Working Principle; Hydrogen Tracer Gas For Leak Detection; Interferences - Adixen Sensistor H2000-P PLUS Benutzerhandbuch

2. Working principle

Hydrogen Tracer Gas for leak detection

When pure hydrogen gas is released in air
its flammability region spans from 4% to
75% of hydrogen in air. Below 4% there is
insufficient chemical energy available for a
flame to propagate. Above 75% hydrogen
there is not enough oxygen left to support a
flame.
When, for example, a mixture of less than
5.7 % hydrogen in nitrogen mixes with air
there is not sufficient energy to support a
flame, irrespective of the ratio of air-to-gas.
When a mixture of more than 5.7 % hydro-
gen in nitrogen is released into air there is a
region of ratios of air-to-gas where the
mixture is flammable. When, for example, a
mixture of 10% hydrogen in nitrogen mixes
with air there is still very little energy
available. Only in exceptional circumstances
can a flame be self-supporting. However,
such mixtures cannot detonate.
Hydrogen/nitrogen
containing more than approximately
15% hydrogen can detonate when
mixed in certain proportions with air.
Warning!
• Never use a gas mixture containing more than 5% hydrogen.
• Never make your own gas mixtures.
USER MANUAL HYDROGEN LEAK DETECTOR - H2000 PLUS
Never make your own mixtures. Only
use ready-made mixtures, or use a certified
hydrogen/nitrogen mixer installed by your
gas supplier.

Interferences

Most tracer gas methods suffer from some
sort of interference. Either the detector is
sensitive to other gases or vapours, or there
are other sources of the gas present to which
the detector is sensitive.
Some examples of hydrogen sources:
- Engine exhaust
- Battery charging stations
- Welding smoke
- Cigarette smoke
- Breathing air
- Human flatulence
- Scratching on aluminium
Hydrogen Leak Detector H2000
is extremely selective. Only Hydrogen
mixtures
Sulphide (extremely toxic) gives a
comparable response to hydrogen.
®
5
GB
PLUS