While hydrogen gas detectors are less effective outdoors, they can be an important safeguard as part of an overall hydrogen system design. They have been used in many cases to automatically shut down equipment and isolate hydrogen supply. Location and type of detectors depend on the system design and siting, but when installed, should be in areas that are most likely to be exposed to hydrogen releases. Dispersion analysis can help with that assessment.

The manufacturer’s calibration requirements should be followed to ensure proper operation of the
detection system. The requirements will vary depending on the type of detector and the environment in
which they are installed. Calibration can usually be performed by the user/owner if properly trained and
supplied with calibration gas, etc.

If the concentration of hydrogen is less than the Lower Flammability Limit (LFL) of 4% in an inert gas, it is unlikely that a leak of this gas mix will form a flammable mixture as it dilutes into air. For example, industry uses ‘forming gas’, a mixture of 4 to 5% H2 in nitrogen, as an oxide reducing agent in materials processing furnaces and soldering operations. This mixture can also be used in conjunction with a hydrogen detector for leak testing gaseous hydrogen equipment.