Siemens VALVEGYR LDU11.523A17 User Manual - Page 9
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Calculation of the leakage rate escaping from a length of pipe
Legend
Example
Building Technologies Division
(P
- P
) x V x 3600
G
W
Q
=
Leck
P
x t
atm
Test
Q
in dm³/h
Permissible leakage rate in dm³ per hour or liters per hour
leck
P
in mbar
Overpressure in pipe section between the valves to be tested, at
G
the beginning of the test phase
P
in mbar
Overpressure set on pressure switch «DW» (normally set to 50
W
% of the gas mains pressure)
P
in mbar
Absolute pressure (1.013 mbar normal pressure)
atm
V
in dm³
Volume of test space confined by the valves to be tested, includ-
ing the space in the valves themselves
T
in s
Duration of proving time
test
P
= 30 mbar
G
P
= 15 mbar
W
P
= 1013 mbar
atm
V
= 10.36 dm³
t
= 27.5 s
Test
Note!
Select volume of pipe section (V) between the gas valves to be checked and over-
pressure (P
set on pressure switch (DW) such that the maximum permissible gas
W)
leakage rate (Q
) will not exceed the rate specified in the local regulations.
Leck
(30 - 15) x 10.36 x 3600
Q
=
Leck
1013 x 27.5
Any valve leakage rate exceeding 20 l/h causes the LDU11...
to initiate lockout
= 20 l/h
CC1N7696en
9/21
20.04.2016