Hydrogen produced by corrosion

Hydrogen produced by corrosion can turn up in unexpected places, as shown by the following incidents  

Many suppliers of sulfuric acid recommend that it is stored in pressure vessels designed to withstand a gauge pressure of 30 psi (2 bar). The acid is usually discharged from tank trucks by compressed air, and if the vent is ehoked the vessel could be subjected to the full pressure of the compressed air. 

In another case, acidic water was used to clean the inside of the water Jacket that surrounded a glass-lined vessel. Some hydrogen diffused through the wall of the vessel and developed sufficient pressure to crack the glass lining. 

Corrosion uses up oxygen, and this has caused tanks to collapse (see Section 5.3 d) and persons to be overcome when entering a vessel (see Section 11.1 d). 

Overflow should end a little above ground level 

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