Helium Inspection Services

ISISAN Engineering offers:-

  • High quality helium leak testing services.
  • Well trained, experienced and certified technicians on job.
  • Guaranteed safety of your job/system, leak-tight and in the best possible condition.
  • Helium Leak Testing service for both in-house manufactured items and onsite.


The basic functions of leak detection are the location and measurement of leaks. These functions are carried out through the use of standard leak test techniques, which are usually selected according to the configuration of the part to be tested, the economics of the test, and the nature of the system.

It is recommended to maintain the same conditions as when the tested product is being used, e.g. the same pressure level and gas flow. For examples, a vacuum system should be tested in a vacuum chamber whereas compressed-air bottles should be tested under high pressure.


Leak location is the testing approach used to find the precise location of individual leaks. It is usually a qualitative procedure only. Leak location does carry out the very valuable function of identifying the sources of measured leaks in order to facilitate repair, remanufacture, or, in some cases, even redesign.

The Helium Leak Detection method is used:-

  • To find small leaks in pressure vessels and other contained systems.
  • Where other pressure testing techniques are not suitable due to operational restrictions
  • Where leaks are so small that other techniques cannot identify the location.


  • It is one of the smallest gas molecules & relatively safe to use.
  • It will not react with any of the materials within the part to be tested.
  • It is a superior choice as tracer gas.
  • It is inert, non-toxic and non-flammable.
  • It can pass easily through leaks due to its small atomic size.
  • It is present in the atmosphere at only 5 ppm.
  • It is highly mobile, allowing rapid desorption and short measurement time.

Helium Leak Testing:-

  • Many times more sensitive than using other leak detection technique.
  • Accurate, quantitative leak analysis (< 1 scf/year).
  • Detailed leak report can be obtained.
  • Environmentally friendly.
  • Initiates and accelerates drying phase.
  • Instruments can be tested.
  • System is inerted.


In the sniffer-probe mode, the test piece is filled with tracer gas and the exterior is scanned with a probe that is attached to the inlet of the leak detector. The probe continuously admits (or "sniffs") some of the air directly surrounding the test piece. This air is inducted to the analytical portion of the leak detector, where any of the tracer gas that may be leaking from the test piece is detected.


In the spray-probe mode, the leak detector is used to evacuate the interior of the test piece, and a probe is used to discretely spray test gas on suspected leak sites. Any leaks are evidenced when the tracer gas flow through the evacuated test piece and is detected by the leak detector.


Leak measurement is the approach used to actually measure the total or partial leakage of a device or system. The most reliable approach is to initially test a system or device for total leakage, and then for individual leaks, which are isolated by using one of the leak location techniques. Use of a leak location technique to measure total leakage usually results in poor reliability and high cost.


In the inside-out mode, the test part is filled with tracer gas and is placed in a test fixture that is subsequently evacuated. Any of the tracer gas that flows out through a leak is captured in a volume surrounding the test part. The contents of this volume are analyzed by the leak detector as representative of total leakage.


In the outside-in mode, the test part is evacuated and is placed in a volume containing the tracer gas, which flows through all leaks to the interior of the test part, where it is detected.

With either of these approaches, the tracer gas may be allowed to accumulate before detection, or may be detected continuously. In general, continuous detection yields a faster test with adequate sensitivity; however, circumstances sometimes require the accumulation of tracer gas prior to analysis.