Residential Lighting - Illuminating Engineering Society

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JP. 1997. Photic Regulation of Melatonin in Humans: Ocular and neural Signal Transduction. J Biol Rhythms, 12(6): 537 - 546 Davis S, Mirick DK, Stevens RG. 2001. Night shift work, light at night, and risk of breast cancer. J Natl Cancer Inst 93(20): 1557- 1562. Figueiro MG, Rea MS, Boyce P, White R, Kolberg K. 2001. The effects of bright light on day and night shift nurses’ performance and well-being in the NICU. Neonatal Intens. Care 14(1): 29-32. Hansen J. 2001. Light at night, shiftwork, and breast cancer risk. J Natl Cancer Inst 93(20): 1513- 1515. Herbert M, Martin SK, Lee C, Eastman CI. 2002. The effects of prior light history on the suppression of melatonin by light in humans. J Pineal Res 33: 198-203. Lewy AJ, Wehr TA, Goowin FK, et al. 1980. Light suppresses melatonin secretion in humans. Science, 210: 1267-1269. Lynch HJ, Deng MH, Wurtman RJ. 1985. Indirect Effects of Light: Ecological and Ethological Considerations. The Medical and Biological Effects of Light. Annals of the New York Academy of Sciences 453: 231 – 241. Miller CL, White R, Whitman TL, O’Callaghan MF, Maxwell SE. 1995. The effects of cycled versus noncycled lighting on growth and development in preterm infants. Infant Behav Develop 18(1): 87-95. Rea MS, Figueiro MG, Bullough JD. 2002. Circadian photobiology: An emerging framework for lighting practice and research. Light. Res. Technol. 34(3): 177-190. Schernhammer ES, Laden F, Speizer FE, Willett WC, Hunter DJ, Kawachi I, Colditz GA. 2001. Rotating night shifts and risk of breast cancer in women participating in the nurses’ health study. J Natl Cancer Inst 93(20): 1563-1568. Van Someren EJW, Kessler A, Mirmirann M, Swaab DF. 1997. Indirect bright light improves circadian rest-activity rhythm disturbances in demented patients. Biol. Psychiatry 1997; 41: 955-963. www.iesna.org Before a stage show comes to Broadway it opens “on the road” to get the kinks out of it. Often the producers hire a “show doctor” to make changes that will help insure the play’s success in New York. Something similar happens with a developer’s speculative office building. A construction cost of $200/sq ft for a million square foot office building makes for a risky investment, even with a major tenant lined up before breaking ground. Since you can’t try out an office building on the road, many developers engage an architect’s architect Energy conservationists recommend that available daylight be used to reduce the electric load, which can easily be done in an office only 15 ft deep to configure the building so that when it is built in New York, or in any major US city, it gets the maximum yield in the form of rental to insure its success. The best known of these building gurus is Der Scutt, who is a Fellow of the AIA as well as the IESNA. I turned to him for help in preparing a talk for the Master Class in Lighting for Architects and Designers, produced each year in New York by Sonny Sonnenfeld, in association with Paul Gregory and Jonathan Speirs. Scutt pointed out that the size of the plot and the zoning of the site determines the footprint and size of the building and the spacing of the structural steel. The most economical module for a developer’s building is five feet, which dictates the spacing of the columns and the size of the various offices. Some tenants are large corporations with office buildings throughout the country. They have their own formula for space allocation. A large communication company has seven different sized private ENERGY CONCERNS offices, one for each of its executive levels, and has rules for how many persons have to share a “private” office, and how many square feet to allow for each occupant in an open plan area. Der Scutt told me that, in general, for a building to reach its maximum rental potential, it should have a 15 ft deep perimeter zone for private offices, each one a multiple of 5 ft, with the smallest office 10 ft wide along the window wall by 15 ft deep, and wider spaces for executives and conference rooms. Then, proceeding inward toward the core, the floor plan should allow 5 ft for a corridor and 10 feet for secretarial offices and records. If the perimeter offices have glass partitions onto the corridor, then everyone in that 30-ft-deep exterior zone has a visual connection to the outdoors, which we know from the Light Right Consortium study is highly valued by employees. Then Scutt recommends another 5-ft-wide corridor for passage and past that, interior offices and conference rooms, the employee cafeteria and utility areas and finally, the reception area and elevator lobby. The glazing in the windowed perimeter offices will have coatings to reduce the sun load, which is highest in the winter when the sun is at its lowest, and to retain the heating or cooling on the inside— depending on the season. Energy conservationists recommend that available daylight be used to reduce Willard L. Warren, PE, LC, FIESNA LD+A/February 2003 19
the electric load, which can easily be done in an office only 15 ft deep, depending on the transmissive density of the coated glazing. For an entire office building to meet ASHRAE/ IESNA 90.1-1999, the allowable Lighting Power Density (LPD) is 1.3 watts per square foot. If the new or renovated office space is part of a substantial alteration to an existing building and it constitutes more than 50 percent of the electrical subsystem of the building, then the allowable LPD is 1.5 w/sq ft. How much illuminance can you provide if limited to 1.5 w/sq ft That depends on the luminous efficacy of the lamp/ballast combination, the shape of the room and the reflection factors of its ceiling, walls and floor, the coefficient of utilization (CU) of the luminaire in that room, and that is for a calculation of the expected average initial footcandle level. Let’s take that exterior private office in our developer’s building that is 10 ft wide by 15 ft long, with an area of 150 sq ft limited to 1.5 w/sq ft You will probably want to provide 50 fc average maintained at a .85 maintenance factor (MF), with hopefully, a way to switch it down to 35 fc when the occupant is working only on the computer, and an occupancy sensor to switch the lights off, or way down, when the person is out of the office, which is generally a third of the time. Two luminaires with CU’s of .55, and three 32-W T-8 lamps in each will provide: 6 lamps x 2850 lumens/lamp x .55 (CUs) x .85 MF/150 sq ft = 53 fc average maintained. And you’ve used 3 x 58 watts/luminaire = 174 watts, only 1.2 w/sq ft, way under the 1.5 Lighting Power Density (LPD) watts/sq ft allowed. I would prefer to use a direct/ indirect unit with premium T-8 lamps and low power electronic ballasts with 3200 lumen lamps and a ballast factor ( BF) of .77 to give: 6 lamps x 3200-lumens/lamp x .77 BF x .55 cu x .85 MF/150 sq ft = 54 fc average maintained with only 144 watts, which is less than one watt/sq ft. Or you could use an efficient indirect luminaire with two- T-5 HO lamps. Or you could provide 35 fc average maintained using only .7 w/sq ft and an under cabinet task light to provide the extra illumination needed when working on a more difficult visual task, and still be under .8 watt/sq. ft. In a larger office, the CU goes up, and the spacing of the luminaires can be greater, (unless you’re lining them up with the windows) and the energy load can be reduced even more. California, which has been first in everything lately, is cutting the allowable LPDs to below ASHRAE/ IESNA 90.1-1999 levels, and accounting for plug loads. In the future, California is considering giving Power Adjustment Factors, which are credits, for the use of bilevel lighting in various occupancies like classrooms, warehouses, corridors, library stacks and offices. There’s a lot of controversy about giving power credits for daylight harvesting, but that will happen when sensors are incorporated within the luminaires and can be more easily calibrated and the energy savings more reliably realized. As pointed out in last month’s column, a number of lighting manufacturers are incorporating combination daylight harvesting and occupancy sensors in their luminaires, along with dimming ballasts, to automatically reduce the electric load. I know I repeat myself in my columns regarding bi-level lighting, but it is becoming an important energy saving measure that’s finally being given the “credits” it’s due. Willard L. Warren, PE, LC, FIES- NA is the founder of Willard L. Warren Assoc. a consulting firm specializing in lighting and energy conservation. He has consulted for many governmental agencies and corporations and is chairperson of the panel that rewrote the lighting sections of the new, New York City Electric Code of 2003. He welcomes all comments on your experiences with energy conservation in lighting at wlwlighting@att.net 20 LD+A/February 2003 www.iesna.org
Page 1 and 2: Lighting Design + Application Febru
Page 3 and 4: President Randy Reid Past President
Page 5 and 6: Thornton’s research suggests that
Page 7 and 8: Do we need a conference and does it
Page 9 and 10: When we are presented with a bright
Page 11 and 12: VIEWS ON THE VISUAL ENVIRONMENT Lou
Page 13 and 14: sion, Brightness. If reflectance is
Page 15: practical applications where the ci
Page 19 and 20: • notes on lighting design Sarato
Page 21 and 22: Myron Kahn, Developed Polarized Cei
Page 23 and 24: Lighting Controls Association Publi
Page 25 and 26: The water feature is accented with
Page 27 and 28: Interchangeable IC-rated pinhole an
Page 29 and 30: (left) The 146,000-sq-ft Life Scien
Page 31 and 32: (top) Decorative pendants with meta
Page 33 and 34: can be easily controlled throughout
Page 35 and 36: (left) High-tech kitchen is luminat
Page 37 and 38: Diners deposit their trust in Chef
Page 39 and 40: Most are stainless steel, some also
Page 41 and 42: authentic art glass and the pendent

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