Transport of hydrogen
Failure of installations and equipment
Inadequate maintenance of installations and equipment can lead to hydrogen leakage, resulting in the risk of ignition of a flammable gas cloud and explosion. Catastrophic failure of equipment can also occur due to defects in the construction of installations and surrounding pipework, especially in the case of poor quality welds. In addition, failure can also be the result of erosion, corrosion, metal embrittlement, cycle fatigue or vibration.
Corrosion
Hydrogen can cause corrosion (hydrogen embrittlement), such as when used in process or loading installations. This occurs when hydrogen is trapped in the hairline cracks of a metal, which can lead to weakening of the metal, making it brittle and more likely to break, resulting in (minor) leakage and possibly further escalation.
Stress corrosion cracking is not normally a risk in hydrogen stations, but may need to be considered depending on operating temperatures, pressures and environmental conditions
Other installation risks and equipment failure
Other installation risks that can lead to equipment failure include closed drain lines, a closed downstream valve or tight vent. Backflow can also occur between equipment when there is a pressure difference between different systems. Failure to correctly inert the installation before and after installation can lead to an explosive mixture of oxygen (in air) with hydrogen.
The installation design must take into account the inherent hazards of hydrogen, as previously described. The materials used in the installation must be properly selected to ensure their compatibility with hydrogen and resistance to corrosion. Adequate safety measures must also be taken to prevent an incident and/or to mitigate its effects.