A steel tube with inner diameter of 6 mm and 10 m length was filled with radiolysis gas (stoichiometric H2-O2 mixture) at 70 bar for boiling water reactor simulations. Via a pneumatic valve, a venting line with similar cross-section and 2 m length, filled with atmospheric air, was connected.

For venting the tube, the valve was opened (fast) and an explosion occurred.

Explanation: Due to diffusion ignition in the leading shock, a flame flashed back into the pre-mixed reservoir and induced a detonation there. The tube system and involved measurement technique was destroyed. For safety reasons, the whole installation was set up in a protective container so that no person or other equipment was threatened.

An explosion occurred at a chemical plant in an analysis room containing various analyzer instruments, including a gas chromatograph supplied with hydrogen. A contract operator was performing work to install a new vent line to a benzene analyzer that was part of a group of CO2 analyzers, but separate and unrelated to the gas chromatograph. During the process of this work, a plant supervisor accompanying the contract operator doing the work had an indication of flammable gas present on a portable detector. This was in conflict with the fixed gas detector in the analysis room that was indicating that no flammable gas was present. As a precaution, the plant supervisor immediately cut off the hydrogen supply and, along with the contract operator, began the normal task of determining if view more

An instrument engineer at a hydrogen production facility was arresting the hydrogen leakage in tapping a pressure transmitter containing 131-bar hydrogen gas. The isolation valve was closed and the fittings near the pressure transmitter were loosened. The pressure dropped from 131 bar to 51 bar. The fitting was further loosened (though very little); the instrument tube slipped out of the ferrule and got pulled out of the fitting. With the sudden release of the 51-bar hydrogen, there was a loud pop (like a fire cracker) and the spark-proof tool was observed to have black spot on it. The volume of the hydrogen gas released was small, since it was in the tapping line only.