Cooling load factors for lights
From ASHRAE (1989), with permission
See tables at bottom of page to determine "a" coefficient and "b" classification
Values for when lights are on for 8 hours
"a" coefficient |
"b" classification |
Number of hours after lights are turned on |
|||||||||||||||||||||||
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
||
45 |
A |
0.02 |
0.46 |
0.57 |
0.65 |
0.72 |
0.77 |
0.82 |
0.85 |
0.88 |
0.46 |
0.4 |
0.3 |
0.24 |
0.19 |
0.15 |
0.12 |
0.1 |
0.08 |
0.06 |
0.05 |
0.04 |
0.03 |
0.03 |
0.02 |
B |
0.07 |
0.51 |
0.56 |
0.61 |
0.65 |
0.68 |
0.71 |
0.74 |
0.77 |
0.34 |
0.3 |
0.28 |
0.25 |
0.22 |
0.2 |
0.18 |
0.16 |
0.15 |
0.13 |
0.12 |
0.11 |
0.1 |
0.09 |
0.08 |
|
C |
0.11 |
0.55 |
0.58 |
0.6 |
0.63 |
0.65 |
0.67 |
0.69 |
0.71 |
0.28 |
0.3 |
0.25 |
0.23 |
0.22 |
0.2 |
0.19 |
0.18 |
0.17 |
0.16 |
0.15 |
0.14 |
0.13 |
0.12 |
0.12 |
|
D |
0.14 |
0.58 |
0.6 |
0.61 |
0.62 |
0.63 |
0.64 |
0.65 |
0.66 |
0.22 |
0.2 |
0.21 |
0.2 |
0.2 |
0.19 |
0.19 |
0.18 |
0.18 |
0.17 |
0.16 |
0.16 |
0.16 |
0.15 |
0.15 |
|
55 |
A |
0.01 |
0.56 |
0.65 |
0.72 |
0.77 |
0.82 |
0.85 |
0.88 |
0.9 |
0.37 |
0.3 |
0.24 |
0.19 |
0.16 |
0.13 |
0.1 |
0.08 |
0.07 |
0.05 |
0.04 |
0.03 |
0.03 |
0.02 |
0.02 |
B |
0.06 |
0.6 |
0.64 |
0.68 |
0.71 |
0.74 |
0.76 |
0.79 |
0.81 |
0.28 |
0.3 |
0.23 |
0.2 |
0.18 |
0.16 |
0.15 |
0.13 |
0.12 |
0.11 |
0.1 |
0.09 |
0.08 |
0.07 |
0.06 |
|
C |
0.09 |
0.63 |
0.66 |
0.68 |
0.7 |
0.71 |
0.73 |
0.75 |
0.76 |
0.23 |
0.2 |
0.2 |
0.19 |
0.18 |
0.17 |
0.16 |
0.15 |
0.14 |
0.13 |
0.12 |
0.11 |
0.11 |
0.1 |
0.1 |
|
D |
0.11 |
0.66 |
0.67 |
0.68 |
0.69 |
0.7 |
0.71 |
0.72 |
0.72 |
0.18 |
0.2 |
0.17 |
0.17 |
0.16 |
0.16 |
0.15 |
0.15 |
0.14 |
0.14 |
0.13 |
0.13 |
0.13 |
0.12 |
0.12 |
|
65 |
A |
0.01 |
0.66 |
0.73 |
0.78 |
0.82 |
0.86 |
0.88 |
0.91 |
0.93 |
0.29 |
0.2 |
0.19 |
0.15 |
0.12 |
0.1 |
0.08 |
0.06 |
0.05 |
0.04 |
0.03 |
0.03 |
0.02 |
0.02 |
0.01 |
B |
0.04 |
0.69 |
0.72 |
0.75 |
0.77 |
0.8 |
0.82 |
0.84 |
0.85 |
0.22 |
0.2 |
0.18 |
0.16 |
0.14 |
0.13 |
0.12 |
0.1 |
0.09 |
0.08 |
0.08 |
0.07 |
0.06 |
0.06 |
0.05 |
|
C |
0.07 |
0.72 |
0.73 |
0.75 |
0.76 |
0.78 |
0.79 |
0.8 |
0.82 |
0.18 |
0.2 |
0.16 |
0.15 |
0.14 |
0.13 |
0.12 |
0.11 |
0.11 |
0.1 |
0.1 |
0.09 |
0.08 |
0.08 |
0.07 |
|
D |
0.09 |
0.73 |
0.74 |
0.75 |
0.76 |
0.77 |
0.77 |
0.78 |
0.79 |
0.14 |
0.1 |
0.13 |
0.13 |
0.13 |
0.12 |
0.12 |
0.11 |
0.11 |
0.11 |
0.1 |
0.1 |
0.1 |
0.1 |
0.09 |
|
75 |
A |
0.01 |
0.76 |
0.8 |
0.84 |
0.87 |
0.9 |
0.92 |
0.93 |
0.95 |
0.21 |
0.2 |
0.13 |
0.11 |
0.09 |
0.07 |
0.06 |
0.05 |
0.04 |
0.03 |
0.02 |
0.02 |
0.02 |
0.01 |
0.01 |
B |
0.03 |
0.78 |
0.8 |
0.82 |
0.84 |
0.85 |
0.87 |
0.88 |
0.89 |
0.15 |
0.1 |
0.13 |
0.11 |
0.1 |
0.09 |
0.08 |
0.07 |
0.07 |
0.06 |
0.05 |
0.05 |
0.04 |
0.04 |
0.04 |
|
C |
0.05 |
0.8 |
0.81 |
0.82 |
0.83 |
0.84 |
0.85 |
0.86 |
0.87 |
0.13 |
0.1 |
0.11 |
0.1 |
0.1 |
0.09 |
0.09 |
0.08 |
0.08 |
0.07 |
0.07 |
0.06 |
0.06 |
0.06 |
0.05 |
|
D |
0.06 |
0.81 |
0.82 |
0.82 |
0.83 |
0.83 |
0.84 |
0.84 |
0.85 |
0.1 |
0.1 |
0.1 |
0.09 |
0.09 |
0.09 |
0.08 |
0.08 |
0.08 |
0.08 |
0.07 |
0.07 |
0.07 |
0.07 |
0.07 |
Values for when lights are on for 12 hours
"a" coefficient |
"b" classification |
Number of hours after lights are turned on |
|||||||||||||||||||||||
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
||
45 |
A |
0.05 |
0.49 |
0.59 |
0.67 |
0.73 |
0.78 |
0.83 |
0.86 |
0.89 |
0.91 |
0.93 |
0.94 |
0.95 |
0.51 |
0.41 |
0.33 |
0.27 |
0.22 |
0.17 |
0.14 |
0.11 |
0.09 |
0.07 |
0.06 |
B |
0.13 |
0.57 |
0.61 |
0.65 |
0.69 |
0.72 |
0.75 |
0.77 |
0.79 |
0.82 |
0.83 |
0.85 |
0.87 |
0.43 |
0.39 |
0.35 |
0.31 |
0.28 |
0.25 |
0.23 |
0.21 |
0.18 |
0.17 |
0.15 |
|
C |
0.19 |
0.63 |
0.65 |
0.67 |
0.69 |
0.71 |
0.73 |
0.74 |
0.76 |
0.77 |
0.79 |
0.8 |
0.81 |
0.37 |
0.35 |
0.33 |
0.31 |
0.29 |
0.27 |
0.26 |
0.24 |
0.23 |
0.21 |
0.2 |
|
D |
0.22 |
0.66 |
0.67 |
0.68 |
0.69 |
0.7 |
0.71 |
0.72 |
0.73 |
0.74 |
0.74 |
0.75 |
0.76 |
0.32 |
0.31 |
0.3 |
0.29 |
0.28 |
0.27 |
0.26 |
0.26 |
0.25 |
0.24 |
0.23 |
|
55 |
A |
0.04 |
0.58 |
0.66 |
0.73 |
0.78 |
0.82 |
0.86 |
0.89 |
0.91 |
0.93 |
0.94 |
0.95 |
0.96 |
0.42 |
0.34 |
0.27 |
0.22 |
0.18 |
0.14 |
0.11 |
0.09 |
0.07 |
0.06 |
0.05 |
B |
0.11 |
0.65 |
0.68 |
0.72 |
0.74 |
0.77 |
0.79 |
0.81 |
0.83 |
0.85 |
0.86 |
0.88 |
0.89 |
0.35 |
0.32 |
0.28 |
0.26 |
0.23 |
0.21 |
0.19 |
0.17 |
0.15 |
0.14 |
0.12 |
|
C |
0.15 |
0.69 |
0.71 |
0.73 |
0.75 |
0.76 |
0.78 |
0.79 |
0.8 |
0.81 |
0.83 |
0.84 |
0.85 |
0.3 |
0.29 |
0.27 |
0.25 |
0.24 |
0.22 |
0.21 |
0.2 |
0.19 |
0.17 |
0.16 |
|
D |
0.18 |
0.72 |
0.73 |
0.74 |
0.75 |
0.76 |
0.76 |
0.77 |
0.78 |
0.78 |
0.79 |
0.8 |
0.8 |
0.26 |
0.25 |
0.24 |
0.24 |
0.23 |
0.22 |
0.22 |
0.21 |
0.2 |
0.2 |
0.19 |
|
65 |
A |
0.03 |
0.67 |
0.74 |
0.79 |
0.83 |
0.86 |
0.89 |
0.91 |
0.93 |
0.94 |
0.95 |
0.96 |
0.97 |
0.33 |
0.26 |
0.21 |
0.17 |
0.14 |
0.11 |
0.09 |
0.07 |
0.06 |
0.05 |
0.04 |
B |
0.09 |
0.73 |
0.75 |
0.78 |
0.8 |
0.82 |
0.84 |
0.85 |
0.87 |
0.88 |
0.89 |
0.9 |
0.91 |
0.27 |
0.25 |
0.22 |
0.2 |
0.18 |
0.16 |
0.15 |
0.13 |
0.12 |
0.11 |
0.1 |
|
C |
0.12 |
0.76 |
0.78 |
0.79 |
0.8 |
0.81 |
0.83 |
0.84 |
0.85 |
0.86 |
0.86 |
0.87 |
0.88 |
0.24 |
0.22 |
0.21 |
0.2 |
0.19 |
0.17 |
0.16 |
0.15 |
0.14 |
0.14 |
0.13 |
|
D |
0.14 |
0.79 |
0.79 |
0.8 |
0.8 |
0.81 |
0.82 |
0.82 |
0.83 |
0.83 |
0.84 |
0.84 |
0.85 |
0.2 |
0.2 |
0.19 |
0.18 |
0.18 |
0.17 |
0.17 |
0.16 |
0.16 |
0.15 |
0.15 |
|
75 |
A |
0.02 |
0.77 |
0.81 |
0.85 |
0.88 |
0.9 |
0.92 |
0.94 |
0.95 |
0.96 |
0.97 |
0.97 |
0.98 |
0.23 |
0.19 |
0.15 |
0.12 |
0.1 |
0.08 |
0.06 |
0.05 |
0.04 |
0.03 |
0.03 |
B |
0.06 |
0.81 |
0.82 |
0.84 |
0.86 |
0.87 |
0.88 |
0.9 |
0.91 |
0.92 |
0.92 |
0.93 |
0.94 |
0.19 |
0.18 |
0.16 |
0.14 |
0.13 |
0.12 |
0.1 |
0.09 |
0.08 |
0.08 |
0.07 |
|
C |
0.09 |
0.83 |
0.84 |
0.85 |
0.86 |
0.87 |
0.88 |
0.88 |
0.89 |
0.9 |
0.9 |
0.91 |
0.91 |
0.17 |
0.16 |
0.15 |
0.14 |
0.13 |
0.12 |
0.12 |
0.11 |
0.1 |
0.1 |
0.09 |
|
D |
0.1 |
0.85 |
0.85 |
0.86 |
0.86 |
0.86 |
0.87 |
0.87 |
0.88 |
0.88 |
0.88 |
0.89 |
0.89 |
0.14 |
0.14 |
0.14 |
0.13 |
0.13 |
0.12 |
0.12 |
0.12 |
0.11 |
0.11 |
0.11 |
a | Furnishings | Air supply and return | Type of light fixture |
0.45 | Heavyweight, simple furnishings, no carpet | Low rate; supply and return below ceiling (V £ 2.5)1 | Recessed, not vented |
0.55 | Ordinary furniture, no carpet | Medium to high ventilation rate; supply and return below ceiling or through ceiling grill and space (V ³ 2.5)1 | Recessed, not vented |
0.65 | Ordinary furniture, with or without carpet | Medium to high ventilation rate or fan coil or induction type air-conditioning terminal unit; supply through ceiling or wall diffuser; return around light fixtures and through ceiling space (V £ 2.5)1 | Vented |
0.75 or greater | Any type of furniture | Ducted returns through light fixtures | Vented or free-hanging in airstream with ducted returns |
1V is the room air supply rate in liters per second per square meter of floor area
Room envelope construction1 (mass of floor area, kg/m2) | Room
air circulation and type of supply and return2 |
|||
Low | Medium | High | Very high | |
50 mm wood floor (50) | B | A | A | A |
75-mm concrete floor (200) | B | B | B | A |
150-mm concrete floor (370) | C | C | C | B |
200-mm concrete floor (590) | D | D | C | C |
300-mm concrete floor (780) | D | D | D | D |
1Floor covered with carpet and rubber pad; for a
floor covered only with floor tile, take the next classification to the right in the same
row.
2These values are defined as follows: