Leak Test with HELIUM (LT)

The Leak Test with Helium is a Non-Destructive Test suitable for leak detection on components such as pipes and tanks.

The principle of the Helium Test is based on the possible transmigration of a fluid (helium gas) through a passage between two separate regions (e.g. internal / external component) placed at a positive or negative pressure differential.

DETECTABLE FEATURES
with the Helium Leak Test (LT)

Leak detection on components such as pipes and tanks. Only passing defects are detected.
The leak test methods are different and are divided into:

VACUUM METHOD

  • Test type = Quantitative
  • Test sensitivity = from 10E-6 mbar.l / s up to 10E-12 mbar.l / s
  • Field of application = all components that require high examination sensitivity
  • In a region (eg internal), by means of pumping groups, the vacuum is carried out, connecting the spectrometer (reading instrument) directly to the region in which the vacuum was carried out. Then the opposite (external) region is placed in the atmosphere or helium over pressure, so that, if there are leaks, the helium will pass through them and will be detected by the spectrometer.

 

METHOD IN PRESSURE (Sniffer Method)

  • Test type = Qualitative
  • Test sensitivity = from 10E-6 mbar.l / s up to 10E-03 mbar.l / s
  • Field of application = all components that require examination sensitivity max 10E-6 mbar.l / s
  • The component under test is pressurized with helium at the test pressure (normally no more than 1 bar) and after a diffusion period the gas will start to flow from any leaks.
  • All the areas involved in the test will be scanned with a probe (sniffer) connected to the spectrometer, allowing the localization and discrimination of leaks.

Reference standards: ASME - UNI EN - ISO - SHELL - TÜV

FUNCTIONALITY
of the Leak Tests with Elio (LT)

High sensitivity, even for very small capillaries not detectable by other methods.

The use of helium as a tracer gas in leak tests and in the search for leaks offers significant advantages such as:

  • it is a noble and inert gas therefore it does not bind with any other molecule;
  • it is present in the environment in small quantities (about 5 ppmV);
  • excellent instrumental sensitivity helium has a molecular mass of 4;
  • great capillarity that allows it to flow in the escape routes more easily than other types of gas with larger molecules.

APPLICATIONS
Leak Testing with Helium (LT)

Tightness test of components under pressure and vacuum.
We also carry out leak tests with the high vacuum method to check even if there are very small leaks.

CONTROLLED PRODUCTS:

  • Valves
  • Valves with cryogenic tests
  • Tanks and exchangers
  • Cryogenic tanks and transportable tanks
  • Chemical reactors – Process columns
  • Thermocouples and sensors
  • Storage lines
  • Underground gas lines
  • Industrial installations
  • Naval gas carriers

CHECKING THE VALVES FOR "FUGITIVE EMISSION"
with the Leak Test with Helium (LT)

  • The valves are tested with tracer gas such as helium or methane, and any leakage can be measured with a mass spectrometer, using the vacuum technique or the sniffing technique as established in the reference standard.
  • During the various stages of the test, the valves are subjected to mechanical opening and closing cycles at different temperatures with alternations and repetitions defined in the standard and established on the basis of the classes they belong to.
  • All temperatures during the test are monitored and recorded with an established pattern.

FUGITIVE EMISSION VALVES

  • Fugitive emissions are emissions of gases or vapors from pressurized equipment due to leaks and other unintentional or irregular gas emissions, primarily from industrial activities. In addition to the economic cost of lost raw materials, fugitive emissions contribute to air pollution and climate change.
  • Fugitive emissions present other risks and dangers. Emissions of volatile organic compounds such as benzene from oil refineries and chemical plants pose a long-term health risk to workers and local communities. In situations where large quantities of flammable liquids and gases are contained under pressure, leaks also increase the risk of fire and explosion.
  • Leaks from pressurized process equipment typically occur through valves, fittings, mechanical seals, or related equipment.
  • Due to the huge number of potential leak sources in large industrial plants and the difficulties in detecting and repairing some leaks, fugitive emissions can represent a significant percentage of total emissions. Although the quantities of escaping gases can be small, gases that have serious health or environmental consequences can cause a significant problem.
  • To minimize and control leaks in process plants, operators regularly perform leak detection and repair activities. Routine inspections of process equipment with gas detectors can be used to identify leaks and estimate the leak rate in order to decide on appropriate corrective actions. Proper routine maintenance of equipment reduces the likelihood of leaks.

Valvole , flange , guarnizioni e raccordi possono essere testati a temperature diverse con < b> gas di prova con elio o metano , usando il metodo di sniffing o vacuum secondo gli standard internazionali riconosciuti o possono essere Secondo le specifiche del cliente per garantire l'idoneità dell'applicazione.

STANDARD EXAMPLES OF FUGITIVE EMISSION VALVES

Type test: ISO 15848-1, API 624, API 641, API 622, TA Luft – VD 2440 (test temperatures: ambient temperature, high and/or low temperature)

Pruduction test: ISO 15848-2, Shell SPE 77/312 (performed at room temperature)

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HELIUM LEAK TEST (LT)