Sullair EES LS32 Series Operator's Manual And Parts List page 16

Section 4
INSTALLATION
duct using the following equation:
Ft. of Straight X Static Press. = Actual Static
Duct (I)
100
DUCT FITTING STATIC PRESSURE LOSS
1. The volume of air to be delivered through the fit-
ting is 30,000 CFM (250HP), and 35,000 CFM
(450HP).
2. Calculate the fitting area through which the air is
flowing. Be sure this area corresponds to the
area used in Table 3 for calculating the loss
coefficient.
For Rectangular Duct:
Area = Width (II) x Height (II)
For Round Duct:
Area = .00545 x Diameter 2 (II)
3. Calculate the air velocity through the fitting.
Velocity (III) = CFM - From Step 1
4. Select the proper loss coefficient from Table 3.
Be sure that the loss coefficient corresponds to
the area calculated in Step #2.
5. Calculate the static pressure loss for the fitting
using the following equation:
C(III) x (Velocity [ft./min.]) 2 = Static Pressure Loss
4005
6. Repeat Steps 2 through 5 for each fitting. The
calculations for each fitting and section of
straight duct should be tabulated on the work-
sheet provided (Table 2).
7. Total the static pressure loss for each duct
branch.
(I) Because fitting static pressure losses are "zero
length" losses, calculation of amount of straight
duct should be from the intersections of the center-
lines of the straight duct sections.
(II) In feet per minute.
(III) Use C, C1, C2, or C0 as indicated in Table 3.
12
Pressure Loss
144
Area - From Step 2
(inches of water)
Table 1- Duct Size Conversion
DUCT SIZE
(INCHES)
18 X 36
18 X 42
18 X 48
18 X 54
18 X 60
18 X 66
18 X 72
24 X 24
24 X 30
24 X 36
24 X 42
24 X 48
24 X 54
24 X 60
30 X 30
30 X 36
30 X 42
30 X 48
30 X 54
30 X 60
36 X 36
36 X 42
36 X 48
36 X 54
36 X 60
42 X 42
42 X 48
42 X 54
48 X 48
48 X 54
54 X 54
54 X 60
60 X 60
60 X 72
72 X 72
EQUIVALENT
ROUND DUCT
DIAMETER
(INCHES)
27
29
31
33
34
36
37
26
29
32
34
37
39
40
33
36
39
41
44
46
39
42
45
49
50
46
49
52
52
56
59
62
66
73
79