7 … 8
6 … 8
MC • Karl Dungs
, Inc.
• HP
SV 10020/604 • Edition 2017.05 • P/N 264712
Pressure drop for other gases
To determine the pressure drop when
using a gas other than natural gas,
use the flow formula below and f value
located in the table below to determine
the “corrected” flow rate in CFH through
the valve for the other gas used. For ex-
ample, when using propane, divide the
volume (CFH) of propane required for
the application by the calculated value
f (f = 0.66 for propane). Use this “cor-
rected” flow rate and the flow curve on
the next page to determine pressure
drop for propane.
Density of Natural gas
Density of gas used
f =
Type of gas
Density
[kg/m
3
]
s.g.
f
Natural gas
0.81
0.65
1.00
Butane
2.39
1.95
0.58
Propane
1.86
1.50
0.66
Air
1.24
1.00
0.80
Determining equivalent flow through valves using another gas
V
gas used
=
V
Natural gas
x f
°
°
Flow Curve
