Key
Characteristics
Rated Voltage:
The lamp’s filament is designed to operate within a specific volt- age range in order for it to deliver its intended light output. Lamps that are burned at volt- ages higher than their rating will result in higher wattage, efficacy (lumens per watt) and lumens. Lamps operated below their rated voltage will significantly increase their life while reduc- ing their wattage, efficacy and lumen output.
Lumen Maintenance:
As the filament of an incandes- cent lamp burns, the tungsten is slowly evaporating and deposit- ing itself on the interior wall of the bulb. This creates the black coating seen after a bulb has been in use for a while.
Additionally, as the filament evaporates, the lumen output decreases until it reaches the end of its life when the wire breaks. It is recommended that a “group replacement” or relamping is conducted once a number of lamps have failed or a notice- able decrease in light output has taken place.
Burning Position:
For the most part, incandescent lamps can be burned in any position. However, take note and observe a lamp manufacturer’s recommendations for use.
Light Output vs. Life
The life of an incandescent lamp | making long life more important than | ||||||
and its lumen output are both | light output? Or will it be a workhorse, | ||||||
determined by the filament design. | illuminating | important | tasks and | ||||
These | characteristics | represent a | needing maximum lumens? | ||||
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be sacrificed to improve the other. | The Federal | Trade | Commission | ||||
There are many choices available to | instituted new packaging labeling | ||||||
the consumer, each one marketed | requirements in 1992 to explain the | ||||||
for a particular application, purpose | function of a lamp better to the | ||||||
or feature. |
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| purchaser. So if you know your way | |||
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| around this labeling, you can suggest | ||
It is important to determine your | optimum choices for your customer, | ||||||
customer’s | priorities | and | needs | or explain the features to customers | |||
when recommending a light source | to allow them to make their own | ||||||
purchase. Is the lamp going to be | educated decisions. |
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placed | in | a | area, |
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These examples of actual labels illustrate the differences between two stan- dard household “A” lamps. One is marketed for longer life, while the other is marketed for greater lumen output. Note the life/light tradeoffs.
High Lumen Output | Longer Lamp Life |
