Lighting Design: Examination of Full-Spectrum

Lighting Design: Examination of Full-Spectrum Lighting Benefits

Studies exist which show that lighting in the office and workspace greatly affects workers whether in a positive or negative manner. This work examines the utility of a design of full spectrum lighting in the office and workspace and one that would includes a customized manual setting allowing users to choose the intensity of light at any time. Recessed lighting which is primarily found in the office environment tend to create a glare when the individual's eyes are focused on the computer monitor causing the eye to become overworked with sensations of burning and fatigue. It is extremely difficult for the eye to focus on a bright monitor and adjust to low intensity wall colors and recessed ceiling lights. It is a generally held misconception that the addition of wall lights for illumination of an office space are sufficient however, research does nor support this. This work examines full spectrum lighting in order to understand the benefits of this type of lighting system and specifically in office cubicles that have handheld remote control capabilities. Finally, this work will examine the impact that full-spectrum lighting has on the individual medically, psychologically, and in terms of employee productivity and effectiveness. In addition, by using full spectrum lighting, which produces a constant flow of power distribution as opposed to the regular neon lights that produce spikes and irregular power distribution of energy, the lighting system within the cubicle will be able to mimic natural sunlight very closely.

IMPORTANCE of STUDY

The importance of this study is that this problem is often overlooked and because most of corporate America spends a large portion of their days in front of computer monitor, it is important that this problem be examined and solutions sought in avoiding problems that arise from poor lighting in the office and workspace.

STATEMENT of THESIS

Poor lighting in the office or workspace has been overlooked for too long. The installation and implementation of a light systems that has a full spectrum of light capacity for the individual office cubicle will eliminate health problems for workers in both the long and short-term.

BACKGROUND of the STUDY

Traditionally the light source, reflector and ballast were that which comprised fluorescent luminaries. The most control generally offered to the user was perhaps a three-switch lamp setting allowing for three different levels of light but having only low, medium and high lighting options with nothing in the ranges in between the three. Contemporary lights is comprised of "new occupancy sensors, photocells, and infrared/RF controls are now being mounted in fluorescent fixture housings to allow 'fine tuning' of the lighting in an office space. With motion detectors and daylight sensors that are either remote-mounted or integrated into a luminaire housing, lights will dim and/or switch off when not needed. Depending on the technology selected, sensors may be programmed using an IR remote controller or administration software." (Knisley, 2005)

LITERATURE REVIEW

The work entitled: "Improve Employee Productivity with Custom Office Lighting" relates that federal and state energy legislation has made "energy-efficient lighting...[a] major component ion the effort to reduce the load and increase building energy savings. Since lighting accounts for more than 30% of electric energy use in offices, lighting control systems should be flexible enough provide the proper illumination for different tasks and respond to changing conditions within the space." (Knisley, 2005) the nature of today's workplace is described as one that is "exceedingly dynamic, with employees shifting among a variety of tasks during a typical day." (Knisley, 2005) Documents often contain very small print and even engineering drawings and other types of schematics and require high levels of lighting while meetings require medium levels of lighting with even a lower level needed for tasks at the computer. Individual requirements of light are different depending on the age of an individual, the vision of an individual, and individual preferences. Knisley relates that "quality light - illumination that can be described as comfortable in all office facilities - is important because it brings tangible returns. And that may include giving the light users more control." (2005) Knisley reports that new studies show that when individual workstation control is offered to employees specifically in terms of the level of light and thermal comfort that employees are more productive and more satisfied and that in fact employees are easier attracted and retained and have more financial success. It is important as noted by Knisley that any investment made in lighting has a solid ROI, or return-on-investment or in other words that the lighting system that will be invested in will have benefits enough to rise above the expenditure for purchasing and maintaining the system and in terms of more productive and happier employees. Knisley relates that comfortable and quality office lighting "can have a measurable effect on your bottom line." (2005) Harris Rothenberg LLC is a New York City-based performance-consulting firm, which replaces employee costs at a rate of: "...1.2 to 2 times their annual salary due to organization inefficiency while the position if vacant and the processing costs related to the new hire. The same research indicated that a new employee reaches maximum efficiency and performance after 13.5 months of employment." (Knisley, 2005) Knisley reports that in studies conducted in the office setting over a period of several years recently demonstrated that benefits of "having personal controls at the workstation.." (2005) a study published by the Light Right Consortium in 2003 states that both satisfaction and performance of workers is linked to individual workstation control. In the study reported by Knisley nine individuals who were "office workers in Albany, New York were subjected" to various lighting settings and then surveyed. Evaluation of the questionnaires showed "availability of lighting control in the workplace directly affected the workers' motivation on the job." (Knisley, 2005) This makes some corporations and organizations greatly desire to "pay premium for a personal lighting control" which enables employees to "tune the lighting according to changing tasks, their mood and the amount of daylight available. For these reasons, tailored lighting has the capacity to provide a significant return on investment." (Knisley, 2005) Contemporary light is comprised of "workspace-specific direct/indirect lighting provides both task and ambient lighting. The following is a depiction of workspace-specific direct/indirect lighting provides both task and ambient lighting.

Workspace-specific direct/indirect lighting provides both task and ambient lighting

Knisley (2005)

Currently there are two manufacturers of "...suspended linear florescent luminaire and a three-lamp direct/indirect luminaries is used to integrate occupancy sensing, daylight sensing and personal dimming which can be accessed remotely using a network communications system." The system is inclusive of "two four foot lamps and a program-start dimming electronic ballast (64 watts active power) providing the direct/task lighting."(Richman, 2008; paraphrased) Additionally an electronic ballast single T* lamp with 31 watts of active power comprises the component for indirect lighting. These types of lighting devices are referred to as a "workplace-specific luminaire, since a single unit can be installed over an employee's cubicle or private-office desk." (Knisley, 2005) This type of fixture is more costly than the standard T9 fluorescent luminaire and is one in which the designer is enabled to "achieve task-appropriate illumination with reduced energy use." (Knisley, 2005) Stated as typical for a 10 to 12-foot office is illumination is the following, which includes: "...a pair of two-lamp or three-lamp florescent troffers Assuming the use of T8 lamps and electronic ballasts, the power density will be about 1W to 1.5W per square foot. However, you'd only need to specify one three-lamp direct/indirect workspace-specific luminaire to achieve up to a 50% reduction in power density." (Richman, 2005) the report states that in the office area that is an open space that workplace-specific lighting has the capacity to bring about a reduction in the number of fixtures necessary as compared to spacing the fixtures in a uniform manner. Further, these type of lighting systems enable the building manager or engineer in tailoring specific patterns of sensor response. The example stated of this system is as follows: "Consider, for example, a typical situation during the work day: if the integral occupancy sensor of the workspace-specific luminaire doesn't detect movement at the cubicle desk directly below, the downlighting will automatically dim to off. Only the uplighting component of the luminaire remains on. Outside of the regular office hours, an occupancy sensor in the luminaire (or elsewhere in the open office) can be set to control both the uplighting and downlighting component of the suspended luminaire. The higher initial cost of a workspace-specific controllable luminaire is an important factor in a new or retrofit project. However, due to ease of installation and a reduction in the number of fixtures required, the luminaire can be price-competitive with a parabolic troffer system on an installed-cost basis and provide enhanced quality of illumination and appreciable energy savings over the system's life." (Knisley, 2005) Next examined are some of the individual control lighting system components that are separate lighting systems from the workspace-specific luminaire. One type of system allows the workers to control the overhead fluorescent lighting through a dimming control through use of a remote IR control that is handheld. This lighting component is connected by the "IR receiver/sensor to the dimming ballast...[which]...provides the control to change the lamp's lumen output." (Richman, 2005)

Another lighting system introduced by Knisley is one that "features a manual override of automated fluorescent lighting settings through use of a wall-mounted control, an infrared handheld remote control device, or a PC workstation." (Knisley, 2005) This system is capable of implementing natural daylight where available which is known as "daylight harvesting" and a strategy which utilizes "ceiling-mounted photocells to measure the changing contribution of daylight and then compares this light level to an established level of light in a room. The controller responds by dimming or brightening the fluorescent lighting to sustain the desired level. The controller is compatible only with specific manufacturer's electronic fluorescent dimming ballasts." (Knisley, 2008) Knisley describes yet another system which combines "fixtures, user controls, and digital communications and as an alternative to circuit enabling group control of fixtures the groups are established "by address and controlled with a group controller." (Knisley, 2005) Options for wall controls are in a range starting with very simple "group dimmers or broadcast controls to programmable scene controllers." (Richman, 2008) Control software for the computer that enables digital controllable ballasts in ceiling-mounted fixtures is also available. Included in system features is individual occupancy control of assigned fixtures, standard lighting control functions, logging of fixture operating levels and reporting of lamp and ballast failures." (Knisley, 2005) Richman states that Florescent lamp dimming that uses electronic ballast is accomplished in three ways as follows: (1) 0-10VDC analog, phase control analog, or digital control; (2) 0-10VDC - analog control system most commonly used presently and has a group of fixtures that are connected to the control circuit to receive the same command signal, allowing the control to extend beyond a single power circuit layout; (3) Phase control technology - Richman states that this is ideal 'for an architectural lighting scheme in a smaller space, such as a conference room or an individual office.' Generally, a phase control dimming ballast uses the same pair of conductors for power and control, thus providing for a simple cost-effective retrofit where control from a single location is desired; and (4) Digital Control System - this send digitally encoded pulse signals free from noise or radio frequency interference and improves the reliability of signal and control flexibility. (Richman, 2005)

The Lighting Research Center states that full-spectrum lighting describes electric light sources "that simulate the visible and ultraviolet (EV) spectrum of natural light." (2005) the Lighting Research Center states that full-spectrum is "not a technical term, but rather a marketing term implying a smooth and continuous spectral power distribution (SPD) without the spikes and troughs in radiant energy common with most discharge light sources. Full-spectrum products are usually marketed as electric light sources that emulate natural daylight; the explicit or implicit message is that 'natural' daylight is always better than 'artificial' electric light. Some full-spectrum light sources are also marketed as emitting ultraviolet (UV) radiation, as well as visible." The following figure demonstrates the SPDS of two electric light sources claimed to be full-spectrum, the Duro-Test Vita-Lite 5500 fluorescent lamp and GE Reveal 60W incandescent lamp, as well as daylight at 5500K correlated color temperature (CCT). Daylight has smooth SPD without sharp spikes or dips, whereas the claimed full-spectrum lamps that have SPDs that differ form daylight and from each other." (2005)

Spectral Power Distribution Comparison

Lighting Research Institute (2005)

Because the full-spectrum lighting is much more costly than others it is important that benefits be understood from using this type of lighting system. The Lighting Research Institute states the following benefits from full-spectrum lighting:

Improves color perception;

Improves visual clarity;

Improves mood;

Improves productivity

Improves mental awareness

Improves retail sales

Improves plant growth

Improves results of light therapy in treating seasonal affective disorder (SAD)

Improves results of light therapy for sleep disorders

Improves scholastic performance of students

Improves vitamin D synthesis in the body

Reduces incidence of dental decay (Lighting Research Institute, 2005) survey was conducted by the Lighting Research Institute in 2003 in order to assess "252 lighting specifiers, including electrical contractors and facility managers were asked 'Compared to other types of lighting, please indicate how you think full-spectrum light sources impact the following..." As shown in the following figure.

Perceived Benefits of Full-Spectrum Light Sources Among Lighting Specifiers

Lighting Research Institute (2005)

The respondents to the survey supported full-spectrum lighting benefits with fifty percent claiming that this type of lighting system had a positive effect and positive response was given by eighty-six percent who responded positively to color perception benefits. Dental health was stated to have positive effects by less than twenty percent of respondents in the survey. Across the range of benefits only a mere four percent of respondents claimed some type of negative impact. Overall, full-spectrum lighting is being adopted and the industry is thriving according to the Lighting Research Institute." (Lighting Research Institute, 2005) the Lighting Research Institute states that visual performance is not actually improved using full-spectrum lighting "under most circumstances" therefore "lumen for lumen...full spectrum light sources are...no better than any other light source." However, it is related in the report that full-spectrum lamps may provide the perception of "brighter architectural spaces than other lamps." (Lighting Research Institute, 2005) This is attributed to the high correlated color temperature (CCT) of 5000K - 7500K of the full-spectrum lighting sources. Further, the full-spectrum light has "color rendering properties meaning that surface colors will appear more saturated. Greater saturation will also give the impress of greater brightness." (Lighting Research Institute, 2005) Finally the full-spectrum florescent lamps produces UV radiation that has a "fluorescing, brightening effect on textiles and paper that have been treated with whitening agents. These combined effects on brightness perception may indeed have positive impact on building occupants, but greater perceived brightness can also be a liability, depending upon the expectations of the space's occupants." (Veitch and McColl, 2001; as cited by the Lighting Research Institute, 2005) Full spectrum light is also stated to not provide health benefits because research conducted recently has provided empirical evidence of circadian cycles in the sleeping and waking cycle of the human being which involves mental awareness, mood and immune system effectiveness all linked to daily patterns of sleeping and waking. The Lighting Research Institute states: "Light is the most important environmental stimulus for regulating these circadian cycles and synchronizing them to the solar day. Short wavelength (blue) light is particularly effective at regulating the circadian system; long wavelength (red) light is apparently inconsequential to the circadian system. Thus, to maximize efficiency in affecting the circadian system, a light source should not mimic a full spectrum, but instead should maximize only short wavelengths. Even if a full-spectrum light source includes short wavelength light in its spectrum, it will not necessarily ensure proper circadian regulation because, in addition, the proper intensity, timing, and duration of the light exposure are all equally important for satisfactory circadian regulation..." citing Rea et al. (2002). However, the psychological benefits to full-spectrum lighting are noted significantly and "particularly in societies that place value on 'natural' environments." The benefits of individual control systems allow individuals in different "latitude are relating to: "...latitude, time of day, season, and so forth" to accommodate the day as natural light does not have a fixed spectrum. Psychological benefits include positive affect in individuals relating to mood and motivation realizing an increase in employee productivity and retail sales. While these benefits are noted there has not been found to be a "...biophysical explanation for these observations" (Heschong, Wright and Okura, 2000; as cited in Lighting Research Institute, 2005) Even so, the Lighting Research Institute states the following: "Still, the power of psychological associations cannot be denied and it is certainly conceivable that cleverly marketed full-spectrum light sources may provide beneficial effects to some people susceptible to that marketing. As NLPIP's survey demonstrated, there appears to be a strong positive association with full-spectrum light sources that has resulted from marketing, presumably because of the association between full-spectrum lighting and "natural" light." (Lighting Research Institute, 2005) Harmful effects are noted in the Lighting Research Institute series which is interestingly that there is no harm caused the human by UV radiation in ultraviolet lighting but architectural items such as materials and cloth are notably affected by UV lighting. In terms of how one would identify the most effective full-spectrum lighting source, the Lighting Research Institute states: "Formally then, the proposed reference full-spectrum light source is an ideal light source with equal energy across the visible region of the spectrum, from 380 to 730 nm, inclusive." (Lighting Research Institute, 2005)