• The European Union has specified general requirements for approval of hydrogen-powered vehicles.Luxury Car sportscar from my luxury car series image by alma_sacra from Fotolia.com
  
  Hydrogen cars are considered environmentally friendly because they produce no greenhouse gas emissions. By introducing these cars to the market, governments hope to achieve a healthier transport system. Two types of hydrogen vehicles are available: internal combustion vehicles and fuel cell vehicles with liquid hydrogen. To ensure that hydrogen is incorporated in these vehicles in a safe way, the European Union has specified general requirements for approval of hydrogen-powered vehicles.
  
  

Conditions

• Manufacturers have to ensure that all components of hydrogen vehicles function correctly and are reliable. All components and systems must be able to operate in various mechanical, thermal, electrical and chemical conditions without deforming or leaking.
  
  

Pressure Protection

• Hydrogen systems need to incorporate protective measures to prevent over-pressurization, and all parts must be reliable in withstanding expected temperatures or pressures during the expected lifetime of the engine.
  
  

Materials

• Materials used in hydrogen components or systems must be hydrogen-compatible. This includes the hydrogen container as well as any other parts that are in direct contact with hydrogen or form part of the hydrogen system.
  
  

Temperatures

• Hydrogen parts have to comply with the implementing measures stipulated by the European Union regarding the operating temperatures they should be able to withstand. Components cannot be installed near any heat source or near the exhaust of an internal combustion engine.
  
  

Passenger Compartment

• The passenger cabin of a hydrogen-powered vehicle must be separated from the hydrogen system to avoid accumulation of hydrogen fumes. No fuel leaks should escape to the passenger compartment. Ventilation and heating systems must be designed in such a way that hydrogen fumes are not drawn into the car.
  
  

Liquid Hydrogen

• Liquid hydrogen containers used in hydrogen vehicles need to go through a series of test procedures stipulated by the European Union: a burst test, which determines whether the container complies with the minimum burst pressure requirements; a bonfire test to prove the container is heat resistant; a maximum filling level test to prove the level of hydrogen does not trigger any pressure relief devices; and a pressure test and leak test to prove that hydrogen does not leak from cracks after the container has been pressurized.