45
K900000000SE 022628A0 071013
•
Open the faucet on the side where the syrynge is applied and withdraw exactly 100 ml (100 cc) of the gas
present in the piping. Press the ' ' button.
•
Inject the gas present in the syringe back into the piping and then close the faucet again.
•
Wait for the pressure in the piping to stabilize. After a few seconds the instrument returns to the volume input
screen in which the measured volume is shown. The proposed value can be accepted by pressing the ' '
button, modified through the arrow keys or rejected through the ' ' key.
Table volumes:
Examples relating to the various lengths of indoor systems, capacity approximately corresponding to
18dm
3
, depending on the material and the diameter of the fuel gas adduction pipe.
Note: When the measurement group can not be excluded from the test, the indicative length of the
plant is given in brackets
.
COMBUSTIBLE GAS:
consider that the amount of the leakage is strictly related to the nature of the gas under
pressure. When the tightness of a piping has to be evaluated it is mandatory to specify the family to which the
gas belongs: Natural Gas or L.P.G..
TEST GAS:
again the amount of the leakage is related to the nature of the gas under pressure, therefore it is
mandatory to specify the type of the gas used: Natural Gas, L.P.G. or air. Please note that the gas used for the
test could also be different from the gas to be used in the plant and could even be a not flammable gas.
Once the stabilization parameter has been set the user can proceed with the tightness test. Selecting the item
‘Start Test’, the test pressure required by the standard is shown, then a screen with actual pressure applied to the
instrument inputs is displayed. After having zeroed the instrument and, subsequently, having charged the piping
to a pressure close to the reference values indicated, tightness test can be started through the option ‘TEST’,
which actually starts the stabilization phase. In the stabilization screen the following values are displayed:
P
:
Actual pressure measured by the instrument, in the selected measurement unit.
∆P
1
'
:
Pressure variation in the last minute, updated every 10 seconds. This value gives a rough indication
about the stabilization level reached in the piping system.
Wait time
: Remaining time before the stabilization phase ends.
Once the stabilization phase is terminated the tightness test is started. This test is performed by observing how
the pressure decays in time during a fixed 1 minute interval for Methane and LPG in air and 2.5 minutes for the
LPG fuel, as stated in the applied standard.
During the tightness test phase the following values are displayed:
P
1
:
Pressure measured at the beginning of the test
P
2
:
Pressure actually measured by the instrument
∆P
:
Pressure variation with respect to the initial value. In case the actual pressure is lower than the initial
value (pressure is decreasing) this value has a negative sign.
Qtest
:
Is the calculated leakage measured in dm
3
/h according to the conditions under which the test has been
performed, i.e. the gas used for the test as well as the final pressure measured during the test.
Qref
:
is the calculated leakage measured in dm
3
/h according to the reference conditions described in the
standard, it is related to the gas to be used in the piping as well as to the reference pressure.
1
2
3
4
5
6
7
8
Steel
Copper / Multilayer/ Polyethylene
Diameter
length (m)
Internal diameter (mm)
length (m)
1/2"
82 (68)
10
228 (190)
3/4"
49 (40)
12
160 (133)
1"
28 (23)
14
116 (97)
1 1/4"
17 (14)
16
90 (75)
19
64 (53)
25
37 (31)
26
34 (28)
34
20 (17)
