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@IST01530EEJ 019175A0 190411
When the 'Volume measurement' option is selected instead, the procedure, described also in the flow charts of
the tightness test according to UNI 11137-1, is described in the following steps:
•
Close both faucets in the kit assembly supplied for the test execution.
•
Connect the graduated syringe to the hose which in the assembly is opposed to the pump.
•
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.
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: City Gas, Natural Gas or L.P.G..
TES T 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: City Gas, 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, 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.
Result: is the result of the tightness test. Compliant (piping suitable for operation): when the leakage flow
calculated in the reference conditions is lower than 1 dm
3
/h. The system is authorized to operate
wihtout restrictions or intervention. Compl. 30 DD (piping temporarily suitable for operation):
when the leakage flow calculated in the reference conditions is included in the range 1 dm
3
/h < Qrif
< 5 dm
3
/h. The system is authorized to operate only for the time needed for the maintenance of the
pipe in order to fix the leakage problem, and in any case for no more than 30 days after the testing
day. Once the fixing has been completed the piping must tested again for its tightness according to
the UNI 7129 standard. Non compliant (not suitable for operation): when the leakage flow is
greater than 5 dm
3
/h. In this situation the measured leakage is such that the piping is not suitable for
operation and must immediately placed out of order. Once the leakage problem has been fixed the
piping must tested again for its tightness according to the UNI 7129 standard
TcK Temperature:
The user can measure the temperatures within the range specified in the technical specifications (e.g. plant
delivery temperature) by using an OPTIONAL Type K thermocouple contact probe connected to the TcK input.
Pt100 Temperature:
The ambient temperature can be measured within the range specified in the technical specifications by
connecting the remote air temperature probe provided with the instrument to the Pt100 input.
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