Airport Parking Garage Lighting Solutions (2015)

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2State of the Art in Lighting Technologies Electric lighting technology is over a century old, and the industry is constantly changing. From incandescent to fluorescent, from high intensity discharge to light-emitting diodes, the range of lamp options is vast. Lamp technologies have been evaluated and compared before now, but not with respect to airport garage lighting. Airport garages require lighting that has high levels of vertical illuminance, low glare, energy efficiency, and controllability. Here, various lamp technologies are described and evaluated based on how well they can be applied to airport garage lighting. 2.1 High Pressure Sodium (HPS) HPS lamps have been used for indoor and outdoor parking lighting, as well as most other exte- rior lighting applications, for the last 20 years. The lamp is a high intensity discharge (HID) lamp that excites sodium, contained in an arc tube, to produce light. Current regulation to the lamp is produced with an induction ballast. HPS lamps are available in a very wide range of wattages and lumen outputs and are considered one of the highest-efficiency HID sources. An example of an HPS lamp is shown in Figure 1. Lamp envelopes are available either as clear or coated, with clear being the most common. HPS lamp light is yellow-gold, and it has a low color rendering index (CRI), so people tend to find it difficult to distinguish colors in areas lit with HPS lamps. The performance metrics of an HPS lamp typically used for parking structures and lots, an Osram-Sylvania Lumalux Ecologic lamp, are shown in Table 1. The data are from a range of Osram-Sylvania lamps, LU50/ECO to LU400/ECO. Factors to be considered with HPS lighting include: Temperature: There are no ambient temperature concerns with HPS lamps. Lumen maintenance: The lumen depreciation of HPS lamps is good, with the output declin- ing to approximately 75% to 84% of initial lumens by the rated end of life, as shown in Figure 2. Fixture efficiencies: Because HPS arc tubes are relatively small, allowing for better reflector designs, this light source it is considered fairly efficient at directing the lamp lumens to the sur- faces requiring lighting. Controllability: HPS sources have a warm-up and a restrike time. The restrike time is a con- sequence of the lamp, once turned off, needing to be cool before the arc can be re-established. A typical lamp takes three to four minutes to stabilize from a cold start and about one minute to restrike after momentary power interruptions. This makes HPS unsuitable for switching requir- ing instant startup. There are, however, dimming systems that can be used with HPS lamps, offering some suitability for adaptive control systems. C H A P T E R 2

State of the Art in Lighting Technologies 3 Figure 1. Example high pressure sodium lamp. Source: http://en.wikipedia.org/wiki/Sodium-vapor_ lamp#mediaviewer/File:SON-T_Master_600W.jpg Lamp lumen/watt 80 to 125 System Efficacy lumen/watt 61 to 107 Rated Life (based on 35% mortality) 30,000 hrs Rated Life (based on 70% lumen output) 30,000 hrs Correlated Color Temperature (CCT) 1900K to 2100K Color Rendering Index (CRI) 22 Source: Data from Osram-Sylvania technical specifications, compiled by Parsons Brinckerhoff Table 1. Lamp characteristics: high pressure sodium. Figure 2. Lumen maintenance of typical high pressure sodium lamp. Source: Compiled by Parsons Brinckerhoff.

4 Airport Parking Garage Lighting Solutions 2.2 Ceramic Metal Halide (MH) MH sources have been one of the key alternative HID options to HPS lamps when white light is desired. In the past, MH lamps were considered fairly efficient, but they had a much shorter rated life than HPS lamps. MH lamps also had other drawbacks, including color shifts during their operating life and some failure issues. However, developments in ceramic metal halide technology have considerably increased the lamp’s efficiency and life. A typical MH lamp is shown in Figure 3. The performance metrics of typical MH lamps for parking structures and lots are shown in Table 2. Data are from a range of Philips MasterColour Elite lamps. Factors to be considered with ceramic MH lighting include: Temperature: There are no ambient temperature concerns with metal halide lamps. Lumen maintenance: The lumen depreciation of ceramic MH lamps is quite low, with the output declining to approximately 90% of rated lumens by 16,000 hours, as shown in Figure 4. Fixture efficiencies: Because an MH lamp is relatively small, allowing better reflector design, it is considered fairly efficient in directing the lamp lumens to the surfaces requiring lighting. Controllability: MH sources have a warm-up and a restrike time. A typical lamp takes 1.5 to 2 minutes to stabilize from a cold start and about 10 minutes to restrike after momentary power interruptions. This makes MH unsuitable for switching required by instant startup operation. There are, however, dimming systems that can be used with MH lamps, offering some suitability for adaptive control systems. Figure 3. Example ceramic metal halide lamp. Source: http://en.wikipedia.org/wiki/Metalhalide_ lamp#mediaviewer/File:150_Watt_Metal_Halide.jpg Lamp lumen/watt 105 to 120 System Efficacy lumen/watt 100 to 111 Rated Life (based on 50% mortality) 24,000 hrs Rated Life (based on 70% lumen output) 24,000 hrs Correlated Color Temperature (CCT) 3000K to 4200K Color Rendering Index (CRI) 90 Source: Data from Philips MasterColour Elite lamps technical specifications, compiled by Parsons Brinckerhoff Table 2. Lamp characteristics: ceramic metal halide.

State of the Art in Lighting Technologies 5 2.3 Fluorescent Lamps (FL) Linear fluorescent lamps have often been used for parking garage lighting. The sources have long lives, are efficient, and sometimes offer instant on/off and some degree of dimming in low brightness, white light sources. Example FL lamps are shown in Figure 5. The performance metrics of a typical FL lamp used in parking lots, an Osram-Sylvania T8 reduced mercury 4-ft lamp, are shown in Table 3. The data are from a single Osram FO32/800/ XPS/ECO3 lamp. Factors to be considered with fluorescent lamps include: Temperature: Depending on the ballast and lamp type, there are limitations to the tempera- tures at which an FL lamp will effectively start. The example shown in Figure 6 uses programmed rapid start ballast, and its minimum starting temperature is -18°C (0°F). For some energy-saving Figure 4. Lumen maintenance of typical metal halide lamp. Source: Compiled by Parsons Brinckerhoff. Figure 5. Example fluorescent lamps. Source: http://en.wikipedia.org/wiki/Fluorescent_ lamp#mediaviewer/File:Leuchtstofflampen- chtaube050409.jpg

6 Airport Parking Garage Lighting Solutions lamps, the starting temperature can be as high as 16°C (60°F). In addition, FL lamps have dif- ferent outputs depending on temperature. Fluorescent lamps in the T8 (one inch diameter) cat- egory are usually rated for a 25°C (77°F) ambient temperature. Temperatures above and below this rated temperature produce fewer lumens than the lamp rating. Temperature around the lamp inside the fixture (luminaire) is dependent upon fixture design, but in garage installations, output will be less in periods of severe cold or heat. Lumen maintenance: The lumen depreciation of many linear fluorescent lamps is quite favorable, as shown in Figure 7. The Octron XPS lamp will maintain approximately 94% of its initial lumen output throughout its rated life. Fixture efficiencies: Because linear FL sources are large, FL luminaires are generally not con- sidered highly efficient in directing the lamp lumens to the surfaces requiring lighting. However, the large size considerably reduces glare. Controllability: Linear FL sources are instant-on, requiring neither strike nor extended warm- up time. They can also be dimmed using dimming ballasts. The programmed start ballasts used in many of these fixtures are often rated for more than 100,000 switching cycles, making FL lamp technology amenable to frequent power cycling required by daytime and occupancy controls. Lamp lumen/watt 97 System Efficacy lumen/watt 85 to 98 Rated Life (based on 50% mortality) 40,000 hrs Rated Life (based on 70% lumen output) 40,000 hrs Correlated Color Temperature (CCT) 3000K to 6500K Color Rendering Index (CRI) 81 to 85 Source: Data from Osram-Sylvania technical specifications, compiled by Parsons Brinckerhoff Table 3. Lamp characteristics: fluorescent. Figure 6. Ambient temperature-to-output relationship for fluorescent lamps (range is from 41F to 131F). Source: Compiled by Parsons Brinckerhoff.

State of the Art in Lighting Technologies 7 Despite having good CRI, FL lamps had the lowest rating for color recognition in an airport garage patron survey. As with the results for HPS lamps, few survey respondents means that these surprising results are not robust. 2.4 Induction Fluorescent Lamps (IFL) IFL lamps are a fluorescent-based technology using a magnetic-induction coil, as opposed to electrodes, to excite the lamp phosphors and generate light. This greatly extends the expected life of the lamp. Example light sources are shown in Figure 8. Various wattages and envelope types are available from different manufacturers. All of the wattages can be used in a parking garage installation. Figure 7. Lumen maintenance of typical fluorescent lamps. Source: Compiled by Parsons Brinckerhoff. Figure 8. Example induction fluorescent lamps. Source: http://en.wikipedia.org/wiki/Electrodeless_lamp

8 Airport Parking Garage Lighting Solutions The performance metrics of typical IFL lamps used in parking garages are shown in Table 4. Factors to be considered in the use of induction fluorescent lamps include: Temperature: Starting temperatures for IFL lamps are quite low, ranging from -32°C (-25°F) to -40°C (-40°F), depending on lamp wattage. Lamp output does vary with temperature, but in a properly designed and enclosed fixture, IFL lamps are suitable for cold-weather operation. Amalgam tip covers are also available to provide faster warm-up under very cold operating conditions. Lumen maintenance: The lumen depreciation of IFL lamps is fair, with the output declining to approximately 64% of rated lumens by the rated end of life, as shown in Figure 9. If the lamp life was rated in terms of L70 (the number of hours before the lamp output is expected to decline to 70% of rated lumens) like LED sources, the life would be rated at approximately 60,000 hours instead of 100,000 hours. Fixture efficiencies: Because IFL lamps are large, they are generally not considered highly efficient in directing the lumens to the surfaces requiring lighting. Controllability: IFL lamps are instant-on, requiring neither strike nor extended warm-up time. So, like FL lamps, they are amenable to controllers that turn the lamps on and off depend- ing on daylight and the presence of patrons. Figure 9. Lumen maintenance of typical induction fluorescent lamps. Source: Compiled by Parsons Brinckerhoff. Table 4. Lamp characteristics: induction fluorescent. Lamp lumen/watt 63 to 84 System Efficacy lumen/watt 63 to 84 Rated Life (based on 50% mortality) 100,000 hrs Rated Life (based on 70% lumen output) 60,000 hrs Correlated Color Temperature (CCT) 3500K to 5000K Color Rendering Index (CRI) 80 Multiple sources, compiled by Parsons Brinckerhoff

State of the Art in Lighting Technologies 9 2.5 Light-Emitting Diode (LED) LEDs have made significant strides in recent years, becoming one of the strongest options for parking garage and lot lighting. LEDs are robust and have a long life, reducing maintenance costs. Single LEDs are small, allowing for excellent optical control, and the driver used to ener- gize the LED is dimmable and digitally controllable. Each LED has relatively low light output and low power requirements. In lighting applications, single LEDs can be arrayed in bars, strips, or fields to provide efficient illumination. Example LEDs are shown in Figure 10. LEDs have drawbacks, however, including sensitivity to heat, reduced efficacy when driven at operating current, and a high initial cost compared to other lamp types. Also, because individual LEDs are so small, they must be carefully combined with optics in a luminaire to prevent glare. Phosphor-based broadband LEDs have more blue output than other lamp types, but they have less output in the green spectrum, leading to color identification challenges. The U.S. Depart- ment of Energy (DOE) is funding research to address this “green hole” in the near term, so the problem might be solved two to four years after this guide is published. LED technology is developing at a rapid pace; there are a large number of chip designs, and LEDs consume much less electricity than other lamp types. Performance metrics of LED lumi- naires typically used in a parking garage installation are shown in Table 5. The data are from CREE “Xlamp” LED series. Factors to be considered in the use of LEDs include: Temperature: LEDs decrease in lumen output as the semiconductor’s temperature rises (junc- tion temperature). LED lumen output ratings are based on 25°C (77°F), depending on the current energizing the LED. Exposure to heat not only reduces the output of an LED, but it also has a cumulative effect on an LED’s lifetime. For example, a CREE XP-G LED is rated at 70% lumen out- put at 50,000 hours, if the junction temperature is less than 80°C (176°F), as shown in Figure 11. Above about 85°C (185°F), the lifetime drops sharply. Junction temperatures of >70°C (158°F) are not uncommon, so heat dissipation is a crucial part of LED circuit and luminaire design. Figure 10. Example LEDs. Source: http://commons. wikimedia.org/wiki/File:Verschiedene_LEDs.jpg Lamp lumen/watt 100 to 140 System Efficacy lumen/watt 80 to 100 Rated Life (based on 70% light output) 100,000 hrs Correlated Color Temperature (CCT) 3500K to 6000K Color Rendering Index (CRI) 70 to 80 Source: CREE Xlamp technical specifications, compiled by Parsons Brinckerhoff Table 5. Lamp characteristics: LED.

10 Airport Parking Garage Lighting Solutions Lumen maintenance: The lumen depreciation of an LED lamp is low. LED lamps main- tain more than 95% of their lumens through the first 10,000 hours of operation, but deprecia- tion increases at an accelerated pace after about 35,000 hours, depending on temperature and amperage. Fixture efficiencies: Individual LEDs are directional and efficiently direct light away from the luminaire, unlike HID, FL, and IFL lamps, which are omnidirectional. Secondary optics have improved LED-lamp efficiency (85% to 95%) as well, because reflector design is very effective with point-source LEDs. Controllability: LED sources are instant-on, requiring neither strike nor extended warm-up time. Glare: LED sources have been found to be about twice as likely than other technologies to be identified as glaring. Therefore extra care should be taken to minimize the effect. 2.6 Organic Light-Emitting Diode (OLED) OLEDs are flexible, transparent, and glare-free, allowing for a number of creative luminaire designs. OLED technology is ideal for decorative lighting and applications where light is inte- grated into the built environment. A possible garage application would be an array of OLED modules creating a luminous ceiling over a walkway. OLEDs are not well suited for parking garage applications, though, because they have very low efficiency and very high cost. An OLED example is shown in Figure 12. OLED components will need to be integrated into luminaire design before they are useful for area lighting. Even though the layers of the substrate can be applied homogeneously to pro- duce extremely uniform brightness, OLEDs are sensitive to water exposure. As a result, OLED luminaires used in exterior applications need to be encased in glass, increasing their veiling luminance. Figure 11. Example LED lifetime and junction temperature (range is from 176F to 320F). Source: Philips Lumileds technical specifications

State of the Art in Lighting Technologies 11 Performance metrics of an OLED lamp are shown in Table 6. The data are from an OSRAM ORBEOS component and module. Factors to be considered in the use of OLEDs include: Temperature: OLED lifetime is a function of the operating temperature. For each 10°C rise above room temperature, an OLED loses 31% of its useful life. Because OLEDs are housed in clear flexible substrates, heat sinking is limited, and luminaires with OLEDs largely depend on natural air convection to maintain temperature. Lumen maintenance: Light output is believed to be constant until the OLED fails. Fixture efficiencies: OLED lighting is made up of large panels producing diffuse, uniform light; therefore, it is not highly efficient in directing the lamp lumens to the surfaces requiring lighting. Controllability: OLEDs are instant-on. Dimming increases efficiency in both lumen output and life expectancy because it reduces an OLED panel’s core temperature. Figure 12. Example OLED lamp. Source: http:// commons.wikimedia.org/wiki/File:OLED_ EarlyProduct.JPG Lamp lumen/watt 40 to 60 System Efficacy lumen/watt 23 Rated Life (based on 70% light output) 10,000 to 20,000 hrs Correlated Color Temperature (CCT) 2900K to 3300K Color Rendering Index (CRI) >80 Source: OSRAM ORBEOS technical specifications, compiled by Parsons Brinckerhoff Table 6. Lamp characteristics: OLED.

12 Airport Parking Garage Lighting Solutions 2.7 Light Emitting Plasma (LEP)/Plasma Lamp LEP lamps, also known as plasma lamps, have the longevity of LED lamps and the high effi- cacy of point-source optics. Unlike LEDs, plasma lamps are full-spectrum and do not require phosphor coatings. Used as grow-lights, high mast lights, and warehouse lighting, plasma lamps have a high lumen density (12,000 lm to 23,000 lm) and directional nature that may make them too bright and glaring for low-bay or parking garage luminaires. A plasma lamp is shown in Figure 13. The chief advantage of an LEP lamp over an HID, FL, or IFL lamp is the LEP’s highly direc- tional “puck” that emits the light, improving fixture efficiency to as high as 90%. The full- spectrum output also provides increased mesopic/scotopic illuminance, greatly increasing nighttime visibility. Various plasma lamp wattages are available from different manufacturers. Performance speci- fications for a plasma lamp likely to be used in a parking garage are shown in Table 7. Data are from a LUXIM 160W STA-25-03. Factors to be considered in the use of LEP/plasma lamps include: Temperature: At ambient operating temperatures above 45°C (113°F), driver reliability is reduced. At temperatures below -40°C (-40°F), start time is longer than is usually acceptable in a garage-lighting application. Lumen maintenance: Light output is relatively steady, dimming throughout life with an LM70 of 50,000 hrs as shown in Figure 14. Figure 13. Example plasma lamp. Source: LUXIM. Lamp lumen/watt 75 System Efficacy lumen/watt 75 Rated Life (based on 70% light output) 50,000 hrs Correlated Color Temperature (CCT) 5200K Color Rendering Index (CRI) 75 Source: Data from LUXIM 160W STA-25-03 technical specifications, compiled by Parsons Brinckerhoff Table 7. Lamp characteristics: LEP/plasma lamp.

State of the Art in Lighting Technologies 13 Fixture efficiencies: Because plasma lamps are highly directional, they have optimal light distribution with minimal loss. Controllability: Start time at 25°C (77°F) is 30 seconds. The lamp does not need to cool down, and restrike is also 30 seconds. 2.8 Lamp Technology Summary A summary of the light source and luminaire technologies is shown in Table 8. Figure 14. Lumen maintenance of typical plasma lamp. Source: Compiled by Parsons Brinckerhoff. SOURCE COMPARISON SUMMARY Lm/W - Source Lm/W - System Life - 70% lumen output (LM70) Color Temp. Color Rendering Index System Cost - Relative FL 97 85–98 40,000 hr 3000K–6500K 81–85 $ IFL 63–84 63–84 60,000 hr 3500K–5000K 80 $$$ HPS 80– 125 61–107 30,000 hr 1900K– 2100K 22 $$ MH 105– 120 100– 111 24,000 hr 3000K– 4200K 90 $$ LED 100– 140 80–100 100,000 hr 3500K– 6000K 70–80 $$$ OLED 40–60 23 10,000 hr– 20,000 hr 2900K– 3300K >80 N/A LEP 75 75 50,000 hr 5200K 75–95 N/A Source: LUXIM, CREE, Osram-Sylvania, and Philips technical specifications, compiled by Parsons Brinckerhoff Table 8. Summary of light source characteristics.