Engineering Utilities 1: Lights and Architectural Lighting System

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Is the branch of physics that relates to the properties of light and
optics
the function of vision.
It involves a study of the human visual system and how it interacts
optics
with light.
Color Blindness Is the inability to distinguish colors.
is energy radiated in the form of a wave caused by an electric field
electromagnetic radiation
interacting with a magnetic field.
is measured as the distance from one peak of one wave to the
Wavelength (»)
next wave.
is the number of wave cycles per second. It is expressed in units
Frequency
of hertz (Hz).
is that part of electromagnetic radiation spectrum capable of ex-
citing the retina and ultimately producing a visual sensation; it is
Visible light
the wavelengths of electromagnetic radiation to which the human
eye is sensitive.
Illuminance is the amount of light incident on (striking) a surface.
Luminance is the amount of light leaving an object.
is the ratio of reflected light versus the light striking the surface
Reflectance (Á)
(illuminance).
is the ratio of light transmitted through the body versus the light
Transmittance (B)
illuminating the surface.
is the ratio of the light absorbed versus the light striking the
Absorptance (±)
surface.
is the ability to distinguish and interpret different wavelengths of
Color perception
visible light.
Visual acuity is the ability to distinguish fine details.
It is the "keenness" of vision that is necessary to perform tasks
Visual acuity
such as reading, writing, drafting, sewing, or surgery.
Lamp is a device that generates light.
is a complete lighting unit, which consists of a lamp (or lamps),
Luminaire lamp socket(s), any lenses, refractors, or louvers, any ballast (or
ballasts), and the housing.
is the luminaire less the lamp(s). It includes the structural parts of
Light fixture a luminaire including any lenses, mounting supports, wiring, and
ballasts, but does not include the lamps.
is the measure of the perceived power of light expressed in lumens
Luminous flux
(lm).
is the SI unit of luminous intensity—that is, the power emitted by
Candela (cd)
a light source in a particular direction.
is the ratio of the light output of a light source (a specific lamp) to
Luminous efficacy
the electrical energy consumed to produce that light source.
Correlated color temperature (CCT) color of lamp rating, Kelvin (K)
Warm lighting color temperature less than about 3500 K
Cool lighting color temperature greater than about 5000 K
color temperature of the lamp is between temperatures of 4500
Daylighting
and 6500 K
is a method of numerically comparing the color distribution of a
Color rendering index (CRI)
light source to a reference lamp.
is a graphic presentation of the quantities of light emitted by a lamp
Spectral power distribution curve
by wavelength component.

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of a lamp is its median life expectancy, expressed in hours. It is the
cumulative time that lapses before 50% of a representative group
Rated life
of lamps has failed and the other lamps in the group continue
operating.
Incandescent lamps (I) emit visible light as a result of heating; they incandesce.
is the familiar threaded base found with ordinary lamps up to 300
Medium base
W
is a smaller threaded base used in ornamental lighting such as
Candelabra base
chandeliers
is a larger threaded base found on lamps that are 300 W or
Mogul base
greater.
are used in applications where the difficulty or cost of changing
Long-life lamps
lamps is prohibitive.
are special versions of the standard lamps that are helpful for
Rough service lamps
rough or vibration service.
Plastic coated lamps in applications where lamps are broken fairly often.
are used in decorative and accent lighting applications that require
Low-voltage lamps
good control or highlighting.
are a smaller, brighter, and more expensive version of the incan-
Tungsten-halogen lamps/ halogen lamps
descent lamp.
produces continuous light by passing electricity through a gas
Gaseous discharge lamp
contained within the lamp.
is a voltage transformer and current limiting device designed to
Ballast start and properly control the flow of power to discharge light
sources such as fluorescent and HID lamps.
is the ratio of a lamp's rated output (lumens) when it is operated
Ballast factor (BF) on a specific commercially available ballast as compared to light
output (lumens) when operated on a reference ballast.
is composed of a tubular glass bulb that is covered with a thin
Fluorescent lamp
phosphor coating on its inside surface.
are filament like coils at the end(s) of the bulb that act as terminals
Cathodes
for the electric arc.
are commercially available in straight, U-shaped of circular tubes
Linear fluorescent lamps (LFL) in a variety of sizes, wattages, voltages, colors, and types of
bases.
Compact fluorescent lamps (CFL) are miniaturized fluorescent lamps.
25 W 7 W CFLs replace ___ incandescent lamps
40 W 11 W CFLs replace ___ incandescent lamps
60 W 13 W CFLs replace ___ incandescent lamps
75 W 19 W CFLs replace ____ incandescent lamps
100 W 23 W CFLs replace ____ incandescent lamps
is the ratio of light (the luminous flux, in lumens) emitted by a
Luminaire efficacy rating (LER) fluorescent luminaire to the electrical energy consumed, including
the ballast.
produce a very bright light by discharging an arc when electrical
High-intensity discharge (HID) lamps current passes through a metal gas contained under high pres-
sure in a glass bulb.
were the first commercially available HID lamps. These lamps are
Mercury vapor (MV) lamps constructed of an internal quartz tube enclosed in an outer glass
envelope
Metal halide (MH) lamps

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are constructed in a manner similar to MV lamps except that
in addition to the mercury and argon, various metal halides are
included in the gas fill.
contain an internal arc tube made of a translucent ceramic ma-
High-pressure sodium (HPS) lamps terial rather than quartz glass because of the high temperature
(2350°F/1300°C) at which it operates.
are really a blend between HID and fluorescent technologies.
Low-pressure sodium (LPS) lamps These lamps are constructed of a large sodium-resistant glass
tube containing sodium and a neon-argon gas mixture.
combine the luminous efficiency of an HID lamp with the good
Blended lamps
color rendering capability of an incandescent lamp.
refers to a type of lighting that uses lightemitting diodes (LEDs),
organic light-emitting diode lights (OLEDs), or polymer light-emit-
Solid-state lighting (SSL)
ting diodes (PLEDs), instead of traditional lighting sources that
use an electrical filament or gas inside a glass bulb.
is a semiconductor that consists of a chip of semiconducting
Light-emitting diode (LED) material treated to create a structure with two electron-charged
materials.
provides uniform illumination throughout the space. It softens
Ambient lighting/general lighting shadows on people's faces and provides the illumination for color
and texture.
is the illumination provided for a specific visual function, which is
Task or local lighting
additional to and controlled separately from the ambient lighting.
is directional lighting used to emphasize a particular object or
Accent lighting
area.
Decorative lighting is the light source that adds a quality of interest to the space.
is required in the critical care and emergency spaces found in
Emergency lighting hospitals, nursing homes, and police, fire protection, and crisis
management areas.
is the part of emergency lighting system that ensures the safety
Safety lighting
of people involved in a potentially hazardous process.
is part of the emergency lighting system. It enables normal activ-
Stand-by lighting
ities to continue substantially unchanged.
provides illumination to ensure that an escape route can be ef-
Escape lighting fectively identified and used in the case of failure of the normal
lighting system.
is the part of the escape lighting system that includes illuminated
Exit lighting signage used to provide clear directions for an emergency exit of
building occupants.
is a luminaire that is hung with a cord, chain, or tube that enables
Pendent it to be suspended from a ceiling or other support. It broadcasts
light over the entire space.
is a luminaire where a shielded light source directs its light to the
Uplight
ceiling, where it is reflected back to the space.
is a luminaire that is usually attached to or recessed in the ceiling
Downlight
and emits a concentrated light downward.
is a type of downlight that is a recessed, canister-shaped luminaire
High hat
with a shielded lamp that emits light downward.
luminaires are mounted above the ceiling or behind a wall or other
Recessed
surface so that any visible projection of light is insignificant.
are decorative, wallmounted luminaires that provide ambient illu-
Sconces mination. They can direct light upward, downward, or in all direc-
tions.

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luminaires are used in high-ceiling areas, 20 ft (6 m) or higher,
that require uniform illumination. High bay fixtures installed in a
High bay
grid pattern are typically used to provide ambient illumination in
warehouses, gymnasiums, and retail superstores.
luminaires are more compact. They are designed for use in low-
Low bay
to medium-ceiling areas, 12 to 20 ft (3 to 6 m).
is illumination where light received at the work plane or light
Directional lighting illuminating an object is incident predominantly from a particular
direction.
is a luminaire that is designed to emit an intense, concentrated
Spotlight beam of light with usually no more than a 20° divergence (spread)
from where it is directed.
is a luminaire that emits an intense light that is broader than a
Floodlight
spotlight and that is capable of being pointed in any direction.
is a directional lighting installation where luminaires are attached
Track lighting
to and are moveable along a metal track.
is a lighting installation in which the light on the working plane or on
Diffused lighting
an object is not incident predominantly from a particular direction.
is a lighting component such as a translucent glass refractor that
Diffuser
redirects or scatters the light from a source.
is a lighting installation where the light source is shielded by a
Cornice lighting panel that is parallel to the wall and attached to the ceiling; it
distributes light over the wall.
is an up-lighting installation where the light source is shielded by
Cove lighting a ledge or recess with light dispersed over the ceiling and upper
wall.
is a lighting installation where the light source is shielded by a
Valance lighting
panel that is parallel to the wall at the top of a window.
is a linear luminaire constructed of an inverted metal trough that
Troffer
serves as a fixture for fluorescent lighting lamps.
Elliptical reflector (ER) lamp is an incandescent lamp with an elliptically shaped reflector.
which may use an incandescent filament, a halogen filament tube,
Parabolic aluminized reflector (PAR) lamp
or HID arc tube, is a precision pressed-glass reflector lamp.
is an advanced lighting technology that transports light from a
Remote-source lighting (RSL) single source over a distance to one or more light outlets or emits
light evenly along the way.
is excessive brightness in the field of vision that causes discomfort
Glare or, in extreme cases, produces a disability from a temporary loss
of vision.
is a rating of a lighting installation expressed as a percentage of
individuals who, when viewing from a specified location and in a
Visual comfort probability (VCP)
specified direction, will be expected to find it acceptable in terms
of discomfort glare.
Lenses are typically made from clear UV-stabilized plastics.
Louvers are slats in a light fixture that create openings for emitting light.
are opaque or translucent elements that shield a light source from
Baffles
direct view.
is the currently accepted method for calculating average illu-
Zonal cavity method minance levels for indoor areas unless the light distribution is
extremely asymmetric.
1. Determine cavity ratio (CR)
2. Determine effective cavity reflectances
Basic steps in any calculation of illuminance level:
3. Select coefficient of utilization
4. Compute average illuminance level
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is the product of all considered factors that contribute to a lighting
Light loss factor (LLF)
installation's reduced light output over a period of time.
Number of lamps in luminaire (n) is the quantity of lamps found in the specified or existing luminaire.
is the minimum required or the given number of luminaires in the
Number of luminaires (#)
space.
is the ratio of the amount of light (lumens) illuminating the work
Coefficient of utilization (CU)
plane to the output of the lamp(s) in a fixture.
is a number indicating cavity proportions from length, width, and
Cavity ratio (CR)
height.
ratio is an approximate maximum spacing-to-mounting height ra-
Spacing criterion (CS)
tio required to ensure uniform illumination on the work plane.
of a lighting installation is the power consumed for illumination
Unit power density (UPD) (W) divided by the area served by the lighting installation. It is
expressed in W/sq.ft or W/sq.m
General fluorescent lighting systems, such as in an office building,
1.5 to 2.0 W
have lighting loads of ______ per square foot
A fluorescent lighting system with both task and ambient lighting
1.2 to 4.0 W
has a lighting load of ______ per square foot
1.0 to 2.0 W An HID lighting system has a load of ______ per square foot

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