Hydrogen leak test

The hydrogen detecting defaults for checking a hydrogen - pressure vessel or installation to leaks used and errors. This is important because concentrations of hydrogen from 4% to 75% mixed with air (approximately 40,000 ppm) can be explosive.

Test procedure

Hydrostatic test

The hydrostatic test. In this case, the apparatus is filled with an almost incompressible liquid, usually water or oil , and after the apparatus has been subjected to excess pressure, it is examined for deformations and leaks. 150% of the nominal pressure is usual here in order to have a certain safety margin.

Helium leak test

In the helium leak test, the apparatus is flooded with helium , the lightest inert gas as the test gas, and a vacuum is created around the apparatus. Then their tightness is checked with a helium detector, which can measure the smallest concentrations (1: 10,000,000 particles). This process takes advantage of the ability of helium to escape through even the smallest cracks.

Hydrogen microsensor test

In the so-called hydrogen microsensor test, the apparatus is flooded with a test gas mixture of 95% nitrogen and 5% hydrogen . This low volume percentage of hydrogen is necessary because a hydrogen mixture with less than 5.7 percent by volume of hydrogen is non-flammable. The system is now checked for leaking hydrogen gas using a microelectronic hand sensor. This sensor can detect hydrogen leaks with a minimum flow rate of 5 · 10 ⁻⁷ cm³ / s. The advantage of this method is that it is much less expensive than the helium leak test. In addition, the test gas used is cheaper than helium.

Uses

Room surveillance

Because hydrogen is the least dense element, it rises. In this way, a stationary measuring instrument is used in room monitoring, which is installed at the highest point in the room where hydrogen could accumulate.

Monitoring in manufacturing plants

A permanently mounted sensor used on production lines and other industrial installations.

Portable measuring device

A lightweight, mobile instrument with a sensor that works with point contact.