Tracer gas methods

The different methods

Tracer gas Helium

The Helium molecule is the smallest of the noble gases. It offers a clean, highly sensitive and, most importantly, non-destructive testing (NDT). Its principle is based on IP mass spectrometry calibrated on Helium. Three modes are possible:
    - Overhead (global or localized),
    - Test (global)
    - Vacuum and sniffing test (global or localized).
This last technique is generally used for applications with high sensitivity (10 Pa.m/s to 10 Pa.m/s). 

Helium is an approved food additive.

Tracer gas Hydrogen

The Hydrogen gas is the less expensive tracer gas, allowing flexible testing procedures for Leak Detection. Fast and accurate, the Hydrogen leak detector brings the efficient solution for a large range of applications either in production, repair lines and maintenance.

Its principle is based on an electronic sensor sensitive to Hydrogen. The tracer gas used is generally a mixture of harmless Hydrogen (5%) and Nitrogen (95%).
Two test modes are possible:
   - Sniffing
   - Accumulation
This last technique is especially designed for industrial or field (distribution of fluids) needs. This method is intended for applications in which a moderate sensitivity (1 Pa.m/s to 10 Pa.m/s) will be required. Given the low cost of the tracer gas H/N and the high sensitivity of the sensors, this method finds its way into many applications in production and maintenance/repair. 
This method has been implemented with success in the aviation and oil refining industries for example. 

Hydrogen and Nitrogen are food additives, they can be put in contact with food.