Chen, K. “Industrial Illuminating Systems” The Electrical Engineering Handbook Ed. Richard C. Dorf Boca Raton: CRC Press LLC, 2000 107 Industrial Illuminating Systems 107.1 New Concepts in Designing an Industrial Illuminating System Determination of Illuminance Levels?Illumination Computational Methods 107.2 Factors Affecting Industrial Illumination Basic Definitions?Factors and Remedies?Daylighting 107.3 System Components Light Sources?Ballasts?Luminaires 107.4 Applications Types of Industrial Illuminating Systems?Selection of the Equipment 107.5 System Energy Efficiency Considerations Energy-Saving Lighting Techniques?Lighting Controls?Lighting and Energy Standards 107.1 New Concepts in Designing an Industrial Illuminating System Determination of Illuminance Levels Among the many new concepts for lighting design, the first to be discussed is the new method of determining illuminance levels. In the past when illuminating engineers wanted to find the recommended illuminance level for a given task, they would look in the lighting handbook to find a recommended level and then design an illuminating system for the task using the value as a minimum. This procedure provides very little latitude for fine-tuning an illumination design. In the new method, a more comprehensive investigation of required illuminance is performed according to the following steps: 1.Instead of a single recommended illuminance value, a category letter is assigned. Table 107.1 shows different category letters for a selected group of industries (partial only; for complete list see IES Lighting Handbook [1993]). 2.The category letters are used to define a range of illuminance. Table 107.2 details illuminance categories and illuminance values for generic types of activities in interiors. 3.From within the recommended range of illuminance, a specific value of illuminance is selected after consideration is given to the average age of workers, the importance of speed and accuracy, and the reflectance of task background. The importance of acknowledging the speed and accuracy with which a task must be performed is readily recognized. Less obvious is the need to consider the age of workers and the reflectance of task background. Kao Chen Carlsons Consulting Engineers ? 2000 by CRC Press LLC TABLE 107.1 Illuminance Categories for Selected Group of Industries Illuminance Illuminance Area/Activity Category Area/Activity Category Aircraft maintenance a Canning Aircraft manufacturing a Continuous-belt canning E Assembly Sink canning E Simple D Hand packing D Moderately difficult E Olives E Difficult F Examination of canned samples F Very difficult G Container handling Exacting H Inspection F Automobile manufacturing Can unscramblers E Bakeries Labeling and cartoning D Mixing room D Casting (see Foundries) Face of shelves D Central stations (see Electric generating stations) Inside of mixing bowl D Chemical plants (see Petroleum and chemical plants) Fermentation room D Clay and concrete products Make-up room Grinding, filter presses, kiln rooms C Bread D Molding, pressing, cleaning, trimming D Sweet yeast-raised products D Enameling E Proofing room D Color and glazing—rough work E Oven room D Color and glazing—fine work F Fillings and other ingredients D Cleaning and pressing industry Decorating and icing Checking and sorting E Mechanical D Dry and wet cleaning and steaming E Hand E Inspection and spotting G Scales and thermometers D Pressing F Wrapping D Repair and alteration F Book binding Cloth products Folding, assembling, pasting D Cloth inspection I Cutting, punching, stitching E Cutting G Embossing and inspection F Sewing G Breweries Pressing F Brew house D Clothing manufacture (see Sewn Products) Boiling and keg washing D Receiving opening, storing, shipping D Filling (bottles, cans, kegs) D Examining (perching) I Candy making Sponging, decanting, winding, measuring D Box department D Piling up and marking E Chocolate department Cutting G Husking, winnowing, fat extraction, D Pattern making, preparation of trimming, piping, E crushing and refining, feeding canvas and shoulder pads Bean cleaning, sorting, dipping, packing, D Filling, bundling, shading, stitching D wrapping Shops F Milling E Inspection G Cream making Pressing F Mixing, cooking, molding D Sewing G Gum drops and jellied forms D Control rooms Hand decorating D (see Electric generating stations—interior) Hard candy Corridors (see Service spaces) Mixing, cooking, molding D Cotton gin industry Die cutting and sorting E Overhead equipment—separators, driers, grid D Kiss making and wrapping E cleaners, slick machines, conveyers, feeders Canning and preserving and catwalks Initial grading raw material samples D Gin stand D Tomatoes E Control console D Color grading and cutting rooms F Lint cleaner D Preparation Bale press D Preliminary sorting Dairy farms (see Farms) Apricots and peaches D Dairy products Tomatoes E Fluid milk industry Olives F Boiler room D Cutting and pitting E Bottle storage D Final sorting E Bottle sorting E a Industry representatives have established a table of single illuminance values which, in their opinion, can be used. Illuminance values for specific operations can also be determined using illuminance categories of similar tasks and activities found in this table and the application of the appropriate weighting factors. Source: IES Lighting Handbook, Application Volume. ? 2000 by CRC Press LLC To compensate for reduced visual acuity, more illuminance is needed. Using the average age of workers as the age criterion is a compromise between the need of the young and the older workers and, therefore, a valid criterion. Task background affects the ability to see because it affects contrast, an important aspect of visibility. More illuminance is required to enhance the visibility of tasks with poor contrast. Reflectance is calculated by dividing the reflected value by the incident value. The data given in Tables 107.3 and 107.4 are taken from the IES Lighting Handbook [1987] and are applied to provide a single value of illuminance from within the range recommended. Illuminating system design can begin after the desired value of illuminance for a given task has been determined. Based on the IES Handbook, the zonal cavity method of determining the number of luminaires and lamps to yield a specified maintained luminance remains unchanged. Illumination Computational Methods Zonal Cavity Method. Introduced in 1964, the zonal cavity method of performing lighting computations has gained rapid acceptance as the preferred way to calculate number and placement of luminaires required to satisfy a specified illuminance level requirement. Zonal cavity provides a higher degree of accuracy than does the old lumen method, because it gives individual consideration to factors that are glossed over empirically in the lumen method. Definition of Cavities. With the zonal cavity method, the room is considered to contain three vertical zones or cavities. Figure 107.1 defines the various cavities used in this method of computation. Height for luminaire to ceiling is designated as the ceiling cavity (h cc ). Distance from luminaire to the work plane is the room cavity (h rc ), and the floor cavity (h fc ) is measured from the work plane to the floor. To apply the zonal cavity method, it is necessary to determine a parameter known as the “cavity ratio” (CR) for each of the three cavities. Following is the formula for determining the cavity ratio: (107.1) where h equals h cc for ceiling cavity ratio (CCR), h rc for room cavity ratio (RCR), h fc for floor cavity ratio (FCR). TABLE 107.2 Illuminance Categories and Illuminance Values for Generic Types of Activities in Interiors Illuminance Ranges of Illuminances Type of Activity Category Lux Footcandles Reference Work-Plane Public spaces with dark surroundings A 20–30–50 2–3–5 Simple orientation for short temporary visits B 50–75–100 5–7.5–10 General lighting throughout spacesWorking spaces where visual tasks are only occasionally performed C 100–150–200 10–15–20 Performance of visual tasks of high contrast or large size D 200–300–500 20–30–50 Performance of visual tasks of medium contrast or small size E 500–750–1,000 50–75–100 Illuminance on task Performance of visual tasks of low contrast or very small size F 1,000–1,500–2,000 100–150–200 Performance of visual tasks of low contrast and very small size over a prolonged period G 2,000–3,000–5,000 200–300–500 Illuminance on task, obtained by a combi- nation of general and local (supplementary lighting) Performance of very prolonged and exacting visual tasks H 5,000–7,500–10,000 500–750–1,000 Performance of very special visual tasks of extremely low contrast and small size I 10,000–15,000–20,0001,000–1,500–2,000 Source: IES Lighting Handbook, Application Volume. cavity ratio 5 (room length+room width) (room length room width) = ′ h ? 2000 by CRC Press LLC TABLE 107.3 Weighting Factors for Selecting Specific Illuminance Within Ranges A, B, and C Occupant and Room Weighting Factor Characteristics* –1 0 +1 Workers’ age (average) Under 40 40 to 55 Over 55 Average room reflectance 1 >70% 30 to 70% <30% Source: IES Lighting Handbook, Application Volume. Note: This table is used for assessing weighting factors in rooms where a task is not involved. 1. Assign the appropriate weighting factor for each characteristic. 2. Add the two weights; refer to Table 107.2, Categories A through C: a. If the algebraic sum is –1 or –2, use the lowest range value. b. If the algebraic sum is 0, use the middle range value. c. If the algebraic sum is +1 or +2, use the highest range value. *To obtain average room reflectance: determine the areas of ceiling, walls, and floor; add the three to establish room surface area; determine the proportion of each surface area to the total; multiply each proportion by the pertinent surface reflectance; and add the three numbers obtained. TABLE 107.4 Weighting Factors for Selecting Specific Illuminance Within Ranges D through I Task or Worker Weighting Factor Characteristics –1 0 +1 Workers’ age (average) Under 40 40 to 55 Over 55 Speed or accuracy* Not important Important Critical Reflectance of task background, % >70% 30 to 70% <30% Source: IES Lighting Handbook, Application Volume. Note: Weighting factors are based upon worker and task information. 1. Assign the appropriate weighting factor for each characteristic. 2. Add the two weights; refer to Table 107.2, Categories D through I: a. If the algebraic sum is –2 or –3, use the lowest range value. b. If the algebraic sum is –1, 0, or +1, use the middle range value. c. If the algebraic sum is +2 or +3, use the highest range value. *Evaluation of speed and accuracy requires that time limitations, the effect of error on safety, quality, and cost, etc. be considered. For example, leisure reading imposes no restrictions on time, and errors are seldom costly or unsafe. Reading engineering drawings or a micrometer requires accuracy and, sometimes, speed. Properly positioning material in a press or mill can impose demands on safety, accuracy, and time. FIGURE 107.1 Basic cavity divisions of space. ? 2000 by CRC Press LLC Lumen Method Details. Because of the ease of application of the lumen method which yields the average illumination in a room, it is usually employed for larger areas, where the illumination is substantially uniform. The lumen method is based on the definition of a footcandle, which equals one lumen per square foot: (107.2) In order to take into consideration such factors as dirt on the luminaire, general depreciation in lumen output of the lamp, and so on, the above formula is modified as follows: (107.3) In using the lumen method, the following key steps should be taken: a.Determine the required level of illuminance. b.Determine the coefficient of utilization (CU) which is the ratio of the lumens reaching the working plane to the total lumens generated by the lamps. This is a factor that takes into account the efficiency and the distribution of the luminaire, its mounting height, the room proportions, and the reflectances of the walls, ceiling, and floor. Rooms are classified according to shape by 10 room cavity numbers. The cavity ratio can be calculated using the formula given in Eq. (107.1). The coefficient of utilization is selected from tables prepared for various luminaires by manufacturers. c.Determine the light loss factor (LLF). The final light loss factor is the product of all the contributing loss factors. Lamp manufacturers rate filament lamps in accordance with their output when the lamp is new; vapor discharge lamps (fluorescent, mercury, and other types ) are rated in accordance with their output after 100 hr of burning. d.Calculate the number of lamps and luminaires required: (107.4) (107.5) e.Determine the location of the luminaire—luminaire locations depend on the general architecture, size of bays, type of luminaire, position of previous outlets, and so on. Point-by-Point Method. Although currently light computations emphasize the zonal cavity method, there is still considerable merit in the point-by-point method. This method lends itself especially well to calculating the illumination level at a particular point where total illumination is the sum of general overhead lighting and supplementary lighting. In this method, information from luminaire candlepower distribution curves must be applied to the mathematical relationship. The total contribution from all luminaires to the illumination level on the task plane must be summed. Direct Illumination Component. The angular coordinate system is most applicable to continuous rows of fluorescent luminaires. Two angles are involved: a longitudinal angle a and a lateral angle b. Angle a is the angle between a vertical line passing through the seeing task (point P) and a line from the seeing task to the end of the rows of luminaires. Angle a is easily determined graphically from a chart showing angles a and b footcandle lumen striking an area square feet of area = footcandle lamps/luminaire lumens/lp CU LLF area/luminaire = ′′′ no. of lamps footcandles area lumens/lp CU LLF = ′ ′′ no. of luminaires no. of lamps lamps/luminaire = ? 2000 by CRC Press LLC for various combinations of V and H. Angle b is the angle between the vertical plane of the row of luminaires and a tilted plane containing both the seeing task and the luminaire or row of luminaires. Figure 107.2 shows how angles a and b are defined. The direct illumination component for each luminaire or row of luminaires is determined by referring to the table of direct illumination components for the specific luminaire. The direct illumination components are based on the assumption that the luminaire is mounted 6 ft above the seeing task. If this mounting height is other than 6 ft, the direct illumination component shown in Table 107.5 must be multiplied by 6/V, where V is the mounting height above the task. Thus the total direct illumination component would be the product of 6/V and the sum of the individual direct illumination components of each row. Reflected Illumination Components on the Horizontal Surfaces. This is calculated in exactly the same manner as the average illumination using the lumen method, except that thereflected radiation coefficient (RRC) is substituted for the coefficient of utilization. (107.6) where RRC = LC W + RPM (LC CC – LC W ), LC W = wall luminance coefficient, LC CC = ceiling cavity luminance coefficient, and RPM = room position multiplier. The wall luminance coefficient and the ceiling cavity luminance coefficient are selected for the appropriate room cavity ratio and proper wall and ceiling cavity reflectances from the table of luminance coefficients in the same manner as the coefficient of utilization. The room position multiplier is a function of the room cavity ratio and of the location in the room of the point where the illumination is desired. Table 107.6 lists the value of the RPM for each possible location of the part in the rooms of all room cavity ratios. Figure 107.3 shows a grid diagram that illustrates the method of designating the location in the room by a letter and a number. Reflected Illumination Components on the Vertical Surfaces. To determine illumination reflected to vertical surfaces, the approximate average value is determined using the same general formula, but substituting WRRC (wall reflected radiation coefficient) for the coefficient of utilization: (107.7) where (107.8) where WDRC is the wall direct radiation coefficient, which is published for each room cavity ratio together with a table of wall luminance coefficients (see Table 107.5 for a specific type of luminance). FC lamps/luminaire lumens/lp RRC LLF area/luminaire RH = ′′′ FC lamps/luminaire lumens/lp WRRC LLF area/luminaire (on work plane) RV = ′′′ WRRC wall luminance coefficient average wall reflectance WDRC= – FIGURE 107.2Definition of angular coordinate sys- tems for direct illumination component. ? 2000 by CRC Press LLC 107.2 Factors Affecting Industrial Illumination Basic Definitions Illuminance. lluminance is the density of luminous lux on a surface expressed in either footcandles (lumens/ft 2 ) or lux (lx) (lux = 0.0929 fc). Luminance (or photometric brightness). Luminance is the luminous intensity of a surface in a given direction per unit of projected area of the surfaces, expressed in candelas per unit area or in lumens per unit area. Reflectance. Reflectance is the ratio of the light reflected from a surface to that incident upon it. Reflection may be of several types, the most common being specular, diffuse, spread, and mixed. Glare. Glare is any brightness that causes discomfort, interference with vision, or eye fatigue. TABLE 107.5 Direct Illumination Components for Category III Luminaire (Based on F40 Lamps Producing 3100 Lumens) Direct Illumination Components 8 5 15 25 35 45 55 65 75 5 15 25 35 45 55 65 75 Vertical Surface Illumination Footcandles at a Vertical Surface Illumination Footcandles at a μ Point on a Plane Parallel to Luminaires Point on a Plane Perpendicular to Luminaires 0–10 .9 2.6 3.6 3.9 3.3 1.9 .7 .1 .9 .8 .7 .5 .3 .1 — — 0–20 1.8 5.0 7.0 7.7 6.6 3.8 1.5 .2 3.6 3.2 2.7 1.9 1.2 .5 .1 — 0–30 2.6 7.2 10.1 11.3 9.8 5.7 2.3 .3 7.7 7.0 5.8 4.3 2.7 1.1 .3 — 0–40 3.2 9.0 12.8 14.5 12.9 7.7 3.2 .5 12.6 11.6 9.7 7.5 4.9 2.1 .6 — 0–50 3.7 10.3 14.9 17.1 15.7 9.6 4.3 .7 17.8 16.6 14.2 11.2 7.7 3.4 1.1 .1 0–60 4.0 11.2 16.3 18.8 17.6 11.3 5.5 1.0 22.6 21.2 18.4 14.7 10.4 5.1 1.9 .2 0–70 4.1 11.6 17.0 19.8 18.9 12.7 6.8 1.4 26.2 24.7 21.8 17.8 13.1 7.2 3.2 .3 0–80 4.1 11.7 17.3 20.2 19.4 13.3 7.4 1.9 28.2 26.7 23.8 19.7 14.9 8.7 4.3 .8 0–90 4.1 11.7 17.3 20.2 19.4 13.4 7.5 2.0 28.6 27.1 24.2 20.1 15.3 9.1 4.7 1.1 F.C. at a Point on Work Plane Category III 0–10 10.6 9.5 7.6 5.5 3.3 1.3 .3 — 0–20 20.6 18.5 14.9 10.9 6.6 2.6 .7 — 0–30 29.4 26.5 21.6 16.0 9.8 4.0 1.1 — 0–40 36.5 33.1 27.4 20.6 12.9 5.4 1.5 — 0–50 41.8 38.1 31.9 24.3 15.7 6.7 2.0 .1 0–60 45.2 41.3 34.8 26.8 17.6 7.9 2.6 .2 0–70 46.9 43.0 36.4 28.3 18.9 8.9 3.2 .3 0–80 47.4 43.6 36.9 28.8 19.4 9.3 3.5 .4 2 T-12 Lamps—Any Loading 0–90 47.5 43.7 37.0 28.8 19.4 9.3 3.5 .4 For T-10 Lamps—CU 3 1.02 Luminance Coefficients for 20% Effective Floor Cavity Reflectance Reflectances Ceiling Cavity 80 50 10 80 50 10 Walls 50 30 50 30 50 30 50 30 50 30 50 30 WDRC RCR Wall Luminance Coefficients Ceiling Cavity Luminance Coefficients .281 1 .246 .140 .220 .126 .190 .109 .230 .209 .135 .124 .025 .023 .266 2 .232 .127 .209 .115 .182 .102 .222 .190 .130 .113 .024 .021 .245 3 .216 .115 .196 .105 .172 .095 .215 .176 .127 .105 .024 .020 .226 4 .202 .102 .183 .097 .161 .088 .209 .164 .124 .099 .023 .019 .212 5 .191 .097 .173 .090 .154 .082 .204 .156 .121 .094 .023 .018 .196 6 .178 .090 .163 .084 .145 .076 .200 .149 .118 .090 .022 .017 .182 7 .168 .083 .153 .078 .136 .071 .194 .144 .115 .087 .022 .017 .170 8 .158 .077 .145 .072 .130 .066 .190 .139 .113 .085 .021 .016 .159 9 .150 .072 .138 .068 .123 .062 .185 .135 .110 .082 .021 .016 .149 10 .141 .068 .130 .064 .116 .059 .180 .131 .107 .080 .020 .016 ? 2000 by CRC Press LLC TABLE 107.6 Room Position Multipliers ABCDEF ABCDEF Room Cavity Ratio = 1 Room Cavity Ratio = 6 0 .24 .42 .47 .48 .44 .48 0 .20 .23 .26 .28 .29 .30 1 .42 .74 .81 .83 .84 .84 1 .23 .26 .29 .31 .33 .36 2 .47 .81 .90 .92 .93 .93 2 .26 .29 .35 .37 .38 .40 3 .48 .83 .92 .94 .95 .95 3 .28 .31 .37 .39 .41 .43 4 .48 .84 .93 .95 .96 .97 4 .29 .33 .38 .41 .43 .45 5 .48 .84 .93 .95 .97 .97 5 .30 .36 .40 .43 .45 .47 Room Cavity Ratio = 2 Room Cavity Ratio = 7 0 .24 .36 .42 .44 .46 .46 0 .18 .21 .23 .25 .26 .27 1 .36 .51 .60 .63 .66 .68 1 .21 .23 .26 .28 .29 .30 2 .42 .60 .68 .72 .78 .83 2 .23 .26 .30 .32 .33 .34 3 .44 .63 .72 .77 .82 .85 3 .25 .28 .32 .34 .35 .36 4 .46 .66 .78 .82 .85 .86 4 .26 .29 .33 .35 .37 .37 5 .46 .68 .83 .85 .86 .87 5 .27 .30 .34 .36 .37 .38 Room Cavity Ratio = 3 Room Cavity Ratio = 8 0 .23 .32 .37 .40 .42 .42 0 .17 .18 .21 .22 .22 .23 1 .32 .40 .48 .51 .53 .57 1 .18 .20 .23 .25 .26 .26 2 .37 .48 .58 .61 .64 .67 2 .21 .23 .26 .27 .28 .29 3 .40 .51 .61 .65 .69 .71 3 .22 .25 .27 .29 .30 .30 4 .42 .53 .64 .69 .73 .75 4 .22 .26 .28 .30 .31 .32 5 .42 .57 .67 .71 .75 .77 5 .23 .26 .29 .30 .31 .32 Room Cavity Ratio = 4 Room Cavity Ratio = 9 0 .22 .28 .32 .35 .37 .37 0 .15 .17 .18 .19 .20 .20 1 .28 .33 .40 .42 .44 .48 1 .17 .18 .20 .21 .22 .23 2 .32 .40 .48 .50 .52 .57 2 .18 .20 .23 .24 .25 .25 3 .35 .42 .50 .54 .58 .61 3 .19 .21 .24 .25 .26 .26 4 .37 .44 .52 .58 .62 .64 4 .20 .22 .25 .26 .26 .27 5 .37 .48 .57 .61 .64 .66 5 .20 .23 .25 .26 .27 .27 Room Cavity Ratio = 5 Room Cavity Ratio = 10 0 .21 .25 .28 .31 .33 .33 0 .14 .16 .16 .17 .18 .18 1 .25 .29 .33 .36 .38 .42 1 .16 .17 .18 .19 .19 .20 2 .28 .33 .40 .42 .44 .48 2 .16 .18 .19 .21 .22 .22 3 .31 .36 .42 .46 .49 .52 3 .17 .19 .21 .22 .23 .23 4 .33 .38 .44 .49 .52 .54 4 .18 .19 .22 .23 .23 .24 5 .33 .42 .48 .52 .54 .56 5 .18 .20 .22 .23 .24 .25 FIGURE 107.3 Grid diagram for locating points on the work plane. ? 2000 by CRC Press LLC Color Rendering Index (CRI). In 1964 the CIE (Commission Internationale de l’Eclairage) officially adopted the IES procedure for rating lighting sources and developed the current standard by which light sources are rated for their color rendering properties. The CRI is a numerical value for the color comparison of one light source to that of a reference light source. Color Preference Index (CPI).The CPI is determined by a similar procedure to that used for the CRI. The difference is that CPI recognizes the very real human ingredient of preference. This index is based on individual preference for the coloration of certain identifiable objects, such as complexions, meat, vegetables, fruits, and foliage, to be slightly different than the colors of these objects in daylight. CPI indicates how a source will render color with respect to how we best appreciate and remember that color. Equivalent Sphere Illumination (ESI).ESI is a means of determining how well a lighting system will provide task visibility in a given situation. ESI may be predicted for many points in a lighting system through the use of any of several available computer programs or measured in an installation with any of several different types of meters. Visual Comfort Probability (VCP).Discomfort glare is most often produced by direct glare from luminances that are excessively bright. Discomfort glare can also be caused by reflected glare, which should not be confused with veiling reflections, which cause a reduction in visual performance rather than discomfort. VCP is based in terms of the percentage of people who will be expected to find the given lighting system acceptable when they are seated in the most undesirable location. Factors and Remedies Quality of illumination pertains to the distribution of luminaires in the visual environment. The term is used in a positive sense and implies that all luminaires contribute favorably to visual performance. However, glare, diffusion, reflection, uniformity, color, luminance, and luminance ratio all have a significant effect on visibility and the ability to see easily, accurately, and quickly. Industrial installations of poor quality are easily recognized as uncomfortable and possibly hazardous. Some of the factors are discussed in more detail below. Direct Glare. When glare is caused by the source of lighting within the field of view, whether daylight or electric, it is defined as direct glare. To reduce direct glare, the following suggestions may be useful: a.Decrease the brightness of light sources or lighting equipment, or both. b.Reduce the area of high luminance causing the glare condition. c.Increase the angle between the glare source and the line of vision. d.Increase the luminance of the area surrounding the glare source and against which it is seen. To reduce direct glare, luminaires should be mounted as far above the normal line of sight as possible and should be designed to limit both the luminance and the quality of light emitted in the 45–85 degree zone because such light may interfere with vision. This precaution includes the use of supplementary lighting equipment. There is such a wide divergence of tasks and environmental conditions that it may not be possible to recommend a degree of quality satisfactory to all needs. In production areas, luminaires within the normal field of view should be shielded to at least 25 degrees from the horizontal, preferably to 45 degrees. Reflected Glare.Reflected glare is caused by the reflection of high-luminance light sources from shiny surfaces. In the manufacturing area, this may be a particularly serious problem where critical seeing is involved with highly polished sheet metal, vernier scales, and machined metal surfaces. There are several ways to minimize or eliminate reflected glare: a.Use a light source of low luminance, consistent with the type of work in process and the surroundings. b.If the luminance of the light source cannot be reduced to a desirable level, it may be possible to orient the work so that reflections are not directed in the normal line of vision. c.Increasing the level of illumination by increasing the number of sources will reduce the effect of reflected glare by reducing the proportion of illumination provided on the task by sources located in positions causing reflections. ? 2000 by CRC Press LLC d.In special cases, it may be practical to reduce the specular reflection by changing the specular character of the offending surface. Distribution, Reflection, and Shadows.Uniform horizontal illuminance (maximum and minimum not more than one-sixth above or below the average level) is usually desirable for industrial interiors to permit flexible arrangements of operations and equipment and to assure more uniform luminance in the entire area. Reflections of light sources in the task can be useful provided that the reflection does not create reflected glare. In the machining and inspection of small metal parts, reflections can indicate faults in contours, make scribe marks more visible, and so on. Shadows from the general illumination systems can be desirable for accenting the depth and forms of various objects, but harsh shadows should be avoided. Shadows are softer and less pronounced when large diffusing luminaires are used or the object is illuminated from many sources. Clearly defined shadows are distinct aids in some specialized operations, such as engraving on polished surfaces, some type of bench layout work, or certain textile inspections. This type of shadow effect can best be obtained by supplementary directional lighting combined with ample diffused general illumination. Luminance and Luminance Ratios.The ability to see details depends on the contrast between the detail and its background. The greater the contrast difference in luminance, the more readily the seeing task is performed. The eye functions most comfortably and efficiently when the luminance within the remainder of the environ- ment is relatively uniform. In manufacturing, there are many areas where it is not practical to achieve the same luminance relationships as easily as in offices. Table 107.7 is shown as a practical guide to recommended maximum luminance ratios for industrial areas. To achieve the recommended luminance relationships, it is necessary to select the reflectances of all the finishes of the room surfaces and equipment as well as control of the luminance distribution of the lighting equipment. Table 107.8 lists the recommended reflectance values for industrial interiors and equipment. High-reflectance surfaces are desirable to provide the recommended lumi- nance relationships and high utilization of light. Color Quality of Light. In general, for seeing tasks industrial areas, there appears to be no effect upon visual acuity by variation in color of light. However, where color discrimination or color matching is a part of the work process, such as in the printing and textile industries, the color of light should be carefully selected. Color always has an effect on the appearance of the workplace and on the complexions of people. The illuminating system and the decorative scheme should be properly coordinated. TABLE 107.7Recommended Maximum Luminance Ratios for Industrial Areas Environmental Classification ABC (1) Between tasks and adjacent darker surroundings 3 to 1 3 to 1 5 to 1 (2) Between tasks and adjacent lighter surroundings 1 to 3 1 to 3 1 to 5 (3) Between tasks and more remote darker surfaces 10 to 1 20 to 1 * (4) Between tasks and more remote lighter surfaces 1 to 10 1 to 20 * (5) Between luminaires (or windows, skylights, etc.) 20 to 1 * * and surfaces adjacent to them (6) Anywhere within normal field of view 40 to 1 * * *Luminance ratio control not practical. A—Interior areas where reflectances of entire space can be controlled in line with recommendations for optimum seeing conditions. B—Areas where reflectances of immediate work area can be controlled, but control of remote surround is limited. C—Areas (indoor and outdoor) where it is completely impractical to control reflec- tances and difficult to alter environmental conditions. Source: IES Lighting Handbook, Application Volume. ? 2000 by CRC Press LLC Veiling Reflections. Figure 107.4 shows that light would reflect into the eyes of the viewer from the “offending zone” and defines the zone of veiling reflection. Veiling reflection would diminish visibility, but the viewer would be unaware of it. The contrast rendition factor (CRF) can be applied as a measure of the amount of veiling reflection. Another important factor is the lighting effectiveness factor (LEF). An overall lighting system efficiency factor considers both the quality of light as reference to equivalent sphere illumination and the effects of veiling reflections. Light patterns such as “batwing” can help solve veiling reflection problems. Figure 107.5 shows the light distribution curve of a typical batwing luminaire. TABLE 107.8Recommended Reflectance Values for Industrial Interiors and Equipment Reflectance 1 Surfaces (%) Ceiling 80 to 90 Walls 40 to 60 Desk and bench tops, machines and equipment 25 to 45 Floors not less than 20 1 Reflectance should be maintained as near as practical to recom- mended values. Source: IES Lighting Handbook, Application Volume. FIGURE 107.4Diagram showing “offending zone” and zone of veiling reflection. FIGURE 107.5A typical “batwing” light distribution. ? 2000 by CRC Press LLC Daylighting The daylight contribution should be carefully evaluated and should always be coordinated with a planned electric lighting system. Fenestration.Fenestration has at least three useful purposes in industrial buildings: a.For the admission, control, and distribution of daylight. b.For a distant focus for the eyes, which relaxes the eye muscles. c.To eliminate the dissatisfaction many people experience in completely closed-in areas. An adequate electric lighting system should always be provided because of the wide variation in daylight. Building Orientation.All fenestration should be equipped with control device appropriate to any luminance problems. Special attention should be given to glare control latitudes where fenestration frequently receives direct sunlight. Diffuse-glaring fixed or adjustable louvers are some of the control means that may be applied. For an industrial building, windows in the sidewalls admit daylight and natural ventilation and afford occupants a view out. However, their uncontrolled luminance may be a problem. There are many control means to make daylight useful to workers’ seeing tasks, resulting in energy savings as the ultimate goal. 107.3 System Components Light Sources Incandescent a.Recent technology made possible a line of energy-saving incandescent lamps that use the rare gas krypton as a fill gas. b.Reflector (R) lamps offer better utilization of the light provided by the lamp compared to a nonreflector type. In this family, there are R lamps, PAR (parabolic aluminized reflector) lamps, and a newer line ER (elliptical reflector) lamps which allow reduction of 50% or more in energy consumption. c.Infrared Halogen (IR)—PAR lamps combine both the infrared heat-reflection technology and the regen- erative halogen cleaning cycle to provide a dramatic increase in lamp efficacy (4% reduction in energy consumption). Available in 30, 60, and 100 W. Fluorescent a.Energy-efficient lamps are now available in all popular sizes and colors for most applications. Limitations of energy-saving reduced-wattage lamps are: ?Ambient temperature must be above 60°F. ?Used on high p.f. fluorescent ballasts only. ?Not to be used where drafts of cold air are directed onto the lamp. b.Typical energy savings are 6 W per lamp for the popular 4-ft 40-W replacement and 15 W per lamp for the 8-ft slimline 75-W replacement. c.Compact fluorescent lamps are gaining popularity because they are energy efficient, fit into a small enclosed housing, and can be adapted for incandescent socket use. d.Virtually all compact fluorescent lamps use the “rare earth” phosphors for good color rendition and lumen maintenance characteristics. e.Utilizing advanced phosphor technology with the optimization of bulb diameter, 40-W lamps are now available that can be retrofitted in a F40 preheat or rapid-start circuit. The new lamp, which could save energy and improve color rendition requirement, has been legislated. f.Refer to Tables 107.9 and 107.11 for the latest energy efficient lamps. High-Intensity Discharge (HID) Today HID lamps include mercury vapor, metal halide, high-pressure sodium, and low-pressure sodium lamps. Metal halide lamps offer the best opportunity from a color acceptability point of view. High-pressure sodium ? 2000 by CRC Press LLC lamps offer the highest luminous efficacy in an environment where color distinction is not critical. Since HID lamps have had very few problems in application, they are likely to experience further development in the coming years. Ballasts Fluorescent. Electronic ballasts are now available for the F40T12, the slimline, the new T8 lamps, and other energy-saving fluorescent lamps on both 120- and 277-V circuits. Using high-frequency ballasts, the efficacy can be raised by nearly 12%. Although electronic ballasts cost more than the standard core-coil ballasts, operating factors should reflect an appreciable reduction in life-cycle cost for a lighting system. There are two types of dimming ballasts: core and electronic. High-frequency ballasts can readily be used to dim fluorescent lamps over a wide range of light level. All external control wiring is low voltage or fiber-optic wiring. A recent study indicates that 2 F40T12 lamps operated on an electronic ballast will attain an efficacy of 75–80 LPW versus 62 LPW for the same lamps if operated on a standard core-coil type ballast. With the dimmable electronically ballasted system, energy savings can be as high as 40% with respect to a core ballasted system. High-Intensity Discharge. The choice of a ballast depends on economic considerations versus performance. A mercury lamp will operate from metal halide ballast, but the converse is not always true. There are several different types of ballasts for high-pressure sodium lamps: a.Reactor or lag ballast—Inexpensive, low power losses, and small in size. b.Lead ballast —Fairly good regulation for both line and lamp voltage variation. c.Magnetic regulated ballast—Provides best voltage regulation with change of either input voltage or lamp voltage. It is the most costly and has the greatest wattage loss. d.Electronic ballast—Maintains a steady constant wattage output with changes in the source impedance as well as excellent regulation. During the life of a high-pressure sodium lamp, it can save 20% more energy by maintaining a constant wattage output in addition to the 15% intrinsic energy savings compared to an equivalent core-coil ballast. Luminaires Types of Industrial Luminaires.Selection of a specific type for an installation requires consideration of many factors: candlepower distribution, efficiency, shielding and brightness control, mounting height, lumen main- tenance characteristics, mechanical construction, and environmental suitability for use in normal, hazardous, or special areas. In general there are five types in accordance with CIE classifications, namely, direct type, semi- direct type, direct-indirect type, semi-indirect type, and indirect type. Figure 107.6 shows luminaire types with the percentage of total luminaire output emitted above and below horizontal. Supplementary Luminaire Types. There are five major types based on the candlepower distribution and luminance: Type S-I—directional Type S-II—spread, high luminance Type S-III—spread, moderate luminance Type S- IV—uniform luminance Type S-V—uniform luminance with pattern High-Pressure Sodium.Proper luminaire design is the key to lighting efficiency. Newly developed luminaires use prismatic glass reflectors that are especially made for high-pressure sodium lamps. In addition to achieving maximum light utilization, they redirect the intense light source with excellent light cutoff and high-angle brightness control. Luminaire manufacturers recommend aluminum reflectors for all general-purpose indus- trial applications and glass-coated reflectors where maintenance practice is compatible with servicing glass. Fluorescent. A new trend for lighting new buildings is the increased use of the reflectorized fixtures. This trend may be traced to an increase in the number of state and national lighting efficiency standards in recent ? 2000 by CRC Press LLC years. However, these fixtures can create a “teardrop-like” distribution that may eliminate glare on a computer screen, but also reduces light to other areas. 107.4 Applications Types of Industrial Illuminating Systems Factory Illumination for Visual Tasks. The prime requirement for industrial illumination is to facilitate the performance of visual tasks through high-quality illumination. There are three types of lighting used in industrial areas. ? General Lighting. It should be designed to provide the desired level of illumination uniformly over the entire area. The variation of light level from point to point within the area should be within 17% of the selected level. A good general lighting system makes it possible to change the location of machinery without rearranging the lighting and also permits full utilization of floor space. ? Localized General Lighting. Within a general area there may be a few areas where tasks performed require a greater quantity of light and a different quality of light. When applied, care must be exercised to eliminate direct or reflected glare from the task and from other workers. ? Supplementary Lighting. Supplementary lighting is specified for different seeing tasks that require a specific amount or quality of light not readily obtained by standard general lighting methods. Supple- mentary lighting is a valuable industrial lighting tool. Typical problems arise where work is shielded from the general lighting system by an obstruction or its brightness is otherwise lowered where low contrast, such as scribe marks on steel, may lead to visual errors, and where the product moves too rapidly to be seen clearly by the unaided eye. To attain a good balance, it is important to coordinate the design of supplementary and general lighting with great care. Security Lighting. Security lighting pertains to the lighting of building exterior and surrounding areas out to and including the boundaries of the property. Security lighting contributes to a sense of personal security and to the protection of property. It may be accomplished through: ? Surveillance lighting to detect and observe intruders. ? Protective lighting to discourage or deter attempts at entrance, vandalism, etc. ? Lighting for safety to permit safe movement of guards and other authorized persons. FIGURE 107.6 General lighting luminaire classifications. ? 2000 by CRC Press LLC Emergency Lighting. Emergency lighting is provided for use when the power supply for the normal lighting fails to ensure that escape routes can be effectively identified and used. Standby lighting is that part of emergency lighting that is sometimes provided to enable normal activities to continue. The following are recommended minimum illumination requirements for exit signs and egress route: ? Internally illuminated signs. An illuminance of 54 lux (5 fc) on the face of the sign is usually specified. ? Externally illuminated exit sign. NFPA 101 requires 54 lux (5 fc) on the face of the sign. ? Egress route. The horizontal illuminance of any escape route should not be less than 1% of the average provided by the normal lighting, with a minimum average of 5 lux (0.5 fc) at floor level. ? Location of egress luminaires. A luminaire should be provided for each exit door and emergency exit door to provide sufficient light to a level of 30 lux (3 fc). Summaries. In large industrial areas, all these lighting systems may be used. In small areas, localized general lighting may also serve as a substitute for general lighting. In this case, additional supplementary lighting may be required to increase the quantity or improve the quality of the illumination. Many factors must be considered in selecting a lighting system. It is not feasible to recommend one or two systems for all conditions. Because of the relationship of ceiling height to light utilization, most industrial applications call for either direct or semi-direct lighting systems. Selection of the Equipment In the selection of equipment, light sources, and luminaires, many variables must be considered. As with any list of variables, it is necessary for purpose of comparison to hold some factors constant. In industrial illumi- nation that factor is usually mounting height and location. High-Bay Areas. The work generally presents visual tasks that are not difficult because of large machinery and other objects. Illuminance levels for high-bay areas generally range from 50 to 150 fc, although more and more areas are being lighted with 200 and 300 fc. At a high mounting height, it is possible to obtain uniform illumination by using a few high-wattage sources rather than a larger number of low-wattage sources. For luminaires with medium and narrow distribution, greater mounting height or closer spacing is ordinarily required for uniform general illumination. Regardless of mounting height, wide distribution luminaires are well suited for use in areas that are wide in respect to mounting height. Large machinery and objects tend to cut off light and cast shadows. Since this makes it difficult to see important vertical and angular surfaces, broad light distribution is essential. High-intensity discharge or fluorescent luminaires for high-bay lighting may be enclosed, ventilated open, or nonventilated open. Enclosed luminaires are usually of a heavy-duty type with a gasketed glass cover to protect the reflector and light source from collection of dirt. The initial luminaire efficiency is lower and the equipment is more costly. Ventilated-open luminaires have largely replaced the nonventilated type. As far as choices of lamps are concerned, metal halide and HPS are preferred over the mercury type. The use of fluorescent lamps in high-bay areas is limited. Only where the area proportions are such that the room cavity ratios are in the range of 1 to 3 may fluorescent lamps be acceptable. Only high or extra high output fluorescent in 8-ft sizes are recommended. Medium- and Low-Bay Areas. Seeing tasks in medium- and low-bay areas are usually more difficult than those encountered in the high-bay areas. Increasing the size and reducing the brightness of the luminaires will improve visual comfort and will improve the visibility of specular objects. It may not improve the visibility of diffuse three-dimensional objects. Luminaires used for general lighting in medium-bay areas are nearly always of the direct or semi-direct type, either fluorescent or wide distribution HID. They may be the ventilated or nonventilated type and the lamps may be shielded by louvers, baffles, or other devices. For lower mounting, the trend is toward the semi-direct type. Some of the visual tasks involve specular or semi-specular objects, for which optimum lighting might be an indirect system. The quality of fluorescent sources, with their broad distribution of light, makes them a prime selection for medium- and low-bay lighting. When the proper quality control can be attained, low-wattage HID sources are finding an increasing number of low-bay applications. ? 2000 by CRC Press LLC 107.5 System Energy Efficiency Considerations Energy-Saving Lighting Techniques Fluorescent Systems Considerations. Fluorescent lamps are sensitive to ambient temperatures. By using reduced wattage lamps or low-loss ballasts, less heat will be generated and the operating temperature point of the lamp will probably change. The critical area is the coldest spot on the bulb surface. Most fluorescent lamps will peak in light output at around a 100°F cold-spot temperature. For enclosed luminaire types that ordinarily operate the lamp at higher temperature, replacing standard lamps with high-efficacy, reduced wattage lamps may result in a net increase in luminaire output even though the reduced wattage lamps are rated for less output than are standard lamps. Using Daylight.Daylight should be dealt with by first analyzing it and then establishing a design technique to integrate it with the electric lighting system. Daylight may be adequate in quantity and quality to reduce the electric lighting load and result in energy conservation. Poor quality of daylight may lead to discomfort and a loss in visibility that may result in a decrease in human performance and productivity. Daylighting Design from Windows.The longhand design procedure involves two steps: ?Determine the quantity of illumination coming to the window surface. ?Use that quantity to determine the daylight contribution to the interior part of the space. Once the contribution of illumination to the window surface has been calculated, two longhand methods are available to determine the illumination contribution to the space. The first method is to follow the point- by-point procedure, which makes two assumptions: (1) interreflected component is ignored and (2) the window is a uniform diffuse emitter. The second method is a lumen method that calculates illumination values at three points defined as the maximum, midway, and minimum. This method includes both the direct and interreflected components of illumination. Task-Ambient Lighting.This is a particular form of nonuniform illumination that combines task illuminance and ambient illuminance. One advantage is improved energy efficiency. The task component of task-ambient lighting may take two forms: (1) furniture-mounted lighting built into a workstation or (2) floor-mounted fixtures that can be placed adjacent to a desk. The ambient lighting component may be supplied in two ways: (1) conventional luminaires on the ceiling or (2) indirect fixtures utilizing HID or fluorescent lamps with the output directed to the ceiling and adjacent walls. For ceiling-mounted troffers used for ambient lighting, a plug-in system of wiring should be considered so that luminaires can be relocated as task locations change. Lighting Controls In order to save energy, it is essential that minimum acceptable lighting levels be used during off-hours, cleaning periods, and for other nonpeak periods as is practical. The ultimate system of control would be to remotely control every fixture and to program the mode of operation, but this is hardly possible. Solid-state dimmers are available, or ballasts can be circuited in separate groupings. Solid-state controls are available for dimming entire areas of ballasted lights, but special ballasts are required and the controls could be expensive. Manual control of a lighting system is often the least expensive, but also the least effective alternative. Automatic controls vary from a simple timer to a sophisticated computer system. Figure 107.7 shows a typical programmable lighting control scheme. A price versus benefit cost analysis will be required for each installation. The system should be programmed for normal operation and have a local manual override. A good convenient practice is to have lights switched in distributed groups so that areas can be lighted or darkened as conditions change. Lighting and Energy Standards In 1976, the Energy Research and Development Association (ERDA) contracted with the National Conference of States on Building Codes and Standards (NCSBCS) to codify ASHRAE 90-75. The resulting document was ? 2000 by CRC Press LLC called “The Model Code for Energy Conservation in New Buildings.” The model code has been adopted by a number of states to satisfy the requirements of Public Laws 94-163 and 94-385. There have been several revisions on the ANSI/ASHRAE/IES 90-75 since 1976. All were included in the lighting portion of ANSI/ASHRAE/IES 90A-1980, “Energy Conservation in New Building Design,” and in EMS- 1981, “IES Recommended Lighting Power Budget Determination Procedure.” ASHRAE/IES 90.1-1989, “Energy Efficient Design of New Buildings Except New Low-Rise Residential Build- ings,” is the third generation document on building energy efficiency since the first publication in 1975. This standard is intended to be a voluntary standard which can be adopted by building officials for state and local codes. FIGURE 107.7 Programmable lighting control scheme. ? 2000 by CRC Press LLC LIGHTING: THE NEXT 10 YEARS any exciting developments are occurring in the lighting industry. However, one of the greatest challenges is the development of a replacement light source for the common cathode ray tube (CRT) found in televisions and other applications. CRTs have gradually expanded from our primary information sources, televisions and computers, into scientific instrumentation, cars, and automatic teller machines. However, the inherent shortcomings of this technology are limiting the further development of existing and new applications that require display technology. CRTs produce few lumens for the power they consume and are inherently large and heavy. Their many weaknesses are compounded in the area of big screen displays. The desire to view ever larger and higher resolution images is pushing the CRT beyond its practical limits. New lighting technologies applied to flat panel displays and projection systems could change the consumer television market if certain barriers are overcome. M ? 2000 by CRC Press LLC One approach has been to adopt large area LCDs (which pose a significant engineering challenge) as the primary imaging device. However, these devices do not inherently emit light and would be useless TABLE 107.9 The Proposed Efficiency Standards for Fluroescent Lamps Nominal Minimum Minimum Lamp Lamp Average Average Type Wattage CRI Lamp Efficacy F40 >35 W 69 75 F40 ￡35 W 45 75 F40/U >35 W 69 68 F40/U ￡35 W 45 64 F96T12 >65 W 69 80 F96T12 ￡65 W 45 80 F96T12/HO >100 W 69 80 F96T12/HO ￡100 W 45 80 Note: The above excludes lamps designed for plant growth, cold temperature service, reflectorized/aperture, impact resistance, reprographic service, colored lighting, ultraviolet, and lamps with CRI of more than 82. in the dark without backlights. The light source of choice for this approach has been cold cathode fluorescent lamps, which are commonly applied in today’s laptop computers. We can expect to see unique lamp shapes and ingenious reflector systems developed to illuminate the LCD uniformly, without adding significantly to the overall depth of the display system. There is also a lot of work in the development of electroluminescent panels as an alternative to fluorescent lamps, although these devices present color difficulties as well as comparatively low efficacies. Large-area LED image displays have already been fabricated since blue LEDs emerged in the market- place. An array of red, green, and blue LEDs are mounted on a panel and individually addressed to generate all colors, including white. This approach will be redefined in the coming decade, but faces a number of challenges. Another approach involves large-area plasma panels that are self-luminescent due to gas discharges. With this technology, the brightness improves considerably over that available from a CRT. Brilliant, high-resolution images have been achieved in medium screen sizes, but cost remains a problem and there is still the challenge of expanding the technology to even larger screen sizes. The approach that is most likely to succeed during the next decade is the use of projection technology. These systems are fundamentally similar to slide or movie projectors where the film has been replaced by either a transmissive or reflective imaging device that provides a continuously variable image illumi- nated and projected onto a screen. The image can be front projected or rear projected. The most pressing challenge remains: development of an illumination source that can provide a brighter image with better colors than CRT technology. If this can be achieved, other benefits will flow from the technology, with the potential to drastically reduce power consumption as well as cabinet size, weight, and cost. Furthermore, the inherent digital nature of the imaging panels would make the resulting product data compatible for the much touted merging of the Internet and television programming. High-resolution rear projection televisions using lamps as the illumination source are already available in Japan from Sony and Sharp. We can expect to see this type of product in the U.S. market this year. However, the overall product cost, lamp life, and screen brightness all need improvement before this technology moves into the mainstream. ? 2000 by CRC Press LLC Ener On Oct equipment; stat fluor equi be ax r the Depar and pub and 150 sa standar gy Policy Act ober 25, 1992, the Energy Policy Act was signed into law by the President. Among the many provisions, the act establishes energy efficiency standards for HVAC, lighting, and motor encourages establishment of a national window energy-efficiency rating system; and encourages e regulators to pursue demand-side-management (DSM) programs. Under the bill, lighting manufacturers will have 3 years to stop making F96T12 and F96T12/HO 8 ft escent lamps and some types of incandescent reflectors. Standard F40 lamps except in the SP and SPX or valent types of high color rendering lamps would also fade away. General service incandescent lamps to ed would include those from 30 to 100 W, in 115 to 130 V ratings, having medium screw bases, of both eflector and PAR types, having a diameter larger than 23/? in. There are no immediate regulations impacting HID lamps. Within 18 months of the legislation’s enactment, tment of Energy (DOE) will determine the HID types for which standards could possibly save energy lish testing requirements for these lamps. As far as the general service lamps are concerned, the most common incandescent lamps — 40, 60, 75, 100, W — are not covered by an efficiency standard because there is no suitable method to ensure energy vings. These types, however, are covered by another provision of the law, namely the energy efficiency labeling The technical challenge for the lighting industry is to produce a miniature point source that delivers high efficacy, high color temperature, and long lifetime. The challenge for the immediate future is to push the arc gap even smaller while extending the lamp life to be comparable to today’s CRTs and maintaining lumen output and good color temperature. Furthermore, all these requirements have to be met at a very low cost. The rewards for the successful manufacturer are immense, considering the size of the market, not to mention the spin-off markets that could pick up on this technology. During the next decade, we are sure to see a lot of exciting developments in this area, which will ultimately affect our daily activities. (Adapted from Ian Edwards, “Fundamentals of Lighting”, Optics & Photonics News, Optical Society of America, 7(11), 20, 1996. With permission.) ds. Effective April 28, 1994, the Federal Trade Commission (FTC) must provide manufacturers with labeling requirements for all lamps covered: fluorescent, incandescent, and reflector incandescent. Though not yet defined, the proposals include: an energy rating for the lamps, probably LPW (lumens per watt), and energy cost per year to operate the lamp. The energy efficiency label will then allow side-by-side comparison of two different lamp types, thus enabling consumers to make a more intelligent choice of lamps; taking into account not just the purchase price, but also the operating cost. Manufacturers must begin applying labels by April 28, 1995. Table 107.9 shows the proposed efficiency standards for the fluorescent lamps, and Table 107.10 shows the proposed efficiency standards for incandescent reflector lamps. There is no requirement to replace all existing lamps in any installation. However, as these lamps burn out, the replacement must meet the new standards. Replacement for popular fluorescent types includes reduced-wattage energy saving types. These lamps will meet the color and efficiency standards, as will the full wattage triphosphor lamps having a CRI over 69. Table 107.11 shows some types of replacement lamps. On the incandescent side, replacements for the standard incandescent spot and flood lamps will be lower wattage halogen type reflector lamps which do meet the LPW requirements. The halogen and halogen/infrared types of reflector lamps will remain the only type of such lamps on the market. ER and BR types, those intended for rough and vibration service will also be excluded here. There is also a provision for lighting fixture manufacturers to come up with voluntary luminaire efficiency standards. If these standards are found to be inadequate, the DOE will come up with the mandatory efficiency standards. The new Energy Policy Act is all-encompassing. It promises to change forever the way industries produce, distribute, and utilize the valued energy resources. The end result should be increased energy security, decreased environmental emissions, and cleaner air and water for all humankind. Defining Terms Candlepower distribution:A curve, generally polar, representing the variation of luminous intensity of a lamp or luminaire in a plane through the light center. Cavity ratio (CR):A number indicating cavity proportions calculated from length, width, and height. It is further defined into ceiling cavity ratio, floor cavity ratio, and room cavity ratio. Coefficient of utilization (CU): The ratio of the lumens reaching the working plane to the total lumens generated by the lamp. This factor takes into account the efficiency and distribution of the lumanaire, its mounting height, the room proportions, and the reflectances of the walls, ceiling, and floor. TABLE 107.10The Proposed Efficiency Standards for Incandescent Reflector Lamps Nominal Lamp Minimum Average Wattage Lamp Efficacy (LPW) 40–50 10.5 51–66 11.0 67–85 12.5 86–115 14.0 116–155 14.5 Note:The above excludes miniature, decorative, traffic signal, marine, mine, stage/studio, railway, colored lamps, and other special application types. TABLE 107.111992 Energy Policy Act — Replacement Lamps Present Type W Acceptable W Improved Type W Max. Savings W F96T12/CW 75 F96T12/CW/SS 60 F96T12/D41/SS 60 F096T8/741 59 F96T12/WW 75 F96T12/WW/SS 60 F96T12/D30/SS 60 F096T8/730 59 ? 2000 by CRC Press LLC Color preference index (CPI): Measure appraising a light source for appreciative viewing of colored objects or for promoting an optimistic viewpoint by flattery. Color rendering index (CRI): Measure of the degree of color shift objects undergo when illuminated by the light source as compared with the color of those same objects when illuminated by a reference source of comparable color temperature. Contrast: The relationship between the luminances of an object and its immediate background. It is equal to (L 1 – L 2 )/L 1 where L 1 and L 2 are the luminances of the background and object. The ratio D L/L 1 is also known as Weber’s fraction where DL = L 1 – L 2 . Contrast rendition factor (CRF): The ratio of visual task contrast with a given lighting environment to the contrast with sphere illumination. Equivalent sphere illumination (ESI): The level of sphere illumination which would produce task visibility equivalent to that produced by a specific lighting environment. Fenestration: Any opening or arrangement of opening (normally filled with media for control) for the admission of daylight. Footcandle: The unit of illuminance when the foot is taken as the unit of length. It is the illuminance on a surface one square foot in area on which there is a uniformly distributed flux of one lumen. Illuminance: The density of luminous flux on a surface expressed in either footcandles (lumens/ft 2 ) or lux (lx). (lux = 0.0929 fc) Lighting effectiveness factor (LEF): The ratio of equivalent sphere illumination to ordinary measured or calculated illumination. Light loss factor (LLF): The ratio of the illumination when it reaches its lowest level at the task just before corrective action is taken, to the initial level if none of the contributing loss factors were considered. Luminance ratio: The ratio between the luminance of two areas in the visual field. Veiling reflection: Regular reflections superimposed upon diffuse reflections from an object that partially or total obscure the details to be seen by reducing the contrast. Visual comfort probability (VCP): This rating is based in terms of the percentage of people who will be expected to find the given lighting system acceptable when they are seated in most undesirable locations. Related Topics 3.1 Voltage and Current Laws ? 3.4 Power and Energy References ANSI/IES, “Recommended Practices for Industrial Lighting,” Illuminating Engineering Society, New York, 1991. K. Chen, Energy Effective Industrial Illuminating Systems, Lilburn, Ga.: The Fairmont Press, 1994. K. Chen, Industrial Power Distribution and Illuminating Systems, New York: Marcel Dekker, 1990. K. Chen, “New concepts in interior lighting design,” IEEE Trans. Industry Applications, Sept./ Oct. 1984. IES Lighting Handbook, Application Volume, Illuminating Engineering Society, New York, 1993. Lighting Handbook, Westinghouse Electric Corporation, Bloomfield, N.J., 1976. Further Information L. Watson, Lighting Design Handbook, New York.: McGraw-Hill, 1991. It focuses on the art and process of lighting design and provides invaluable, up-to-date technical details on equipment, color use, scenic projection, lasers, holograms, fiber-optics, computers, and energy conservation. C.L. Robbins, Daylighting—Design and Analysis, New York: Van Nostrand Reinhold, 1986. Organized to cor- respond to the building design process, the book contains data for calculation of annual cost and energy savings as well as many case studies. Software—Lighting Calculations by Zonal Cavity Method, Orloff Computer Services, 1820 E. Garry Ave., Santa Ana, CA 92705. ? 2000 by CRC Press LLC