LIGHTING Reference Guide

LIGHTING Reference Guide
Reference Guide
DISCLAIMER: CEA Technologies Inc., Natural Resources
Canada, the Ontario Ministry of Energy, Energy @ Work or any
other person acting on their behalf will not assume any liability
arising from the use of, or damages resulting from the use of any
information, equipment, product, method or process disclosed in
this guide.
It is recommended to use certified practitioners for the applications
of the directives and recommendations contained herein.
Funding support provided by:
© Her Majesty the Queen in Right of Canada, 2005
Revisions provided by: Mr. Gerry Cornwell, LC,
Architectural Lighting Design; Mr. Scott Rouse, P.Eng., MBA,
CEM, Energy @ Work,
Appreciation to Ontario Hydro, Ontario Power Generation and
others that have contributed to material that has been used in
preparing this guide.
Page Section
6 1 Introduction
7 2 Energy Savings
9 3 Emission Reduction Credits
11 4 Applications
11 a. Lighting Project Management
12 b. Evaluation Methods
14 c. Lighting Levels
14 d. Light and the Environment
15 e. Technology Integration
15 f. Case Studies
24 5 Understanding the Theory
24 a. Definition of Light
26 b.Visual Effect of Light
27 c. Spectral Power Distribution
29 d. Lighting and Colour
34 e. Lighting Quantities and Units
37 f. Lighting Levels
40 6 Generation of Light
40 a. Light Sources
42 b. Lamp Types
45 c. Lighting Systems
47 7 Incandescent Lamps
47 a. Incandescent Lamps (Shapes and Designation)
52 b. Tungsten Halogen Lamps
56 c. Halogen PAR Lamps
60 d. IR Halogen Lamps
61 e. Infrared Heat Lamps
66 8 Fluorescent Lamp Ballasts
66 a. Ballasts General
71 b. Electronic Ballasts for Fluorescent Lamps
77 9 Fluorescent Lamps
77 a. Fluorescent Lamps General
(Shapes and Designation)
89 b. Premium T-8 Lamps
89 c. Low-Wattage T-8 Lamps
89 d. T5 Fluorescent Lamps
91 e. Fluorescent Fixture Reflectors
95 f. Compact Fluorescent Lamps
102 10 HID Lamp Ballasts
102 a. Ballasts General
102 b. Probe Start Ballasts
102 c. Pulse Start Ballasts
103 d. Electronic HID Lamp Ballasts
104 11 HID Lamps, LPS Lamps
104 a. Mercury Vapour Lamps
110 b. Metal Halide Lamps
117 c. High Pressure Sodium Lamps
123 d. Low Pressure Sodium Lamp
126 12 Other Light Sources
126 a. Induction Lighting
127 b. Fiber Optic Lighting
128 c. LED Lighting
130 13 Exit Signs
137 14 Emerging Technologies
139 15 Codes, Standards and Regulations
141 16 Worksheets 141 a. An Audit Data Worksheet 143 b. A Measure/Savings Worksheet
144 17 Bibliography
145 18 Glossary of Terms
149 19 Index
1 Introduction
This is a practical guide, designed to provide information on
lighting technology that will help to improve energy
efficiency opportunities through a designed approach by
understanding components and technologies that are
commercially available.
It is strongly recommended that individuals or companies
undertaking comprehensive energy efficiency projects secure
the services of a professional energy efficiency specialist
qualified in lighting design, to maximize the benefits and
return on investment by considering the internal rate of
return and related benefits of a ‘quality’ design.
2 Energy Savings
Increasing energy costs have become a significant concern
and are expected to continue to increase in the
foreseeable future. Businesses, institutions and consumers
will be searching for more efficient products and solutions.
Business applications for more efficient products are available
and even greater opportunities exist in the largely untapped
residential market. Lighting is recognized as a major area for
economic energy savings.
Programs are in place to influence market and consumer
choices towards more energy efficient products. For example,
“Energuide for Houses and R2000”, Energuide for Existing
Buildings (EEB), and Commercial Building Incentive
Program (CBIP)” along with the use of the Energy Star
labelling program are some of the NRCan programs to
promote energy efficient lighting products.
There are also national efforts to mandate and in some cases
regulate energy efficiency and appear in various forms such as
codes and standards and building guidelines to limit energy
use within a building such as ASHRAE-IES 90.1, DOE
Standard for Federal Buildings, Equipment regulations - US
National Appliance Energy Conservation Act Amendment
of 1988 and Energy Policy Act of 1992, etc.
2 Energy Savings
Achieving lighting energy savings is considered one of the
fundamental energy efficiency measures with numerous
opportunities and supporting benefits. Choices include:
- replacing incandescent with fluorescent or HID lamp
- redesigning older fluorescent lamp configurations to
meet present applications, such as in industrial plants
with upgraded fixtures or better technology. The HID
example was suggested in the case study.
Lighting projects, executed properly and comprehensively
can be easily justified for a number of reasons including:
• energy savings, often a 25% internal rate of return
or better;
• emission reductions, direct correlation between energy and emission reduction;
• maintenance cost savings from replacing
inefficient systems;
• increasing light levels for tenant comfort or improved safety considerations;
• improved CRI to enhance comfort.
3 Emission Reduction Credits
Canada ratified the Kyoto Protocol on February 16, 2005.
This will lead to the economic value of emmission
Reducing energy use can be directly tied to emission
reductions and calculated from the energy saved either on site
or off site by the type of generation. The quantification of
the emissions has been successfully used to create ‘Emission
Reduction Credits’ (ERCs) or in some cases, ‘offset
allowances’. These are usually measured in either sulfur
dioxide (SO2), nitrogen oxides (NOx) or gases e.g.,
Equivalent Carbon Dioxide (CO2e). The credits or
allowances can be created when a company takes an initiative
to improve efficiency and reduce emissions to offset
greenhouse gases.
Credits or allowances will be allocated through numerous
methods. The most common are process modifications,
energy efficiency, fuel switching, new equipment, etc.
Lighting becomes a major opportunity because the
technology is considered ‘proven’ and can be easily replicated.
Energy savings are usually calculated in kilowatt-hours,
(kWh) and converted to Emission Reduction Credits or
allowances, based on the method by which the energy
was generated.
3 Emission Reduction Credits
Industry pilots, such as the Pilot Emission Reduction
Trading or “PERT” as well as Greenhouse Gas Emission
Reduction Trading or “GERT” established the viability and
suggested rules for registering and trading emission credits.
Information is available from Environment Canada’s website:
Ratification of Kyoto is expected to accelerate the
commercial value of emission reduction credits with eventual
trading of emission credits or approved allowances. The
federal government is in the process of defining the rules for
the creation of greenhouse gas allowances within Canada.
Provincially there are specific initiatives underway for SOx
and NOx reduction. For example, in Ontario offsets can be
created and made available through a provincial registry. The
allowances can be created from energy improvements,
especially lighting improvements.
A good source of information in this dynamic area is from
Environment Canada’s Envirozine online:
or specific information on Canada’s Kyoto commitment from
the Government of Canada’s climate change website:
4 Applications
a. Lighting Project Management
The objective of a “quality” lighting design is to provide a
safe and productive environment – whether for business or
pleasure. This is accomplished by a redesign or upgrade to
ensure that the appropriate quality and quantity of light is
provided for the users of the space, at the lowest operating
and maintenance cost.
A “quality” lighting design addresses more than ‘first cost’
issues. Either Net Present Value (NPV) or the Internal Rate
of Return (IRR) can properly evaluate life cycle costs.
Proper evaluation of the data, planning and execution are
essential for successful implementation. Building systems
are inter-related. For example, removing 10 kW of lighting
energy from a commercial building will have a significant
impact on the heating, ventilation air conditioning system.
Cooling cost will be reduced, but replacement heating may
be required. It is necessary for the lighting designer to have a
clear understanding of all the building systems and how they
Typical ‘lowest (first cost)’ projects save energy, but they
usually do not maximize the saving potential in the building.
This can result in a ‘re-lamping’ exercise that provides a 10 to
30% savings, but prevents a lighting designer from returning
to the project to maximize savings at a later date. Valuable
energy reductions are sacrificed.
4 Applications
For example, in a commercial building in Toronto, the
original scope of work would have resulted in electrical
lighting savings of 37%, which on the surface would appear
to be a respectable objective. However, a lighting designer
was retained and a comprehensive design solution was
provided. The project achieved:
• lighting energy savings of 63%;
• reduced payback;
• an Internal Rate of Return of more than 30%; and
• solutions for related building issues such as maintenance,
end of fixture life, etc.
The ‘first cost’ was higher, however the life cycle cost as
calculated using either the Net Present Value or the Internal
Rate of Return proved a significantly superior solution.
b. Evaluation Methods
The methodology used to evaluate the energy savings for
a lighting project, either for a retrofit or a comparison
for new projects, is critical to the success of installing a
complete energy efficient solution. Too often the simple
payback method is used which undervalues the financial
benefit to the organization. Following are brief descriptions
of the various payback evaluation methods. It is important
that the choice of method reflects the same principles the
company uses when evaluating other capital investments.
4 Applications
Life Cycle Costing
A proper life cycle costing analysis will provide a more
realistic financial picture of an energy retrofit project than a
simple payback evaluation. Unfortunately, energy efficiency
has been a low priority and for convenience, the ‘Simple
Payback’ analysis is often used to evaluate energy projects,
particularly for lighting projects.
• Simple Payback consists of the project capital cost
divided by the annual energy savings realized. The
result is the number of years it takes for the savings to
pay for the initial investment, e.g.; $100,000 project
that saves $35,000 annually has a three-year payback.
• Life Cycle Costing analysis is a similar calculation,
however, it looks at a realistic timeline and includes the
maintenance cost savings, the potential increased cost
of replacement lamps, and the cost of money, and can
only be properly evaluated by considering the cost of
money by either the Internal Rate of Return, or the Net
Present Value, as discussed below.
Discounted Cash Flow
Discounted cash flow methods recognize the time value
of money and at the same time provide for full recovery of
investment in depreciable assets.
• The Net Present Value method discounts the stream of
annual savings by the company’s required return on
investment or Cost of Capital.
4 Applications
• The Internal Rate of Return method finds the discount
rate, which matches the cash inflows, and the cash
outflows leaving a Net Present Value of zero. A
company can then make capital investment decisions
based on the projects that have the highest Internal
Rate of Return; e.g., with interest rates below 10%, a
project that delivers an IRR above 10% creates a
positive cash flow.
c. Lighting Levels
Light level, or more correctly, Illuminance Level, is easily
measured using an illuminance meter. Illuminance is the light
energy striking a surface. It is measured in lux (SI) or foot
candles (Imperial). The IESNA (Illuminating Engineering
Society of North America) publishes tables of recommended
illuminance levels for all possible tasks. It is important to
realize that the illuminance level has no relevance to the
lighting quality; in other words, it is entirely possible to have
the recommended illuminance in a space but with a light
source that produces so much glare that it is impossible to
work. This accounts for many of the complaints of either too
much or not enough light.
d. Light and the Environment
There are a number of methods for determining whether
a lighting installation is efficient. One method is for the
lighting designer to check with the current version of the
ASHRAE/IESNA 90.1 lighting standard. This document,
which is revised regularly, provides a recommendation for
the Lighting Power Density or watts per square meter or
square foot attributable to lighting. It is usually possible for
4 Applications
a capable lighting designer to achieve better results than the
ASHRAE/IESNA 90.1 recommendations.
e. Technology Integration
While this handbook is divided into sections dealing with
individual lighting technologies, it is essential to realize that
the best lighting measures combine technologies to maximize
the efficiency of systems. Experienced lighting designers will,
for example, select the fluorescent ballast Power Factor, the
lamp, and the control system that provide the best possible
results for the particular environment and client objectives.
The best solution is a derived by matching client
requirements with the technology. Therefore, one application
may use T-5 technology while another uses metal halide.
f. Case Studies
The following are three case study examples
Case Study One
A School Board Project in Ontario
School boards are usually the owners of their facilities, similar
to municipalities, universities, schools and hospitals, i.e., the
MUSH sector. In reaction to the baby boom in the mid
sixties there was a tremendous expansion in the construction
of facilities for this sector. Thus, facility managers have
inherited 45-year-old facilities, with much of the
infrastructure needing replacement.
4 Applications
This is particularly true for schools. There are limited funds
for replacement, so upgrading the systems in these facilities is
often the only option.
Lighting systems, just like furnaces, chillers, motors and
pumps, are part of the 45-year-old facilities and have a
defined life span. Over time, lamp sockets and internal
wiring deteriorate, lenses become cracked and broken.
Therefore, at some point it is more economical to replace
rather than to continue to repair.
Another significant concern for the facility manager is
change in use. Computers were unheard of in primary and
secondary education when these facilities were constructed,
but they are now in common use both in the classroom and
for facility management. Curriculums have also evolved, and
some facilities, such as science labs, now have very
different uses. As a result, there are many classrooms where
the lighting technology is out-dated, the equipment is due
for replacement, and the light fixtures are no longer
appropriate for the illumination of the task.
Lighting technology changes lead to more choice. School
gymnasia provide a good example. Older schools may have
incandescent, fluorescent or mercury vapour lighting in their
gyms. In these facilities 50% or more of the energy in the
gymnasium can be saved by redesigning the space with more
efficient fluorescent systems using T8 or T5 lamps, combined
with occupancy sensors. Some school boards prefer to use
metal halide high bay fixtures because fewer fixtures are required, meaning lower maintenance costs. These fixtures can
be specified with ‘high-low’ ballasts combined with
occupancy sensors for additional savings.
4 Applications
Situation:This project consisted of a survey of 130
building evaluations, including administration,
secondary and elementary schools. The
challenge in most school board projects is the
relatively low hours of building use compared
to commercial projects.
Area: 5,750,000 square feet
Action:A company specializing in the design and
delivery of energy programs retained a lighting
specialist to help the school board provide a
full assessment of savings and costs to achieve a
comprehensive energy project.
Technology: Existing lighting throughout the 130
buildings consisted of 34 W T12 lamp
fluorescent fixtures, some mercury vapour
fixtures in gymnasiums, and incandescent exit
signs and decorative lighting.
Solutions:The design team specified a comprehensive
approach including lighting upgrades and
redesign, lighting controls, building automation, fuel change, envelope improvements,
HVAC upgrades, and solar panels.
• In the classrooms, the fluorescent fixtures
were upgraded to T8 fluorescent systems with
electronic ballasts, and where appropriate,
replaced with new, more efficient fixtures.
Where the patterns of use made it
economical, occupancy sensors were installed.
• In the washrooms the existing systems were
replaced or retrofit to T8 lamps with
4 Applications
electronic ballasts. Occupancy sensors were
installed where appropriate.
• In the gymnasia, most locations received new
luminaires, either T8 fluorescent or metal
halide high bay fixtures. Occupancy sensors
were installed where appropriate.
• In offices, the fluorescent fixtures were
upgraded to T8 fluorescent systems with
electronic ballasts, and where appropriate,
replaced with new, more efficient fixtures.
Where the patterns of use made it
economical, occupancy sensors were installed.
• Exit signs were replaced with new Light
Emitting Diode (LED) exit signs.
• Outdoor lighting systems were upgraded
with new controls, using timers and in some
cases, photocells, and new luminaires were
installed with high pressure sodium lamps.
Results: Total Project Cost: $12,000,000
Savings: 21.9 million ekWh (equivalent kilowatt
Cost Savings: $1,500,000 per year
Internal Rate Return greater than 11%.
Note: The owner included other measures
that provided better results and still exceeded
their hurdle rate.
Measures:Lighting retrofit, fuel change, building
automation system, envelope improvements,
HVAC upgrades, solar panels.
4 Applications
Case Study Two
A Commercial Building in Downtown Toronto.
Commercial property managers are constantly looking for
opportunities to enhance tenant comfort and decrease costs.
Lighting is considered a proven technology that meets
both objectives.
Commercial buildings commonly use variations on the
fluorescent solution. There are a number of issues for
the lighting designer to consider. The lighting layout, the
arrangement and geometry of light fixtures, may no longer
suit the location of work stations. The light levels may be too
high for use in computer environments. The light fixtures
may have lenses which create reflections on computer screens.
The controls are often limited to circuit beakers in an
electrical room on each floor. The use of 347 V systems in
Canada can also limit the options available to the
lighting designer.
A major consideration for building owners and tenants is
the disruption caused by a lighting project. Issues requiring
substantial cooperation and coordination include:
• access to secure floors or rooms,
• elevator access,
• storage of tools and equipment,
• disposal of packaging materials,
• clean-up at the start and end of each shift.
In order to expedite a project in a timely manner with a
minimum of disruption for tenants, skilled project
management is required. Obtaining spot energy consumption
measurements for both ‘pre’ and ‘post’ conditions are
4 Applications
Situation: This project was for a Class A building in
Toronto, with 35,000 existing ‘base building’
Area: 2,670,000 square feet
Action: The building owner hired an engineering firm
specializing in energy-efficient systems to
provide a cost analysis for retrofitting existing
lighting systems with more efficient T8
lighting systems.
Technology: Existing base building light fixtures were an
inefficient design which used a costly ‘U-Tube’
fluorescent lamp. Each fixture contained 3
lamps and 2 electromagnetic ballasts.
Solutions: The lighting designers provided a redesign of
the fixture incorporating a reflector, an
electronic ballast and linear T8 lamps.
On-site testing proved that light level
requirements were met and that a savings of
63% of the lighting energy compared to the
existing system. This solution also avoided the
cost premium of the ‘U-Tube’ lamps.
Other measures undertaken as part of the
overall program included boiler replacement,
fresh air improvements, and water measures.
This project shows the value of integrating
measures. For example, 3,500 kW of lighting
load was removed from the building, as well
as the resulting heat. This created significant
cooling savings but also made boiler upgrades
essential. Modern, more efficient boilers and
4 Applications
controls replaced the required heat with
substantial savings, and provided
improvements to indoor air quality.
Results: Project Cost: $17,000,000
Savings: 19.4 million ekWh (equivalent kilowatt hours)
Cost Savings: $1,800,000 per year
Internal Rate Return greater than 10% (Note the owner
included other measures that provided better results and still
exceeded their hurdle rate.)
The 3,500 kW reduction translated to about a $1 million
annual saving, and the lighting project cost was about
$2.5 million; an internal rate of return of 30%. As is usually
the case with these projects, the owner bundled other
measures with significantly longer paybacks into this project
to maximize the improvements to the building and to better
accommodate ‘required’ system upgrades such as the new
Case Study Three
Situation:An industrial facility in southern Ontario was
receiving increased complaints and concerns
about existing light levels. Operators were
finding poor light levels an increasing concern
in certain areas. In addition, there were
unusually high maintenance costs due to
annual lamp replacements attributed to the
plant having a dusty environment.
4 Applications
Action:An industrial lighting designer was retained
to tour the facility, interview staff and suggest
potential options.
Technology:Typical two lamp 34 W, T-12 open fixture
fluorescent fixtures were in use throughout
the plant as per the original installation in a
standard ‘grid’ pattern. Although changes had
occurred in the plant over the years, the
lighting remained the same. Light levels in
some areas had deteriorated to as low as 5
foot candles, compared to IESNA
recommended 15 foot candles. Staff was
concerned and offered to demonstrate the
challenges of operating equipment in
constraint areas.
Solutions:A three phase solution was proposed
and accepted.
Phase 1: A short 15 page preliminary assessment was
prepared to summarize the data on the
existing situation including light levels,
estimated lighting fixtures, lamp, ballast and
fixture types, as well as recommended options.
Phase 2: Because there were other plants with similar
opportunities, it was decided to arrange a tour
so staff could see similar industries that had
installed, and operated with, the proposed
technologies; e.g.,
• Metal halide
• Low pressure sodium
• T-8 fluorescents
4 Applications
Phase 3: A demonstration pilot project was selected for
the recommended option to confirm staff
acceptance, light levels and recommendations.
A design level of 20 foot candles was specified
to offset loss of light output due to:
• coefficient of utilization (CU),
• lamp lumen depreciation factor (LLD), and
• luminaire dirt depreciation factor (LDD).
The reflectance in the test area was considered
zero because of the dirty environment. There
was no prior experience in modeling this type
of space due the complexities of the structures
and type of work for maintenance, so flexibility
was rated very high.
The test area called for 27 metal halide 400 W
fixtures and was increased to 32 at the request
of plant staff.
The pilot demonstrated a 36% IRR, to
exceed the plant internal hurdle rate of 14%.
Light levels went from 5 fc to 18 fc and 20 fc
in the pilot areas, lamps were reduced from
256 W to 32 W with a 30% energy saving.
Results:Metal Halide 400 W enclosed fixtures were
selected and provided the following results:
• 31% energy savings
• 51% fixture and ballast reduction
• 75% reduction in lamps
• four times more light
• 100% client satisfaction with quantity and
quality of light!
5 Understanding the Theory
a. Definition of Light
• Light is that which makes things visible.
• Light is defined as electromagnetic radiation or energy
transmitted through space or a material medium in the
form of electromagnetic waves (definition in physics).
• Light is defined as visually evaluated radiant energy – light
is that part of the electromagnetic spectrum visible by the
human eye (illuminating engineering definition).
5 Understanding the Theory
Electromagnetic Spectrum
• The electromagnetic spectrum is shown in the figure below.
• The visible portion of the spectrum covers a narrow band of
wavelength from approximately 380 nm to 770 nm
(1 nm = 10-9m). Wavelengths shorter or longer than these
do not stimulate the receptors in the human eye.
Violet Blue Green
380 400
Yellow Red
700 770
Wavelength (nm)
Visible Light
Gamma Rays
X-rays Ultraviolet
10�14 10�12 10�10 10�8 10�6 10�4
Wavelength (m)
5 Understanding the Theory
b. Visual Effect of Light
• Light is defined as visually evaluated radiant energy.
• The visible portion of the radiant energy that reaches the
eye is absorbed by special receptors (rods and cones) in the
retina, which covers the inner wall of the eye.
• In the retina, the rods and cones convert the radiant energy
into electrical signals. The nerves transmit the electrical
impulses to the brain where the light sensation is created.
Spectral Sensitivity of the Eye
• The sensitivity of the human eye is not uniform over the
visible spectrum. Different wavelengths give different colour
impressions and different brightness impressions.
• The “relative spectral luminous efficiency curves” (shown
on the next page) give the ratio of the sensitivity to each
wavelength over the maximum sensitivity.
• The curve for photopic (or day) vision applies when the eye
is in bright viewing conditions. The curve is denoted by
V (λ). The visual response is at maximum at the yellowgreen region of the spectrum, at a wavelength of 555 nm.
• The curve for scotopic (or night) vision applies when the
eye is in dark-adapted condition. The curve is denoted by
V' (λ). The visual response is at maximum in the blue-green
region of the spectrum, at a wavelength of 507 nm.
5 Understanding the Theory
Relative Spectral Luminous Efficiency Curves
d eye)
V (�)
Spectral Luminous Efficiency
Yellow Orange
V‘ (�)
Wavelength (nm)
c. Spectral Power Distribution
• Each light source is characterized by a spectral power
distribution curve
or spectrum.
Spectral Power Distribution Curve
• The spectral power distribution (SPD) curve, or spectrum,
of a light source shows the radiant power that is emitted
by the source at each wavelength, over the electromagnetic
spectrum (primarily in the visible region).
5 Understanding the Theory
Relative Power
•With colour temperature and colour rendering index
ratings, the SPD curve can provide a complete picture of
the colour composition of a lamp’s light output.
Noon sunlight
500 W incandescent
Wavelength (nm)
Incandescent Lamp Spectrum
• Incandescent lamps and natural light produce a smooth,
continuous spectrum.
High Intensity Discharge Lamp Spectrum
• HID lamps produce spectra with discrete lines or bands.
Fluorescent Lamp Spectrum
• F luorescent lamps produce spectra with a continuous curve
and superimposed discrete bands.
• The continuous spectrum results from the halophosphor
and rare earth phosphor coating.
• The discrete band or line spectrum results from the
mercury discharge.
5 Understanding the Theory
d. Lighting and Colour
• Each wavelength of light gives rise to a certain sensation
of colour.
• A light source emitting radiant energy, relatively balanced
in all visible wavelengths, such as sunlight, will appear white
to the eye.
• Any colour can be imitated by a combination of no less
than three suitable primary colours.
• A suitable set of primary colours usually chosen is red,
green and blue.
• A beam of white light passing through a prism is dispersed
into a colour spectrum.
Optical Prism
p03 f
5 Understanding the Theory
Surface Colours
• The perceived colour, or colour appearance, of a surface is
the colour of the light reflected from the surface.
• Certain wavelengths are more strongly reflected from a
coloured surface than others, which are more strongly
absorbed, giving the surface its colour appearance.
• The colour depends on both the spectral reflectance of the
surface and the spectral power distribution of the
light source. In order to see the colour of the object, that
colour must be present in the spectrum of used light source.
Colour Properties of Light Source
• The colour properties of a light source depend on its
spectral power distribution.
• The colour properties of a light source are described by
three quantities:
• chromaticity - or colour temperature (CT)
• colour rendering index
• efficiency (lumen/watt)
Chromaticity or Colour Temperature
• All objects will emit light if they are heated to a sufficiently
high temperature.
• The chromaticity or colour temperature of a light source
describes the colour appearance of the source.
•The correlated colour temperature of a light source is the
absolute temperature, in Kelvin (K), of a black-body
radiator, having the same chromaticity as the light source.
5 Understanding the Theory
• Sources with low colour temperatures - below 3,000 K have
a reddish or yellowish colour, described as warm colour.
• Sources with high colour temperatures - above 4,000 K
have a bluish colour, described as cool colour.
• Warm colour is more acceptable at low lighting levels and
cool colour at high lighting levels.
• The colour description and application is summarized as
• below 3,000 K warm reddish lower lighting levels
• above 4,000 K cool bluish higher lighting levels.
Colour Temperature of Common Light Sources
Light Source Sky - extremely blue Sky - overcast Sunlight at noon Fluorescent - cool white Metal halide (400 W, clear) Fluorescent - warm white Incandescent (100 W) High Pressure Sodium (400 W, clear) Candle flame Low pressure sodium Colour Temp
(K) 25,000 6,500 5,000 4,100 4,300 3,000 2,900 2,100 1,800 1,740 Description
5 Understanding the Theory
Colour Rendering Index (CRI)
• Colour rendering is a general expression for the effect of a
light source on the colour appearance of objects, compared
with the effect produced by a reference or standard light
source of the same correlated colour temperature.
• The colour rendering properties of a light source are
expressed by the (CRI).
• The CRI is obtained as the mean value of measurements for
a set of eight test colours.
• The CRI has a value between 0 and 100.
• A CRI of 100 indicates a light source, which renders
colours as well as the reference source.
• The CRI is used to compare light sources of the same
chromaticity (or colour temperature).
• The CRI is used as a general indicator of colour rendering:
a higher CRI means a better colour rendering.
• It is essential to understand that the CRI value has no
reference to ‘natural’ light, although colours under a high
CRI lamp will appear more natural.
• The most important characteristic of a lamp, from an
energy viewpoint, is its ability to convert electrical energy
into light. This measure is referred to as efficacy, in lumens
per watt or light output per watt input. The chart below
shows the general range of lumens per watt and the CRI for
various light sources.
5 Understanding the Theory
Colour Rendering Index and Efficacy of Common Light Sources
Mercury Vapour (HID)
Light Emitting Diode
Metal Halide (HID)
High Pressure Sodium (HID)
Low Pressure Sodium
10 to 35
20 to 60 20 to 40
40 to 100
50 to 110
50 to 140
100 to 180
20 to 40
60 to 90
65 to 90
20 to 30 (60)
Colour Rendering Description
CRI Colour Rendering
75-100 60-75 50-60 0-50 Excellent
Poor (not suitable for colour critical applications)
Technology and Performance
• Incandescent lamps produce smooth, even SPD curves and
outstanding CRI values.
• Halogen versions of incandescent lamps produce whiter
light with +95 CRI.
• With gaseous discharge technology, colour characteristics
are modified by the mixture of gases and by the use of
phosphor coatings.
• HID lamps are chosen mostly for their exceptional energy
efficiency; metal halide versions have acceptable CRI levels.
5 Understanding the Theory
Application Notes
• Warm colour light is associated with indoors, nighttime and
heat, and fits better indoors and in cool environments.
• Warm colour light makes warm colour objects (red-yellow
colours) look richer.
• Cool colour light is associated with outdoors, daytime and
cold, and fits better in warm environments.
• Cool colour light mixes better with daylight
(daytime lighting)
• Cool colour light makes cool colour objects (blue-green
colours) look refreshing.
• Match light source colour with room objects’ colour
(interior decoration).
• Sources with high CRI cause the least emphasis or
distortion of colour.
e. Lighting Quantities and Units
Luminous Flux or Light Output
• The luminous flux, or light output, is defined as the total
quantity of light emitted per second by a light source.
• Sensitivity of the human eye varies, reaching its maximum
at a wavelength of 555 nm during daytime (photopic vision)
and 507 nm for night vision (scotopic vision)
• The unit of luminous flux is the lumen (lm).
• The lumen is defined as the luminous flux associated with a
radiant flux of 1/683 W at a wavelength of 555 nm in air.
5 Understanding the Theory
• Lamp Lumens (lm) = the quantity of light emitted by a
light source.
Luminous Efficacy
• The luminous efficacy of a light source is defined as the
ratio of the light output (lumens) to the energy input
• The efficacy is measured in lumens per watt (lm/W).
• The efficacy of different light sources varies dramatically;
from less than 10 lumens per watt, to more than 200
lumens per watt.
• Efficacy of a light source = lamp lumens/lamp watt
5 Understanding the Theory
Luminous Flux Density or Lighting Level
• The luminous flux density at a point on a surface is defined
as the luminous flux per unit area.
• The luminous flux density is also known as the illuminance,
or quantity of light on a surface, or lighting level.
• The SI unit of the lighting level is the lux (lx),
1 lx = 1 lm/m2.
• W hen measurement is in Imperial units, the unit for the
lighting level is the foot candle (fc): 1 fc = 1 lm/ft2.
• The relation between the fc and lux is 1 fc = 10.76 lux.
Incidentally, this is the same as the relationship between
square meters and square feet.: 1 m2 = 10.76 ft2.
• The lighting level is measured by a photometer, as shown in
the figure below.
• Minimum recommended lighting levels for different tasks
are included below.
• Lux = the unit of illuminance at a point of a surface.
• Lux = lumens/area.
5 Understanding the Theory
f. Lighting Levels
• Recommendations for lighting levels are found in the 9th
Edition of the IESNA Lighting Handbook. The
Illuminating Engineering Society of North America is the
recognized technical authority on illumination.
• The data included in the tables below is approximate and
describes typical applications.
Lighting Levels by Visual Task
Lighting Level
Type of Visual Task fc
lux Comments
Tasks occasionally performed Simple orientation/short visits
Working spaces/simple tasks High contrast/large size
High contrast/small size or inverse
Low contrast/small size Tasks near threshold 3
10 30
30 50
100 300
Orientation & Simple Visual Tasks
Orientation & Simple Visual Tasks
Orientation & Simple Visual Tasks
Common Visual Tasks
50 500 Common Visual Tasks
100 1,000 Common Visual Tasks
300-1,000 3,000-10,000 Special Visual Tasks
5 Understanding the Theory
Examples of Lighting Levels by Building Area
and Task
Lighting Level
Building Area and Task fc lux Comments
Auditoriums 10 100 Include provision for higher levels
Banks - Tellers’ Stations Barber Shops Bathrooms Building Entrances (Active) 50 50 30 5
Cashiers Conference Rooms Corridors 30 30 5
300 50
Dance Halls Drafting - High Contrast Drafting - Low Contrast Elevators Exhibition Halls 5
50 100 5
10 50
Floodlighting - Bright Surroundings (Vertical)
50 Less for light surfaces – more for dark
Floodlighting - Dark Surroundings (Vertical) 3
30 Less for light surfaces - more for dark
Hospitals - Examination Rooms 50 500 Hospitals - Operating Rooms 300 3,000 Kitchen Laundry Lobbies Office - General 50 30 10 30 500
Parking Areas - Covered Parking Areas - Open Reading/Writing Restaurant - Dining 2
.2 50 10 20
Plus task lighting
Include provision for higher levels
High colour rendition
Variable (dimming or switching)
Lower at night
Higher for enhanced security
Varies with task difficulty
5 Understanding the Theory
Lighting Level
Building Area and Task fc
lux Comments
Stairways Stores - Sales Area Streetlighting - Highways Streetlighting - Roadways 5
30 0.9 0.7 50
Varies with traffic density
Varies with traffic and pedestrian density
Lighting Level Adjustment
Reduce Lighting Level by 30% Increase Lighting
Level by 30%
Reflectance of task background Speed or accuracy Workers’ age (average) Greater than 70% Not important Under 40 Less than 70%
Over 55
6 Generation of Light
a. Light Sources
Many different processes convert energy into visible
radiation (light).
Some basic processes are described below.
Generation of Light
Gas Discharge
p04 a
6 Generation of Light
• Solids and liquids emit visible radiation when they are
heated to temperatures above 1,000 K.
• The intensity increases and the appearance becomes whiter
as the temperature increases.
• This phenomenon is known as incandescence or
temperature radiation.
• Application: incandescent lamps.
• Luminescence is the emission of light not ascribed directly
to incandescence.
• Two important types of luminescence are electric or gas
discharge, and fluorescence.
• Electroluminescence is the emission of light when low
voltage direct current is applied to a semi-conductor device
containing a crystal and a p-n junction.
• The most common electroluminescent device is the LED.
Electric or Gas Discharge
• W hen an electric current passes through a gas, the atoms
and molecules emit radiation, whose spectrum is
characteristic of the elements present.
• In low pressure discharge, the gas pressure is approximately
1/100 atm or 0.147 PSI.
6 Generation of Light
• In high pressure discharge, the gas pressure is approximately
1 to 2 atm or 14.7 to 29.4 PSI.
• Application: gas discharge lamps.
• Radiation at one wavelength is absorbed, usually by a solid,
and is re-emitted at a different wavelength.
• W hen the re-emitted radiation is visible and the emission
happens only during the absorption time, the phenomenon
is called fluorescence.
• If the emission continues after the excitation, the
phenomenon is called phosphorescence.
• In the fluorescent lamp, the ultraviolet radiation resulting
from the gas discharge is converted into visible radiation by
a phosphor coating on the inside of the tube.
• Application: fluorescent, phosphor-coated HID lamps.
b. Lamp Types
An electric lamp is a device converting electric energy
into light.
Lamp Types by Light Generation Method
• Incandescent lamps
• Gas discharge lamps
• Low pressure discharge
- fluorescent lamps
- low pressure sodium (LPS) lamps
6 Generation of Light
• High pressure or HID
- mercury vapour (MV) lamps
- MH lamps
- high pressure sodium (HPS) lamps
• Electroluminescent lamps
- LEDs
Lamp Types by Standard Classification
• Incandescent lamps
• Fluorescent lamps
• HID lamps
• mercury vapour (MV) lamps
• metal halide (MH) lamps
• high pressure sodium (HPS) lamps
• Low pressure sodium (LPS) lamps
• LED sources
6 Generation of Light
Lamp Efficacy or Efficiency
The efficacy of the various types of lamps is
shown below:
Lamp Type (Lumens per Watt)
Incandescent Mercury Vapour Light Emitting Diode
Fluorescent Metal Halide High Pressure Sodium Low Pressure Sodium 10 to 35
20 to 60
20 to 40
40 to 100
50 to 110
50 to 140
100 to 180
Rated Average Life (hours)
1,000 to 4,000
see below
6,000 to 24,000
6,000 to 20,000
24,000 to 40,000
Rated Average Life
• Rated average life is the total operated hours when 50% of
a large group of lamps still survive; it allows for individual
lamps to vary considerably from the average.
• Incandescent lamp life can be extended by use of dimming
to reduce maximum power.
• Compact fluorescent lamps have relatively long lives of
about 10,000 hours.
• Gas discharge lamps have long lives of about 20,000 hours
or more.
• LED sources have life based on different criteria. When
the LED has lost 50% of its original output, it is considered
failed. This is a range from 50,000 to 100,000 hours. This
methodology is used by most manufacturers.
6 Generation of Light
c. Lighting Systems
Lighting Unit or Luminaire
A lighting unit consists of:
• a lamp or lamps,
• a ballast (for gas discharge lamps),
• a fixture or housing,
• an internal wiring and sockets,
• a diffuser (louver or lens).
Lighting System
A typical lighting system consists of:
• luminaires,
• lighting control system(s).
Lighting System Environment
A lighting system environment consists of:
• room (ceiling, wall, floor),
• room objects.
6 Generation of Light
Lighting System Illustration
7 Incandescent Lamps
a. Standard Incandescent Lamps
• A typical construction of an incandescent lamp is shown in
the figure on the next page.
• An incandescent lamp produces light by using electric
current to heat a metallic filament to a high temperature
(above 5000° C/ 9000° F).
• A tungsten filament is used because of its high melting
point and low rate of evaporation at high temperatures.
• The filament is coiled to shorten the overall length and to
reduce thermal loss.
• The filament is enclosed in a glass bulb filled with inert gas
at low pressure.
• The inert gas permits operation at higher temperatures,
compared to vacuum, resulting in a smaller evaporation rate
of the filament.
• The bulbs are often frosted on the inside to provide a
diffused light instead of the glaring brightness of the
unconcealed filament.
7 Incandescent Lamps
7 Incandescent Lamps
Shape Code
Arbitrary (standard) - universal use for home lighting
Bullet - decorative
BR Bulging reflector - for substitution of incandescent R lamps
Cone shape - used mostly for small appliances and indicator lamps
ER Elliptical reflector - for substitution of incandescent R lamps
Flame - decorative interior lighting
Globe - ornamental lighting and some floodlights
Pear - standard for streetcar and locomotive headlights
Parabolic aIuminized - used in spotlights and floodlights reflector
Straight - lower wattage lamps - sign and decorative
Tubular - showcase and appliance lighting
Lamp Designation
A lamp designation consists of a number to indicate the
wattage, a shape code and a number to indicate the
approximate major diameter.
Example: 60A19
60: Wattage (60 W)
Bulb shape
19: Maximum bulb diameter, in eighths of an inch.
7 Incandescent Lamps
Colour rendering index - 97 (CRI)
- excellent CRI
Colour temperature - 2,500 to 3,000 K
- warm colour
Luminous efficacy - 10 to 35 lumens per watt
- lowest efficacy of all light sources
- efficacy increases with lamp size
Lamp life (hours) - 1,000 to 4,000 (typical 1,000)
- shortest life of all light sources
- longer life lamps have lower efficacy
General - first developed and most common lamps
Lamp configuration - point source
Lamp watts - 1 to 1,500 W
Lamp lumen - 80% to 90%
depreciation factor (LLD)
Warm-up time - instant
Restrike time - instant
Lamp cost - low
- lowest initial cost
- highest operating cost
Main applications - residential - merchandising display lighting
More Information:
• Refer to lamp manufacturers’ catalogues.
7 Incandescent Lamps
Designation Lamp Watts Rated
Life Initial per Mean per (hrs) Lumens Watt Lumens Watt Colour
25 40 60 100 150 200 300 500 1,000 1,500 1,000 270 1,000 510 1,000 855 1,000 1,650 1,000 2,780 1,000 3,400 1,000 5,720 1,000 10,750 1,000 23,100 1,000 33,620 2,550 2,650 2,790 2,870 2,925 2,925 3,000 3,050 3,030 3,070 0.79
25 A 19 40 A 19 60 A 19 100 A 19 150 A 23 200 PS 30 300 PS 30 500 PS 35 1000 PS 52 1500 PS 52 10.8 12.8 14.3 16.5 1,535 18.5 2,585 17.0 19.1 5,205 21.5 9,783 23.1 21,252 22.4 28,241 15.4 17.2 17.4 19.6 21.3 18.8 R Lamps
30 R 20 50 R 20 75 R 20 30 50 75 2,000 2,000 2,000 200 6.7
320 6.4
500 6.7
BR & ER Lamps
50 ER 30 75 ER 30 120 ER 40 50 75 120 2,000 320 6.4
2,000 580 7.7
2,000 1,475 12.3
65 75 120 150 200 300 500 2,000 2,000 2,000 2,000 2,000 2,000 2,000 PAR Lamps
65 PAR 38 75 PAR 38 120 PAR 38 150 PAR 38 200 PAR 46 300 PAR 56 500 PAR 64 Note:
765 1,040 1,370 1,740 2,300 3,840 6,500 11.8
11.6 11.5
1,462 9.7 0.78
• CRI for incandescent lamps is typically 97.
• The lamp charts throughout this publication are intended for comparison purposes only;
please refer to the most recent lamp manufacturer’s catalogues or websites for up-to-date
information on lamp part numbers and availability.
7 Incandescent Lamps
b. Tungsten Halogen Lamps
• The quartz tungsten halogen lamp is another type of
incandescent lamp.
• The conventional incandescent lamp loses filament material
by evaporation which is deposited on the bulb wall, leading
to bulb blackening and reduced lamp efficacy during the life
of the lamp.
• W hen a halogen element is added to the filling gas under
certain design conditions, a chemical reaction occurs, as a
result of which evaporated tungsten is redeposited on the
filament, preventing any deposits on the bulb wall.
• The bulb of the tungsten halogen lamp is normally made
of quartz glass to withstand the lamp’s high-temperature
operating conditions.
• The fixture often incorporates a reflector for better heat
dissipation and beam control.
7 Incandescent Lamps
Shapes and Designation
Shape Code
Tubular:T3 Line voltage tungsten halogen lamp - double-ended
Tubular:T10 Line voltage tungsten halogen lamp - single-ended
Tubular:T6 Line voltage tungsten halogen lamp - single-ended
Tubular:T-4 Line voltage tungsten halogen lamp - without reflector
Tubular:T-3 Low voltage tungsten halogen lamp - without reflector
Maxi-spot Low voltage tungsten halogen lamp - with reflector
Mini-spot Low voltage tungsten halogen lamp - with reflector
PAR 36 Low voltage tungsten halogen lamp - PAR36 reflector
Low voltage tungsten halogen lamp - MR16 reflector
7 Incandescent Lamps
Low Voltage Tungsten Halogen
• Operates at low voltage - mainly 12 V,
• Each fixture includes a transformer - supplying the low
voltage to the lamp and are compact in size,
• These are more efficient than standard incandescent,
• These have longer life than standard incandescent,
• These are used mainly for display lighting.
7 Incandescent Lamps
Designation Lamp Watts Rated
(hrs) Initial
Initial per Mean per Lumens Watt Lumens Watt Colour
Deg K 2,000 750 1,000 2,000 2,000 2,000 1,400 1,800 2,800 5,000 8,250 10,450 18.7
18.0 18.7 2,688 20.0 4,850 20.6 20.9 17.9 19.4 3,000
2,850 2,950 2,950
1,500 2,000 2,000 2,000 2,000 2,000 3,460 5,950 7,750 11,100 23,400 35,800 17.3 19.8 19.4 22.2 10,767 23.4 23.9 34,726 21.5 23.2 2,850 2,950 2,950 3,000 3,050 3,050 4,000
700 CBCP
2,000 CBCP
2,100 CBCP
Single-Ended Quartz
Q 75CL Q 100 CL Q 150 CL/DC Q 250 CL/DC Q 400 CL/MC Q 500 CL/DC 75 100 150 250 400 500 0.96
Double-Ended Quartz
Q 200 T3/CL 200 Q 300 T3/CL 300 Q 400 T4/CL 400 Q 500 T3/CL 550 Q1000 T6/CL 1,000 Q1500 T3/CL 1,500 0.96
Low Voltage MR Types
• CRI for incandescent lamps is typically 97.
• CRI for tungsten halogen (quartz) lamps is slightly better than other incandescent lamps.
• CBCP = Centre Beam Candle Power, used instead of lumens with the low voltage
reflector lamps
See Also:
• Lamp manufacturers’ catalogues.
7 Incandescent Lamps
c. Halogen PAR Lamps
Halogen Capsule
General Description
• Halogen PAR lamps are lamps
with a Parabolic Aluminum
Reflector (PAR) which use a halogen capsule instead of a
simple filament.
• The halogen capsule includes a tungsten filament and
halogen gas.
PAR Lamp Families
• PAR lamps have evolved into four families, listed below,
from lowest to highest efficiency:
• standard PAR lamps
• energy saving PAR lamps
• halogen PAR lamps
• Infra Red (IR) halogen PAR lamps.
7 Incandescent Lamps
• All PAR lamps have an aluminum or silver coating reflector
on part of the bulb’s surface.
• PAR lamps are used for directional lighting,
i.e., highlighting or spot lighting.
• Most common size is the PAR38.
• Other sizes include PAR30, PAR20 and PAR16.
• Beam spreads are described as narrow spot (NS), spot (SP)
and flood (FL).
Standard PAR Lamps (see also Section 7a,
Incandescent Lamps)
• Use a tungsten filament but no halogen gas,
i.e., no halogen capsule.
• Lamp watts: 75 W, 100 W, 150 W
• Life: 2,000 hours.
Halogen PAR Lamps
• Halogen PAR lamps use a halogen capsule instead of a
tungsten filament.
• Lamp watts: 45 W, 65 W, 90 W.
• Life: 2,000 hours.
7 Incandescent Lamps
PAR 38 Lamp Replacements
Standard PAR 75 100 150 -
Life Hours
2,000 Energy -
GE Brand PAR Philips Brand PAR Sylvania Brand PAR Notes:
Energy Saving PAR Halogen PAR IR Halogen
55,65 45
120 90 -
2,000 2,000 20% less 40% less same same same whiter Watt-Miser Halogen PAR Performance Plus PAR
Econ-O-PAR Masterline
Super Saver Capsylite
60% less
• Replacements provide about the same light beam candlepower around the centre of the beam.
• The standard PAR is used as a basis for the comparisons shown in the table.
Highlighting merchandise in stores and window displays:
• Downlights,
• Accent lighting,
• Outdoor lighting.
Halogen PAR lamps have many advantages over standard
and energy saving PAR lamps:
• energy savings in the order of 40% - 60%;
• whiter light;
• constant light output throughout lamp life without
lamp darkening.
7 Incandescent Lamps
Halogen PAR lamps are more expensive than standard and
energy saving PAR.
• Halogen PAR lamps provide energy savings which
outweigh the lamp price difference in less than a year.
• Halogen PAR lamps provide better quality light.
Designation Lamp Watts Rated
(hrs) Initial Lumens Initial Mean
Lumens Lumens
per Mean per Watt Lumens Watt Colour
PAR Quartz
Q90 PAR38 90 2,000 Q150 PAR38 140 4,000 1,740 19.3 2,000 13.3 1,900 12.7
Q250 PAR38 250 6,000 3,220 12.9 2,900
Q500 PAR56 500 4,000 7,000 14.0 2,950
Q1000 PAR64 1,000 4,000 19,400 19.4 3,000
7 Incandescent Lamps
d. Halogen PAR and MR IR (Infrared) Lamps
• Halogen PAR IR lamps use a halogen capsule with an
infrared (IR) coating film on the capsule surface.
• The IR film is visually transparent and reflects heat back to
the filament, making the lamp more efficient.
• These lamps are the most efficient incandescent PAR
• Lamp watts: 40 W, 50 W, 55 W, 60 W, 80 W, 100 W,
and others.
• Life: 3,000 to 6,000 hours.
• These are an excellent replacement for conventional
incandescent PAR lamps.
Standard incandescent PAR Lamp:
150PAR38fl, 2,000 hrs, 1,700 initial lumens, 11.3 lm/W
Halogen PAR Lamp:
120PAR38FL, 2,000 hrs, 1,900 initial lumens, 15.8 lm/W
Halogen HIR PAR Lamp:
90PAR38HIR/FL, 4,000 hrs, 2,030 initial lumens, 22.5 lm/W 7 Incandescent Lamps
e. Infrared Heat Lamps
Conventional IR-lamp
The new IR-PAR lamp
• The Energy Radiator reflects
• The heat loss in
the heat forward
the conventional
p05_d (Soft Glass) IR lamp
• Skirted PAR lamp base for
increased support
General Description
Infrared heat lamps, also known as IR lamps, or simply heat
lamps, are specially-designed incandescent lamps which
produce mostly heat and little light.
• There are two basic types:
• PAR type - i.e., parabolic aluminum reflector lamps
• R type - i.e., reflector type lamps.
7 Incandescent Lamps
• PAR type lamps are newer and more efficient. They include
the following sizes:
• 175 W PAR 38,
• 100 W PAR 38.
• R type lamps are older and have been used more extensively.
They include the following sizes:
• 250 W R40,
• 175 W R40,
• 150 W R40.
• The 250 W R40 lamp is presently the most widely-used
heat lamp in the market.
• Most infrared heat lamps have a red front glass, but lamps
with clear white glass are also available.
PAR Lamps Can Replace R Lamps
• PAR lamps are newer and more efficient than R lamps.
• PAR lamps can replace higher wattage R lamps with an
equivalent heat output.
• Typical replacements:
• 175 W PAR can replace 250 W R lamp
• 100 W PAR can replace 175 W and 150 W R lamps
• The parameters used to compare the two types of lamps are
listed below.
7 Incandescent Lamps
Technical Data
Wattage Lamp Type (W) 175 W PAR 100 W PAR 250 W R 175 W R 150 W R 175 100 250 175 -
Output (W) 115 65 144 95 -
Heat Lamp 0 to 30
Efficiency Heat
(%) Output (W)
65.7 65.0 57.6 54.3 -
• Input wattage is the nominal lamp wattage.
• Heat output is the useful heat available from the front of
the lamp i.e., the heat produced in a solid angle of
90° around the lamp axis in the front hemisphere.
• The heat output numbers included in the table above have
been measured in a laboratory test.
• Heat lamp efficiency is defined as the ratio of the heat
output over the nominal input wattage.
• Heat output in the 0° to 30° zone is the heat output near
the centre axis of the lamp.
• Nominal lifetimes are listed below (manufacturers’ data):
Lamp Type Expected Lifetime(hrs) 175 W PAR 100 W PAR 250 W R 175 W R 150 W R 5,000
7 Incandescent Lamps
• Lamp life is defined statistically as the time in hours at
which 50% of the lamps are still functioning (while 50%
have failed).
• The expected lifetime of a single lamp is 5,000 hours, but
by definition, the actual lifetime can be higher or lower.
• PAR lamps have a more rugged construction and use a
tempered glass not easily broken by thermal shock or
mechanical impact.
• In farm applications, typical conditions include high
humidity, i.e., RH at least 75% and ammonia levels from 25
to 35 ppm, with an expected negative effect on lamp life.
• F luctuations in voltage are common in farms and have a
negative effect since higher voltages reduce the
expected lifetime.
• Monitoring line voltage of a large number of lamps in a
real farm setting and recording failure rates would provide a
comparison of reliability and lamp life between PAR and R
type lamps.
175 W PAR Lamps Can Replace 250 W R
• The technical data listed on the previous page indicates that
the 175 W PAR lamp can be a more efficient replacement
for the 250 W R lamp.
• Replacement results in savings of 75 W per lamp, i.e., 30%
energy savings.
• Heat output is reduced by 29 W.
7 Incandescent Lamps
• Heat output in the 0° to 30° zone, i.e., heat output near the
lamp axis zone, is almost the same for the old and the new
lamp (only 3.5 W less).
• The heat lamp efficiency is improved.
100 W PAR Lamps Can Replace 175 W R
• The 100 W PAR lamp can be a more efficient replacement
for the 175 W R lamp.
• Replacement results in savings of 75 W per lamp, i.e., 43%
energy savings.
• Heat output is reduced by 30 W.
• Heat output in the 0° to 30° zone, i.e., heat output near the
lamp axis zone, is almost the same for the old and the new
lamp (only 4 W less).
• The heat lamp efficiency is improved.
• Farm animal heating;
• In farm animal heating where lamps are on continuously;
• Restaurants also use them for keeping food warm.
• PAR heat lamps offer a more efficient and overall better
alternative to R type of heat lamps.
8 Fluorescent Lamp Ballasts
a. General
A ballast is a device used with a gas discharge lamp to
provide the necessary starting and operating electrical
• The ballast supplies the right voltage to start and operate
the lamp.
• The ballast limits current to a gas discharge lamp during
operation - the resistance of a gas discharge lamp becomes
negligible once the arc has been struck.
• The ballast prevents any voltage or current fluctuations
caused by the arc discharge from reflecting into the
line circuit.
• The ballast compensates for the low power factor
characteristic of the arc discharge.
Ballast Construction
• A simple standard ballast is a core and coil assembly.
• The core is made of laminated transformer steel.
• The coil consists of copper or aluminum wire which is
wound around the core.
8 Fluorescent Lamp Ballasts
• The core-coil assembly is impregnated with a nonconductor
to provide electrical insulation and aid in heat dissipation.
• Capacitors may be included in the ballast circuit to assist in
providing sufficient voltage, start the lamp, and/or correct
power factor.
• Some ballasts are housed inside the lighting fixture.
Simple Ballast Illustrations
Reactor Ballast
Reactor Ballast
PF Capacitor
8 Fluorescent Lamp Ballasts
Typical Wiring Diagrams
Ballast Losses
• A ballast, as an electric circuit, has electric energy losses.
• Ballast losses are obtained from catalogues of
ballast manufacturers.
• Energy efficient ballasts have lower losses.
• Basic types of ballasts based on ballast construction and
efficiency are:
• energy efficient ballasts (core-coil magnetic);
• electronic ballasts (solid-state);
• standard magnetic ballast (core-coil design).
8 Fluorescent Lamp Ballasts
• Ballasts are also classified by the type and function of their
electric circuit.
• Note that electro-magnetic fluorescent ballasts are gradually
being removed from the market place by energy regulations.
• Each ballast is designed to be used with a specific type and
size (wattage) of lamp.
• The lamp type and size compatible with the ballast are
listed on the ballast label.
• Ballasts should meet ANSI (American National Standards
Institute) specifications for proper lamp performance. The
Canadian standard for ballast efficiency is
CAN/CSA-C654-M91 Fluorescent Lamp Ballast Efficacy
• The CBMA (Certified Ballast Manufacturers Association)
label indicates that the ballast has been tested and meets
ANSI specifications.
• The UL (Underwriters Laboratories ) label indicates that
the ballast has been tested and meets UL safety criteria (US
standard) as well as the Canadian CAN/CSA-C654-M91
• The CSA (Canadian Standards Association) label indicates that the ballast has been tested and meets CSA safety
• Under the North American Free Trade Agreement, both
UL and CSA can certify electrical products for sale in both
8 Fluorescent Lamp Ballasts
Thermal Protection
• The NEC (US National Electrical Code) and the
Canadian Electrical Code require that all indoor ballasts
must be thermally protected.
• This is accomplished by a thermal switch in the ballast
which turns power off above a maximum temperature
(1050˚C approximately).
• Ballasts meeting this standard for protection are designated
Class P.
• A cycling ballast, which turns power off and on, indicates
an overheating problem.
Sound Ratings
• All core-coil ballasts produce a sound commonly described
as a “hum”.
• Manufacturers give the ballasts a sound rating from A to F
• An A ballast produces the least hum, and should be used in
quiet areas (offices, homes).
• An F ballast produces the most audible hum, and may be
used in places where noise is acceptable (factories,
8 Fluorescent Lamp Ballasts
Ballast Life
• Most ballasts are designed for about 50,000 hours under
standard conditions.
• If ballast and lamp heat is not dissipated properly ballast life
is reduced.
• An 8-10˚C increase over rated temperature on the case will
cut ballast life in half.
• Ballasts are rated typically for 75˚C. 90˚C ballasts are a
special design called “Extreme Temp”. Some
manufacturers list 8˚C instead of 10˚C.
• Similarly, a 100˚C decrease will approximately double
ballast life.
b. Electronic Ballasts for Gas Discharge Lamps
Typical Circuit Component Diagram
Supply AC
Line Filter
Line Filter
or Inductor
(≈25 kH
or Inductor
(≈25 kH2,AC)
Functional Block Diagram
Supply AC
DC to
AC to DC
High Frequency
DC to
AC to DC (AC<≈25
Output Stage
High Frequency
(AC<≈25 kH )
Output Stage
8 Fluorescent Lamp Ballasts
• Some ballasts have fewer components.
• Some ballasts have components to reduce total harmonic
distortion, improve power factor and provide thermal
General Description
• A rapid start ballast starts one or more gas discharge lamps
by first heating the electrodes of the lamps to the proper
electron emission temperature before initiating the arc.
• An instant start ballast does not preheat the electrodes but
initiates the arc by a higher starting voltage.
• A modified start ballast starts the lamp in the same way as
the rapid start ballast. It then reduces or cuts off the
electrode heating voltage after the lamp arc has stabilized.
• Both types of ballast stabilize the arc by limiting the current
to proper levels.
• Older technology (i.e., electromagnetic) ballasts are made
of laminated cores wound with copper or aluminum wires;
some have capacitors to control voltage and/or to correct
power factor.
• Electromagnetic ballasts operate the lamps at line
frequency, 60 Hz.
• Electronic ballasts for fluorescent lamps have electronic or
solid-state components.
• Electronic ballasts operate the lamps at a high current
frequency, typically from 25-50 kHz.
8 Fluorescent Lamp Ballasts
• Electronic ballasts in both the rapid start, instant start and
‘program start’ modes are available.
• Operation of rapid start lamps by instant start or modified
start ballasts can potentially shorten lamp life if combined
with other control technologies such as occupancy sensors.
Refer to the ballast and lamp manufacturers’ data.
• In comparison with the electromagnetic ballast, the
electronic ballast weighs less, operates at lower temperatures
and at a lower noise level, and is more energy efficient, but
costs more.
• It is essential to match the electrical characteristics of both
lamps and ballasts.
Technical Data
• Models are available for one-lamp, two-lamp, three-lamp or
four-lamp fixtures.
• Available in 120 volts, 277 volts and 347 volts. Some
ballasts are now available for universal voltage, i.e., 120 V to
277 V, and less common voltages such as 240 V.
• Ballast specification is based on: number of lamps, lamp
type (F32T8/841 or other) and line voltage.
• Example: two-lamp F32T8/841 120V electronic ballast.
• Some electronic ballasts are dimmable.
• The efficacy of electronic ballasts is 21% to 43% better than
electromagnetic ballasts.
• Total harmonic distortion (THD) indicates the strength of
electromagnetic noise generated.
• Lower ballast temperature means lower electrical losses and
a smaller cooling load.
8 Fluorescent Lamp Ballasts
Total Harmonic Distortion
• Harmonics are frequencies that are integral multiples of the
fundamental frequency.
• For a 60 Hz fundamental frequency, the second harmonic is
120 Hz, and the third is 180 Hz.
• Harmonics can be present in voltage and/or current.
• Harmonics occur whenever the wave shape is distorted
from a pure sine wave.
• Electric utilities supply voltage and current very close to the
sinusoidal wave form.
• If the user’s load is nonlinear, drawing short pulses of
current within each sine wave cycle, the sinusoidal current
wave shape will be distorted and a harmonic current will
be present.
• The characteristics of the nonlinear load determine the
form of the distortion, the magnitude of each harmonic and
the corresponding harmonic current.
• Total current is a combination of the fundamental
frequency and a contribution from each of the harmonics.
• THD in the current is the root mean square (rms) of all the
harmonic currents as a percentage of the fundamental
current, and is defined as follows:
THD = sum of squares of rms magnitudes of all harmonics* X 100%
rms magnitude of fundamental
* Does not include the fundamental.
• IEEE Standard 519-1981 refers to the Distortion Factor
(DF) which equals the THD. However, THD is the
preferred term in this guide as it is more descriptive.
8 Fluorescent Lamp Ballasts
• Most electromagnetic ballasts have THD between 18%
and 35%.
• Electronic ballasts generate less than 32% THD. Most of
them are below 20%. Some are below 10%.
• D ue to higher efficiency, the T8 electronic ballast system
typically draws 30% less current than the conventional
electromagnetic ballast system.
Electromagnetic Interference (EMI) or Radio Frequency Interference (RFI)
• EMI/RFI may cause interference with communication
equipment, such as radio, TV, computer.
• F luorescent lamps energized by electromagnetic or
electronic ballasts radiate EMI directly into the air.
• EMI from the lamps may feed back to the line conductors
via the ballasts.
• EMI at the electronic ballast fundamental frequency and its
harmonics propagate from the ballast’s electronic circuits
to the line conductors. This EMI may interfere with other
electrical equipment on the same distribution network.
• EMI may radiate from the line conductor into the air.
• EMI may be radiated from the high frequency electronic
components of the electronic ballast.
• In the US, electronic ballasts must comply with Federal
Communications Commission Part 18, Subpart C, Class A
for industrial and commercial applications, or Class B for
residential applications. As yet no Canadian standard has
been set.
8 Fluorescent Lamp Ballasts
Power Factor
• Power factor can be calculated by two methods:
• wattage (W), voltage (V) and current (I)
• wattage (W) and reactive power (VAR).
• If calculated correctly – the results should be the same using
both methods.
• A low power factor will increase the demand component of
your electricity bill for a given lighting load
Rated Average Life
• Ballasts are designed to operate for about 50,000 hours.
• Lower ballast operating temperature reduces
air-conditioning load.
• The early models had lower reliability than the
present ballasts.
• W hen used with light sensors, dimmable electronic ballasts
can reduce the lighting load by providing just the required
light level, if other light sources exist.
• Similarly, an energy management and control system uses
dimmable ballasts to partially shed the lighting load.
9 Fluorescent Lamps
a. General
• For typical construction of a fluorescent lamp, see the
figure below.
• A fluorescent lamp is a low-pressure mercury electric
discharge lamp.
• A fluorescent lamp consists of a glass tube filled with a
mixture of argon gas and mercury vapour at low pressure.
• W hen current flows through the ionized gas between the
electrodes, it emits ultraviolet (UV) radiation from the
mercury arc.
• The UV radiation is converted to visible light by a
fluorescent coating on the inside of the tube.
• The lamp is connected to the power source through a
ballast, which provides the necessary starting voltage and
operating current.
9 Fluorescent Lamps
Typical Construction of a Linear Fluorescent Lamp
Basic Types of Fluorescent Lamps
• Preheat lamps
• Instant start lamps
• Rapid start lamps
Preheat Lamps
• The cathodes of the lamp are preheated electrically for a
few seconds before a high voltage is applied to start
the lamp.
• The preheating is accomplished by the use of an automatic
switch, called a “starter”, which applies current to the
cathodes for sufficient time to heat them.
• The preheat lamps have a bi-pin (double-pin) base at
each end.
• Preheat lamps operate normally in a preheat circuit (preheat
ballast, starter, lamp and lamp holders).
9 Fluorescent Lamps
• Preheat lamps can also be used in rapid start circuits.
• Preheat lamps are not widely used today
Instant Start Lamps
• The instant start lamp requires a high starting voltage,
which is supplied by the ballast.
• Since there is no preheating of the cathodes, there is no
need for a starter.
• Electrode heating is provided by the arc once it has
been established.
• The instant start lamps have a single-pin base at each end
of the bulb.
• A few instant start lamps have bi-pin bases, with the pins
connected together inside the base.
• Instant start lamps operate normally only in an instant start
circuit (instant start ballast, lamp and lamp holders).
Rapid Start Lamps
• The ballast quickly heats the cathodes causing sufficient
ionization in the lamp for the arc to strike.
• The cathodes may or may not be continuously heated after
lamp starting, depending on ballast design.
• Rapid start lamps start almost instantly (in one or
two seconds).
• No starter is required - eliminating the time delay of
preheat systems.
• Less voltage is required for starting than with instant start
lamps, thus using smaller, more efficient ballasts.
9 Fluorescent Lamps
• The rapid start lamps have a bi-pin (double-pin) base at
each end.
• Rapid start lamps can also be used for dimming and
flashing applications.
• Rapid start lamps operate normally only in a rapid start
circuit (rapid start ballast, lamp, and lamp holders).
• Rapid start lamps are the most widely used fluorescent
Types of Rapid Start Lamps
• Linear fluorescent lamps – new types, both T8 and T5 sizes
• Linear fluorescents (430 mA for F40) - old types, primarily
T12 size
• Energy saving fluorescents, primarily T12 size
• U-shaped fluorescents, in both T8 and T12 sizes
• Circular lamps, in T9 and T5 sizes
• High output lamps, available in T12, T8 and T5 sizes
• Very high output lamps (1500 mA), primarily T12 size
• Lamp diameters range from 5/8˝ to 2.5˝
9 Fluorescent Lamps
High Output and Very High Output
T-5 miniature bi-pin (5/8˝ diameter)
T-8 medium bi-pin (1˝ diameter)
T-12 medium bi-pin (11/2˝ diameter)
T-12 recessed double contact (11/2˝ diameter)
T-6 single-pin (3/4˝ diameter) SLIMLINE
T-6 single-pin (3/4˝ diameter) SLIMLINE
T-17 mogul bi-pin (21/8˝ diameter)
T-12 single-pin (11/2˝ diameter) SLIMLINE
Compact Fluorescent
T4, T-5
Medium bi-pin (11/2˝ diameter)
9 Fluorescent Lamps
Lamp Designations
Bi-pin lamps (preheat, instant start, rapid start)
Identified by wattage, bulb diameter and colour.
Example: F40TI2/CW/ES
40 T
12 CW : Fluorescent lamp
: Wattage (34 W for ES types)
: Tubular bulb shape
: Maximum tube diameter - in eighths of an inch (12/8 = 1.5˝)
: Cool white colour
• Example: F32 T8/41K
32 T
41K : Fluorescent lamp
: Wattage (32 W)
: Tubular bulb shape
: Maximum tube diameter - in eighths of an inch (8 x 1/8 = 1˝)
: 4,100 K, Cool white colour
Single-pin lamps (instant start)
• Identified by length and colour rather than wattage because
they can operate at more than one wattage.
• Example: F96T12/WW
96 T
12 WW : Fluorescent lamp
: Lamp length in inches
: Tubular bulb shape
: Maximum tube diameter - in eighths of an inch
: Warm white colour
9 Fluorescent Lamps
Lamp Lengths
Some typical lamp lengths are:
• F20 lamp - 24˝ (2´)
• F30 lamp - 36˝ (3´)
• F32 T8 lamp - 48˝ (4´) – becoming the industry
standard lamp
• F40 lamp - 48˝ (4´)
• F96 lamp - 96˝ (8´)
Colour Codes
(e.g., 841 = 80% CRI and 4100 Kelvin)
C50 C75 CW CWX D
SP SPX WW WWX 741 735
Deluxe CRI
: Chroma. 50 (5,000K, CR190+)
90+ 5000
: Chroma 75 (7,500K, CR190+)
90+ 7500
: Cool White
62 4200
: Cool White Deluxe
87 4100
: Daylight
76 6500
: Lite White
48 4150
: Natural
86 3600
: Spectrum Series
70+ varies
: Spectrum Series Deluxe
80+ varies
: Warm White
52 3000
: Warm White Deluxe
74 2950
: T8 Cool lamp colour
70+ 4100
: T8 Neutral lamp colour
70+ 3500
: T8 Warm lamp colour
70+ 3000
: T5 & T8 Cool lamp colour
85+ 4100
: T5 & T8 Neutral lamp colour
85+ 3500
: T5 & T8 Warm lamp colour
85+ 3000
: Means better CRI, but with older style T12 lamps, also lower efficacy
9 Fluorescent Lamps
Lamp Type Code
The lamp type code follows the colour code.
Lamp type codes are listed below.
• IS • RS • HO • VHO •U
• WM • SS • EW : Instant Start
: Rapid Start
: High Output
: Very High Output
: U-shaped
: WattMiser (General Electric)
: Super Saver
: Econowatt (Philips)
General 84
- A fluorescent luminare consists of:
a ballast, usually shared by two lamps,
fixture and lense or louvers
Lamp Configuration- Linear, U-shape, circular or compact
Lamp Watts - 7 W to 215 W
Ballast Watts - varies according to type,
electromagnetic or electronic, and
Ballast Factor
Rated Average Life - 20,000 hours for typical F32T8 lamps
- 24,000 hour T8 lamps are available
- 20-24 times the life of a typical
Luminous Efficacy - 40 to 100 lumens per watt
Lamp Lumen - 70% to 90%
9 Fluorescent Lamps
Depreciation Factor (LLD)
Colour Temperature - 2,700 K to 7,500 K
- Wide range of colour temperatures
Index (CRI)
Colour Rendering - 62 to 94
Warm-up Time - Instant
- Sensitive to extremes of temperature
- Slower than incandescent
Restrike Time - Immediate
Lamp Cost - Low
- Energy-saving and energy-efficient
lamps more expensive
Main Applications - Offices, commercial
9 Fluorescent Lamps
Designation Lamp Watts Including 1 Lamp Rated Lamp Ballast Life (2 Lamp) (hours) Initial Lumens Initial
Lumens Colour
per Temp
Watt Deg K CRI
2,775 1,925 2,825 2,350 2,925 2,925 2,925 2,925
2,925 2,925
2,925 2,925
59.0 41.0 60.1 50.0 62.2 62.2 62.2 62.2 62.2 62.2 62.2 62.2 Energy Saving, Rapid Start, Bi-Pin Base
F4OT12/.... /RS/....EW, SS or WM
LW 3OU 35U 41U 5OU SPEC30 SPEC35 SPEC41 86
34 34 34 34 34 34 34 34 34 34 34 34 47 47 47 47 47 47 47 47 47 47 47 47 (81) (81) (81) (81) (81) (81) (81)
(81) (81) (81) (81) (81) 20,000 20,000 20,000
20,000 20,000 20,000 20,000 20,000 20,000
20,000 20,000 20,000 4,100 4,100 3,000 6,500 4,160 3,000 3,500 4,100 5,000 3,000 3,500 4,100 Notes:
• Refer to lamp manufacturers for colours other than shown here.
• Rated Average Life for fluorescent lamps is based on three hours per start.
• Mean Lumens for fluorescent lamps are listed at 40% of lamp life.
See Also
• Lamp manufacturers’ catalogues.
9 Fluorescent Lamps
Lamp Designation Including Lamp Ballast Watts 1 Lamp (2 Lamp) Rated Initial Mean
Lamp Lumens Lumens Colour
Life Initial per Mean per Temp
(hrs) Lumens Watt Lumens Watt Deg K CRI LLD
Compact Fluorescent
7W + 9W +
13W + 7
13 10 10 17 10,000 10,000 10,000 400 40.0 600 60.0 900 52.9 2,700 81 0.80
2,700 81 0.80
2,700 81 0.80
Circlite (retrofit for incandescent)
FCA22/SW + FCA44/SW + 22 44
22 44
32 40 27 44 56 10,000 870 39.5
7,500 1,750 39.8
Rapid Start Circline
FC8/CW/RS + 1 FC12/CW/RS + FC16/CW/RS + 12.000 1,050 38.9 805 29.8 4,300 62 0.72
12,000 1,800 40.9 1,465 33.3 4,300 62 0.82
12,000 2,500 44.6 1,910 34.1 4,300 62 0.77
Instant Start, 200 milliamp, Single Pin Base
F72T8/CW F96T8/CW
38 50 55 (100) 7,500 3,100 56.4 2,700 49.1 4,300 62 0.83 70 (130) 7,500 4,200 60.0 3,860 55.1 4,300 62 0.89
Instant Start, 430 milliamp, Single Pin Base
F48Tl2/CW F48TI2/LW F72Tl2/CW F96T12/CW F96TI2/LW 39
30 55 75
60 65 (104) 9,000 55 (84) 9,000 80 (150) 12,000 97 (172) 12,000
82 (142) 12,000
2,675 4,600 6,300 6.000 46.2 48.6 57.5 64.9
73.2 2,760 42.5 2,460 44.7 4,320 52.9 5,8DO 59.8 5,430 66.2 4,3DO 4,100 4,300 4,300 4,100 62 49 62 49
49 0.82
Rapid Start, 430 milliamp, Bi-pin Base
cool white cool while deluxe
warm white warm white deluxe
daylight 30 46 (76) 18,000 2,300 50.0 2,010 43.7 4,300 62 0.81
40 40 53 (93) 20,000 3,150 59.4 2.715 51.2 4,300 62 0.84
53 (93) 20,000 2,220 41.5 1,800 34.0 4,200 87 0.84
40 53 (93) 20,000 3,200 60.4 2,715 51.2 3,000 52 0.84
53 (93) 20,000 2,150 40.6 1,765 33.3 3,100 73 0.84
40 53 (93) 20,000 2,600 49.1 2,245 42.4 6,500 75 0.84
9 Fluorescent Lamps
Lamp Designation Including Lamp Ballast Watts 1 Lamp (2 Lamp) Rated Initial Mean
Lamp Lumens Lumens Colour
Life Initial per Mean per Temp
(hrs) Lumens Watt Lumens Watt Deg K CRI lite white 35 48 (83) 20,000 lite white deluxe 34 47 (81) 20,000 full spectrum 5000 40 53 (93) 20,000 full spectrum 7500 40 53 (93) 20,000 prime colour 3000 40
53 (93) 20,000
prime colour 4000 40 53 (93) 20,000
*indicates low power factor ballast only available
3,050 3.050 2,200 2,000 3,400 3,400
63.5 4,160 64.9 4,100 41.5 1,850 34.9 5.000 37.7 1,685 31.8 7,500
3,000 64.2 4,000 48 67 92
94 85 85 0.84
2,800 2,950 2,900 3,000 93.0 98.0 96.6 100 Rapid Start T8, Bi-pin Base
F032/730 F032/830 F032/830 6
32 32 30 (59) 30 (59) 30 (59) 30 (59) 20,000 20,000 24,000 24,000 2,520
2,714 2,755
2,850 84.0
90.0 91.8 95.0 3,000 3,000 3,000 3,000 75 82 85 85 0.90
3,740 5,785 8,005 7,915 44.0 54.6 57.2 66.5 4,300
4,300 4,300 4,160 4,100 62
62 62 48 67 0.82
32.5 37.2 44.6 49.2 49.2 4,300 4,300 4,300 4,300 4,160 62
62 62
62 48 0.69
Hiqh Output Rapid Start, 800 milliamp, Recessed Double Contact Base
F48TI2/CW/HO 60 F72Tl2/CW/HO 85
F96Tl2/CW/HO 110
F96TI2/LW/HO 95 F96Tl2/LWX/HO 95 85 (146) 106 (200) 140 (252) 119 (231) 119 (231) 12,000 12,000 12,000
4,300 6,650 9,200 9,100 9,100 50.6 62.7 65.7
76.5 76.5 Very High Output Rapid Start, 1500 milliamp, Recessed Double Contact Base
F96PG17/CW F96PG17/LW 110 165 215 215 185 146 (252) 213 (326) 260 (450) 260 (450) 230 (390) 10,000 6,250 10,000 9,900 10,000 14,500
12,000 16,000 12,000 14,900
42.8 4,750 46.5 7,920 55.8 11,600
61.5 12,800
64.8 11,325 *indicates low power factor ballast only available
Notes: Some lamps listed here are no longer commercially available, notably the full output F40/CW lamp; they are
included here for comparison only.
9 Fluorescent Lamps
b. Premium T-8 Lamps
Lamp manufacturers now offer premium grade T-8 lamps for
special applications where exceptional colour, longer life and
improved lumen output are required.
Standard F32 T-8 Lamp:
20,000 hrs, 82 CRI, 2,950 initial lumens,
98.3 initial lm/W
Premium F32 T-8 Lamp:
30,000 hrs, 86 CRI, 3,100 initial lumens,
103.3 initial lm/W
c. Low-Wattage T-8 Lamps
Lamp manufacturers now offer reduced output or
low-wattage T-8 lamps for increased savings on retrofit
projects, or for new construction.
Standard F32 T-8 Lamp:
20,000 hrs, 82 CRI, 2,950 initial lumens, up to
80 lm/W depending on ballast
Low-Wattage F28 T-8 Lamp:
2 4,000 hrs, 82 CRI, 2,562 initial lumens, up to
93 lm/W, depending on ballast
• These lamps have some limitations, for example, they
cannot be dimmed, and don’t operate in cool
temperatures (<60˚F)
• Some operate on programmed start ballasts and all operate
in instant start ballasts.
d. T-5 and T5-HO Fluorescent Lamps
• Lamp manufacturers now offer T-5 fluorescent lamps in
both standard and High Output (HO) versions.
• The smaller diameter tube yields a more compact lumen
package, which is easier to control.
9 Fluorescent Lamps
• T-5 fluorescent lamps are available in various lengths and
wattages from 14 W to 80 W, and in a circline version in
22 W, 40 W, and 55 W.
• T-5 lamps are nominal length lamps, which means that they
cannot be retrofit into fixtures using standard T-12 or T-8
lamps. Therefore, they are generally used for re-design or
new construction projects.
• T-5 fluorescent lamps require the use of electronic ballasts
and unique sockets.
• T-5 lamps are driving miniaturization and can be used in
indirect applications.
• T5-HO is an increasingly popular fluorescent lamp;
primarily used in normal to high bay applications, big box
retail, warehouse and distribution centres, industrial
applications and gymnasiums. T5-HO are also dimmable
and operate on instant start ballasts.
• T5 and T5-HO have maximum light output at higher
ambient temperatures.
Standard T-5 Lamps: 14 W, 24˝ (nom), 20,000 hrs, 82 CRI, 1,350 initial lumens
2 1 W, 36˝ (nom), 20,000 hrs, 82 CRI, 2,
100 initial lumens
2 8 W, 48˝ (nom), 20,000 hrs, 82 CRI, 2,900 initial lumens
3 5 W, 60˝ (nom), 20,000 hrs, 82 CRI, 3,650 initial lumens
9 Fluorescent Lamps
High Output T-5 Lamps:
24 W, 24˝ (nom), 20,000 hrs, 82 CRI, 2,000 initial lumens
3 9 W, 36˝ (nom), 20,000 hrs, 82 CRI, 3,500 initial lumens
5 4 W, 48˝ (nom), 20,000 hrs, 82 CRI, 5,000 initial lumens
e. Fluorescent Fixture Reflectors
General Description
Fluorescent fixture reflectors are sheets of aluminum placed
inside fluorescent fixtures, which divert light directed toward
the ceiling down toward the work area.
• Illustration of a recessed reflector for a 2´ x 4´ fixture, with
removal of two lamps.
Before installation of the reflector:
After installation of the reflector:
9 Fluorescent Lamps
Physical Data
• There are three basic types of reflectors:
• Anodized aluminum or steel reflectors - in which the
surface is painted with a highly reflective electrostatic or
powder-epoxy finish.
• Anodized aluminum reflectors - in which the
aluminum surface is treated (polished)
• Silver film reflectors - in which a thin film of silver is
laminated to an aluminum substrate.
• The reflector finish can be high gloss paint, specular
(mirror-like), semi-specular, or diffuse (matt).
• The reflector shape is specially designed to optimize light
distribution (custom-designed by the supplier).
• Reflectors are made in the following sizes:
• Single reflectors - 4´ or 8´ long, one-lamp use
• Double reflectors - 4´ or 8´ long, two-lamp use
• Recessed reflectors - for 2´ x 2´ or 2´ x 4´ fixtures.
Technical Data
• The average total reflectivity for anodized aluminum
reflectors is about 90% to 91%.
• The average total reflectivity for silver film reflectors is
about 94% to 97%.
• Life expectancy of a silver film reflector is about 15 years.
• Life expectancy of an anodized aluminum reflector is about
20 years.
9 Fluorescent Lamps
• Reflectors are used for lighting energy conservation.
• Reflectors are used for fixture retrofitting or in new energy
efficient fixtures.
• A typical application is the installation of a recessed
reflector in a 2´ x 4´ fixture, with removal of two of the
four tubes.
• In most instances, it is necessary to re-centre the two
remaining lamps in the fixture to avoid dark spots.
• The reflector creates the image of a lamp in the place of the
removed lamp; this allows delamping without creating
dark spots.
• The light output of a retrofitted fixture with half the lamps
removed typically decreases by about 35%, depending on
reflector material and design.
• Cleaning and relamping at the same time increases light
output by 5% to 20%.
• Costs depend on the type, size and design of the reflector.
9 Fluorescent Lamps
• Reduces lighting power consumption;
• Improves luminous efficacy in the work area;
• Reduces cooling load, in the case of delamping;
• Extends ballast and lamp life by decreasing
operating temperature;
• Fewer lamps and fixtures are required;
• Reduces maintenance costs.
• May have long payback period;
• Not cost-effective if fixtures of different size and type
are involved;
• May create a ‘cave effect’ in some situations, causing
walls to appear dark at the top because the light is
focused downwards.
• Has clear benefits from a lighting efficiency point of view.
• Should be compared to other lighting conservation
9 Fluorescent Lamps
f. Compact Fluorescent Lamps
• Compact fluorescent lamps are small-size fluorescent lamps.
• There are two general types of lamps:
- self-ballasted or screw based lamps, for direct
replacement of incandescent lamps
- pin-based lamps for compact fluorescent light fixtures
• They are also available in a large variety of sizes and
wattages, and in twin-tube, quad-tube, long tube, twisted,
reflectorized and fully enclosed versions.
T4, T5
Screw Base
Compact Fluorescent
p07 d
9 Fluorescent Lamps
9 Fluorescent Lamps
Ballast Lumens Colour
per Length Length Temp
Lamp Watts Lumens Watt (mm) (in.) K
CRI Life Base
2-tube or Bi-tube
5 W
13 W 8 W
10 W 12 W 17 W 250 400 600 90O 50 57
67 69 105 4 1/8
135 5 5/16 167 6 9/16 178 7 1/2 2700 2700 2700 2700 82 82 82 82 10,ODO 10,ODO 10,000 10,000 G23
14 W 600 17 W 900 23 W 1,250 32 W 1,800 60 69 69 69 108 140 170 190 4 1/4 5 5/8
6 7/8 7 1/2 2700
2700 2700 2700 82 82 82 82 10,000 10,000 10,000 10,000 G24D-1
69 79 83 221 8 11/16 320 12 9/16 417 16 7/8 2700 3000 4000 2700 3000
4000 2700 3000 4000 82 82 82 82 82 82 82 82 82 10,000 10,000 10,000 10,000 10,000 10,000 10,000 10,000 10,000 2G11
4-tube or Quad-tube
10 W 13 W
18 W 26W Long-tube or High Output
18W 25 W 1,250 24 W 32 W 1,900 36 W 48 W 3,000 Self-ballasted Types
Lumens per Watt
To Replace
6,000 hrs 25 W chandelier lamp
6,000 hrs
60 W A lamp
6,000 hrs
60 W G lamp
6,000 hrs
75 W A lamp
6,000 hrs
70 W ER lamp
6,000 hrs
100 W A lamp
9 Fluorescent Lamps
General Remarks
• The self-ballasted (screw base) lamps are available with
incandescent-like features (small size, shape, dimming,
3-way, etc.)
• Compact fluorescent lamps are about four times more
efficient than standard incandescent lamps.
• Efficacy or lamp efficiency increases with lamp size and
wattage. The smaller size, lower wattage lamps are generally
less efficient than the larger size and higher wattage lamps.
• Compact fluorescents have an average life that is 10 times
longer than that of standard incandescent lamps, and have a
lower maintenance costs.
• They have a high colour rendering index, generally >82, but
lower than incandescent lamps.
• They need a ballast to operate, as do all fluorescent lamps.
• Lamps of different manufacturers are interchangeable.
• Maximum overall length
• Most compact fluorescent lamps are available with a variety
of colour temperature values, similar to T5 and T8
fluorescent lamps (3,000 K, 3,500 K, 4,100 K).
• There is an Energy Star program for compact fluorescent
lamps in North America.
9 Fluorescent Lamps
Compact Fluorescent Fixtures
• Many manufacturers produce fixtures for compact
fluorescent lamps which include a specially designed ballast
and socket (lamp holder). These are available in recessed,
outdoor and decorative versions.
• Lamp manufacturers produce retrofit adapters which
include the ballast and lamp socket, and have a base to
screw directly into a standard incandescent socket
(see Self-Ballasted Types, above.).
• Recessed compact fluorescent fixtures should have a
properly designed reflector, otherwise light will be trapped
inside the fixtures and be wasted.
Two-tube Compact Fluorescent Lamps
• Can be used as replacements for small incandescent lamps.
• Compact fluorescent lamp sizes 5 W, 7 W, 9 W and 13 W
can replace incandescent lamp sizes 25 W, 40 W, 50 W and
60 W respectively.
• Compact fluorescent lamps of different wattage rating use
slightly different bases and sockets, to eliminate the
possibility of plugging a lamp into a fixture with the wrong
ballast for that lamp. For example, it is not possible to plug
a 13 W lamp into the socket of a fixture with a ballast rated
for a 26 W lamp.
9 Fluorescent Lamps
• Lobby areas, hallways and corridors, any area where there
are long hours of use.
• Recessed downlight fixtures.
• Wall and ceiling-mounted fixtures.
• Directional signs.
• Security lighting fixtures.
• Desk and task lighting fixtures.
• Display lighting (museums, stores).
• To replace light bulbs in fixtures which are not readily
Four-Tube Compact Fluorescent Lamps
• Made by combining two two-tube compact fluorescent
• Also known as double twin-tubes, quad or cluster lamps.
• Same length as two-tube compacts, but double the light
output (lumens).
• Four-tube compact fluorescent lamp sizes 9 W, 13 W,
22 W and 28 W can replace incandescent lamp sizes 40 W,
60 W, 75 W and 100 W respectively.
9 Fluorescent Lamps
• Similar to the applications of the two-tube compact
fluorescent lamp (see above).
• The four-tube compact fluorescent lamps replace relatively
higher wattage incandescent lamps than the two-tube
Long Tube Compact Fluorescent Lamps
• Longer than the two-tube and four-tube compact
fluorescent lamps.
• Can replace standard fluorescent lamps.
• Long tube compact fluorescent lamp sizes 18 W, 24 W and
36 W have the same light output as standard fluorescents
F20, F30 and F40 respectively, but are only one third of
the length.
• Longer compact fluorescent lamps also feature longer lamp
life, up to 20,000 hrs.
10 HID Lamp Ballasts
a. Ballasts General
Like fluorescent lamps, HID lamps are electric discharge
lamps. A ballast is required to provide proper starting and
operating voltage and current in order to initiate and sustain
the arc.
b. Probe Start Ballasts
The standard core and coil HID ballast or probe start
ballast consists of a series of electrical coils on a core of steel
laminations. The coils are impregnated with a varnish to
provide electrical insulation, reduce noise and dissipate heat.
Some ballasts for interior use are housed in metal cans and
potted with insulating materials.
c. Pulse Start Ballasts
• Pulse start HID Ballasts incorporate a different starting
technique which reduces ballast losses and increases lamp
• Pulse start retrofits can be a good measure for existing metal
halide installations in schools, industrial and commercial
• A 320 W metal halide pulse start system can replace a
400 W system.
• The pulse start lamp gives less lamp lumen depreciation,
better colour consistency over lamp life, and faster
hot restrike.
10 HID Lamp Ballasts
d. Electronic HID Ballasts
Designed primarily for the low wattage Ceramic Metal Halide lamps, the electronic HID ballasts are gradually expanding to higher lamp wattages.
• Significantly smaller size and lower weight than core and
coil systems.
• More efficient, up to 20% savings over conventional ballasts.
• Square wave output increases lamp life.
• Automatic end-of-life detection; shuts lamp down instead
of trying to restart.
11 HID Lamps & LPS Lamps
a. Mercury Vapour (MV) Lamps
Use of MV Lamps should be discouraged. They are no more
efficient than fluorescent applications in indoor applications,
in outdoor applications they should be replaced with one
of the other gas discharge lamps. The disposal of mercury
vapour lamps require special methods because of the mercury
inside the lamp. Local disposal authorities should be
contacted for approved disposal methods.
• The mercury vapour (MV) lamp, or mercury lamp, is a
high-intensity discharge (HID) lamp.
• Light is produced by current passing through the mercury
vapour at relatively high pressure.
• The MV lamp is the oldest HID source.
• An MV lamp, like all HID lamps, consists of an arc tube
enclosed in an outer bulb (a bulb in a bulb).
• The arc tube contains the mercury vapour, a starting gas
(argon) and the electrodes.
• The outer bulb contains an inert gas (nitrogen) to prevent
oxidation of internal parts and to maintain the operating
• The outer bulb also provides an inner surface for an
optional phosphor coating.
11 HID Lamp & LPS Lamps
Typical Construction and Circuit of an MV Lamp
• W hen the lamp is turned on, a voltage is applied to
initiate an arc between a starting electrode and the nearby
main electrode, which vaporizes the mercury.
• The “warm-up” time until the lamp develops full light output is five to seven minutes.
• The “restrike” time (time required to start up after a
momentary power interruption) is about 10 minutes.
• D uring operation, when the electric arc is formed the
mercury vapour emits light and ultraviolet (UV) radiation.
• UV radiation can be converted to light by a phosphor
coating on the inside of the outer bulb.
• MV lamps, like all HID lamps, require ballasts.
11 HID Lamp & LPS Lamps
• Standard MV, 40 to 1,000 watts.
• Self-ballasted MV, 160 to 1,250 watts.
Rated Average Life
• 24,000 hours + for most MV lamps.
• There are two types of MV lamps, clear and
• Clear MV lamps have a bluish-white colour and poor
colour rendering.
• Phosphor-coated MV lamps have a better colour
appearance and colour rendering.
• MV lamps are the least efficient of all HID lamps.
• MV lamps are more efficient than incandescent lamps, but
less efficient than fluorescent lamps.
• Efficacies range from 10 to 63 lumens per watt.
11 HID Lamp & LPS Lamps
• MV lamps are no longer specified for new construction or
retrofit due to poor efficacy.
• The disposal of mercury vapour lamps will require special
disposal methods because of the mercury inside the lamp.
Local disposal authorities should be contacted for approved
disposal methods
• Interior industrial applications.
• Street lighting, security lighting, floodlighting.
• Retail shops, indoor shopping malls, restaurants, cafeterias,
air/bus terminals, lobbies, foyers, gymnasiums, banks, barns.
11 HID Lamp & LPS Lamps
MV vs Other High Intensity Discharge Lamps
• It may be more economical to replace MV lamps with metal halide or high pressure sodium (HPS) lamps, which
have much better luminous efficacy.
• These direct replacement lamps may improve the efficacy
by 70%+.
• Refer to chapters on MH lamps and HPS lamps
• MV lamps are rarely used in new lighting systems.
Shape code
A :Arbitrary
BT :Bulged-tubular
E :Elliptical
:Parabolic aluminized
11 HID Lamp & LPS Lamps
Lamp Data
Lamp Designation Including Lamp Ballast Watts I Lamp (2 Lamp) Rated Initial Mean
Lamp Lumens Lumens Colour
Life Initial per Mean per (hrs) Lumens Watt Lumens Watt Temp
25.6 27.0 32.4 352
37.2 41.6
48.1 46.0
7,000 7,000 7,000 6,800 5,900 5,900
5,900 5,900 22
22 22 22 22 22
22 22 0.73
20.0 23.7 28.2 34.0 36.4 37.9 40.9 44.5 43.2 4.000
4,000 4,000
4,000 4,000 4,000 4,000 4,000
43 43
43 43 43 43 43 0.61
H43 75
75 95 (190) 24,000 2,800 29.5 2,430 H38 100 100 125 (250) 24,000 4,100 32.8 3,380
H42 125 125 155 (310) 24,000 5,700 36.8 5,020 H39 175 175 210 (410) 24,000 7,900 37.6 7,400 H37 250 250 290 (580) 24,000 12,000 41.4 10,800 H33 400 400 450 (880) 24,000 20,500 45.6 18,700 H35 700 700 775 (1,550) 24,000 41,000 52.9 37,300 H36 1000 1,000 1,100 (2,200) 24,000 57,500 52.3 50,600
Phosphor Coated
H46 50/DX 50 63 (125) 16.000 1,575 25.0 1,260 H43 75/DX 75 95 (190) 16,000 2,800 29.5 2,250 H38 100/DX 100 125 (250) 24,000 4,200 33.6 3,530 H42 123/DX 125 155 (310) 24.000 6,350 41.0 5,270 H39 175/DX 175 210 (410) 24,000 8,600 41.0 7,650 H37 250/DX 250 290 (580) 24,000 13,000 44.8 11,000 H33 400/DX 400 450 (880) 24,000 23,000 51.1 18,400 H35 700/DX 700 775 (1,550) 24,000 44,500 57.4 34,500 H36 1000/DX 1,000 1,100 (2,200) 24,000 63,000 57.3 47,500 Self-Ballasted (for replacement of incandescent)
H160 H250 H450
160 250 450 750
160 250 450 750 12.000 2,300 14.4 l,600 12,000 5,000 20.0 3,750 16,000 9,500 21.1 7,125 16,000 14,000 18.7 10,500 10.0
15.0 15.8
•Mounting for position-oriented lamps is indicated as HOR (horizontal) or VER (vertical) only.
•When position is unspecified the lumen output value given applies to vertical mounting. Slightly reduced values will result if lamp is mounted in other positions.
•Life and mean lumen ratings for HID lamps are based on 10 hours per start.
•H indicates MV lamp (H for Hg - the chemical symbol for mercury).
•These lamps are being phased out.
11 HID Lamp & LPS Lamps
b. Metal Halide Lamps
• The metal halide (MH) lamps are generally similar in
construction to the MV lamps.
• They operate on the same principle as all HID lamps.
• The main difference is that the arc tube contains metallic salts (scandium and sodium) in addition to the mercury
vapour and argon gas.
• Like all HID sources, MH lamps consist of an arc tube
enclosed in an outer bulb.
Typical Construction and Circuit of an MH Lamp
Note: Pulse Start lamp uses higher open circuit voltage for starting.
11 HID Lamp & LPS Lamps
• Warm-up time is about 4 minutes.
• Restrike time is about 10-12 minutes standard - 4-7 min.
for pulse start.
• MH lamps generally cannot be burnt in any position.
• Horizontal-burning lamps have the arc tube bowed upward,
to follow the natural curve of the arc stream in the
horizontal burning position.
Available Wattage
• Sizes range from 40 to 1,500 watts.
Rated Average Life
• 6,000 hours (70 W) to 20,000 (400 W).
• MH lamps are available in both clear and
phosphor-coated versions.
• Clear lamps produce a slightly bluish-white colour and have
a CRI far superior to MV lamps.
• Phosphor-coated lamps produce a warmer-looking white
light and an improved CRI.
• MH lamps exhibit some colour variation from lamp to
lamp and normally change colour throughout their life.
11 HID Lamp & LPS Lamps
• The MH lamp is the most efficient source of “white”
light available.
• Efficacies range from 50 to 110 lumens per watt.
• MH lamps are more efficient than MV and fluorescent
lamps, but less efficient than HPS and low pressure sodium
(LPS) lamps.
• CRI - 65-70
• Similar to MV lamps.
• MH lamps are effective replacements for MV lamps.
• Large wattages are used for floodlighting, streetlighting,
large industrial areas and sports arenas.
• Smaller wattages are used in merchandising areas, assembly
spaces, schools and public buildings.
• Clear lamps are used for colour TV broadcasting, colour
photography, industrial/commercial lighting.
• Phosphor-coated lamps are used for industrial/commercial
indoor lighting, area lighting.
Major manufacturers carry a variety of metal halide lamps.
11 HID Lamp & LPS Lamps
BT :Bulged-tubular
T :Tubular
Numbers indicate maximum diameter in eighths of an inch.
MH Lamps Safety
• Fixtures with MH lamps should be fully enclosed.
• MH and MV lamps operate under high pressure and very
high temperatures and there is a possibility that the arc tube
may rupture.
• W hen this happens, the outer bulb surrounding the arc tube
may break, and particles of extremely hot quartz (from the
arc tube) and glass fragments (from the outer bulb) create a
risk of personal injury or fire.
11 HID Lamp & LPS Lamps
• Sylvania and General Electric have issued warnings to the
users of their MH lamps.
• Sylvania’s warning:
- All MH lamps should be used in enclosed fixtures.
- Enclosures must be made of suitable material, such
as tempered glass.
•General Electric’s warning:
- All MH lamps in horizontal, or more than 15% off-vertical position, should be used in
enclosed fixtures.
-175 W, 250 W, 1500 W MH lamps, regardless of position, should be used in enclosed fixtures.
-325 W, 400 W, 950 W, 1000 W MH lamps, in vertical position, or less than 15% off-vertical
position, can be used in open fixtures.
-In continuously operating systems, turn the lamps off once a week for at least 15 minutes.
-MH lamps near the end of their life may not start.
-Relamp fixtures at or before end of rated life.
Direct Replacement of MV Lamps
• Some MH lamps are designed as direct replacements for
MV lamps and use the existing MV lamp fixtures
and ballasts.
• In comparison with the MV lamps, the efficacy may be
improved by 70%+, but the rated average life is
generally shorter.
• An energy conservation retrofit.
11 HID Lamp & LPS Lamps
Lamp Designation Total Watts Including Lamp Ballast Watts 1 Lamp (2 Lamp) Rated Initial Mean
Lamp Lumens Lumens Colour Life
Initial per Mean per Temp
(hrs) Lumens Watt Lumens Watt K CRI LLD
Standard Clear
M175 M250 M400 M1000 M1500 175 200
10,000 14.000 70.0 10,800 250 275 10,000 20,500 74.5 17,000 400 450 (880) 20,000 34,000 75.6 25,600 1,000 1,075 (2,160) 12.000 110,000 102.3 88,000 1,500 1,6200 3,000 155,000 96.3 142,500 54.0 4,500 65 0.73
61.8 4,700 65 0.72
56.9 4,000 65 0.69
81.9 4,000 65 0.72
88.5 3,900 65 0.88
Standard Phosphor-Coated
M175/C 175 200 10,000 M250/C 250 275 10,000 M400/C 400 450 (880) 20,000 M1000/C 1,000 1,075 (2.160) 12,000 14.000 70.0 20,500 74.5 34,000 75.6 10,000 102.3 10,200 16,000 24,600 84.000 51.0 3,900 70 0.67
58.2 3,900 70 0.67
54.7 3.700 70 0.63
78.1 3,400 70 0.67
High Performance Clear
M175/HOR 175 200 10,000 15,000 75.0 12,000 60.0 4,700 65 0.70
M400 400 450 (800) 20,000 40,000 88.9 32,000 71.1 4.500 65 0.71
M1000/VER 1,000 1,075 (2,160) 12,000 125,000 116.3 100,000 93.0 3,500 65 0.72
High Performance Phosphor-Coated
M175/C/HOR 175
200 10,000 15,000 75.0 11,300 56.5 4,200 70 0.66
M400/C 400 450 (800) 20,000 40,000 88.9 31,000 68.9 3,800 70 0.64
M1000/C/VER 1,000 1,075 (2,160) 12,000 125,000 116.3 95,800 89.1 3,100 70 0.64
MH Operable on Mercury Vapour Ballast Clear
M325 M400 M1000 325 375 400 450 1,000 1,100 20,000 28,000 15,000 34,000 12,000 107,000
74.7 18,200 48.5 4,000 65 0.57
75.6 20,400 45.3 4,000 0.45
97.3 85,600 77.8 3,800 0.75
20,000 28,000 15,000 34,000 74.7 17,600 46.9 3,700 70 0.54
75.6 19,600 43.6 3,700 0.45
M325/C M400/C Notes:
325 400 375 450 •Mounting for position-oriented lamps is indicated as HOR (horizontal) or VER (vertical) only.
•When position is unspecified the lumen output value given applies to vertical mounting. Slightly reduced values will result if lamp is mounted in other positions.
•Life and mean lumen ratings for HID lamps are based on 10 hours per start.
11 HID Lamp & LPS Lamps
Ceramic Metal Halide Lamps
General Description
• In order to counter the poor colour consistency of metal
halide lamps over life, lamp manufacturers have combined
the ceramic arc tube from HPS lamps with the gas mix and
metals used in Metal Halide lamps to produce Ceramic
Metal Halide (CMH) lamps.
• These lamps offer significant advantages over typical Metal
Halide lamps and are available in PAR packages to fit
smaller recessed and track-mounted luminaires.
• These sources and luminaires offer significant savings
compared to incandescent lamps typically used in retail
(stores) and display lighting.
120 W Halogen PAR 38 Flood:
25°, 3,000 hrs, 7,700 MBCP, 1,800 lm, 95 CRI
39 W CMH PAR 30 Flood (55W with electronic ballast):
30°, 9,000 hrs, 7,400 MBCP, 2,300 lm, 85 CRI
11 HID Lamp & LPS Lamps
c. High Pressure Sodium Lamps
• High pressure sodium (HPS) lamps are HID lamps that
ionize sodium vapour.
• Like all HID sources, HPS lamps consist of an arc tube
enclosed in an outer bulb.
• The arc tube contains xenon (starting gas), sodium
and mercury.
• The mercury is in the form of an amalgam with the sodium.
• HPS lamps do not have starting electrodes because of the
arc tube’s small diameter.
• The arc tube is made of a ceramic that can withstand high
temperatures (1,300°C) and resist the corrosive effects of
hot sodium.
Typical Construction and Circuit of an HPS Lamp
11 HID Lamp & LPS Lamps
• The ballast provides a high-voltage pulse (2,500 V) for one
microsecond for lamp start.
• This high-voltage spike establishes the xenon arc between
the main electrodes.
• Mercury and sodium then vaporize rapidly and maintain
the arc.
• Warm-up time is three to four minutes.
• Restrike time is about one minute—shortest restrike time
of all HID sources.
• HPS lamp sizes range from 35 to 1,000 watts.
Rated Average Life
• 24,000 hours for most HPS lamps.
• The light colour of HPS lamps is usually described as
• HPS lamps are available in either clear or diffuse-coated
• Improved colour lamps operating under increased pressure
have better colour rendering properties at the expense of
lamp life and luminous efficiency.
11 HID Lamp & LPS Lamps
• HPS lamps are the most efficient source of
golden-white light.
• HPS lamps are more efficient than MH lamps, but less
efficient than Low Pressure Sodium (LPS) lamps.
• Efficacies range approximately from 50 to 140 lumens
per watt.
• Efficacy increases with lamp size.
• All applications where colour is less important.
• Clear lamps are used in roadway lighting, floodlighting,
industrial lighting, area lighting, airport lighting.
• Coated lamps are used in area and floodlighting, security
lighting, industrial and commercial indoor lighting and
parking lots.
11 HID Lamp & LPS Lamps
Shape Codes
: Bullet
BT : Bulged-tubular
: Elliptical
PAR : Parabolic aluminized reflector
: Tubular
Numbers indicate approximate maximum diameter, in
eighths of an inch.
11 HID Lamp & LPS Lamps
Total Watts Incl. Lamp Lamp Ballast Designation Watts 1 Lamp Rated Lamp Life Initial (hrs) Lumens Initial Mean
Lumens Lumens C olour
per Mean per Temp
Watt lumen Watt Deg K CRI LLD
S 35 S 50 S 70 S 100 S 150 S 200 S 250 S 400 S 1000 35 55 50 70 70 95 100 130 150 190 200
250 250 305 400 475 1,000 1,095 16,000 24,000 24,000 24,000
24,000 24,000
24,000 24,000 24.000 2,250 4,000 5,800 9,500 16,000 22,000
27,500 50,000 140,000 40.9 2,025 57.1 3,600 61.1 5,220 73.1 8,500 84.2 14,400 88.0 19,800 90.2 24.750 105.3 45,000 127.9 126,000 36.8 1,900
51.4 1,900 54.9 2,100 65.8 2.100 75.8 2,050 79.2 2,100 81.1 2,100 94.7 2,100 115.1 2,100
21 0.84
21 0.81
21 0.83
21 0.79
21 0.84
21 0.84
21 0.84
21 0,86
21 0.84
55 70 95 130 190 305 475 16,000 2,150 24,000 3.800 24,000 5,400 24.000 8.800 24,000 15,000
24,000 26,000
24,000 47,500 39.1 1,935 54.3 3,420 56.8 4,860 67.7 7.920 78.9 13,500
85.2 23,400 100.0 42,750 35.2 1,900 48.9 1,900 51.2 1,900 60.9 2.100 71.1 2,100 76.7 2,100 90.0 2.100 21 0.84
21 0.81
21 0.83
32 0.83
32 0.83
32 0.84
32 0.80
190 250 305 7,500 I3,600 7,500 19,000 10,000 25,500 71.6 12,240 64.4 2,400 65 027
76.0 17,100 68.4 2,400 65 0.87
82.0 22,500 73.8 2.400 65 0.87
10,000 13,000
10,000 23,000 10,000 39,500
68.4 75.4 82.1 Diffuse-Coated
S 35/D S 50/D S 70/D S I 00/D S 150/D S 250/D S 400/D 35 50 70 100 150 250 400
Colour Improved Clear
150 200
250 150 200 250 Colour Improved Diffuse-Coated
150 250 400 150 250 400 190
305 475 2,300 70 0.89
2,300 70 0.89
2,300 70 0.89
11 HID Lamp & LPS Lamps
Direct Replacement of MV Lamps
• Some HPS lamps are designed as direct replacements for
MV lamps and use the existing MV lamp fixtures
and ballasts.
• In comparison with the MV lamps, the efficacy may be
improved by 70%+, but the rated average life is
generally shorter.
• Often used in energy conservation retrofits.
• For lamp information, refer to the table below:
Total Watts
Including Lamp Lamp Ballast
Designation Watts I Lamp Rated
Lamp Life
Initial (hrs) Lumens
Initial Mean
Lumens Lumens Colour
per Mean per Temp
Watt Lumens Watt Deg K CRI LLD
HPS Operable on Mercury Vapour Ballast
150 215 360
880 I50
215 360 880
250 405 930 12,000 13,000 12,000 20,000 16,000 38,000 12,000 102,000 72.2 11,700 80.0 18,000 93.8 34,960 109.7 91,800 I80 380 405 12,000 12,000 16,000 30,000 16,000 36,000
66.7 10,800 78.9 27,000
88.9 32,400 65.0 72.0 86.3 98.7 1,800 2,060 2,060 2,100 0.85
150 330 360 150 330 360 60.0 1,800 71.1 2,000
80.0 2,060
Notes: •HPS lamps can be operated in any position without affecting lumen output.
•Life and mean lumen ratings for HID lamps are based on 10 hours per start.
30 0.73
11 HID Lamp & LPS Lamps
d. Low Pressure Sodium Lamps
• Low pressure sodium (LPS or SOX) lamps are HID lamps,
operated at low pressure, in which the arc is carried by
ionized sodium vapour.
• LPS lamps are more closely related to fluorescent than
HID lamps, since they have a low-pressure, low-intensity
discharge source and a linear lamp shape.
• An LPS lamp consists of a U-shaped arc tube enclosed in a
clear tubular outer bulb.
• An indium oxide coating on the inside of the outer bulb
reflects most of the infrared radiation back to the arc tube.
• The arc tube is enclosed in a vacuum to minimize heat loss.
• The lamp is designed to fully utilize its generated heat.
• The arc tube can maintain an operating temperature of
about 2,600°C, resulting in an extremely high
luminous efficacy.
• At start-up, the current is carried by the starting gas (neon
and argon) producing a red glow.
• As the lamp warms up, sodium is vaporized and the
discharge begins to exhibit the characteristic yellow colour
of an LPS lamp.
• Warm-up time is about nine minutes.
• Restrike time is less than one minute.
11 HID Lamp & LPS Lamps
Typical Construction
LPS lamp sizes range from 18 to 180 watts.
Rated Average Life
• SOX 18 - 14,000 hours
• Others
- 18,000 hours
• The light of an LPS lamp has a yellow colour
• The colour rendition is very low—it turns every colour to
either yellow or muddy brown.
• The CRI value does not apply to this lamp.
11 HID Lamp & LPS Lamps
• The LPS lamp has the highest efficacy of all light sources.
• Lamp efficacies range from 100 to more than 180 lumens
per watt.
• Efficacy increases with lamp size.
• The LPS lamp has the highest efficacy because it emits
monochromatic yellow light close to the peak of the eye
sensitivity curve.
• The LPS lamp is generally not used in new construction,
but it may be found in existing sites.
• All applications where colour rendering is not important
• Roadway lighting
• Security lighting
• Area floodlighting
• Warehouses
Total Watts lncluding Lamp Lamp Ballast Designation Watts SOX 18 SOX 35 SOX 55 SOX 90 SOX 135 SOX 180 18 35 55 90 135 180 Rated Lamp Life Initial 1 Lamp (hrs) 32 60
80 125 170 215 14,000 18,000 18,000 18,000 18,000 18,000 Initial Lumens per Lumens 1,800 4,800 8,000 13,500 22,500 33,000 Mean Watt 56.3 80.0 100.0 108.0 132.4 153.5 Mean
Lumens Colour
per Temp
Lumens Watt Deg K LLD
1.800 53.7 1,740 4,800 76.2 1,740 8,000 95.2 1,740 13,500 103.1 1,740 22,500 126.4 1,740 33,000 146.7 1,740 1.03
Notes: • The wattage and lumen output for LPS lamps will increase by approximately 7% and 5% respectively, by the end of lamp life.
• Due to the monochromatic nature of LPS lamps, CRI is not applicable.
12 Other Light Sources
a. Inductively Coupled Electrodeless System.
An induction coil is powered by a high frequency generator.
The induced current causes acceleration of charged particles
inside the lamp bulb. The metal vapour atoms are excited and
ionized causing the release of ultra-violet energy. The UV
energy causes the phosphor coating on the lamp wall to glow,
creating white light.
• These products are seeing gradual implementation,
especially in roadway lighting where long lamp life
is beneficial.
• Two major lamp manufacturers have products available.
• These products are proprietary and are therefore not
• They require special sockets and electronic control gear.
• Extremely long lamp life, typically 100,000 hours.
• At present still has high cost.
• Icetron from OSRAM/Sylvania
System Watts
System Lumens
Average Rated Life
• QL Induction Lighting from Philips
System Watts
System Lumens
Average Rated Life
12 Other Light Sources
b. Fiber Optic Lighting
In a fiber optic lighting system there are a number of
components. The illuminator is the active component,
containing either a halogen incandescent or a metal halide
light source, a power supply, and some way of collecting the
light into a focused beam. The illuminator may also contain
a cooling fan to extend lamp life and a colour wheel or other
beam modifying system, so that the light intensity, pattern
and colour can be changed. The fiber itself is of either glass
or plastic construction, and uses the principal of internal
reflection to transmit the light down the length of the fiber.
The fiber may be end-emitting or side-emitting. Endemitting fiber is used by itself or in conjunction with various
lenses to give control of the beam. Side-emitting fiber gives
a continuous line of light down the length of the fiber and is
used for decorative lighting around buildings and swimming
• Fiber optic lighting is not truly a light source, but a method
of transmitting light over a short distance.
• Manufacturers have developed more efficient illuminators
using Metal Halide lamps and advanced optical
reflector designs.
• Specialty areas where lamp access is a problem, notably
pools and display cases.
• Applications where heat from light sources may be
detrimental, such as produce displays in a grocery store.
12 Other Light Sources
c. LED Lighting
General Description
An LED (light emitting diode) is an electro-chemical light
source. When the diode is forward-biased, light is generated.
The light is monochromatic; the colour is dependent on the
materials used. White light can be produced by using
phosphors similar to those used in fluorescent and coated
HID lamps.
The efficacy of LED sources is improving continuously;
currently about 30 lm/W is typical.
Lamp lumen depreciation in a light source is the gradual
reduction in light output over time, caused by normal
deterioration of phosphors, cathodes, filaments and the other
components of the system. LED systems last up to 100,000
hours, based on the fact that when the light output has
depreciated to less than 50% of initial output, then the light
source has effectively expired. Life of LED systems is
dependent on a number of factors including the colour; red
and green LEDs last significantly longer than blue and
white LEDs.
12 Other Light Sources
• Low power consumption and low heat generation.
• Extremely long life.
• Negligible early failures.
• High colour efficiency, because they are monochromatic.
• Very small.
• Resistant to damage from shock and vibration.
• No infra-red or ultra-violet energy is emitted.
• Typically used in exposed source applications such as
signage, decorative festive lighting, marketing displays, and
automotive applications
• Traffic signal lamps
• Exit signs
• Seasonal light strings
13 Exit Signs
Physical Data
• Most exit signs are approximately 12˝ long, 8˝ high and
between 1˝ and 4˝ in depth.
Physical Dimensions of a Typical Exit Sign
Types of Signs
There are two types of exit signs:
• externally lit (rare)
• internally lit (most common).
1“- 4”
13 Exit Signs
Externally Lit
• An external light is aimed on the sign.
• Bulb replacement is easy.
• Sign is difficult to see in smoky conditions.
• Power consumption is high (generally incandescent lamps
are used).
Internally Lit
• Single- or double-sided sign with light source inside
the fixture.
• Some exit signs have an opening fitted with a diffractive
lens at the bottom to help light the exit route.
Light Sources of Internally Lit Signs
There are four light sources for internally lit exit signs:
•Incandescent lamps
•Compact fluorescent lamps
•Low-voltage lamps: LED and miniature
incandescent lamps
•Tritium gas (Tritium gas signs do not meet current code requirements for brightness of internally lit signs. Consult your lighting designer.)
13 Exit Signs
LED Signs
• LED (light emitting diode) type sign has LEDs in plastic
tubes which form the letters.
• These signs use plastic as the medium to transmit the light.
• Require less depth than incandescent and compact
fluorescent signs.
• More uniform illumination of letters.
• Manufacturers expect 10- to 15-year lamp life.
• Consumes approximately 2 to 3 watts of power.
Compact Fluorescent Signs
• More expensive than incandescent signs.
• Most incandescent exit signs can be retrofitted with
compact fluorescent if there is sufficient space inside the
sign to accommodate the lamp and the ballast, although
this has become an unusual practice due to the efficiency of
LED retrofit units.
Compact Fluorescent Lamp Retrofit Lamp
13 Exit Signs
Compact Fluorescent Lamp - Hard-Wired
• Compact fluorescent lamps of 5, 7 and 9 watts provide
lighting levels similar to incandescent lamps of 25, 40 and
60 watts respectively. p11_d
• Lighting of each letter is not uniform.
• Lamp life is generally one to two years.
• Consumes approximately 12 to 20 watts.
Tritium Gas Signs
• Illumination principle is similar to that of a television.
• Radioactive tritium gas undergoes beta decay, releasing
an electron which is incident on a phosphor-coated tube,
shaped into the word EXIT
• A modern tritium exit sign uses 25 curies (about 2.5
milligrams of tritium in the gaseous form).
• No external energy source required.
• Lamp life is 10 to 20 years; it must then be replaced.
• Highest capital cost for lamp and fixture.
13 Exit Signs
Incandescent Signs
Existing incandescent signs should be immediately replaced
because of cost of operation and in commercial and industrial
applications cost of maintenance.
• Can no longer be purchased in Canada.
• Incandescent signs usually have two 15 to 25 watt bulbs.
• D uring a power failure, a sign may be energized by either
the emergency power supply system or a 12 V bulb in the
middle of the sign powered by a battery.
• Cost varies due to construction features such as
vandal-proofing, internal battery etc., and aesthetic features.
• Incandescent signs were the most common type of exit sign
in the past.
• Lighting of each letter is not uniform.
• Bulb life is generally one to six months.
• Consumes approximately 30 to 50 watts of power.
13 Exit Signs
Code Requirements
• The National Building Code of Canada requires that:
“Lettering on exit signs shall be:
(a)red letters on a contrasting background or white
letters on a red background, at least 114 mm high
with 19 mm stroke spelling EXIT or SORTIE when
the sign is internally illuminated, and
(b)white letters on a red background or red letters on a
white background at least 150 mm in height with 19
mm stroke spelling EXIT or SORTIE when the sign
is externally illuminated.
“The lighting for exit signs shall:
(a) be supplied by an electrical circuit that
(i) is separate from the other circuits, or
(ii) serves other emergency equipment, and
(b) be connected to an emergency power supply...”
• The National Fire Protection Association of the United
States requires the exit signs “... be illuminated by not
less than 5 foot candles (54 lx) and shall employ a
contrast ratio of not less than 0.5”.
This is not a requirement in Canada.
13 Exit Signs
• Incandescents are inexpensive to purchase but expensive to
operate and maintain.
• Compact fluorescents can be retrofitted into most
incandescent fixtures to reduce energy and
maintenance costs.
• LED signs consume less electricity and provide more
uniform illumination, as well as being more
aesthetically pleasing.
• Tritium gas signs do not consume electricity. The energy
comes from the radioactive decay of tritium. They have a
high initial cost but require very little maintenance.
• The energy efficiency of Exit Signs are now regulated in
Canada and LED technology is the only one able to meet
these performance levels.
14 Emerging Technologies
Reduced Size Sources
• An area of continuing research and development is
reducing the size of efficient light sources. Very small, T4.5
39 W ceramic metal halide lamps are presently available,
and smaller lamps are being developed.
White Light LEDs
• The LED segment of the market is growing and is believed
to be the technology of the future for lighting; efficient,
long-life white light LEDs in convenient packages, such as
a medium screw base lamp module, could replace traditional
incandescent lamps.
Lighting Controls
• W hile outside the scope of this publication, significant research is being carried out in the area of lighting controls, to
allow better and more consistent dimming of sources such
as low wattage metal halide, compact fluorescent and LED
14 Emerging Technologies
Intelligent Ballasts
The universal adoption of electronic fluorescent ballasts has
lead to the development of intelligent ballasts
incorporating dimming with addressability of individual
ballasts. The DALI (Digital Addressable Lighting
Interface) protocol allows users and building operators to
combine luminaires into control zones in software, thereby
eliminating costly rewiring whenever a tenant changes a
partition location. In combination with photocells and
occupancy sensors, the lighting system becomes a proactive
element in the building to optimize the control of
illuminance levels.
15 Codes, Standards and Regulations
Adherence to the appropriate codes and standards is best
achieved by following the recommendations of a
qualified lighting specialist. There are considerable
revisions and changes which will continue to evolve both
at the national and provincial/state level. For example, the
Canadian Federal Energy Efficiency Act of 1992 provides for
the establishment and enforcement of regulations concerning
minimum energy performance levels for energy-using
products. The act also enforces labeling of energy-using
products as well as the collection of data on energy use. These
regulations refer to many industry testing and performance
standards, and are administered in Canada by Natural
Resources Canada (NRCan) These
regulations apply to regulated energy-using products
imported into Canada or manufactured in Canada and
shipped from one Province to another. It is important to
consult the acts and regulations which are enforced in your
There is also the Energy Policy Act of 1992, an amendment
to the Energy Policy & Conservation Act that was passed in
1975. It included provisions for utilities to invest in
conservation and energy efficiency, as well as funding for
establishing energy efficient lighting and building centers.
There are further enhancements expected that have resulted
from the realization and support for energy efficiency.
15 Codes, Standards and Regulations
Code for Buildings
Similarly, it is important to remain current on local and
regional requirements. There are often references to national
codes or standards, but may also be enhanced requirements.
Examples of national efforts include:
• Residential buildings: Council of American Building
Officials (CABO) Model Energy Code.
• Commercial Buildings: ASHRAE/IESNA standard
• Guide to Canada’s Energy Efficiency Regulations - Natural
Resources Canada, 1999.
16 Worksheets
a. An Audit Data Worksheet
Project: Project Manager:
Project Engineer:
Lighting Specialist:
Total Area (sq.ft.):
Lighting Designer:
Date of Report:
Regional Office:
Project No.:
Building No.:
Existing Electrical Use - (Base Year Electrical Data):
Annual Electrical Demand - Peak Average:
Annual Electrical Consumption:
Annual Hours of Use (Average):
Annual Electrical Cost:
Electrical Rates Information
Demand Charge (kW) - ($)
Consumption Charge (kWh) - ($)
Blended Rates
16 Worksheets
Lighting Energy Savings Summary
Electrical Consumption
Current Usage
Proposed Retrofit
Lighting Cost and Savings Summary
Outside Materials Cost
[Calculated + Adjustments]
Outside Labour Cost
[Calculated + Adjustments]
Total Outside Cost
[Sum Above 2]
Outside Service Markup (17.0%)
[Cost Multi. + % Noted - Calc. Cost/sq.ft.]
Rose Technology Labour (15%)
[Cost Multi. + % Noted - Calc. Cost/sq.ft.]
[Sum Above 3]
Guarantee (0.0%)
[Cost Multi. + % Noted - Calc. Cost/sq.ft.]
[Sum Above 2]
Lamp & Ballast Savings
[User Entry + Calc. Cost/sq.ft.]
Utility Incentive
[User Entry + Calc. Cost/sq.ft.]
Annual Savings
[From Above + Calc. Cost/sq.ft.]
Simple Payback (years)
[Total Cost/Total Savings]
NOTES: (a) Standard voltage (120 V) and lamps (34 W/40 W) existing.
[User entry]
(b) Demand charge and consumption rate see chart below. [User entry]
(c) Handling of P.C.B. ballasts not included in project cost.
(d) Asbestos content taken into account.
(e) Highlighted areas represent altered design due to asbestos conditions.[User entry]
(g) [User entry]
[User entry]
[User entry]
[User entry]
16 Worksheets
b. A Measures/Savings Worksheet
Existing Energy Balance
Demand Electrical Consumption
[As Above]
[User Entry]
Mech. Measures
[User Entry]
Material Adj.:
[Material Adj. Table]
Trailer Storage:
[Material Adj. Table]
Disposal Bin:
[Material Adj. Table]
[Material Adj. Table]
Electrical Inspection Cert.: [Material Adj. Table]
Handling of PCB ballasts: [Material Adj. Table]
Lamp Disposal:
[Material Adj. Table]
Material Adjustment Total:
Labour Adj.:
Patching & Painting
[Labour Adj. Table]
Labour Adjustment Total: $0.00
[Sum Material Adj.]
[Sum Material Adj.]
17 Bibliography
• Lighting Reference Guide, Seventh Revision, January 2002
• Rae, Mark S., ed. The IESNA Lighting Handbook,
Reference & Application, 9th edition, New York, NY,
IESNA, 2000
• General Electric Catalogues.
• Philips Lighting Catalogues.
• OSRAM/Sylvania Lighting Catalogues.
18 Glossary of Terms
• a device used with a gas discharge lamp to provide the
necessary starting and operating electrical conditions.
candela (cd)
• the fundamental unit from which all other lighting units are
derived. Candlepower, the intensity of light in a specified
direction, is measured in candelas. An ordinary wax candle
has a candlepower of about one candela.
• candelas are used to compare intensities of different kinds
of directional light sources. In a 75 W spotlight lamp the
centre of beam is 1,730 candelas and in a 75 W floodlight
lamp it is 430 candelas, i.e., the centre of the spotlight’s
beam is four times as intense as the floodlight’s.
• a device commonly put on the bottom and/or sides of a
luminaire to redirect or scatter the light from a source.
• the scattering of light that falls on a surface.
• the ratio of total lumens produced by the light source to
the watts consumed by the source, expressed in lumens per
• the ratio of the total lumens emitted by the luminaire to
those emitted by the lamp, expressed as a percentage.
18 Glossary of Terms
electromagnetic spectrum
• the total range of wavelengths of frequencies of electro
magnetic radiation. The visible portion covers a wavelength
from approximately 380 nm to 780 nm (1 nm = 10-9m).
foot candle (fc)
• the practical working unit for the measurement of lighting
level equal to one lumen falling uniformly on an area of one
square foot.
• luminous flux density or lumens per unit area incident on a
surface. The unit of illuminance is the lux (lx) where
1 lx = 1 lm/m2 (SI units) or the foot candle (fc) where
1 fc = 1 lm/ft2 (Imperial units). The relationship between lux and foot candle
is 1 fc = 10.76 lx.
Illuminating Engineering Society of North America
• the recognized technical authority in the illumination field
in North America
• a generic term for an electric source of light. A lamp usually
consists of a light-generating element (arc tube or filament),
support hardware, enclosing envelope and base.
• any radiation which makes things visible. It is radiant
electromagnetic energy capable of exciting the retina of the
eye and producing a visual sensation.
18 Glossary of Terms
lumen (lm)
• the unit of luminous flux, i.e., the quantity of light emitted
by a lamp. 1 lumen = 1 candela, x 1 steradian.
• a complete lighting unit consisting of a lamp(s) and parts
designed to distribute the light, to position and protect the
lamp(s) and to connect the lamp(s) to the power supply.
• the luminous intensity of a surface in a given direction per
unit of projected area. The unit for luminance is
NIT = candela/m2 or foot-lambert = p candela/ft2. A
surface emitting or reflecting light in a given direction at a
rate of one candela per square meter of projected area has a
luminance in that direction of 1 cd/m2 or 1 NIT.
luminous exitance
• the light leaving a surface at a point is measured in lumens
per square foot.
lux (lx)
• a unit of illuminance or lighting level equal to one lumen
uniformly falling on an area of one square meter.
photometer (light meter)
• an instrument for measuring photometric quantities such as
illuminance (in foot candles or lux). The light sensitive cell,
typically a selenium cell, must be cosine corrected and
Vλ corrected.
• the ratio of light emitted from a surface to the light falling
on that surface.
18 Glossary of Terms
• the bending of light rays as they pass through clear glass
or plastic.
specular surfaces
• surfaces from which the reflection is predominantly regular,
e.g., highly polished or mirror finished surfaces.
• the ratio of light transmitted through a light-passing
material (e.g. glass or ceramics) to the incident light falling
on that material.
19 Index
30 Chromaticity
30 Colour Rendering index
30 Colour Temperature
30 Correlated Colour Temperature
24 Electromagnetic Spectrum
68 Electronic Ballast, Fluorescent Lamps
41 Fluorescence
146 Illuminance
138 Illuminance Levels
41 Incandescence
42 Lamp
24 Light, Definition
34 Lumen
41 Luminescence
35 Luminous Efficacy
36 Luminous Flux Density
36 Photometer
34 Photopic Vision
29 Primary Colours
44 Rated Average Life
27 Relative Spectral Luminous Efficiency Curves
34 Scotopic Vision
27 Spectral Power Distribution
36 Unit of Illuminance
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