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lamps
Lamps classification
Lamp
Incandescent
Low pressure
Mercury Sodium
discharge
high pressure
Mercury Sodium
Metal halide lamps
Incandescent lamps
Lamp spectrum
Strengths
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Low initial cost
Excellent color rendition
Instant starting
Inexpensive dimming capability
Small size, which allows it to be used in point fixtures, such as spot lamps
Wide variety of shapes, sizes, colors and wattages are available
Output unaffected by high or low ambient temperatures
Simple to operate and install
Requires no ballast
High brightness light source
Available in many colors
Variety of filament design possibilities offer optical control, accurate
distribution patterns and critical service operation
Weaknesses
• Relatively short useful life with poor overvoltage tolerance. At 10% over voltage,
life is reduced about 75%!
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Very inefficient source of light. On
average, less than 10% of the wattage
goes to produce light; the remainder
becomes heat.
• High heat component can create
hidden energy costs due to increased
cooling needs
High Intensity Discharge
• High Intensity Discharge or "HID" is the term
commonly used to designate four distinct types of
lamps that actually have very little in common.
They are high pressure sodium, low pressure
sodium, metal halide, and mercury vapor. Each
requires a few minutes (one to seven) to come up
to full output. Also, if power to the lamp is lost or
turned off, the arc tube must cool to a given
temperature before the arc can be re-struck and
light produced. Up to seven minutes (for mercury
vapor lamps) may be required.
Metal Halide lamps
Strengths
• Designed for general lighting applications.
• Relatively long lamp life.
• Interchangeable with mercury lamps in
many applications.
• Concentrated source is easily controlled
by special fixtures.
• Good color rendering characteristic.
• Light output is a bright crisp white light.
• Twice as efficient as mercury lamps and 6
times as efficient as incandescent
Weaknesses
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Short life compared to other HID lamps (6,000 to 20,000 hours depending on
size and manufacturer).
Different lamps have to be used for base-up versus base down burning
configurations.
Horizontal operation may severely reduce lamp life.
Require a ballast.
Some lamp types require 2 to 5 minutes to warm-up before giving full light
output and 10 minutes to cool-down. Others have instant restart capability.
Color may vary from lamp to lamp (color shift)
Many wattages require operation in enclosed fixtures due to the risk of lamp
breakage upon failure.
Lamp Order Code
Burning Position Codes
U – Universal
H - Horizontal ONLY
BU - Base Up
BD - Base Down
HBU - Horz to Base Up
HBD - Horz to Base Down
VBU - Vert to Base Up
VBD - Vert to Base Down
Spectral Distribution for Metal
Halide Lamps
Mercury Vapor lamps
standard "white" mercury vapor
lamps
• Color Improved: very poor on reds,
marginal color, not recommended.
• Deluxe White, DX: increased red, good
color, recommended.
• Warm White Deluxe, WWX: excellent reds,
excellent color, highly recommended,
decreased lumens.
Strengths
• Three times as efficient as incandescent.
• Available in a wide variety of ratings,
colors, sizes and shapes.
• Relatively low unit cost and a high
average rated life (about 24,000 hours
when operated on a 10 hour cycle). This is
24 times longer life than incandescent.
Weaknesses
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Except for incandescents, they are the most inefficient source of light, with
an efficacy in the 25 to 55 lumens per watt range.
Mercury lamps may be greatly affected by lamp lumen depreciation and
should be replaced after 24,000 hours.
Poor lumen maintenance compared to other HID sources.
Have a distinctive bluish cast light output.
Require a maximum warm-up period of five to seven minutes before giving
full light output, depending on lamp type, ballast and ambient temperature.
They can be used only where this delay is acceptable.
Four to five minute cooling and restart time.
New outdoor installations are illegal under some state laws.
Lamps are quite voltage sensitive. Unless special ballasts are used, care
must be taken to keep the supply voltage within plus or minus 5% of the
rated voltage.
Mercury lamp ballasts are noisy. When this presents a problem, remote
mounted ballasts may be an alternative.
A special dimming ballast is required to dim mercury lamps
Spectral Distribution Curve for
Mercury Vapor Lamps
Lamp Order Code (ANSI Code)
Fluorescent lamps
ballast
starter
Fluorescent lamps circuit
Strengths
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4 to 5 times more efficient than incandescent, and an exceptionally
long life (10 to 20 times greater than incandescent).
Easy to maintain.
Lamp life is greatly affected by the average number of hours the lamp
is cycled on and off.
The lamps are also low cost and available in a wide range of sizes
and colors.
Relatively low surface brightness and heat generation, and are
relatively insensitive to small changes in building voltage. This can be
very important where brownouts are common.
Weaknesses
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Most lamps are relatively large and require a relatively expensive fixture.
The ballasts in fluorescent fixtures can have an objectionable hum (some louder
than others).
Ballasts are now given a noise rating. Quiet ballasts are recommended for office
areas, louder and less expensive ballasts can be used in industrial facilities.
Fluorescent lamps are temperature sensitive and may have difficulty starting at
low temperatures. Also, lumen output drops at low and high temperatures.
Special ballasts are available for low and high temperature applications.
While dimming of fluorescents is possible, it requires special, relatively
expensive ballasts.
Spectral Distribution for the
Standard Fluorescent Lamps
Lamp Ordering Code
High-press. sod. vap. lamps
Strengths
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Most efficient member of the HID light family, 7 times as efficient as
incandescent and over 2 times as efficient as mercury vapor.
Warm-up period is 3-4 minutes, which is somewhat less than that of
a mercury vapor or metal halide lamp.
Long lamp life -- 24,000 hours.
Excellent lumen maintenance.
Wide range of lamp types with wattages ranging from 35 to 1000
watts.
Most HPS lamps can operate in any position.
Weaknesses
• The light produced is a golden white color, which
may not be appropriate for certain applications.
• Requires a ballast.
• Once started can take from five to ten minutes
to reach full light output. They also require at
least a one minute cool-down to re-strike.
• End of life is characterized by on-off-on cycling,
and continued operation can damage the lamp
ballast if not replaced quickly.
Lamp Order Code
Spectral Distribution for High
Pressure Sodium Lamp
Low Pressure Sodium
Strengths
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Most energy efficient light source commercially
available, with an efficacy of 100 to 185 lumens per watt.
• Lamps have average life in the 14,000 to 18,000 hour
range and have excellent lumen maintenance (very little
reduction in lumen output over life of lamp).
• Most lamps will restart immediately after interruption of
power supply, but require some time to come up to full
brightness.
• Provides superior uniformity of light distribution over all
HID lamps.
Weaknesses
• These lamps have the poorest color rendering
characteristics. In fact, it is almost impossible to
distinguish colors under an LPS lamp because
light produced by this source is monochromatic
(a single color).
• Most expensive lamps to install.
• Run time to full light output is the longest (7 to
15 minutes).
• Wattage will increase over the life of the lamp
to maintain lumen output.
• Requires special disposal considerations.
Spectral Distribution for a Low
Pressure Sodium Lamp
Lighting measurement units
Radiation flux
Luminous flux
Luminous intensity I
Illuminance E
Luminance L
Methods of lighting measurement
‫‪Lighting measurement methods‬‬
‫تعداد منابع روشنايي •‬
‫تعداد رديف ها •‬
‫نقاط اندازه گيري •‬
‫‪•N‬‬
‫‪•M‬‬
‫‪P,Q,R,T‬‬
‫سطح منظم با المپ منفرد‬
‫‪P1+P2+P3+P4‬‬
‫‪4‬‬
‫=‪AI‬‬
‫سطح منظم با يک رديف المپ بصورت پيوسته‬
‫‪QN+P‬‬
‫=‪AI‬‬
‫‪N+1‬‬
‫سطح منظم با المپ های فضايي قرينه در دو يا‬
‫چند رديف‬
‫سطح منظم با المپ های فضايي قرينه دردو يا چند‬
‫رديف‬
‫)‪Q(N-1)+T(M-1)+P+R(N-1)(M-1‬‬
‫=‪AI‬‬
‫‪NM‬‬
‫سطح منظم با المپ های منفرد دريک رديف‬
‫‪Q(N-1)+P‬‬
‫=‪AI‬‬
‫‪N‬‬
‫سطح منظم با المپ هاي متصل و ممتد دردو يا چند‬
‫رديف‬
‫)‪QN+T(M-1)+P+RN(M-1‬‬
‫=‪AI‬‬
‫)‪M(N-1‬‬
Measurement instruments
• Hagner universal photometer
• Hagner digital luxmeter
Hagner universal photometer s1,2
Hagner universal photometer s1,2
Hagner universal photometer s1,2
Hagner universal photometer s1
Hagner universal photometer s1,2
Hagner universal photometer s3
Hagner universal photometer s3
Hagner universal photometer s3
View when looking into a Hagner
photometer
Hagner universal photometer s3
Hagner digital luxmeter