Term
| What is Candlepower (cp) ? |
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Definition
The units of luminous intensity approximately equal to the horizontal light output from an ordinary wax candle.
In the metric system of measurment,this unis is called candela (cd). |
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Term
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Definition
| The unit of luminous flux equal to the flux in a unit solid angle of one steradian (1sr) from a uniform point source of one candlepower (1cp). |
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Term
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Definition
| The unit of luminous flux equal to the flux in a unit solid angle of one steradian (1sr) from a uniform point source of one candlepower (1cp). |
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Term
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Definition
| The unit of luminous flux equal to the flux in a unit solid angle of one steradian (1sr) from a uniform point source of one candlepower (1cp). |
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Term
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Definition
| The density of luminous flux incident on a surface in lumens per unit area. |
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Term
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Definition
The luminous flux per unit of projected (apparent) area and unit solid angle leaving a surface, either reflected or transmitted.
Also refered to as brightness. |
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Term
| What is Luminous intensity? |
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Definition
| The solid angular flux density in a given direction measured in candlepower or candelas. |
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Term
| What does IESNA stand for? |
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Definition
Illuninating Engerineering Society of North America
established a method of determining a range of illumination levels, in footcandles appropriate to particular design conditions. categories from A to I (A represents the lowest values for general lighting in noncritical areas and I represents requirements for specialized and difficult visual tasks) |
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Term
| What are important considerations for light quality? |
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Definition
1. Glare
2. Contrast
3. Uniformity
4. Color |
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Term
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Definition
| Glare resulting whe a light source in the field of vision causes discomfort and interference with the visual task. |
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Term
| How do you evaluate direct glare? |
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Definition
| the Visual Comfort Probability (VCP) factor was developed. This facor is the percentage of people who, when viewing from a specified location and in a specified directions, will find the situation acceptable in terms of discomfort glare. |
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Term
| At what angle is direct glare most offensive? |
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Definition
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Term
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Definition
| Occures when a light source is reflected from a viewed light surface into the eye. |
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Term
| What are Veiling reflections? |
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Definition
| A complex interation of light source and brightness, position of the task, reflectifity of the task, and position of the eye. |
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Term
| What is contrast with regards to lighting? |
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Definition
| the differnece in illumination level between one point and nearby points. |
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Term
| What is uniformaty of lighting? |
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Definition
it affects a person's perception of a space as being comfortable and pleasant to be in.
complete uniformity is not disirable. some amount of shad and shadow provide interest. |
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Term
| What is color in lighting? |
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Definition
| An interaction between the color of the light source and the color of the objects that reflect the light. |
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Term
| What are the four most common light sources? |
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Definition
1. Daylight
2. incandescent
3. fluorescent
4. high-intensity discharge |
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Term
| What are the considerations that influence the slection of light source? |
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Definition
1. color rendition characteristics
2. initial cost
3. operation cost
4. efficacy
5. size
6. operating life
7. ability to control output from a luminare
8. heat waste |
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Term
| What is ment by light source efficacy? |
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Definition
| the ratio of luminous flux emitted to the total power input of the source and is measured in lumens per watt. |
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Term
| What are the disadvantages of incandescent lamps? |
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Definition
1. low efficacy
2. Short lamp life
3. high heat output |
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Term
| What are the advantages of Tungsten-halogen? |
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Definition
1. Longer lamp life than incandescent
2.low lumen depreciation over lamp life
3. more uniform light color than incandescent.
4. smaller than incandescent lamps
5. comes in standard and low voltage
6. Whiter light than incandescent
7. greater efficacy than incandescent |
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Term
| What are the disadvantages of Tungsten-halogen? |
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Definition
High heat
can result in explosive shattering of lamp. |
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Term
| What voltage typically are low voltage lamps? |
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Definition
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Term
| What are the advantages of low voltage lamps? |
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Definition
| They require a transformer which results in a bulkier luminaire and higher initial cost. |
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Term
| What are the advantages of low voltage lamps? |
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Definition
1. compact lamps
2. better beam control |
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Term
| What are the three types of fluorescent lamps? |
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Definition
1. Preheat
2. rapid start
3. instant start |
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Term
What kind of lamp is this discribing?
F40T12WW/RS |
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Definition
| Fluorescent lamp that is 40 watt tubular, with a 12/8" diameter (1.5") warm white color, and rapid start circuit. |
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Term
| How is the size of a fluorescent lamp measured? |
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Definition
In eighths of an inch
example: T8 = 8/8" = 1" |
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Term
| What color temperature is a daylight lamp? |
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Definition
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Term
| What color temperature is a warm-white delux lamp? |
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Definition
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Term
| What are the advantages to fluorescent lamps? |
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Definition
1. low initial cost
2. long life
3. available in a variety of color temps.
4. Can be dimmed (more expensive than incandescent)
5. energy savings |
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Term
| What are the disadvantages to fluorescent lamps? |
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Definition
| 1. more difficult to control precisely |
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Term
| What does HID stand for with regards to light fixture lamps? |
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Definition
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Term
| What is the advantage and disadvantage to Mucury-vapor HID lamps? |
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Definition
Advantage: long lamp life
Disadvantage: poor color rendering |
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Term
| What is the advantage and disadvantage to metal-halide HID lamps? |
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Definition
Advantage: better color rendering and efficancy compared to mercury-vapor
Disadvantage: shorter lamp life compared to murcury-vapor |
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Term
| What are the three types of outbulbs for metal-halide HID lamps and what are they used for? |
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Definition
1. Clear: used when potical control is required
2. Phosphor-coated: used for better color rendition
3. Diffuse: specified in recessed downlight fixtures installed in low ceilings. |
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Term
| What is the advantage and disadvantage to high-pressure sodium(HPS) HID lamps? |
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Definition
Advantage: most efficient, long life
Disadvantage: yellowish light (but collor correction versions) |
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Term
| what are the restart warm up times for the 3 types of HID lamps? |
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Definition
Mercury-vapor: 3-10 min
Metal-halide: 10-20 min
high-pressure sodium: 1 min |
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Term
| what other types of lamps are considered HID that are a-typical? |
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Definition
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Term
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Definition
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Term
| What are the advantages of LEDs? |
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Definition
1. brightness
2. long life
3. low power consumption
4. produce no heat
5. controled by digital interface |
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Term
| What are the disadvantages of LEDs? |
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Definition
1. low efficacy (lumens/watt)
2. high cost |
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Term
| What are the seven types of ighting systems? |
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Definition
1. Direct
2. semi-direct
3. direct-indirect
4. general diffuse
5. semi-indirect
6. indirect
7. task-ambient |
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Term
| What are the two ways to measure color temperature? |
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Definition
1. in Degrees Kelvin
2. Color rendering index (CRI) |
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Term
| step 1: In determining fuction of a space what aspects would need to be adressed with regards to lighting? |
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Definition
1. determin light level needed
2. sigle or multi use in space
3. spacial conditions that would dictate a particular kind of lighting
4. existing daylighting contributions
5. ceiling height
6. ceiling construction
7. size of room |
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Term
| Step 2A: In selecting lamp types what should the decision be based on? |
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Definition
1. color rendition
2. overall economy
3. type of control needed |
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Term
| Step 2B: in selecting Luminares what are the major concerns? |
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Definition
1. control glare
2. cost effective
3. provide adjustability if required
4. fit into structure of room
5. complement design of space
6. provide quality of light required for visual tasks |
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Term
| Step 3: in determining the locations of luminaires what are the major concerns? |
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Definition
1. light level required
2. task to be performed |
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Term
| What is the lamp lumen depreciation factor? |
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Definition
| The gradual loss of light output of the lamps over time. |
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Term
| What is the luminaire dirt depreciation factor? |
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Definition
| The amount of dirt collected on the lamps over time. |
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Term
What does CU stand for with regards to lighting?
What does it mean? |
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Definition
Coefficient of Utilization
a number used in the luminaire dirt depreciation factor and lamp lumne depreciation factor calculations that represents how efficiently the luminaire destribues the light from the lamps under various degrees of finish reflectivity of the floor, walls, and ceiling. |
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