Light Concept Flashcards
Range of all types of electromagnetic radiation
Electromagnetic spectrum
Energy in the form of waves, including gamma rays, x rays, UV, visible light, IR, microwave, and radio waves
Classified by wavelengths using nanometers
Electromagnetic radiation
Distance between two points on a wave in which the wave repeats itself
Wavelengths
Wavelengths range from
400 nanometer to 700 nm
Can cause skin and eye damage
UV light
Can cause air or objects to heat up, raise building temp
Infrared
Great source of illumination with positive effect on health
• too much can cause glare and affect visual acuity
Natural light
Converts electrical energy into light
Lamp
Complete lighting unit that includes the components that distribute light, position, and protect the lamps ,and provide connection to power supply
Luminaire
4 types of lamps
Incandescent
Fluorescent
High intensity discharge (HID) lamps
LED light emitting diode
lamp that produces light by flow of current through tungsten
Low cost, but low electrical efficiency and shorter life than other lamps
Incandescent
Low pressure discharge lamp where mercury vapor transforms UV light to visible light
Contains mixture of inert gas (argon and mercury vapor), provides UV light
Fluorescent Light
Produces light from an arc tube
High Intensity Discharge Lamps
Light producing element of an HID light
Arc tube
Contains metallic and gaseous vapors and electrodes
Includes in a bulb, may include phosphor that improves color rendering, increases light output, and reduces surface brightness
Types include low pressure sodium, mercury vapor, metal halide and high pressure sodium lamps
Arc tube
Lamp with semi conductor devices that produce visible light when current passes through them
LED Lamp
Benefits of LED Lamp
- Uses less energy and generate less heat
- Some contains combination of red green and blue
- This combination allows a fixture to be tunable, the color of light can be changed via external control
3 types of lighintg
Ambient lighting
Task lighting
Accent lighting
Known as general lighting, main source of nonspecific illumination of the space
Bright enough to allow safe movement
Should be integrated with daylight control system to maintain proper light levels in spaces
Ambient lighiting
Used to illuminate an area in order to allow the performance of a specific function
Often controlled by building occupants
- Level of control may be mandated by building codes
- Can reduce the glare on reflective surfaces, reducing eye strain and increasing productivity
Task Lighting
Decorative lighting, used to highlight architectural or design features of space
Generally small percentage of the lighting load but may be used to influence a positive effect on visual acuity and occupant health
Accent lighting
color of light produced by light source
color temperature
spectral distribution of EM radiation measured in Kelvin
correlated color temperature CCT
Lower the Kelvin, the xx the light?
warmer
Higher the Kelvin, the xx the light?
cooler
Warm light - shade?
Cool light - shade?
Warmer light has yellow shade
Cooler light has blue shade
Caused by fluctuation of voltage
Occurs more frequently with fluorescent lights with older ballasts
Flicker
Total luminous output of a light source
Luminous Flux
Measured in lumens and weighted to the visual sensitivity of the human eye
Total perceived amount of light being given off in all directions
Luminous Flux
Radiant power weighted to human vision that describes light emitted by source
Measured by candela
Luminous intensity
Amount of light incident on a given surface
Measured in lux or foot candles
Illuminance
One lumen per sqm
One lux
Equivalent to one lumen per sq ft
Foot candle
One foot candle is how many lux?
One foot candle is approximately 10.8 lux
Measurement of how bright a surface or light source will appear to the eyes
Measured in candela per sqm cd/m2 or footlambers
Luminance
Internal clock that keeps body’s hormones and bodily processes on a roughly 24hr cycle, even in continuous darkness.
Can influence sleep/wake, hormone release, body temp, and metabolism
Circadian Rhythm
light that enters eye is picked up by three photoreceptive cells who absorb light and transmit info and signals. To brain
Photoreceptive cells
Facilitate vision, peripheral vision and vision in dim places, but offer low visual acuity and color perception
Sensitive to green blue light 498nm
Rodes
- Facilitate synchronization of circadian rhythms
- Peak sensitivity to teal blue light 480nm
- Contain melanopsin - photopigment that aids in maintaining circadian rhythms
- Exposure to 480nm light later in the dat can alter and cause disruption in biological cycles
Intrinsically Photosensitive retinal ganglion cells (ipRGCs)
Align physiological functions to 24hr solar day and influence
Zeitgebers
Difference between visual lux and amount of light that will affect circadian rhythms
Measure of light that is used to quanify how much a light source will stimulate light response of melanopsin
equivalent melanopic lux EML
clarity or sharpness of vision
Visual acuity
Feature 53: Visual Lighting Design precondition for?
NEI and NEB
Feature 53: Visual Lighting Design requires what?
Task lighting must be available upon request if ambient light not enough
Narrative for brightness is also required
Feature 53: Visual Lighting Design. Part 1: Visual Acuity for Focus includes
- requirement for ambient light?
- controlled lighting?
- intensity of task lighting?
Part 1a - ambient lighting of 215 lux (20 fc) be maintained as measured on horizontal work place
May be dimmed if daylight supplements the lighting, but electrical lighting must be able to achieve this level in the absence of light source
Part 1b - specifies the size of independently controlled lighting zones for ambient lighting system
Max size that meets the requirements of 46.5 sqm or 20% of open floor space, whichever is larger
Part 1c - If ave ambient light is below 300 lux (28 fc) then task lighting must be used to provide 300 lux to 500 lux (28 fc to 46 fc) at work surfaces
Feature 53: Visual Lighting Design. Part 2 requires what?
at least ___ of 4?
for corridors and stairwells?
for task surfaces and adjacent surfaces?
for task surfaces and remote rooms?
for ceilings?
Require narrative. At least 2 of 4.
Main room cannot exhibit 10x greater or lesser luminance than an ancillary space.
Surface cannot exhibit 3x greater or lesser luminance than adjacent surface
Cannot exhibit 10x greater or lesser luminance than a remote surface in the same room
One part of a ceiling cannot exhibit 10x greater or lesser luminance than another part of the ceiling in the same room
Feature 54: Circadian Lighting Design precondition for ?
NEI and NEB
Light levels that affect a person’s physiology by influencing circadian rhythms
Measured on the vertical plane at the average eye level of the building occupants
EML Equivalent Melanopic Lux
Feature 54: Circadian Lighting Design. Part 1: Melanopic Light Intensity for Work Areas requires what?
requires \_\_\_ of 2 options \_\_\_ EML for \_\_\_\_ of workstations Measured on \_\_\_\_\_ plane facing forward at \_\_\_\_\_ meters above finishes floor at what time?
Maintained illuminance on the ____ of ____ EML or greater
Requires light models or light calculations demonstrating that one of two options is met
200EML is present at 75% or more of workstations,
Measured on vertical plane facing forward, 1.2m or 4inches above finished floor
From 9-1pm
Part 1b - requires that electrical lights for all workstations provided a maintained illuminance on the vertical plane facing forward of 150 EML or greater
excessive brightness, contracts and quantity of light
Glare
Feature 55: Electric Light Glare Control. Part 1: Luminaire Shielding. Requires shielding angles Less than 20K cd/m2? 20K to 50K? 50K to 500K? 500K and above?
Requires that minimum shielding angles be observed in regularly occupied spaces depending on the ff:
no shielding required
20K to 50K - shielding of 15 deg
50-500K - shielding angle of 20 deg
500 and above - shielding angle of 30 deg
Feature 55: Electric Light Glare Control. Part 2: Glare Minimization applies to?
Requires any light source more than ____ degree must have luminance values of less than _____ cs/m2
Requires workstations to achieve UGF of _____
Applies to all workstations
Part 2a requires any light source more than 53 deg must have luminance values of less than 8000cs/m2
Part 2b requires workstations to achieve unified glare rating of 19 or less
rating helps indicate degree of discomfort caused by glare from luminaires and bright light sources
Ranges from 5 to 30,the lower the number the less glare
UGR unified glare rating
Feature 56: Solar Glare Control optimization for?
Core and Shell
Glazing required for View windows below 2.1m:
Requires at least 1 of 3 be implemented for glazing less than 2.1
Part 1a - option of interior window shading or blings that are manual or automatic
Part 1b - option of exterior sharing systems to prevent glare
Part 1c - option of variable opacity glazing that reduces transmissivity by 90% or more
Smart glass that has ability to control amount of light passing through it
Variable opacity glazing
Daylight management for greater than 2.1m - requires at least ____ of 5.
1 of 5.
Shading options that have manual or automatic controls eg:
- Interior window shading or blinds
- External shading
- Interior light shelves
- Micromirrors on the windows that reflect light toward ceiling
- Variable opacity glazing
Feature 57: Low glare workstation design optimization for?
NEI and NEB
Feature 57: Low glare workstation design. Part 1: Glare Avoidance - has 2 requirements that must be met which are?
Part 1 a-requires all screen at desk located within 4.5M 15 inches of view windows must be able to be oriented within 20 deg angle perpendicular to the plane
Part 1b - requires overhead luminaires not be aimed directly at computer screens
Feature 58: Color Quality optimization for?
NEI and NEB
Color quality is measured using what?
CRI
Index that features a comparison of appearance of 8 to 14 colors under light source in comparison o a blackbody source of the same color
o Measured using palate of reference R1 to r14
o CRI RA - value of 1 to 100 based on R1 through r8
CRI
Color Rendering Index applies to?
Applies to all electric lights, except for decorative, emergency, or special purpose lighting
Feature 58: Color Quality requires CRI to be?
CRI R1 to R8 be
CRI R9 be
Part 1a - CRI Ra be 80 or higher
Part 1b - requires CRI Ra be 50 or higher. R9 represents red tones and allows a more accurate representation of actual color
Feature 59: Surface Design optimization for?
NEI and NEB
2 forms of lighting
Direct and reflected light
Comes from luminaires and incoming sunlight
Direct light
Direct light reflected in ceilings, walls
Reflected light
Rating of how much usable light is reflected, with values ranging from o to 1
o 0 means black
o 1 means white
LRV
Feature 59: Surface Design. Part 1: Working and Learning Area Surface Reflectivity requires what
for ceilings?
for vertical surfaces?
for furniture systems
Requires 3 sets of surfaces meet minimum LRVs
Ceilings - 0.8 or 80% of surface area
Vertical surfaces - 0.7 or 50% of surface area
Furniture systems - 0.5 or 50% of surface area
Feature 60: Automated Shading and Dimming Controls optimization for?
NEI and NEB
Feature 60: Automated Shading and Dimming Controls. Part 1: Automated Sunlight Control - applies to windows
size?
requires sensors that does 2 things. cite these.
Larger than 0.55m2 6ft2
Requires that windows have automatic shading device for reducing glare at workstations and other seating areas.
A sensor controlled sunlight control system that automatically raises and lowers shades
Can be integrated into building systems
Feature 60: Automated Shading and Dimming Controls. Part 2 Responsive Light Control requires what?
o Part 2a: requires lighting to automatically dim to 20% or less or shut off when zone is unoccupied
o Part 2b: requires fixtures in the space be programmed to dim continuously as daylight levels increase
Feature 61: Right to Light. Part 1: Lease Depth - requires what?
Requires that 75% of area be within 7.5m or 25 inches of view windows.
Near perimeter of building
Feature 61: Right to Light. Part 2: Window Access requires what?
Requires workstations be given distance of an atrium or allow views of the exterior
Allows natural daylight
Part 2a: requires 75% of workstations be within 7.5m or 25i of a view window or atrium
Part 2b: expands this to 95% but moves the threshold back to 12.5m
Feature 62: Daylight Modeling optimization for?
3 project types
Feature 62: Daylight Modeling involves what?
Process of using a computer program to stimulate effects of natural light on the interior
Allows teams to achieve appropriate lighting
Minimum levels of natural lighting in a space are defined with spatial daylight autonomy sDA and the maximum levels of sunlight are defined annual sunlight exposure
% of floor space in which min light level can be met during operating hours
Saptial daylight autonomy sDA
Feature 62: Daylight Modeling requirements
sDA - 300, 50% minimum level 300 lux (28fc) for the area for 50% of the analysis period.
Ade 1000,250 space received 1000 lux 93fc for at least 250 hours per year
if ASE value is over, then glare and thermal discomfort is apparent
Feature 62: Daylight Modeling. Part 1: Healthy Sunlight Exposure - has 2 requirements. Cite these.
Part 1a - Sda 300,50% for 55% of spaces
Part 1b - ASA 1000250 for no more than 10% of space
Feature 63: Daylighting Fenestration optimization for?
3 project types
Feature 63: Daylighting Fenestration. Part 1: Window Size for Working and Learning Spaces
Two conditions for facades
Part 1a - window wall ratio on external elevations be between 20-60%
ratio is > 40%, strategies, internal and external shading must be in place
Part 1b - requires that 40-60% of window area be at least 2.1m 7’ off the floor, which means it must a daylight window
Glazing designed to hide construction features.
Not included in this calculation
Spandrel
Feature 63: Daylighting Fenestration. Part 2: Window Transmittance in Working and Learning Areas - requires what?
Part 2a - requires non decorative glazing, excluding skylights, located above 2.m 7i have a VT of 60%
- Allows increased daylight
Part 2b - requires non decorative glazing located below 2.1m have VT of 50% or more
-Lower value reduces amount of glare
Feature 63: Daylighting Fenestration. Part 3: Uniform Color Transmittance - requires what?
Requires VT of wavelengths between 400nm and 650 nm not vary by more than a factor of 2 for daylight glazing
Highest VT for any wavelength between 400nm and 650 nm cannot be more than 2 x the lowest VT for any wavelength bet 400 nm and 650nm
