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Typical lighting situations
Roadways

The lighting of a roadway must be designed to protect the safety of all users. Quality of illumination is extremely important in the following situations:

  1. busy pedestrian zones;
  2. places where pedestrians come into proximity with vehicles;
  3. intersections.

In order to create good visibility, illuminance should also be uniform, that is, the ratio of average to minimum illuminance should not exceed 6.

Urban areas

Streets in city centres typically contain high densities of both cars and pedestrians. Illuminance of these roadways should correspond to the greatest recommended average illuminance, i.e., 17 lux.

 
Hydro-Sherbrooke and the University of Sherbrooke
 
Before
Before
 
Before
Before
 
The campus exit from the University of Sherbrooke connects to the University Boulevard.  These two roadways each contain four lanes and are lighted by double-headed luminaires from a height of 9 m.  The lampposts are spaced 25 m apart on the exit highway and 40 m apart on the boulevard.  Before bulb conversion (photo on left), the campus exit was intensely illuminated (75 lux) by 400 W high-pressure sodium lamps.  The University Boulevard (photo on right) received less illuminance (17 lux), but the 250 W high-pressure sodium bulbs emitted a high proportion of luminous flux towards the sky and in the glare zone.


After
After
 
Installation of new Helios luminaires allowed for maintenance of the standardized 17-lux illuminance level using only 150 W high-pressure sodium bulbs.  Replacing all 90 luminaires along the routes adjacent to the university led to an energy saving of about 100,000 kWh/year.


Rural and residential areas

Roadways in rural areas are less busy than in built-up areas and, as a result, lower illuminance levels are required. In certain residential sectors, it is sometimes sufficient to only illuminate intersections of roads.



The town of La Patrie alters the roadway lighting system
 
The town of La Patrie is situated at the foot of Mt. Megantic.  The main road, which is approximately 12 m wide, used to be illuminated by a series of luminaires that were 8 m high and 30 m apart.  These luminaires did not control any of the distribution of the luminous flux and supplied an excessive illuminance of 15 to 20 lux on the ground using 150 W high-pressure sodium lamps.


Thanks to the lighting conversion program of the Mt. Megantic ASTROLab, Helios type luminaires fitted with 70 W high-pressure sodium lamps were used to replace the old luminaires.  The careful control of luminous flux now assures that the luminaires do not illuminate the sky or the walls of nearby houses.  Also, the roadway is more discretely illuminated at 8 to 10 lux.


Building facades and surroundings
Building facades and surrounding areas are often illuminated at night.  This type of lighting serves several purposes.  It can illuminate commercial signs, building entrances and adjacent parking spots.

High-power wall sconces or floodlights are often utilized to this end.  However, these fixtures are inefficient, produce glare and usually direct over 15% of the luminous flux to the sky.  In order to decrease light pollution and save energy, choose a moderate lighting system that will allow clients to safely enter buildings without producing over-illumination.


Businesses lead the way!
Businesses lead the way!
This funeral home in Lac Megantic was illuminated by 13 wall sconces fitted with 150 W (11 bulbs) or 400 W (2 bulbs) high-pressure sodium lamps.


Following the lighting conversion program of the Mt. Megantic ASTROLab, the same business only uses 70 W bulbs, which reduces energy consumption by 1,500 W.  Also, certain wall sconces were repositioned to be above, rather than below, the areas to be illuminated.  This stopped directing light to the sky.


Only 35 W to see clearly!
Only 35 W to see clearly!
The entrance to this school is sufficiently illuminated by a full cutoff FPM luminaire by Keene that utilizes a 35 W high-pressure sodium bulb.  Here we see all the characteristics of an appropriate lighting fixture: good visibility, energy efficiency, concentrated light and pleasing design.


Moderation and style look good together!
Moderation and style look good together!
The illumination of the front facade of this bakery makes for a safe entrance.  It is therefore not necessary to install extra luminaires in the parking area.  The discrete lighting provided by the recessed luminaires in the eaves adds lots of style to the building.  This example shows that one need not over-illuminate a business to promote it.


Parking lots and shopping centres
Replacing the 21 luminaires in the parking lots of the University of Sherbrooke reduced the total power consumed by a factor of four.  Each fixture used to contain four high-pressure sodium bulbs and was replaced by a single floodlight of the same power (400 W).  The illuminance on the ground was maintained at 15 lux and savings add up to 120,000 kWh/ year.
Parking lots and shopping centres

These two photos demonstrate good planning for urban lighting.  In both cases, the lighting fixtures do not direct light to the sky nor beyond the limits of the commercial property.



A service station that doesn't illuminate neighbouring properties!
A service station that doesn't illuminate neighbouring properties!
This gas station provides adequate lighting without glare, by using recessed luminaires in the ceiling of the roof.


A dealer who sets a good example!
A dealer who sets a good example!
This dealer displays the rows of cars with luminaires that take 400 W metal halide lamps.  The luminaires supply an average illuminance of about 60 lux to the ground.  This is four times less than that normally generated for this type of application using floodlights of 1,000 to 1,500 W.  In addition, it is strongly recommended to extinguish at least some of the lighting outside business hours.  Reducing illuminance levels and occasionally turning off the lights in a dealership with 32 such luminaires could save 115,000 kWh/year, which would result in a difference of about $10,000 per year.  The initial investment will be quickly returned!


Loading and handling zones
Although it is generally preferable to use moderate lighting, certain circumstances require increased illuminance levels.  This applies notably to agricultural and industrial situations and businesses having exterior loading zones.  It is necessary, however, to be careful not to exceed actual requirements.

The use of security lighting and floodlights is currently widespread for this type of application.  These luminaires waste energy because not only do they create glare but they also direct up to 50% of the light output towards the sky.  Floodlights typically utilize 400 W mercury vapour bulbs or 1,000 W halogen lamps.  Mercury vapour bulbs have an efficacy that is one fourth that of high-pressure sodium bulbs.  Also, mercury vapour bulbs  and have a high lumen depreciation over time.


This sawmill used to illuminate the loading zones with mercury vapour security lights.  Defects in the lighting system are literally glaring.


Now the new high-performance RW-115 luminaires illuminate the sawmill with 150 W bulbs.  The company gains through energy savings and improved safety.


Before converting the lighting system, this factory produced glaring and polluting light with its 21 mercury vapour lamps (400 W each).


The factory currently illuminates its buildings with luminaires that offer improved control of the luminous flux and utilize 70 W high-pressure sodium bulbs.  This conversion reduced energy consumption by 32,000 kWh/ year.  Given that electricity costs $0.08 per kWh in Quebec, this represents an annual saving of $2,500.


Agricultural applications
Here is an example of an agricultural property where the mercury vapour security light was replaced by a luminaire having a 70 W high-pressure sodium bulb.


Residences
 
This private property is now illuminated by a high-pressure sodium wall sconce of 35 W (photo on right) instead of a mercury vapour security light (photo on left).  The driveway is as well lighted as before, but the treetops, the roof of the house, the sky and the neighbouring property are no longer illuminated, which results in savings of $150/ year!