Understanding
Indoor
Photometric
Test Reports
“Serving the lighting industry since 1989”
905 Harrison Street Allentown, PA 18103 Ph: 610.770.1044 Fax: 610.770.8912
www.luminairetesting.com
Description Section
The description section is the first section of an LTL indoor photometric test
report. It provides the specific information about the luminaire being tested as
well as the conditions of the test procedure. Here you will find the number of
lamps, the model number, the manufacturer of the lamps, as well as the rated
lumens for each lamp. Following the lamp information, the ballast manufacturer
and model number are shown. The mounting position of the luminaire is noted,
followed by the electrical characteristics recorded during the test. Finally, the
orientation of the 0 plane is indicated (parallel with the lamps, perpendicular
to the lamps, or neither in the case of luminaires with vertical lamps).
LTL NUMBER: 04983
DATE: 1-1-2000
PREPARED FOR: LUMINAIRE TESTING LABORATORY, INC.
CATALOG NUMBER: SAMPLE INDOOR TEST
LUMINAIRE: FORMED STEEL HOUSING, FORMED WHITE ENAMEL STEEL
REFLECTOR, 16 CELL, 3" DEEP, FORMED SEMI-SPECULAR
ALUMINUM LOUVER.
LAMPS: TWO SYLVANIA FBO31/31K RATED AT 2800 LUMENS EACH
BALLAST: ONE MAGNETEK B232I120RH
MOUNTING: RECESSED
TOTAL INPUT WATTS = 54.7 AT 120.0 VOLTS
THE 0 DEGREE PLANE IS PARALLEL WITH THE LAMPS.
Luminaire Sketch
The luminaire sketch is used to communicate pictorially any information about the luminaire that
the description does not explain. This includes critical dimensions of the luminaire, lamp
positioning, and orientation during testing. A circled plus sign ( ) indicates the photometric
center of the luminaire as tested.
#04983
21.500“
10.250“
20.875“
23.750“
Photometric Center
Luminaire Testing Laboratory, Inc.
-2-
Candela Distribution Table
The candela distribution table is a tabular listing of the candela readings at each
given angle. These candela values are actually candelas per rated lamp lumens.
This means these values do not take into consideration ballast factor, lamp
depreciation, or temperature effects. By using candelas per rated lumen, it is more
convenient to compare various test reports on a common ground. In standard
indoor photometry, the 0 vertical angle denotes the measurement directly below
the luminaire (also referred to as nadir). Following from this, 90 is at the equator,
and 180 is directly above the luminaire (zenith).
Vertical Angles
Lateral Angles
CANDELA DISTRIBUTION
0.0 22.5 45.0
0 1401 1401 1401
5 1399 1396 1393
15 1321 1313 1283
25 1198 1156 1124
35 1034
977 1050
45
803
789
979
55
508
557
706
65
82
103
123
75
18
20
21
85
0
0
0
90
0
0
0
67.5
1401
1391
1267
1170
1177
1167
823
107
21
0
0
90.0
1401
1390
1260
1199
1252
1277
921
97
21
0
0
FLUX
132
363
538
682
763
597
125
24
3
The lumens (flux) column is a summary of the
lumens (flux) emitted within a zone centered
around the corresponding vertical angle.
Ex. The vertical angle 15 has 363 lumens in a
cone ranging from 10 to 20 .
10
20
Luminaire Testing Laboratory, Inc.
-3-
Polar Candela Plot
The polar candela plot is typically found in the lower right hand corner on the first page
of an LTL test report. It is the graphical representation of the candela distribution table.
The angles are vertical angles (again with 0 pointed straight down) and the deflection is
in candelas per rated lumens. The lateral planes are represented by a solid line (0 plane) and
a dot-dash line (90 plane). In the case of a completely symmetrical fixture, only the 0
plane is shown (see Figure 1). For a four quad symmetry fixture, the 0 and 90 plane is
shown (see Figure 2). Finally, in both bilateral symmetry fixtures and asymmetrical fixtures,
the plot shows the 0 , 90 ,180 , and 270 ,planes (see Figure 3). In the bilateral symmetry plot,
the 270 plane is a mirror image of the 90 plane.
Figure 1
180 165 150
135
Figure 2
120
180 165 150
105
135
120
105
90
Candelas
75
6520
60
9780
13040
Vertical Angles
3260
90
15
75
600
60
900
1200
45
0
300
45
0
30
15
30
0 Deg. Plane
0 Deg. Plane
90 Deg. Plane
Figure 3
120
135
150 165 180 165 150
135
120
105
105
90
90
60
75
75
120
60
60
180
240
45
45
300
30
0
15
180 Deg. Plane
270 Deg. Plane
15
0 Deg. Plane
Luminaire Testing Laboratory, Inc.
-4-
30
90 Deg. Plane
Zonal Lumen Summary
The zonal lumen summary is a brief description of the flux (flow of light) emitted from the
luminaire within a specific zonal range. The ranges represent vertical angles and the flux
found within the area of the cone.
The 0-30 zone represents the flux
found within the cone through
0 and 30 . This area is shown in
gray shading
10
ZONAL LUMEN SUMMARY
ZONE
LUMENS
0- 30
1034
0- 40
1716
0- 60
3076
0- 90
3228
90-180
0
0-180
3228
Vertical Angle Range
20
30 40
%LAMP
18.5
30.6
54.9
57.6
0.0
57.6
The lumens column
shows how many lumens
are produced within the
given zone.
This column gives the lumen sum within the given zone as a
p e r c e n t a g e o f t h e t o t a l r a t e d l a m p l u m e n s.
(Lumens in given zone/rated lumens).
This column gives the lumen sum within the
given zone as a percentage of the total luminaire
lumen output. (Lumens in Given Zone/Lumens 0-180)
Luminaire Testing Laboratory, Inc.
-5-
%FIXT
32.0
53.2
95.3
100.0
0.0
100.0
Total Luminaire Efficiency
The total luminaire efficiency is simply the ratio between the lumen output of the
luminaire and the lumen output of the bare lamps. This value is the percentage of the bare lamp’s
light that exits the luminaire.
TOTAL LUMINAIRE EFFICIENCY:
TOTAL REFLECTANCE OF PAINT:
57.6%
92.4%
CIE TYPE:
DIRECT
PLANE:
0-DEG 90-DEG
SPACING CRITERIA:
1.2
1.4
SHIELDING ANGLES:
30
35
LUMINOUS LENGTH: 20.875 20.875
The average of 4 diffuse
reflectance samples taken from
varying sections of the reflector.
CIE Type:
A classification system specified by the International Commission on Illumination
(CIE) which uses luminous intensity or flux distribution of the indoor luminaire to
categorize it in one of the following 5 classifications. These classifications are based
o n t h e a m o u n t o f f l u x t h a t i s d i r e c t e d u pwa r d o f d ow n wa r d .
(1) Direct- 90-100%of flux is directed downward
(2) Semi-Direct - 60-90% of the flux is directed downward. The
remainder of the flux is above the 90 vertical
angle (horizon).
(3) General Diffuse- both upward and downward flux are
comparable.
(4) Semi-Indirect-60-90% of flux is directed upward
(5) Indirect-90-100% of flux is directed upward above the 90
vertical angle (horizon).
Shielding Angle
The shielding angle is the angle between the
first sight of the bare lamp and a horizontal line through the lamp center. This is expressed
on the test report for both the 0 and 90
horizontal planes.
35
Spacing Criteria (Criterion) is a ratio
used to estimate the farthest spacing of luminaires that will still yield a relatively
u n i f o r m i l l u m i n a n c e o n t h e f l o o r.
This ratio is presented
in units of spacing per mounting height.
EX: Mounted at 8 feet, this luminaire should be mounted:
8’ * 1.4=11.2’ crosswise from the next luminaire
8’ * 1.2=9.6’ lengthwise from the next luminaire
Luminaire Testing Laboratory, Inc.
-6-
Luminance Table
The luminance table is a tabular listing of the average brightness when viewed from specific viewing
angles. Average luminance is measured in candela per square meter and is very important in glare
calculations. Two light sources may produce the same candela value at a given angle. If we suppose
one is a small projector lamp and the other is a two foot by four foot recessed luminaire, the luminance
of the projector lamp will be much greater than that of the two foot by four foot luminaire. Essentially,
the average luminance describes whether a luminaire is small and bright, or large and dim.
LUMINANCE IN CANDELA PER SQUARE METER
Lateral Angles
ANGLE
IN DEG
0
45
Vertical Angles 55
65
75
85
AVERAGE AVERAGE AVERAGE
0-DEG 45-DEG 90-DEG
4983.
4983.
4983.
4039.
4924.
6423.
3150.
4378.
5711.
690.
1035.
816.
247.
289.
289.
0.
0.
0.
Candela Distribution & Zonal Lumen Summary
This section presents the same information found on the summary tables on the front page
of the report, however the data is shown in finer degree increments.
The candela distribution table displays candela
values in finer increments.
The ver tical
angles are in 5 increments instead of 10 increments.
CANDELA DISTRIBUTION
0.0 22.5 45.0
0 1401 1401 1401
5 1399 1396 1393
10 1365 1363 1360
15 1321 1313 1283
20 1263 1245 1195
25 1198 1156 1124
30 1121 1067 1078
35 1034 977 1050
40 925 881 1019
45 803 789 979
50 668 694 898
55 508 557 706
60 248 322 391
65
82 103 123
70
38
43
44
75
18
20
21
80
10
10
10
85
0
0
0
90
0
0
0
67.5
1401
1391
1343
1267
1199
1170
1173
1177
1191
1167
1033
823
352
107
44
21
9
0
0
The Zonal Lumen Summary found here represents the
lumen values at given zonal ranges. The zonal ranges
now are in 5 increments beginning at 0 vertical.
ZONAL LUMEN SUMMARY
0- 5
33.
5- 10
99.
10- 15
157.
15- 20
207.
20- 25
249.
25- 30
289.
30- 35
325.
35- 40
357.
40- 45
382.
45- 50
382.
50- 55
351.
55- 60
246.
60- 65
92.
65- 70
33.
70- 75
16.
75- 80
7.
80- 85
3.
85- 90
0.
90.0
1401
1390
1332
1260
1204
1199
1222
1252
1307
1277
1133
921
298
97
42
21
10
0
0
Luminaire Testing Laboratory, Inc.
-7-
Coefficients of Utilization
The coefficients of utilization table is a listing of the luminaire’s efficiency relative to
room surface reflectances and space configuration. The top numbers in the “RC” row
represent the reflectance of the ceiling. The next row of numbers in the “RW” row
represent the reflectance of the walls. The column on the left hand side of the table is the
“room cavity ratio” or RCR. The RCR is a factor that is calculated to classify the room
proportions. A high RCR means that the room has either a high ceiling or a large perimeter
length relative to its square foot area (ex. hallway/corridor). A low RCR would indicate a
low ceiling or a small perimeter length relative to its square foot area (ex. square room).
Each value in the table is the percentage of the barelamp’s light that can be used to illuminate
a horizontal work plane.
LTL NUMBER: 04983
DATE: 1-1-2000
PREPARED FOR: LUMINAIRE TESTING LABORATORY, INC.
COEFFICIENTS OF UTILIZATION - ZONAL CAVITY METHOD
EFFECTIVE FLOOR CAVITY REFLECTANCE 0.20
“RCR”
Room
Cavity
Ratio
RC
RW
80
70 50 30 10
70
70 50 30 10
50
50 30 10
30
50 30 10
10
50 30 10
0
0
0
1
2
3
4
5
6
7
8
9
10
69
64
60
56
51
47
44
40
37
34
31
67
63
59
54
50
46
43
39
36
33
31
64
59
53
48
44
39
35
32
28
25
23
61
56
52
47
42
38
34
31
28
25
22
59
54
50
46
41
37
34
30
27
24
22
58
52
46
41
36
31
27
23
20
17
15
69
62
56
51
46
41
37
33
29
26
24
69
60
53
47
42
36
32
28
25
22
19
69
59
51
44
38
33
29
25
22
19
16
67
61
55
50
45
40
36
33
29
26
24
67
59
53
47
41
36
32
28
25
22
19
67
58
50
44
38
33
29
25
22
19
16
“RC” indicates the
Reflectance of the Ceiling
64
57
51
45
40
36
31
28
24
21
19
64
56
49
43
38
33
29
25
21
18
16
61
55
50
44
39
35
31
27
24
21
19
61
54
48
42
37
32
28
25
21
18
16
“RW” indicates the
Reflectance of theWalls
Luminaire Testing Laboratory, Inc.
-8-
59
54
48
43
39
34
30
27
24
21
19
59
53
47
42
37
32
28
25
21
18
16