Module Overview and Learning Outcomes
Overview
In this module, we will start by discussing the specialized terminology used with reference to light and
lighting systems.
We will then look at how light is measured and evaluated as per OHS regulations in all Canadian
jurisdictions, and the levels of lighting that are required for safety and security in the workplace.
We will also explore the technology behind the various lighting systems: lamps, luminaries, and security
lighting systems.
Learning Outcomes
Upon successful completion of this module, you should be able to:
 Define the terms light, lamp and luminaire.
 Distinguish between luminance and illuminance.
 Describe common lighting metrics.
 Demonstrate an ability to interpret OHS-related lighting regulations and take measurements in
the workplace to determine compliance with the regulations.
 Outline the advantages and disadvantages of common lamp types for safety and security
applications.
 Discuss the lighting technology options available for security and emergency lighting.
Introduction
Lighting systems are used extensively to enhance safety and security in the workplace.
Increased visibility reduces the chance that a worker will miss seeing a hazard, whether it is a tripping
hazard, an opening, or an overhead hazard. Increased levels of lighting mean that personal and facility
security are increased.
Correct selection of lighting system elements allows workers to adequately view and rapidly assess
conditions in today’s high-speed work environment. Additionally, emergency lighting systems are critical
safety features in buildings.
Lighting system design is an engineering specialty that comes with its own vocabulary and field
assessment techniques. In this module, we will learn the parts of illumination engineering that are
critical for all OHS professionals. Our discussion will also focus on the design of lighting systems for
safety and security.
OHS professionals tend to concern themselves more with the quantity of light than with the details of
the quality of light. We will not deal with the subject of lighting for work efficiency, which is an area of
ergonomics. Ergonomists will spend as much time evaluating the quality of light as the quantity.
Lighting Technology
There is an entire vocabulary surrounding the use of lighting for safety and security. This section will
introduce students to a variety of the terminology relevant to the field.
Light is a form of nonionizing radiation in the portion of the electromagnetic energy spectrum that is
visible to the human eye.
Visible Light has wavelengths that run between 380 and 770 nanometres (nm). The 380 nm end of the
visible light spectrum appears violet/purple to the human eye.
Electromagnetic wavelengths just shorter than 380 nm are called the ultraviolet portion of the spectrum
and are not visible to the human eye (ultraviolet = “above violet”). The 770 nm end of the visible light
spectrum appears red to the human eye. Electromagnetic wavelengths just longer than 770 nm are
called infrared and are also not visible to eye (infrared = “beyond red”).
Each type of lamp used in a lighting system has its own unique light spectrum. A light spectrum is a
descriptor of the various light wavelengths that are emitted by that lamp.
You may be familiar with the term Full Spectrum Lighting. Full spectrum lamps emit wavelengths of
visible light more or less across the entire range of 380–770 nm compared to other types of lamps (for
example, Blacklight lamps emit wavelengths of almost exclusively 400 nm or less).
Knowing the spectrum of a particular lamp is not as critical in the safety and security applications of
lighting systems as it is in the ergonomics applications of lighting systems, but it is still important for the
OHS professional to understand that each lamp type will have a unique spectrum.
#definition
A lamp is any device that transforms electricity into light. Lamp is the correct term for what most people
call a light “bulb.”
/definition
Luminaire is a term used to describe a complete lighting unit that includes the lamp. A luminaire is a
device designed to produce, control, and distribute light.
Illuminance (Illumination Level) is the measure of the amount of light falling onto a surface.
/definition
When we measure illuminance, we are measuring the amount of visible electromagnetic radiation from
a luminaire that is falling directly onto a surface or task.
A surface or object that is not adequately illuminated cannot be properly seen. A surface or object that
is too highly illuminated may be the cause of complaints by workers (“it’s too bright!”).
#definition
Luminance is the measure of the amount of light that is being reflected by a surface. A highly reflective
surface will be highly luminous when illuminated. A poorly reflective surface will not be very luminous
even if it is highly illuminated.
/definition
Luminance levels need to be adequately controlled to prevent interference with vision: A surface that is
too luminous (similar to a shiny mirror) can be difficult to look at. A surface that is not luminous enough
(similar to a matte black background) cannot be adequately distinguished.
#definition
A Brightness Ratio is the mathematical ratio of the luminance of one surface to the luminance of any
second surface. Whenever you have stood looking out of the window of a room on a sunny day you
have noted a situation in which there is a high brightness ratio. The luminance value of the window
glass is much higher than the luminance of the surfaces in the room.
A Contrast Ratio is a specific type of brightness ratio. Contrast ratio is the ratio of the luminance of a
task or object to the luminance of the immediate background of that task or object.
/definition
A white sheet of paper on a white desktop would be said to have a contrast ratio of about 1.0 because
the luminance of the paper and the desktop would be about equal.
A white sheet of paper on a black desktop would be said to have a contrast ratio much greater than 1.0
because the luminance of the paper would be higher than that of the desktop.
OHS professionals need to be aware of the advantages and disadvantages of various contrast ratios. A
high contrast ratio makes the task or object highly visible, but makes it difficult to distinguish anything in
the immediate background. Too little contrast means that the task or object tends to blend in with its
background.
#definition
Reflectance ratio is the ratio of the luminance of a surface to its illumination level. It is an indicator of
how much light is being absorbed or reflected by the surface. A surface with a reflectance ratio of 0.6
means that 60% of the light striking the surface (illumination) is being reflected back off that surface, the
remaining 40% is being absorbed or scattered at extreme angles.
Glare is a term used to describe excessive brightness in the field of vision that causes loss of visual
performance or eye fatigue. This excessive brightness can come to the eye directly from luminaires or
from reflecting surfaces.
/definition
Lighting specialists and ergonomists talk about direct glare and reflected glare. Direct glare is when the
brightness comes to the eye directly from the light source (e.g., sunlight through a window). Reflected
glare is the light that has been bounced off at least one surface (e.g., light reflected off a monitor
screen).
Interaction: DnD: connect lines matching
Test your knowledge of the technical terminology that we described in this section. Click on the question
mark of each term and connect it with the correct definition.
Term
Definition
Illuminance
The measure of the amount of light falling onto a surface
Luminance
Reflectance Ratio
The measure of the amount of light that is being reflected by a
surface
The mathematical ratio of the luminance of one surface to the
luminance of any second surface
The ratio of the luminance of a task or object to the luminance of
the immediate background of that task or object
The ratio of the luminance of a surface to its illumination level
Glare
Excessive brightness in the field of vision
Luminaire
A complete lighting unit that includes the lamp
Brightness Ratio
Contrast Ratio
Lighting Metrics and Measuring
The basic tool used by the OHS professional to measure light is the light meter (also called a photometer
or luxmeter).
Handheld Light Meter
The basic light meter is primarily used to measure illuminance, but can be used to obtain estimates of
other parameters such as luminance, contrast ratio, and reflectance ratio. Specialized meters are
required to obtain accurate measures of luminance, contrast ratio, and reflectance ratio, and are not
often used by OHS professionals.
The basic light meter is really a very simple device. It is a device that collects one form of energy and
then converts it into another measurable form of energy. The light meter used in OHS is essentially the
same as the light meter used in photography. It consists of a meter body, a photocell (photodiode), a
device used to measure the electrical voltage generated by the photocell, and an analogue or digital
readout.
How it Works:
Light energy strikes the photocell and is converted into a proportional amount of electrical
energy. The meter determines the amount of electrical energy that has been produced by the
photocell and converts that measure into a measure of illuminance.
Watch this video to see how to operate a light meter: Hyelec MS6612 Digital Lux Light Meter Review
The very simplest light meters require no power source and are used to measure the illuminance from
all types of lamps. These simple and inexpensive meters are generally acceptable for OHS field
measurements.
Some OHS regulations require that a light meter used to take measurements for regulatory purposes be
color and cosine corrected to take into account lamps of various types, and the influence of reflected
light. One of the potential problems of measuring light levels is that some light strikes the photocell at
large angles of incidence is reflected away from the meter and is not properly measured (cosine effect).
Some light is also reflected off the meter case around the photocell. Research suggests that unless this
light that is reflected away is accounted for, the measured illuminance may be 25% lower than actual
illuminance. Most modern light meters use engineering techniques to correct for the cosine effect.
Again, various design techniques are used so that the light meter can be made to appropriately respond
to variations in lamp color. If you are required to purchase a light meter, ensure it meets the regulation
you are governed by, so that your tests results are valid.
Light has a large number of measurable properties as noted in Table 4-1, but for OHS fieldwork the most
common measure of light is the measure of the quantity of light falling onto a surface, the illuminance.
Illuminance is measured in the SI/metric unit of lux. The older illuminance measure of footcandles is still
used in the USA (1 footcandle = 10.76 lux).
Table 4-1
Some Measurable Characteristics of Light, Light Sources, and Lighting Materials
Characteristic
Wavelength
Color
Flux density
(illuminance)
Orientation of
polarization
Degree of polarization*
Energy radiated
Color temperature
Luminous intensity
Luminance
Spectral power
distribution
Power consumption
Light output (total flux)
Zonal distribution
Reflectance
Transmittance
Spectral reflectance
Dimensional Unit
Equipment
Light
Spectrometer
Spectrophotometer
and colorimeter
Lumen per unit area
Photometer
(lux and footcandle)
Degree (angle)
Analyzing Nicol prism
Nanometer
None
Technique
Laboratory
Laboratory
Laboratory or field
Laboratory
Percent (dimensionless Polarization
ratio)
photometer
Light Sources
Joule per square meter Calibrated radiometer
Kelvin (K)
Colorimeter or filtered
photometer
Candela
Photometer
Candela per unit area
Photometer or
luminance meter
Watts per nanometer
Spectroradiometer
Laboratory
Watt
Laboratory or field
Wattmeter or
voltmeter and
ammeter for dc, and
unity power factor ac
circuits
Lumen
Integrating sphere
photometer
Lumen or candelas
Distribution or
gonlophotometer
Lighting Materials
Percent (dimensionless Reflectometer
ratio)
Percent (dimensionless Photometer
ratio)
Percent (at specific
Spectrophotometer
Laboratory
Laboratory or field
Laboratory or field
Laboratory or field
Laboratory
Laboratory
Laboratory
Laboratory or field
Laboratory or field
Laboratory or field
and transmittance
Optical density
wavelengths)
Dimensionless number
Densitometer
Laboratory
Reproduced from the IESNA Lighting Handbook, 9th edition (IESNA Lighting Education Fundamental Level) courtesy of the
Illuminating Engineering Society of North America.
How bright is a lux? Click on the tubs below to see what spaces have that level of illuminance.
#accordion
100 lux or less
Storage closets and other areas with minimal lighting would have illuminance levels of this range.
300 to 700 lux
A standard office will have an illuminance level in this range.
2000 lux and greater
Outdoor on a sunny day typically reach these levels of illuminance.
/accordion
So how do we use the standard light meter to measure illuminance?
First, read the manual for the light meter thoroughly. Although the measurement technique is similar
for all meters, each meter manufacturer will have some of their own unique methods.
The photocell on the most basic light meters is directly mounted in the meter body. On more
sophisticated meters the photocell is separate and connected to the meter body by an electrical cable.
The light meter or photocell is placed directly on the task or at a height simulating the task, taking care
not to obstruct or shade the photocell with your body. A series of measurements is then taken (there
are no legal requirements for the number of measurements you must take) and an average value
recorded.
If you have performed meter-based sampling in the past, this may seem “too simple” and lacking
statistic validity. Although this is quite true, the illumination levels required by regulation (or
recommended in guidelines) are understood to be approximate values. Slight variations resultant from
the sampling process are not going to create unsafe conditions.
#note
The largest challenge for the OHS professional will involve taking measurements that are representative
of the actual work:
1. Ensure that nothing (or anyone) artificially shades the photocell.
2. Sample the actual work conditions as closely as possible.
/note
Standard light meters can also be used to obtain an estimate of brightness ratio.
The photocell is placed first on one surface and then on the other and the ratio calculated.
This is not the most technically correct way to evaluate brightness ratio because brightness ratios are
most correctly calculated from luminance values, but for OHS fieldwork this method is acceptable.
Luminance and various ratios require the measurement of light that has been reflected off of a surface.
In fact, the standard unit of measurement of luminance is not the lux, it is the candela per square metre
(cd/m2). Standard light meters are not designed to take such measurements. Standard light meters are
generally of the incidence meter type, that is, they are designed to measure light that is directly incident
(falling on) the photocell from the light source. Specialized reflectance type light meters (luminance
meters) are required when measuring light that has reflected off of a surface, but these meters are
generally more expensive, so it is standard practice in OHS fieldwork to use the basic light meter to get
an estimate of luminance and various light ratios rather than an accurate measurement.
Luminance of a surface can be estimated simply by directing the photocell of the light meter down
toward the surface. The question is, how far from the surface should the photocell be positioned.
Generally, the photocell would be placed at about the position of the eye of the person that is subject to
the light being reflected from the surface. Brightness ratio can also be estimated by this method. The
photocell is used in the reverse position to first estimate the luminance of one surface and then of the
other. The photocell must be held at the same distance from each surface in order for this estimate to
have any value at all.
Reflectance ratio can also be estimated with a standard light meter. A measuring point is chosen at a
known distance from the surface and the illuminance determined at that point (photocell is directed
toward the light source). The photocell is then reversed at the same measuring point and the luminance
estimated.
Because of the lack of availability of sophisticated photometers to most OHS professionals, most OHS
regulators have chosen to not include anything other than measurements of illuminance into
regulations.
If you are interested in further details about the technical aspects of measuring light, then you may wish
to consult the current edition of Lighting Handbook — Reference and Applications published by the
Illuminating Engineering Society of North America.
#activity
We have provided here links to four manufacturers. Please review their products and create a list of
criteria that an ideal light meter for your work environment should include.
 Extech
 PCE-Instruments
 Sper Direct
 Lutron
/activity
Lighting Regulations and Guidelines
OHS regulators in Canada have generally taken one of two approaches to the issue of lighting in the
workplace. Some regulators have chosen to incorporate both prescriptive and performance-based
requirements.
#example
Which of these examples is prescriptive?
Section 4.65(1) BC Occupational
Health and Safety Regulation
An employer must provide and maintain minimum illumination
levels to ensure safe working conditions…22 lux in areas of low
activity and 54 lux in areas of high activity.
Section 4.66 BC Occupational
Health and Safety Regulation
The illumination required must be provided by general or local
lighting or an effective combination of the two.
/example
Others have simply established performance-based requirements and then provide guidance to OHS
professionals that are seeking to meet the performance requirements.
#example
Section 186(1) Alberta
Occupational Health and Safety
Code
An employer must ensure that lighting at a work site is sufficient to
enable work to be done safely
/example
The following table is an example of prescriptive minimum illumination levels established by one OHS
regulator, WorkSafeBC: Illumination levels for task categories
Where specific safety hazards have been identified, the OHS regulator may choose to prescribe
minimum illumination levels for specific workplace situations.
#example
Section 22.36 BC Occupational
Health and Safety Regulation
/example
The employer must ensure that the minimum illumination
measured 1 m above the floor or ground in an underground
working is 22 lux (2 foot candles) in a tunnel, shaft, incline and
haulage way and 54 lux (5 foot candles) at a working face or other
area of high activity.
When minimum levels of illumination are prescribed in regulation, then the job of the OHS professional
is quite simple: Use the light meter to determine whether the required illumination is available or not.
However, it stands to reason that these illumination levels could be achieved in many ways (one very
large light source or multiple smaller light sources). Most regulators allow the employer to choose the
method by which the illumination will be provided.
We will look at lamp and luminaire choices later in this module so that you will be better prepared to
help an employer determine what an effective lighting system looks like.
Not all lighting systems that would provide adequate levels of illumination would be effective in the
workplace. This is the language in the WorkSafeBC OHS Regulation:
4.67 Brightness, reflectance and glare
As far as practicable, the workplace must be designed and maintained in such a manner to adequately
control
(a) brightness ratios,
(b) reflectance values, and
(c) glare.
It is not difficult to choose a lamp and luminaire that provides illumination levels well above the
minimum value specified in a regulation, but the OHS professional also needs to consider how effective
that lamp and luminaire combination will be in providing effective lighting. One blindingly bright lamp in
a corner of a work area may well be able to provide 1000 lux or more at all work stations in the area
when the minimum required is 100 lux, but this lighting system design will definitely produce brightness
ratio and glare problems.
Where should the OHS professional look for guidance if the regulations do not specify minimum
illumination levels or are at least in part performance-based (adequately controlled brightness ratio)?
For many years, OHS professionals and regulators have recommended values published by the
Illuminating Engineering Society of North America (IESNA) in The IESNA Lighting Handbook: Reference
and Applications.
IESNA advises that the following values represent the absolute minimum illuminance at any time and
location where safety is related to visibility:
Hazards Requiring
Visual Detection
Normal Activity
Level
Illuminance Levels
Lux
Footcandles
Slight
Table 4.2
Illuminance Levels for Safety
High
Low
High
Low
High
5.4
0.5
11
1
22
2
54
5
These values represent absolute minimum illuminance at any time and location where safety is related to visibility. However,
in some cases higher levels may be required (such as where security is a factor). In other conditions, especially involving work
with light-sensitive materials such as photographic film, much lower illuminances must be used. In these cases, alternate
methods of ensuring safety must be employed.
Source: IESNA, (2000). Reproduced from the IESNA Lighting Handbook, 9th edition (IESNA Lighting Education Fundamental
Level) courtesy of the Illuminating Engineering Society of North America.
Another good reference source is the IES Footcandle Recommendations. You may be able to find
additional resources that are more relevant to your area of responsibility.
The following tables include other lighting-related values recommended by IESNA:
Application
Large open areas
Buildings
Perimeter fence
Entrances
Gatehouses
Table 4-3
Recommended Average Illumination Levels for Security Lighting
Illuminance, Ix (fc)
Notes
5 to 20 (0.5 to 2)
The greater the brightness of
the surrounding area, the
higher the illuminance required
to balance the brightness in the
space.
5 to 20 (0.5 to 2)
Vertical illuminance on the
building façade. The greater the
brightness of the surrounding
area, the higher the illuminance
required to balance the
brightness in the space.
5 (0.5)
Illuminance on the ground on
either side of the fence.
100 (10)
Illuminance o the ground in the
inspection area.
300 (30)
Illuminance on the work-plane
in the gatehouse. This lighting
must be dimmable to low levels
at night so the guard can see
outside the gatehouse.
Source: IESNA, (2000). Reproduced from the IESNA Lighting Handbook, 9th edition (IESNA Lighting Education Fundamental
Level) courtesy of the Illuminating Engineering Society of North America.
Table 4-4
Recommended Maximum Luminance Ratios
Environmental Classification*
A
B
C
1. Between tasks and adjacent
3 to 1
3 to 1
5 to 1
darker surroundings
2. Between tasks and adjacent
1 to 3
1 to 3
1 to 5
lighter surroundings
3. Between tasks and more
10 to 1
20 to 1
†
remote darker surfaces
4. Between tasks and more
1 to 10
1 to 20
†
remote lighter surfaces
5. Between luminaires (or
20 to 1
†
†
windows, skylights, etc.) and
surfaces adjacent to them
6. Anywhere within normal field
40 to 1
†
†
of view
*Classifications are:
A- Interior areas where reflectances of the entire space can be controlled in line with
recommendations for optimum seeing conditions.
B- Areas where reflectances of the immediate work area can be controlled, but control or remote
surround is limited.
C- Area (indoor and outdoor) where it is completely impractical to control reflectances and difficult
to alter environmental conditions.
† Luminance ratio control not practical.
Source: IESNA, (2000). Reproduced from the IESNA Lighting Handbook, 9th edition (IESNA Lighting Education Fundamental
Level) courtesy of the Illuminating Engineering Society of North America.
Table 4-5
Recommended Reflectance Values
Surfaces
Ceiling
Walls
Desk and bench tops, machines, and equipment
Floors
*Reflectance should be maintained as near as practical to recommend values.
Reflectance*
(percent)
80 to 90
40 to 60
25 to 45
Not less than 20
Source: IESNA, (2000). Reproduced from the IESNA Lighting Handbook, 9th edition (IESNA Lighting Education Fundamental
Level) courtesy of the Illuminating Engineering Society of North America.
#reveal
Test your knowledge
Refer to Table 4-2 to check the required minimum illumination level for each of the following:
a. Working spaces where visual tasks are only occasionally performed.
b. Very prolonged and exacting visual tasks.
c. Log loading and unloading areas.
d. Vehicle repair garages.
Click Reveal to see the correct answers
a)
b)
c)
d)
100 lx
5000 lx
50 lx
500 lx
/reveal
#activity
Measuring illumination
Click through the steps to see how you would determine the actual illumination levels in a vehicle repair
garage.
Interaction: Measuring illumination
/activity
Lamps
There are basically four types of lamps used in safety and security applications. Click on each of the
names of the bulbs to read about the advantages and disadvantages of each of them.
#accordion
Incandescent Lamps
The bulb of a standard incandescent lamp is filled with an inert gas mixture
(usually argon/nitrogen) or simply contains a vacuum. Halogen-based
incandescent lamps contain iodine or bromine in a quartz capsule that
surrounds the filament.
Incandescent lamps have several advantages in safety and security
applications:
1. They are inexpensive to purchase (“long life” industrial incandescent
bulbs cost only $1–2).
2. The lamps are small and easily handled and mounted.
3. They are essentially instant starting.
4. They do not require an electric/electronic ballast.
5. They are produced in a variety of shapes to accommodate most
requirements.
But they also have a number of disadvantages:
1. They have poor energy efficiency and are expensive to operate.
2. They have a relatively short life.
3. They produce a significant amount of heat which results in a very high
bulb wall temperature and heating of the immediate environment.
Incandescent lamps are becoming less common in the workplace (mainly because of their energy
inefficiency), but are still often found in use in storage areas, stairwells and stair landings, and for
individual task lighting (e.g., desk lamp).
The use of incandescent lamps is being phased out in many countries, including Canada. Other
countries have already prohibited their use.
Fluorescent Lamps
Fluorescent Lamps are common in most workplaces, primarily for area lighting, but
increasingly for individual task lighting (compact fluorescent lamps replacing
incandescent lamps).
When an electric current flows through the tube, some of the electrical energy is
converted into ultraviolet light (which cannot be seen). The ultraviolet light then
strikes the powdery phosphor coating on the inside of the bulb. The energy from the
ultraviolet light causes the phosphor to fluoresce visible light. The small amount of
mercury in a fluorescent lamp vaporizes, and the mercury vapour facilitates the
production of ultraviolet light and the fluorescence of the phosphor.
The advantages of fluorescent lamps in safety and security applications, especially in comparison to
incandescent lamps are:
1. Higher energy efficiency
2. Low heat output, and therefore, less heating of the environment and a much lower bulb wall
temperature.
3. Relatively long life.
4. Available in a wide variety of shapes and sizes.
5. Available in a wide variety of light spectra.
Fluorescent lamps do have some disadvantages:
1.
2.
3.
4.
Higher initial cost.
Require an expensive electric/electronic ballast.
Not all are instant starting.
Disposal is an issue (due to the mercury content).
There are numerous fluorescent lamp choices available. Not only are these lamps available in a variety
of sizes (96, 48, 12 inches long, etc.) and shapes (standard straight tube, u-shaped, and spiral tubes,
etc.), but lamps can be found that produce a rainbow of light spectra (cool white, warm white, daylight,
etc.)
Most manufacturers of fluorescent lamps employ a standard coding system to identify their fluorescent
tubes. The coding is normally printed directly onto the lamp.
A lamp coded as F40T12/CW/RS/ES:
Fluorescent (F),
48 inches long (the industry standard, and therefore, not
noted in the code),
40 watt (40),
Tubular in shape (T),
1.5 inches in diameter (12 which means 12/8 of an inch in
the industry coding system),
Cool white spectrum (CW),
Rapid starting (RS),
Energy efficient/energy saving (ES).
High Intensity Discharge (HID) Lamps
High Intensity Discharge (HID) lamps are familiar to all of us because
these types of lamps are almost exclusively used in street lighting
and in the lighting systems of arenas, swimming pools, and gymnasiums. They are also the most
common type of lamp found in warehouses and manufacturing facilities.
HID lamps look somewhat like very large incandescent bulbs, but the construction and principle of
operation is different. Electric current passes between electrodes in an arc tube filled with mercury
vapour, sodium vapour or other metal halide vapours. This construction causes a “high intensity”
discharge of visible light. The construction of a typical HID lamp is as follows:
HID lamps are used in safety and security applications because they have the following advantages:
1. Highly energy efficient and have a high light output for the electrical energy put in.
2. Have a very long life.
3. Produced in sizes such that a single lamp/luminaire system can be used to illuminate a large area.
The disadvantages of HID lamps are:
1.
2.
3.
4.
They have long warmup and re-light times (they are not instant start).
They have a very high initial cost (price range of $15–40).
Present some disposal issues.
Some types provide very poor color rendering (i.e., you do not see true colors because the light
spectra from the lamp is far removed from the full spectrum of visible light)
Most street lighting is high pressure sodium, HID lighting, and as we have all seen, everything pretty
much appears pink-orange under this type of lighting.
Light Emitting Diodes (LED)
Light Emitting Diodes (LED) are beginning to be found more
frequently in safety and security applications. Many vehicle
brake and running light systems which have traditionally
used incandescent lamps are now equipped with LED.
Emergency exit signs are often lit with LED.
An LED is typically a small bulb that contains a semiconductor
chip. The chip has a gap in the centre that separates an area
containing a large number of positive charges from an area
containing a large number of electrons (negative charges).
When sufficient voltage is applied, the LED electrons move
across the gap and combine with the positive charges and
ultimately release photons of light. The spectrum of the light
produced depends on the chemical characteristics of the
semiconductor material.
Current LED technology has its advantages in safety and security applications:
1. Inexpensive to purchase
2.
3.
4.
5.
6.
Extremely long life.
Resistant to damage from motion/vibration.
Extremely low heat output.
High energy efficiency.
Highly visible light when sufficient numbers of LED are combined with appropriate reflecting
material in the diode and in the luminaire.
The disadvantages of current LED technology for safety and security applications are:
1. Not practical for use as area lighting.
2. Does not produce a significant amount of illumination on a task any distance from the luminaire)
tends to produce a rather harsh (“bright”) light.
Nevertheless, it is likely you will see more LED used in the future, especially in those areas in which there
is a need to reliably maintain a highly visible luminaire with minimal maintenance (brake lights on
commercial vehicles, emergency exit signs, etc.).
/accordion
#activity
Interactivity: Drag and Drop
Drag the characteristics listed below to the most appropriate lamp.
Incandescent Lamps
Fluorescent Lamps
High Intensity Discharge
(HID) Lamps
Light Emitting Diodes
(LED)
Inexpensive
Higher energy
efficiency
Highly energy efficient
Inexpensive
Instant starting
Low heat output
High light output
Extremely long life
Poor energy efficiency
Relatively long life
Very long life
High energy efficiency
Relatively short life
Higher initial cost
Long warmup and relight times
Poor choice for area
lighting
/activity
Luminaires
According to IESNA a luminaire is a device to produce, control, and distribute light.
#definition
A luminaire is a complete lighting unit consisting of:
1. One or more lamps.
2. Devices designed to distribute the light.
3. Sockets to position and protect the lamps and connect them to the electrical supply.
4. Mechanical components needed to support or attach the luminaire.
/definition
Any of the lamps listed in the previous section produces a significant amount of light. The aim of the
luminaire is to provide control of that light. The light needs to be contained and directed where it is
needed.
Although some types of lamps have their own built-in light control features (e.g., silvery coating that
acts as a light reflector), there are four types of light control components commonly used in luminaires.
Click on each one to learn more.
#accordion
Reflectors
Reflectors are highly reflective devices that are shaped to re-direct the light produced by the lamp. The
device may be made of polished or coated metal or plastic. Pot lights and floodlights typically make use
of reflectors.
Refractors
Refractors use “lenses” of glass or plastic to refract light coming from the lamp to the desired direction.
Office fluorescent lighting systems and warehouse HID systems often make use of refractors.
Diffusers
Diffusers are opaque glass or plastic sheets that scatter the light from the lamp in many directions. They
are typically used to spread out light that comes from high luminance lamps.
Baffles and Louvers
Baffles and Louvers also scatter the light from the lamp in many directions, but in this case the
scattering is done to break up the image of the lamp that might otherwise be seen as direct and indirect
glare. Office fluorescent lighting systems make use of diffusers so that the fluorescent lamp is not
directly visible and does not appear as glare off of monitor screens.
/accordion
Various luminaire classification systems have been developed to help OHS professionals and others
most correctly select and specify what is needed for their particular application. Classification by
application (residential, commercial, and industrial) is a simple system, but probably not specific enough
for the OHS professional. Instead, two, more detailed systems are used.
The International Commission on Illumination (CIE) classification system for luminaires used indoors is
based on the proportion of upward and downward directed light output. The following luminaire
classes exist in the CIE system:
Class
Direct
Semi-direct
General Diffuse
Semi-indirect
Indirect
% of Light
Directed Downward
90–100%
60–90%
40–60%
10–40%
0–10%
The IESNA classification system for luminaires used outdoors is simply based on the shape of the area
that is illuminated by the luminaire.
Security Lighting
Security lighting is generally provided in the workplace to protect
people and property from criminal activity. In most workplaces, the
security lighting system is primarily aimed at exterior security
(parking lots, entrances, and walkways).
IESNA has proposed the following principles of security lighting:
1. Integrate light into the total security system, and thereby
facilitates the effectiveness of other parts of the security
system.
2. Illuminate people and places to allow observation and
identification, and thereby reduce criminal concealment.
3. Use security lighting to deter criminals by creating a fear of
detection and identification.
4. Reduce the fear of crime for people by enhancing the perception of security.
Although all types of lamps and luminaries have been used for exterior security lighting, HID lamps that
are surface or pole-mounted tend to be the most preferred. As discussed, HID lamps have long service
lamps and high light output — characteristics that are appropriate for exterior security applications.
#note
A variety of recommended exterior security light levels have been proposed, but most designers follow
IESNA’s recommendations:
Parking Lots



Walkways



Covered Parking Facilities
Minimum of 30 lux on the pavement
No less than 3 lux at 1.5 metres above the pavement
Uniform lighting levels across the parking lot so that the ratio of average
level to the minimum is no greater than 4:1 (uniformity ratio)
Minimum of 6 lux on pavement and 1.5 metres above
Uniformity ratio of 4:1
Minimum of 60 lux on pavement and 1.5 metres above

Uniformity ratio of 4:1
/note
Emergency Lighting
We will look only briefly at emergency lighting in this section as it is covered in depth on the fire safety
courses.
Requirements for emergency lighting systems are typically found in building codes. For example, the BC
Building Code includes requirements such as:
3.2.7.3.
Emergency Lighting
1) Emergency lighting shall be provided to an average level of illumination not less than 10 Lx at floor or
tread level in
a) exits;
b) principal routes providing access to exit in open floor areas
<and in service rooms>,
c) corridors used by the public,
d) corridors serving patients’ sleeping rooms,
e) corridors serving classrooms,
f) underground walkways,
g) public corridors,
h) floor areas or parts thereof where the public may congregate
i) In Group A, Division 1 occupancies, or
ii) In Group A, Division 2 and 3 occupancies having an occupant load of 60 or more,
i) < floor areas or parts thereof of daycare centers where persons are cared for, and
j) food preparation areas in commercial kitchens.>
2) Emergency lighting to provide an average level of illumination or not less than 10 Lx at floor or
catwalk level shall be included in a service space referred to in Sentence 3.2.1.1.(8).
9.9.11.2
Required Lighting in Egress Facilities
1) Every exit, public corridor or corridor, providing access to exit for the public shall be equipped to
provide illumination to an average level of not less than 50 Lx at floor or tread level and at all points
such as angles and intersections at changes of level where there are stairs or ramps.
9.9.11.3
Emergency Lighting
1) Emergency lighting shall be provided in
a) exists,
b) principal routes providing access to exit in an open floor area,
c) corridors used by the public,
d) underground walkways, and
e) public corridors.
2) Emergency lighting required in Sentence (1) shall be provided from a source of energy separate from
the electrical supply for the building.
3) Lighting required in Sentence (1) shall be designed to be automatically actuated for a period of at
least 30 min when the electric lighting in the affected area is interrupted.
4) Illumination from lighting required in Sentence (1) shall be provided to average levels of not less than
10 Lx at floor or tread level.
5) Where incandescent lighting is provided, lighting equal to 1 W/m² of floor area shall be considered to
meet the requirement in Sentence (4).
6) Where self-contained emergency lighting units are used, they shall conform to CSA C22.2 No. 141,
“Unit Equipment for Emergency Lighting.”
Source: Province of British Columbia. British Columbia Building Code, 2006.
This code and other codes say that emergency lighting shall be
designed and installed using good engineering principles. It is
again IESNA that provides the most widely accepted engineering
practices for emergency lighting. The IESNA Lighting Handbook
provides detailed direction to designers of emergency lighting.
The OHS professional that is evaluating the adequacy of an
emergency lighting system needs to consider each of the following:
1. Illuminance and luminance provided by the system.
2. The length of time the system will provide emergency light.
3. The degree to which the illuminance and luminance
adequately identifies special hazard areas such as stairs.
4. The degree to which the lighting and signage provide a
clear and conspicuous means of egress.
Illuminance
IESNA advises “The minimum recommended illuminance at the beginning of emergency operation is 10
lux along the centreline of the path of egress and 1 lux along a one metre band throughout the means of
egress.”
Building codes, including the BC Code have substantially adopted this recommendation.
Luminance
Numerical luminance values in relation to emergency lighting systems are not listed in codes nor
recommended by IESNA, mainly because of the difficulty of measuring luminance.
Instead, the OHS practitioner should pursue a performance-based evaluation of the luminance of walls,
stairs, floors, and other critical features along the means of egress: Is there sufficient illumination and
arrangement of emergency lighting systems to provide sufficient luminance of objects? Can the critical
objects along the path of egress be seen well enough that they will not impede escape?
Duration
Various codes and other laws require that, depending on the location in a facility, an emergency lighting
system must be designed so that it can provide the required illumination for times ranging from 30
minutes to some number of hours.
Emergency lighting equipment is available in a number of designs. We list here the three most common.
Click on each to learn more.
#accordion
Unit Equipment
Self-contained units that include a rechargeable battery and a lamp. You will see these battery
box/lamp units in many workplaces and public buildings.
The battery is charged by hard or soft-wired AC power during normal times. In the event of a power
failure, electronic devices activate to power the lamp from the battery (this system normally uses 6 or
12 volt batteries. Special incandescent lamps, usually halogen-type that can operate on 6 or 12 V DC
current, are typically used in these units. These lamps have a much shorter life than a standard
incandescent lamp (perhaps 50 hours versus 1000), but provide significantly more light output. Some
new unit equipment systems are using high light output compact fluorescent lamps.
Unit Inverters
Similar to unit equipment, but in this case the rechargeable battery and associated electrical equipment
are found mounted in a typical fluorescent lamp luminaire. In the event of a power failure, DC battery
power is changed (“inverted”) to 120 volt AC power, to power one or more of the standard fluorescent
tubes in the luminaire.
Central DC and Inverter Systems
Similar in principle to the two types of self-contained units described above, but batteries located in a
central location provide DC or AC power to a number of lamps in the event of a power failure.
/accordion
#activity
Apply your knowledge!
Take an evening trip to the nearest public area (library, arena, school) or to your workplace. Look for
the emergency and security lighting systems. Where are they situated? Are they effective?
/activity
Choosing Workplace Lighting
As we have seen, there is a relatively simple process available to help the OHS professional choose the
workplace lighting level and system that is most appropriate to ensure safety and security.
Quantity of Light
1. Identify minimum illumination levels required by regulation (prescriptive regulation).
2. If the regulation is performance-based, refer to industry-standard recommended illumination levels
(e.g., IESNA Illuminance Levels for Safety).
3. In consultation with lighting system supplier and facility manager, determine preferred lamp type(s)
for the specific application.
4. In consultation with lighting system supplier and facility manager, determine preferred luminaire
type(s) for the specific application.
Quality of Light
1. Identify lighting system quality parameters prescribed in regulation.
2. If the regulation is performance-based, refer to industry-standard light quality recommendations
(e.g., IESNA Maximum Recommended Luminance Ratios).
3. In consultation with facility manager and workers, determine layout of work area (work station
locations, surface coatings, etc.) and available options for re-arrangement of the work area.
4. In consultation with lighting system supplier and facility manager, determine preferred luminaries,
lamps, and workplace arrangements to meet light quality objectives.
Summary
In this module, we learned many of the terms used in lighting and security. The characteristics of light
described will help you better understand the impact of light on a working environment or emergency
situation.
A Lamp is any device that transforms electricity into light. A Luminaire is a term used to describe a
complete lighting unit that includes the lamp.
We learned that Illuminance is the measure of the amount of light falling onto a surface, whereas
Luminance is the measure of the amount of light that is being reflected by a surface.
We also learned that the Brightness Ratio is the mathematical ratio of the luminance of one surface to
the luminance of any second surface. A Contrast Ratio is the ratio of the luminance of a task or object to
the luminance of the immediate background of that task or object.
Another ratio, the Reflectance Ratio is the ratio of the luminance of a surface to its illumination level. It
is an indicator of how much light is being absorbed or reflected by the surface.
This module also outlined the advantages and disadvantages of common lamp types for safety and
security applications as well as options available for security and emergency lighting.