Facilities management paper
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ZemkeCh8PPT.pptxLighting Systems
Chapter 8
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What is light?
Light is classified as a form of radiant energy
Infrared & ultraviolet waves, microwaves, X-rays, radio waves, gamma rays, etc.
Each type of radiant energy various in frequency range and wavelength
The electromagnetic spectrum is the term used by scientists to describe the entire range of light that exists. From radio waves to gamma rays, most of the light in the universe is, in fact, invisible to us.
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Electromagnetic Spectrum
Energy waves in 380-780 nanometer range visible to the human eye.
All other light falls above or below the visible spectrum
Color is a light wavelength that is not absorbed by an object
Ex: a red apple absorbs all color wavelengths except the one displaying red color
White is visible when an object reflects all color wavelengths and black when an objects absorbs all color wavelengths.
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Above & below the visual spectrum
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What does good lighting provide?
Safety and security
Aesthetics and décor
A sense of welcome and hospitality
Facilitates employee productivity
Reduces fatigue; increases well-being
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Types of lighting
General lighting: ambient light allows people to see space and move through it
Task lighting: targeted lighting, assist with specific task
Accent lighting: highlight objects or areas, provides corrct color to maintain design integrity
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Lighting principles & factors
PRINCIPLES
Identify and meet target light levels
Efficiently produce light
Efficiently deliver light
Balance efficiency with aesthetics, lighting quality & visual comfort
FACTORS
Quantity Quality
Amount of light required in FC Color Rendering Index –CRI
Efficacy in lumens/watt Color temperature in Kelvins
Lumen output of lamps & fixtures Types of light sources
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Lighting terminology
Many technical terms in lighting mean something else outside of the industry; you should know the technical terms when discussing lighting
Lamp =
Lamp Life: Hours that 50% of the same type of lamp will burn before failing (burn-out). Rated life is measured in burn hours (hours of actual use)
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Terminology (cont.)
Fixture / luminaire =
Lumens/lux = a unit of light, brightness, amount of light emitted
Foot-candles (fc) = luminance (brightness) at the surface of object being lit, measured with a meter
consensus standards for light levels set by the Illuminating Engineering Society (IES).
Footlamberts = amount of light the eye actually registers
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Efficacy
Efficiency of the light source/lamp. Measured by lumens/watts (output/input)
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Update
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Color rendering index (CRI)
A measure of how well an artificial light source (lamp) shows and object’s color
Benchmarked against sunlight’s color rendering ability, which is 100 -- perfect!
The closer your lamp’s CRI is to 100, the better
The lower the CRI, the muddier or duller the colors will appear
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CRI
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Correlated color temperature (CCT)
Describes the color of the lamp when it is lit
The color is compared, or correlated, with the color of a piece of black metal when it is heated
Described as the temperature the metal will turn as it continues to heat up expressed in Kelvins (not Celsius or Fahrenheit)
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How CCT affects spaces
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How does CCT affect appearance?
Lower CCTs will appear “warmer”, but are a lower temperature
Higher CCTs will appear “cooler”, but are a higher temperature
Affects the mood or ambience of the space
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CCT: Color and brightness
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A higher CCT does not automatically increase brightness (lumens), especially when the same type of lamp is used.
The higher the degrees Kelvin, the whiter the color temperature. The lights will appear "brighter" than those of a lower Kelvin, the amount of lumens do not change, brightness is not affected.
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Types of lamps
Incandescent
Conventional
Tungsten-Halogen
Electric discharge lamps:
Fluorescent
High intensity discharge (HID)
Light emitting diodes
(LEDs)
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Incandescent: traditional and halogen
Traditional “light bulb” that was developed by Thomas Edison
Glass bulb, commonly containing a metal, most commonly tungsten, filament in an oxygen-free (vacuum) environment
Filament has high electrical resistance (ohms), so it gets hot when electricity tries to pass through it; glows
Tungsten-halogen (a.k.a., halogen) puts the filament into a halogen-filled capsule to create brighter light
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Incandescent
Tungsten-halogen
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Incandescent (traditional)
Pros
Great light quality; CRI = 100!
Can be:
Focused
Dimmed
Operated in a wide variety of temperatures
Instant strike time
“Sparkle”
No special disposal
Cons
Low efficacy; most energy going in is emitted as waste heat, not light
The waste heat increases our cooling costs
Short lamp life; increases material and labor costs
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Incandescent (tungsten-halogen)
Pros
Very similar to traditional
CRI=100
CCT low-mid
easy disposal
instant strike
Better than traditional
efficacy
life
Great for highlighting or accenting objects
Cons
More expensive than traditional
Focused, no diffuse light
Excessive heat
increase heat load
can explode
Fire hazard
Lower initial cost than LEDs or CFLs, but lower long-term savings
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Incandescent (cont.)
General purpose incandescent lamps are being phased out by manufacturers
Many governments are banning production, due to poor energy efficiency
Specialty lamp shapes are still on the market at this time, but may phase out eventually
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Electric discharge lamps – fluorescent and HID lamps
Lamps use a glass tube/globe filled with an inert gas
Electric arc is created by a ballast, then shot into the lamp
The arc excites the inert gas, as well as a small blob of mercury (Hg)
These in turn bounce against the lamp’s walls. Fluorescent lamps are coated with phosphors, which glow when the gas and mercury vapor hits them
Phosphors create the color temperature
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Fluorescent initial start
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Fluorescent (linear)
Pros
Much more energy efficient than incandescent
Generates less waste heat, which reduces cooling costs
Longer lamp life than incandescent; reduces material and labor costs
Cons
Must be disposed of as hazardous waste
Lower CRI, lower light quality than incandescent
Usually cannot be:
Focused
Dimmed
Operated in very high or low temperatures
Emits ultraviolet (UV) rays
No “sparkle”
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Fluorescent (CFL)
Pros
Similar with linear vs. incandescent
more efficient
less waste heat
longer life, reduced cost
Internal ballast
direct replacement for incandescent
Cons
Similar with linear
hazardous waste
lower CRI
Fragile
Dimmable
reduced life
“drop-out”
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High intensity discharge (HID)
High-pressure sodium vapor
Low-pressure sodium vapor
Metal halide
Similar technology to fluorescent, but more energy efficient, high lumen output (brighter) and longer lamp life
Usually used in outdoor (street, parking, stadium) applications or indoor in large areas with high ceilings (arenas, exhibit halls, big box stores, warehouses)
Relatively low CRI; use where color rendering is not critical
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HID technology
Many configurations, shapes, sizes,
wattages, lumens, etc.
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High/low-pressure sodium vapor
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Sodium burns with a yellow color
Poor CRI: ≈ 20
Efficient: 64-133 lm/w
Long lamp life approx. 16,000-24,000 hrs
Rarely if ever used indoors
streets, parking area
Quickly being replaced with LED
Low-pressure
Some industrial use
Higher levels of mercury
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Metal halide
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Electric arc ignites argon and mercury gases
Variety of CRI’s, up to approx. 90
Various CCT options
Approx. 75 lm/w
Uses
big box retail stores
public spaces, high-ceilings
stadiums, arenas,
Some require enclosed fixtures, breakage upon failure
Emerging market for LED
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Light Emitting Diodes (LED)
Technology has been around since the 1960’s
Rapidly replacing incandescent and electric discharge lamp technology
Light is generated using a semiconductor chip (diode)
Requires a driver to control it (just like your computer does)
Very energy efficient – almost all energy that goes in is emitted as light; very little waste heat
If you detect heat, it is probably generate by the driver, not the diode itself
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LED evolution: selection, style, applications
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LED (cont.)
Pros
Very energy efficient
Little waste heat; reduces cooling costs
Does not require a glass bulb; can use plastic!
Can achieve CRI up to 93
Wide variety of CCTs
Can program driver to change color
Extremely long lamp life
No UV emissions
Cons
Sensitive to electrical “noise”
color shifting
flickering
Driver generated heat
adequate ventilation
enclosure, self-contained
early failure
Material cost is still high, but reducing each year
Reduced “wash”, directional
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Hospitality “sweet spots” for lighting
Many designers now specify lighting CCTs for front-of-house areas in the 2700K – 2800K
Provides a warm, hospitable glow
Back-of-house areas often have a higher CCT (cooler ambience) to increase the employee’s energy and productivity
Fast-food restaurants have long employed a “cheap and cheerful” lighting scheme with higher CCTs
Believed to move guests through the seating area faster
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Hospitality lighting CCT “sweet spot”
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2,700K-2,800K
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Choosing the right lamp – you should consider:
QUANTITATIVE
lamp/fixture cost
energy cost/efficacy
labor cost
location-difficult to access
lamp life
disposal cost
temperature conditions
QUALTATIVE
CRI: importance in lit space?
CCT-desired ambience
dimmability
light “wash”
lumen output (desired brightness)
sparkle
strike time
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Maintaining your lighting systems
Group relamping programs
You might waste a tiny part of a “perfectly good lamp”, but save a ton of money in labor costs!
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Relamping Exercise: Spot relamping
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Assumptions
Large hotel
Labor rate (hourly/benefits) = $30.00/hour
Time to change 1 lamp = 30 minutes (actual time & travel)
Lamp cost = $4.00 per lamp
Scenario: Management only replaces lamps as they burnout, regardless of the frequency. Answer these questions.
1. What is the labor cost to change 1 lamp?
2. Total cost (labor + material) to replace 1 lamp?
3. Total cost to replace 100 lamps using this maintenance practice?
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Relamping Exercise: Group relamping
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Assumptions
Same labor rate material cost as spot relamping
5 minutes to change each lamp (move lift/ladder, clean fixture)
Relamp at 80% of lamp life
Scenario: Management has a group relamping policy that is implemented when lamps are at 80% of rated life. Answer these questions.
1. What is the labor cost per lamp?
2. Total cost (labor + material) to replace 100 lamps?
3. What is the cost of the remaining 20% lamp life?
4. Which practice (spot vs. group relamping) is most economical?
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Cleaning lamps and fixtures
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Dirt & dust can:
increase internal heat; shorten lamp life
decrease light omitted
increase risk of fire
present an unclean/neglected appearance
Schedule
usually 4 times per year
Special considerations/solutions
lamps produce electrostatic charge that attracts dust
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Specification and purchasing practices to maintain design integrity
purchasing policies
specification reviews
vendor requirements
same or equal, not similar
availability
order lead time
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Current trends
Programable lighting
Wi-Fi
Daylighting
Technical Memorandum-30
(TM-30)
use/incorporate several factors
to establish light quality
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