contains summary of the westinghouse book about school and office lighting

1. School and Office Lighting

2. Team-ang /Group 1:
Brasileño, Nelyn Mae
Belleza, Marc Elo
Balbasin, Prince David
Muyco, Lara Jen
Talisic, Mary Jean

4. • The requirements for office lighting are similar in many
respects to those for the school lighting.
• Quality of lighting is of paramount importance and
should not be subordinated to any other consideration.

5. QUANTITY OF LIGHT

6. Daylight
- a variable source of illumination
from a quantity standpoint.

8. QUALITY OF ILLUMINATION

9. QUALITY
• an abstract characteristic of a lighting system in
that it cannot be measure directly

10. ROOM SURFACE
REFLECTANCES

11. Room surface reflectances are highly important in maintaining
comfortable brightness ratios within the field of view .

12. Room Surface Reflectance

13. Luminaire Brightness
• Comfortable seeing conditions in offices and schoolrooms can be
obtained only if luminaire brightness are limited by adequately
shielding the light source. The degree of brightness control
required is dependent upon the source used, the size of the room,
the illumination level, the reflectances and the finish of room
surfaces and furniture and the nature of visual task.

14. DIRECT GLARE ZONE is usually considered to be at
angles above 45degrees
REFLECTED GLARE ZONE may be extend from 0 to
60 degrees or even higher in some instances.

16. • Luminaire brightness are usually specified, measured, and
reported as maximum brightness (the brightest square inch as
seen from any viewing direction. However, recent investigations
indicate that for the direct glare zone average brightness is a better
criterion to use, provided the maximum brightness is not greater
than about five time the average.
• The brightness of luminaires used in office and classrooms
should be limited to approximately 225 footlamberts throughout
the zone from 0 to 87 degrees.

17. Choice of light source
• Either fluorescent or incandescent lamp may be used to achieved good
quality of office and school lighting.
• At level in excess of 35footcandles the attainment satisfactory quality
becomes more difficult with incandescent than with fluorescent lamp.
• Appearance, architectural appropriateness, and personal preference may also
influence the choice of light source.

18. INCANDESCENT
• Operational life up to 2,500
hours. On average 750 to 1,000
hours.
• Price is must cheaper
• Operating temperature is high
FLUORESCENT
• Operational life up 10 to 20 times
more than the incandescent bulb. Up
to 10,000 hours.
• Expensive
• Operating temperature is low

19. Other situation;
• If it is desired to raise the footcandle level in an office or classroom which
is currently lighted with incandescent lamps, it may be less expensive to
install fluorescent equipment than a new incandescent lighting system
requiring increased wiring capacity. Incandescent lamps also radiates
more heat on the same amount of light and it is not suitable to hot
weather.

20. Direct System
• A direct source of light is cast downward from a fixture to provide lighting with
uniform levels of illumination.
Indirect System
• Lighting provide by reflection usually from wall or ceiling surfaces.
• an indirect source of light which is cast upwards from a fixture and bounced down
to provide lighting with minimal glare and more uniform levels of illumination.
Semi – Indirect system
• 60 to 90 percent of the light Is directed downward with the remainder directed
upward
Semi- direct system
• 60 to 90 percent of the light Is directed upward with the remainder directed
downward

21. Description
Indirect and Semi – Indirect fixtures are linear fluorescent
fixtures that are suspended from the ceiling or mounted on a wall.
Indirect and Semi-Indirect System
- an indirect source of light which is cast upwards from a fixture and bounced
down to provide lighting with minimal glare and more uniform levels of
illumination.

23. APPLICATIONS:
Best suited for office, classroom, and retail applications.
Limitations:
Higher fixture cost in some installations
Requires a greater floor to ceiling heights
It is designed only for not more than 75 footcandles without uncomfortably high
ceiling brightness and resultant direct and reflected glare.
Benefits:
Distributes light more evenly than do direct lighting systems
Eliminates glare and shadows
Reduces electricity use and cooling loads
Reduces required light levels.

24. DIRECT – INDIRECT SYSTEM
Direct
• A direct source of light is cast downward from a fixture to provide lighting
with uniform levels of illumination.

25. DIRECT – INDIRECT SYSTEM
- a source of light in which is cast both upwards and downwards from a fixture to
provide a combination of led direct indirect lighting illumination.

26. Applications
• often used for classrooms and offices.
Advantages
• Good balance between ambient illumination of the room and accent lighting
• Relatively good energy efficiency even in large spaces
• Renders three dimensional objects well without harsh shadows.
Disadvantages
• Relatively High installation and maintenance cost
• Users often need instruction how to use the system effectively

27. DIRECT AND SEMI-DIRECT
LIGHTING SYSTEM
• Can be positioned to direct reflected images away from
the eyes, or if all room machine and task surfaces are
matte.
• Produce much same lighting result as good indirect
system.

28. LUMINOUS AND CEILINGS
• Used in offices and classrooms
With louverall ceilings
• Care must be taken to provide matte finishes on all surfaces and
equipment.
• Produce much same lighting result as good indirect system.

30. POSITIONING OF LUMINAIRES IN
ROOMS
FACTORS TO BE CONSIDERED FOR COMFORTABLE LIGHTING
AND PLEASING APPEARANCE IN ROOMS:
• ORIENTATION / POSITIONING OF LUMINAIRES
• SUSPENSION HANGER LENGTHS
ORIENTATION AND POSITIONING
Luminaires are positioned or oriented in such a manner that nearly everyone is
relatively free from both direct and reflected glare, even though the luminaires exceed
brightness limitations from some angles of view.

31. SHOULD BE MINIMIZE:
(EVERYONE MUST BE RELATIVELY FREE FROM
THESE)
DIRECT GLARE REFLECTIVE GLARE

32. SUSPENSION HANGER LENGTHS
• Suspension limit = 225 footlambers
• *Luminaires mounted too close to the ceiling cause the ceiling brightness too high for
comfort
• *Longer suspension lengths result in lower maximum ceiling brightness and greater
uniformity and generally produce higher utilization of the light emitted.
• *For a given ceiling height, the larger the room the greater the likelihood that the luminaires
will appear to be mounted too low, because a greater number will be in the normal line of
sight.*

34. OFFICES & CLASSROOMS DRAFTING ROOMS
7
7 14
28 & UP
8 6
8 16 6
32 &UP 6
9 6 12
9 18 6 12
36 & UP 6
10 18 21
10 20 12 18
40 & UP 6 12
11 21 21
11 22 18 21
44 & UP 12 18
12 21 21 OR 24
12 24 21 21 OR 24
48 & UP 21 21 OR 24
13 21 OR 24 24
13 26 21 OR 24 24
52 & UP 21 OR 24 24
14 30 30
14 28 24 24
56 & UP 24 24
15 36 36
15 30 30 30
60 & UP 24 24
16 42 42
16 32 36 36
64 & UP 30 30
18 42 42
18 36 36 36
72 & UP 30 30
20 54 54
20 40 42 42
80 & UP 36 36
CEILING HEIGHT (FT) ROOM WIDTH (FT)
HANGER LENGTH (INCHES)
PRACTICAL HANGER LENGHTS FOR SUSPENDED LUMINAIRES
IN OFFICES AND SCHOOLS

35. Note:
1. Indirect and semi-indirect luminaires provide low utilization when
suspended less than 18 inches. If mounted too close to the ceiling,
luminaires having a substantial upward component may cause excessively
high ceiling brightness.
*Two-lamp fluorescent units normally should be suspended at least 12
inches. For four-lamp units = 24 inches
*Indirect incandescent luminaires with 500-watt lamps should be suspended
at least 20 inches. For 750-watt units at least 24 inches.
2. Also for libraries, reception rooms, etc.
3. Luminaire should be surface-mounted or hung very near the ceiling

36. LUMINAIRE LOCATION AND
ORIENTATION
LARGE OFFICES
• LUMINAIRE BRIGHTNESS - This is especially important because of the large
number of luminaires that fall within the normal field of view.
- Luminaires for large offices should be of low brightness when viewed from any
direction.
• POSITIONING OF THE LUMINAIRE – not that critical but should be properly
spaced to give uniform distribution of light throughout the room.

37. Luminaires should be provided near the
wall where desk it. This is to keep the
illumination up to room average.

38. CLASSROOMS AND CLASSROOM SIZE OFFICES
• predominant line of sight is more clearly defined than in large offices.
• luminaires should always be positioned so that the smallest luminous
area or the lowest brightness is presented to the line of sight.
• supplementary lighting should be installed to increase brightness of
relatively low-reflectance surfaces(chalkboards).

39. SMALL OR PRIVATE OFFICES
• luminaires mounted in “U”, “L”, or rectangular-shaped pattern provide the
most efficiently utilized and best quality of lighting for rooms of this size
• luminaires should be positioned around the actual work areas in such way
that there is no reflected glares from desk or table tops.
• fluorescent luminaires mounted at right angle to each other provide better
diffusion than mounted in parallel.

41. DRAFTING ROOMS
• Quality is the utmost important.
• If indirect or semi-indirect luminaires are not used, quality of lighting may be
improved by mounting the luminaires diagonally across the ceiling to reduce
the shadows that are formed by the T squares or triangles used parallel or
perpendicular to the rows of luminaires.
• Mounting luminaires in grid pattern reduces shadows to an even greater
extent.

42. CORRIDORS, HALLS, AND STAIRWAYS
• Distribution need not be as uniform as that required for general
lighting in rooms.
• It is permissible to exceed the usual maximum spacing-to-
mounting-height ratio by as much as 50%.