Table of Contents
1.5
Determination of the capacity
To determine the pressure loss of a safety device with fully open valve, you may use this
formula:
Qn
.
d
.
Tu
273
p
2
13
,
57
.
Cg
For natural gas with q
When using other gasses
d= q
with Q
= flow rate in m
n
p
= inlet pressure in bar (abs)
i
Cg = capacity rate
d
= relative density (air = 1)
Tu = inlet temperature of the gas (
q
= gas density (Tu = 273 K = 0
n
DN
1"
2"
C
480
1950
g
Table II: Capacity rates C
To limit the flow forces we would advise not to exceed the following flow rate. You
have to use the formula below for this purpose.
K
Q
p
D
1
max
i
min
in which
D
= nominal diameter in mm
1
pi
= minimum inlet pressure in bar (abs)
min
Q
= maximum flow in m
max
K= 100 for DN = 1" up to 6"
K= 200 for DN = 8" up to 12"
K= 300 for DN =16" up to 24"
2
.
pi
= 0.831 kg/m³
n
d = 0.643
gas / 1.29
n
3
/h
n
o
C)
o
C)
3"
4"
6"
4300
7050
15100
(up to 600#, high pressures on request)
g
3
/h
n
© 2017 Honeywell International Inc
Operation and maintenance manual HON HSV086
8"
10"
12"
26060
40800
60050
16"
20"
104150
166640
287953
7
24"
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