System effect factors for single-width single-inlet fans
From ASHRAE (1988), with permission
![]() |
Notes:
|
KSEF values for single-width single-inlet fans
Ratio of blast area to outlet area | Outlet elbow position |
No duct |
12% effective duct length |
25% effective duct length |
50% effective duct length |
100% effective duct length |
0.4 |
A |
3.20 |
2.68 |
1.76 |
0.84 |
No system effect factor
|
B |
4.00 |
3.32 |
2.24 |
1.04 |
||
C |
5.80 |
4.84 |
3.20 |
1.52 |
||
D |
5.80 |
4.84 |
3.20 |
1.52 |
||
0.5 |
A |
2.28 |
1.88 |
1.28 |
0.60 |
|
B |
2.84 |
2.36 |
1.56 |
0.72 |
||
C |
4.00 |
3.32 |
2.24 |
1.04 |
||
D |
4.00 |
3.32 |
2.24 |
1.04 |
||
0.6 |
A |
1.60 |
1.32 |
0.88 |
0.40 |
|
B |
2.00 |
1.68 |
1.12 |
0.52 |
||
C |
2.92 |
2.44 |
1.64 |
0.76 |
||
D |
2.92 |
2.44 |
1.64 |
0.76 |
||
0.7 |
A |
1.08 |
0.88 |
0.60 |
0.28 |
|
B |
1.32 |
1.08 |
0.72 |
0.36 |
||
C |
1.96 |
1.64 |
1.08 |
0.52 |
||
D |
1.96 |
1.64 |
1.08 |
0.52 |
||
0.8 |
A |
0.76 |
0.64 |
0.44 |
0.20 |
|
B |
0.96 |
0.80 |
0.52 |
0.24 |
||
C |
1.40 |
1.16 |
0.76 |
0.36 |
||
D |
1.40 |
1.16 |
0.76 |
0.36 |
||
0.9 |
A |
0.60 |
0.48 |
0.32 |
0.16 |
|
B |
0.79 |
0.64 |
0.44 |
0.20 |
||
C |
1.12 |
0.92 |
0.64 |
0.28 |
||
D |
1.12 |
0.92 |
0.64 |
0.28 |
||
1.0 |
A |
0.56 |
0.48 |
0.32 |
0.16 |
|
B |
0.68 |
0.56 |
0.36 |
0.16 |
||
C |
1.00 |
0.84 |
0.56 |
0.28 |
||
D |
1.00 |
0.84 |
0.56 |
0.28 |