of light. Equally significant to the fact that different tasks require different The first practical electric lamp, developed by Thomas Edison in 1879, amounts of lighting is that actual lighting needs vary among individuals. converted less than one percent of electricity into light. Today’s house - The older we get, the more light we need to see. Research indicates hold incandescent bulbs convert 6–7 percent of their electrical input into that the visual performance of those in their 20s is about eight times light. The rest is wasted as heat. Classic 4-ft fluorescent systems convert better than those in their 60s, almost four times better than those in approximately 19% of their energy into light. their 50s. In fact, persons in their 60s require 250 percent more contrast Today’s compact fluorescent lamps, five inches in length, or less, than persons in their 20s. can be 50 times more efficient than Edison’s original lamp and far The increased need for light is due to a number of physiological more efficient than an incandescent light source capable of the same changes in our visual system, which occur as we age. The term light out put. For example, a 13-watt compact fluorescent task light presbyopia means “old eye” and is a vision condition involving the loss will produce the same light output as a 60-watt incandescent light, of the eye’s ability to focus on close objects. An additional symptom burn cooler and consume only one-quarter of the electricity. is the declining ability of the eye to receive light. Symptoms are usually n oticeable by age 45 and continue to develop until the process Light Bulb stabilizes some 10–20 years later. Comparison Incandescent Halogen LED Compact Eyestrain and accompanying headaches, which can result from Chart Bulb 100 W Bulb 100 W Bulb 60 W Fluorescent 26 W

working under inadequate illumination, are aggravated by aging. Eye Lumens Produced 1690 1900 1800 1825

fatigue may result in blurry vision and dim lighting aggravates the Very bright, Available from Cool problem. Task lighting allows us to achieve the correct levels of illu - Light Quality White/Yellowish white light warm to crisp/cool mination, regardless of the task or vision requirements, by changing CRI >90 >98 70-80 >80

the distance between the light source and the lit object—closer for Energy Consumption 100 W 100 W 60 W 26 W more light, further away for less. It also allows us to correctly position the angle of light to eliminate glare and veiling reflections. Bulb Surface Temperature 500ºF 1800ºFN/A 125ºF Source: U.S. Department of Energy Bulb Options and Energy Effciency Today’s task lights utilize one of four types of lighting source: incan - LED Lighting descent, halogen, compact fluorescent or light-emitting diode (LED The next generation light source to make headlines is solid-state LED or solid-state lighting), which works by running electricity through a lighting. Around since the 1960s, it has only relatively recently been chemical chip, causing the chip to glow. Compact fluorescents burn marketed for commercial interiors because of its apparent energy effi - cooler and have proven to be more energy efficient than any other ci ency and other features. Approximately one-quarter-inch in diameter, available task light source. A regular incandescent or halogen bulb each diode uses about one-tenth of a watt to operate and can be assembled works by heating a metal wire to a temperature at which it glows. This together to deliver higher intensity light. LED fixtures require a plug- requires high temperatures, relatively large amounts of energy and creates in transformer or a driver—typically built-in—which is comparable a hot bulb surface. In fact, halogen bulbs can reach temperatures of to the ballast in fluorescent fixtures. The plug-in transformer used for 1800 degrees F and have, therefore, been banned from many university portable fixtures, enables the lamp to use 120 volt AC. dormitories because of their risk as a fire hazard. LED lights are more rugged and damage-resistant than compact A compact fluorescent bulb is a low-pressure mercury, electric- fluorescents and incandescent bulbs. They do not flicker, are low main - discharge lamp in which phosphor coating transforms ultraviolet energy, tenance, are dimmable and, what makes them especially attractiv e to created by electric discharge, into visible light. The fluorescent bulb those seeking LEED certification, have the potential of low energ y remains much cooler and uses less energy than the other two, while consumption. Since they operate at 3,300 to 5,000 Kelvin (sunlight at

176 11.07 Educational Advertising Section N O I T A C

Light Source Efficacy Range in Im/W U D E  Incandescent 10-18 

G M 

a N Halogen incandescent 15-20 P  I a F U White LED 3300K 17-34 N I

White LED 5000K 25-43 T N O

Compact fluorescent (CFL) 

35-60 C L

Source: U.S. Department of Energy 2006

Recent U.S. Department of Energy research found compact fluorescent bulbs 50% to 100% more energy-efficient than LED bulbs. Under-bin lights are not a suitable alternative to task lighting. Depending on sunrise is 1800K, overcast sky is 6500K) they have a “cool” color that workstation layout, they may put more light on the monitor than on documents and typically don’t put light where paper-based work is being performed. ranges from blue to daylight fluorescent. They can also be a major source of glare. Many designers are now specifying LED lighting believing that it is the most energy efficient lighting solution available. Unfortunately, Polytechnic Institute and director of research and organizer of the there is much misunderstanding surrounding this new technology. Alliance for Solid-State Illumination Systems and Technologies While there are considerable potential advantages to solid-state light - (ASSIST). ing, the technology is not sufficiently advanced to make it an energy At some point, perhaps in another two to three years, LEDs will over - efficient choice at present. take CFLs in efficiency because LED technology is improving . But for The major cause of misunderstanding results from there being no now, CFLs are clearly the best solution in terms of energy efficiency. standard testing criteria. In their product literature, manufacturers use different evaluation criteria to compare their LED products with Task Lighting Saves Eyes traditional fluorescent or incandescent lighting. Another difficulty in Because they are closer to the work surface, positionable task lights testing existing LED luminaires is their susceptibility to colorshift and are a considerably more effective means of lighting a desktop than inadequate performance when subject to high heat (some manufacturers are overhead fixtures, which are costly and inefficient. They can be have added fans and diffusers to disperse heat.) directed to light documents or moved to avoid screen glare. After a pilot round of testing several LED products, the U.S. “The most common design error, clearly, is the mismatch between Department of Energy released its conclusions in December 2006. It where light is being delivered and where people are utilizing that light,” found that products fell short of manufacturers claims and implied that says Alan Hedge. “All too often we put light into a building without claims are based on how much light isolated LED produces rather than knowing the ultimate layout. Even if the layout is known, things can how much light an LED fixture actually delivers. The study concluded happen that are not foreseen. Offices may be partitioned differently that “solid-state based luminaires (lighting lamps or fixtures) have the by new tenants, for instance, and the new layout can result in a feast potential to provide high-quality light which consumes far less energy or famine situation, so far as light is concerned. Some workers may than more traditional lighting technologies, but recent testing of com - complain of glare and headaches; some may be in the dark.” mercially available products show that some being sold today actually In a study conducted in 1990, Cornell researchers drew on an provide less light output than traditional light sources and are less American Society of Interior Designers survey in which 68 percent of efficacious than products using fluorescent light sources.” employees complained about the light in their offices and 79 percent U.S. Department of Energy testing found that LED bulbs with a of VDT users wanted better lighting. The Cornell study came to the temperature of 3300K are about half as energy efficient as standard conclusion that eyestrain was the number one health hazard in the compact fluorescents (17-34 lumens/watt versus 35-60 lumens/watt workplace—ahead of radiation, asbestos, or exposure to AIDS. for compact fluorescents). Higher temperature LED bulbs (5000K) Hedge says eyestrain remains the number one complaint in the were somewhat more efficient, but still well below the efficiency of office environment, and the degree of dissatisfaction is difficult to CFLs. Moreover, LED bulbs are not ideal for task lighting because the ignore. It confirms the need to identify the best available methods of color is too cool (blue) for most users. In other words, LED products lighting. “Combined ambient-task lighting is likely to be the most now on the market use more energy and provide less light than their effective solution in any environment in which workers are doing both compact fluorescent counterparts. paperwork and computer work,” says Hedge. I Meanwhile, researchers are addressing the issue of testing criteria and comparison methods. “We have developed technology-neutral, This article continues online at fixture-based testing methods that allow fixtures of the same type but http://construction.com/CE/articles/0711humanscale-1.asp with different light sources to be compared appropriately,” says N. See Quiz on the Next Page Narendran, Ph.D. of the Lighting Research Center at Rensselaer

11.07 177 C Educational Advertising Section O N T I N To receive AIA/CES credit, you are required to read the additional online text, which can be found at http://construction.com/CE/articles/0711humanscale-1.asp U The quiz questions below include information from this online reading. I N G

Program title: “Task Lighting Solutions: Their Economic and Ergonomic Benefits ” (11/07, page XXX). AIA/CES Credit: This article will earn you one AIA/CES LU hour of health, safety, E

D and welfare credit. (Valid for credit through November 2009). Directions: Refer to the Learning Objectives for this program. Select one answer for each question in the exam and fill in the box by the appropriate letter. A minimum score of 80% is required to earn credit. To take this test online, go to construction.com/CE/ U

C 6. A 13-watt compact fluorescent task light will produce the same light output as a :

A Learning Objectives J a.

T After reading this article, you should be able to: 100-watt incandescent bulb. J b I • Evaluate office lighting design for effective work environments . . single solid-state LED light.

O J • Recognize the importance of incorporating task lighting into an overall lighting plan. c. 60-watt incandescent light.

N J • Identify the environmental, economic and human factor benefits of task lighting. d. 150-watt halogen bulb.

Questions 7. Which task lighting bulbs on the market are the most energy efficient? J a. 1. Using positionable task lighting in addition to low ambient light can lead to : Incandescent J b. J a. improved comfort and control for workers. Solid-state LED J c. J b. energy waste. Compact fluorescent bulbs J d. J c. emotional and physical discomfort for office workers. Halogen J d. increased glare on computer screens. 8. Solid-state LED products: J a. 2. Illuminance: have undergone a standard means of performance testing. J b. J a tells us how much light will reach a given surface. are not subject to change under high heat. J c. tested by the U. S. Department of Energy used far less energy and J b. describes the total amount of light given off by a bulb. provided more light than traditional light sources. J c. is measured in lumens. J d. tested by the U.S. Department of Energy used far more energy and J d. is a representation of the amount of light seen by the eye. provided less light than traditional light sources. 3. Optimal illuminance for computer use is : 9. Lighting may contribute to LEED ® points by : J a. 25 to 45 footcandles J a. meeting energy use requirements for varying percentages below J b. 5 to 10 footcandles. ASHRAE 90.1–2004 standards. J c. 20 to 50 footcandles. J b. specification of recyclable products. J d. 10 to 20 foot candles. J c. providing task lighting to 90 percent of employees. J d. 4. Visual performance of persons in their 20s is how many times better than All of the above those in their 50s? J a. Eight 10. Color Rendering Index (CRI) of a bulb : J a. should always be 100. J b. Four J b. refers to its cool or warm appearance. J c. Three J c. refers to how colored objects appear . J d. Six J d. is the first consideration before selecting a bulb. 5. Today’s household incandescent bulbs convert what percentage of their electrical input into light? : J a. 6 to 7 percent J b. 3 percent J c. 19 percent J d. 28 percent

Last First Check below: Name Name J To register for AIA/CES credits: Answer the test questions and send the completed Job Title form with questions answered to address at left, or fax to 888/385-1428. Firm Name J For certificate of completion: As required by certain states, answer test questions, Address fill out form, and mail to address at left, or fax to 888/385-1428. Your test will be scored. Those who pass with a score of 80% or higher will receive a certificate of completion. City State Zip Material resources used: Article: This article addresses issues concerning health and safety. Tel. Fax I hereby certify that the above information is true and accurate to the best of my E-mail knowledge and that I have complied with the AIA Continuing Education Guidelines AIA ID Number: Completion date (M/D/Y): for the reported period.

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Humanscale is the premier designer and manufacturer of high-performance ergonomic products for a more comfortable workplace. Our innovative and award-winning solutions — including seating, keyboard supports, monitor arms, task lighting and more — are based on the belief that if a design solves a problem as simply and elegantly as possible, the resulting form will be honest and timeless. For more information about Humanscale, visit www.humanscale.com

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CONTINUING EDUCATION C Educational Advertising Section O N T I N

U program, which includes appropriate training for employees, can help Most fluorescent lamps operate at 3000K to 4100K,with a CRI from

I a project earn an additional point. the low 50s to 86, but recent technology gains now give us fluorescents N

G with CRIs above 90.

The Color of Light E

D One aspect of lighting that often gets overlooked is bulb color temper - Ballast Technology U ature, which describes the color appearance of the bulb, not the object All fluorescent lamps require ballasts, which stabilize and control the C

A being viewed. Color temperature ranges from 2600 Kelvin for “warm” electrical current that gets sent to the lamp. These ballasts are available

T sources like incandescent lamps, to approximately 6500 Kelvin for in two primary types: magnetic and electronic. While magnetic ballasts I

O “cool” sources like daylight fluorescent. Color temperature data is use long-standing technology and last for 20 years or more, electronic N readily available from lamp manufacturers. The selection of color ballasts have the edge in performance and, because they reduce percep - temperature should be considered relative to the application. tible flicker, health considerations. Virtually all compact fluorescen t Lamps that are high to very high in color temperature (5000K and lamps specified today use electronic ballasts. above) provide improved visual acuity compared to lower-color temperature lamps (typically 2700K) at the same light level. Visual Karin Tetlow writes frequently about architecture and construction. acuity is generally defined as sharpness of vision, with normal visual acuity rated at 20/20. High color temperature lamps are rich Frequently Asked Questions in the blue portion of the color spectrum and have a noticeably “cool” appearance. What is task lighting and why should we use it? The Color Rendering Index (CRI) of a bulb specifies on a scale of 1 Task lighting provides workers with total control over where and how to 100 how colored objects appear under that bulb’s light compared to much light they need for other tasks, such as reading a document. When their appearance in daylight. A CRI of 100 means no difference, while utilizing task lighting, energy can be saved by lowering ambient lighting a low CRI could mean a big difference. Incandescent lamps typically to a level appropriate for monitor viewing. have CRIs above 90, but that doesn’t mean that they always give suitable results. Suppose, for example, we wish to illuminate white cabinets in Why choose a compact fluorescent (CFL) task light? a kitchen or a hospital examination room. A design objective might be CFL bulbs use less energy than incandescents (about one fourth), output to enhance the impression of whiteness, cleanliness and sterility. In more light and last up to 10 times longer. Compact fluorescent bulbs are this case, the color temperature of incandescents would be too low to also much cooler in operation than regular incandescent bulbs or halogen achieve the desired effect. As a general rule, one should, therefore, bulbs and are, thereby, safer and more comfortable to work near. Tests select color temperature first, then select the lamp giving the optimum show they are also more energy efficient than LED lighting. CRI for the application. What Color Rendering Index (CRI) should task light bulbs have? CRI describes the effect of a light source on the color appearance of Glossary objects. A CRI of 100 represents the reference condition of daylight. In general, low CRI illumination may render some colors unnatural and Color Rendering Index (CRI): method for describing the effect of lamps with a CRI under 60 should not be used. At a certain point, the a light source on the color appearance of objects being illuminated. A higher the CRI, the lower the illuminance. A CRI in the 80s is good for CRI of 100 represents the reference condition of daylight (and thus the all general tasks. maximum CRI possible). In general, low CRI illumination may render some colors unnatural. I don’t like the light given off by fluorescent bulbs. Can they be made to give off a warmer light like incandescents? Footcandle: unit of measurement indicating how much illumination Yes, compact fluorescent bulbs are available in color temperatures ranging reaches a surface, equal to one lumen striking an area of one square foot. from 2700K for warmer light to approximately 4100K for cooler sources like daylight fluorescent. Ballast: a device used with a fluorescent bulb to obtain the necessary circuit conditions (voltage, current and wave form) for starting and operating. Should I specify LED task lighting? At present, LED technology is about half as energy efficient as compact LED Lighting: solid-state light-emitting diode. fluorescent lights and lacks brightness. But the technology is improving and eventually will overtake that of CFLs. Lumen: the unit of measurement used to describe the output from a light. Is “full-spectrum lighting” better than regular fluorescent lighting? Lux: unit of illumination closely equivalent to 1/10 of one footcandle. The short answer is “no.” Any bulb with a CRI of over 90 is considered a full spectrum bulb. Full-spectrum lighting is neither better nor worse Two-Component Lighting: combination of indirect general (ambient) than any other lamp type. Claims made for its beneficial effects go light and task lighting. beyond what scientific literature will support.