Fluid Flow
HEAD LOSS
TABLE 1
Typical Values ofLeq
D
Item
Leq
D
Globe Valve
Conventional
Y-Pattern
Gate Valve
Fully Open
75% Open
50% Open
25% Open
Standard Tee
Flow through Run
Flow through Branch
90° Standard Elbow
45° Standard Elbow
Return Bend
400
160
10
35
150
900
10
60
30
16
50
Example:
A fully-open gate valve is in a pipe with a diameter of 10 inches. What equivalent length
of pipe would cause the same head loss as the gate valve?
Solution:
From Table 1, we find that the value of Leq/D for a fully-open gate valve is 10.
Leq
= (L/D) D
= 10 (10 inches)
= 100 inches
By adding the equivalent lengths of all components to the actual length of pipe in a system we
can obtain the Leq value for the entire piping system.
Rev. 0
Page 35
HT-03
