Standard is a document that sets out requirements for a specific item, material, component, system or service, or describes in detail a particular method or procedure.

Code is a document that describes the end-result – what a product should conform to- rather than how it should be done.

Codes and standards are not mandatory- they are optional - in contrast to regulations that are mandatory.

Codes and standards on European level are developed and issued by CEN (European Committee for Standardization) or CENELEC (European committee for Electro-technical Standardization).

On the international level, their counterparts are ISO (International Standards Organization) and IEC (the International Electro-technical Commission). 

Within these organisations, the preparation of the standards belongs to the TC’s (technical committees) that work on the basis of national participation by the CEN members (NSB’s - National Standardization Body). The real standard development is done by a WG (working group).  A working group is established by the technical committee to undertake a specific task within a target date.

CEN and ISO, and CENELEC and IEC work closely together, as is arranged by the Vienna Agreement established in 1991 and revised in 2001.

The most relevant TC’s for hydrogen and its applications within CEN/CENELEC and ISO/IEC and the relevant regulations are: