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Task Lighting
Published in Michael Stiller, Quality Lighting for High Performance Buildings, 2020
Another task-ambient system that combines both the cost-effectiveness of a localized general lighting scheme and the flexibility of portable task lighting is one that employs furniture-mounted direct/indirect fixtures. Like the localized general lighting scheme, this system also provides a complete task-ambient solution with a single fixture type, keeping costs for both equipment and installation as low as possible. And since the lighting fixtures are mounted directly to the furniture, they are easy to relocate in an open office as the workstations are reconfigured to satisfy the changing needs of the occupants. Figure 8-6 shows an open office utilizing these fixtures, which are mounted to the desks at a height that prevents direct glare from both the uplight and downlight component. The lighting fixtures contain lamps that project light up to the ceiling to create a visually comfortable, indirect, ambient light, as well as lamps that direct light down to the work-plane, to raise the illuminance to the required levels at the task area. Controls are easily integrated to provide manual switching, occupancy sensing, and dimming of the task lighting component for even greater energy cost savings. This system does rely on a highly reflective ceiling plane, and the effectiveness will depend to some degree on the ceiling height, with very high ceilings creating a greater challenge.
Design of The Luminous Environment
Published in Samuel Mills, Fundamentals of ARCHITECTURAL LIGHTING, 2018
This design approach can save significant energy when compared with general lighting systems. In a task-ambient design, lighting fixtures might be concentrated over work areas for the task lighting, locating the light sources on either side of the work space, and slightly behind, eliminating shadows and directing light away from the viewer’s eyes. An indirect lighting system can provide low levels of general (ambient) illumination. When compared to a traditional uniform lighting design, the average light level may be lower, and the number of required fixtures may be reduced. It is ideal for visual tasks and saves energy by providing and locating the illumination only where needed. Additional energy savings can be accomplished with the utilization of user-controlled practices, along with occupancy and vacancy sensors. Vacancy sensors are somewhat different than occupancy sensors in the sense that they do not turn the lights on when detecting motion, but twill turn them off when no motion is detected.
What are architectural lighting systems?
Published in Samuel L. Hurt, Building Systems in Interior Design, 2017
Task lighting is provided specifically for tasks—writing, reading, typing, sewing, cooking, horse-shoeing, taxidermy, surgery, etc. This can be provided by many different types of fixtures with many different sources, but it must be pointed out that it accomplishes nothing from an energy savings point-of-view if it does not save energy. So we tend to avoid incandescent task lighting to the greatest degree feasible (with surgical lights being a prime exception—even these are being replaced with LEDs now). Today, there are many good compact fluorescent fixtures for task lighting on the market but also a number of even better LED fixtures. The latter would be preferred. Whatever the task lighting is, it must be separately controlled from the ambient lighting. Even if the ambient light is to be left on for some reason, there certainly is no reason to have task lights on if no one is there. Task lights can be controlled by occupancy sensors.
Smart lighting systems: state-of-the-art and potential applications in warehouse order picking
Published in International Journal of Production Research, 2021
Marc Füchtenhans, Eric H. Grosse, Christoph H. Glock
Depending on the industry, daylighting is often not sufficiently available in industrial facilities. Similar to desk level lighting in offices, task lighting depending on the available daylight is very important in an industrial environment to improve the visual performance and better control the biological and psychological effects of lighting. A performance improvement can also be achieved due to controllable lighting technology by generating feelings of autonomy and job satisfaction (see Juslèn, Wouters, and Tenner 2005; Juslèn and Tenner 2007; Juslèn, Wouters, and Tenner 2007). Adapted and localised lighting leads to an increased well-being and productivity, and employees feel less sleepy during shift work, especially at night (cf. Juslèn, Verbossen, and Wouters 2007b; Juslèn and Fassian 2005). An increase in bright light exposure inhibits the release of melatonin and thus improves the adjustment to night shift work (Lowden, Akerstedt, and Wiborn 2004). Adapting the level and colour of light for different light conditions to worker and task needs increases employees’ health and alertness and leads to improved safety and fewer failures in the industrial working environment (Van Bommel and Van den Beld 2004).
Lighting Prescriptions for Low Vision
Published in Journal of Housing For the Elderly, 2019
Mary Butler, Keri McMullan, Susan E. Ryan
Although the lighting prescriptions were personalized, most of the recommendations were very simple. These included the use of brighter bulbs; LED ceiling buttons (a dish-shaped diffuser luminaire); adjustable task lamps for table and floor; and strip lighting. For example, a recommendation for one client was replacing all ceiling lights with LED at 1400 lumen and 6500K (north light). The preferred task lighting for this client was 3500 lux, compared to the usual recommendation of 200–1000 lux for reading (Figueiro, Sahin, Wood, & Plitnick, 2016). The color of the light favored by clients was variable. Other clients could not tolerate bright lights and suggestions were made to address issues of glare. Lighting was provided from multiple sources, rather than a single point, in order to avoid contrast between light and dark; lighting was also positioned for tasks, for example, over the armchair or on a table; bright lighting was also frequently recommended in the kitchen, particularly for cooking and washing up. Solutions for glare included getting darker curtains and ensuring that lampshades covered the light.
A review of advances for thermal and visual comfort controls in personal environmental control (PEC) systems
Published in Intelligent Buildings International, 2019
Sam Babu Godithi, Enna Sachdeva, Vishal Garg, Richard Brown, Christian Kohler, Rajan Rawal
Recent advances in Solid State Lighting (SSL) led to energy efficient indoor lighting systems and a widespread adaptation of LED (Light Emitting Diode) lighting luminaries for task lighting. The white light is produced either by using blue LED in conjunction with a yellow phosphor or by using trichromatic (RGB) LED chips. The blue light from LED can suppress visual fatigue more effectively than incandescent and fluorescent lighting (Wang et al. 2015). However, exposure to blue light may be detrimental to one's health and affect circadian cycle (Pauley 2004). Hence, there is a need to personalize the lighting for individual needs and requirements that can be easily achieved by personalized task-ambient lighting systems. Non visual biological effects on human can be parameterized by the circadian action factor (CAF) (Hye Oh, Ji Yang, and Rag Do 2014; Chew et al. 2017) and “Circadian Lighting Design | WELL Standard” (2018) defines Equivalent Melanopic Lux (EML) to measure biological effects of light on humans. PEC systems with color tunable lights can help achieve EML. There are three basic categories of color-tunable LEDs (“Understanding LED Color Tunable Products | Department of Energy” 2018): (1) dim-to-warm which usually designed for dimmable from 2700 to 3000 K at full output and 1800 K at the lowest; (2) white-tunable which have two phosphor-coated LEDs (one is warm-white color (2700 K) and the other is cool-white color (usually 5000–6500 K)); and (3) full-color-tunable (spectrally tunable/color changing) which have at leats three different LEDs (RGB, RGBA, RGBW) that can be controlled independently to create a kind of white light. More sophisticated control strategies can be designed using PEC systems with tunable LEDs (Afshari et al. 2014), and further studies in this direction are required. Moreover, the latest computer monitors, laptops, and mobile phones come with a blue light filter to change the color palette of the displays. Further studies are required to understand how to take advantage of these features and can be integrated into PEC systems to provide personalized visual comfort to the users for circadian rhythm.