Lighting Flashcards
Vocab
Lamp or bulb
Socket
Fixture or Luminaire
Light Output
Lumens and footcandles
Lumens (or Lux – metric)
Measures perceived power of light. The amount of visible light that actually falls on a given surface.
Footcandles
Measurement of illumination or light density.
1 footcandle = a light intensity of 1 lumen/SF
Colour
CCT and CRI
CCT –Correlated Colour Temperature
Measures Kelvin range – colour temperature (warm to cold)
CRI –Colour Rendition Index
Ability of the light source to reproduce the colours of objects faithfully (results similar to sunlight)
Efficacy
How well a light source produces light
Efficacy - lumens/watt
Warm Kelvin range (yellows to reds)
3000K
Neutral Kelvin range (yellows to reds)
3500K
Cool Kelvin range (whites to blues)
4100K
Daylight Kelvin range (whites to blues)
5000K
Kelvin range
Warmer –> low
Cooler –> high
CRI Range
80-85 is acceptable for the hospitality industry. Designers are more particular. Some tech only work outside or inside. The higher the number, the more accurately the bulb reproduces colours accurately.
Strike Time
The amount of time it takes from the time the switch is turned on and the lamp reaches its full brightness
-new CFLs (Compact fluorescent lamps) are almost instantaneous
-street lights with mercury vapour can take up to 15 minutes
Incandescent Lighting
Electric current sent through the base of the bulb travels up a filament
The filament heats up, then turns to incandescence, producing light
These lamps are easily dimmable
They have high operating costs
These are being phased out in favour of more efficient lamps
Electric Discharge Lighting
Two components:
-gas-filled tube
-electric or magnetic ballast
Electricity heats up gas inside the lamp which produces light
These lamps require ballasts
Most common, fluorescent (including CFLs)
Types of florescent light tubes
T5, T8, T12
“T” in T5, T8, T12
The “T” in lamp nomenclature represents the shape of the lamp – diametre