

Engineering
& Design > Flow Velocity
Liners
Liquid or gas applications conveying media at high velocity should incorporate
an interlock liner in the hose assembly design. The liner will decrease
the turbulence caused by the high velocity and reduce the resonant vibration
that may occur. A liner is recommended if the velocity is greater than
the following:
Media

Hose
Alignment

Maximum
Velocity
without Liner (ft./sec.)

liquid 
straight 
75 
liquid 
45° bend 
56 
liquid 
90° bend 
37 

gas 
straight 
150 
gas 
45° bend 
112 
gas 
90° bend 
75 
Conversion Formulas
Definitions^{a} 
Feet Per Second
(ft./sec.)

gph: gallons per
hour 
(gph ÷ ID^{2})
x 0.0068 
gpm: gallons per
minute 
(gpm ÷ ID^{2})
x 0.4083 
cfh: cubic feet per
hour 
(cfh ÷ ID^{2})
x 0.0509 
cfm: cubic feet per
minute 
(cfm ÷ ID^{2})
x 3.0558 
cfs: cubic feet per
second 
(cfs ÷ ID^{2})
x 183.35 

^{a}ID = nominal hose size in inches 
Example
Given: 

3" nominal hose size
500 gallons per minute flow
Media is water
Hose is installed in 90° bend 
Computation: 

From the formula above, (gpm ÷ ID^{2}) x 0.4083 or
(500 ÷ 3^{2}) x 0.4083 = 22.68 ft./sec. flow velocity 
Result: 

Since the calculated flow velocity of 22.68 ft./sec. is less
than 37 ft./sec., a liner is not required for this application. 
