4.1.2 Standards and guidance
General guidance on the safety of hydrogen systems can be found in the International Standard Organisation’s Technical Report ISO/TR 15916:2004 [19].
The International Standards Organisation (ISO) has published or is developing standards specifically dealing with hydrogen production systems. ISO 16110-1:2007 [20] covers the safety of stationary hydrogen generators intended for indoor or outdoor commercial, industrial and residential applications using fuel-processing technologies. It applies to packaged, self-contained or factory matched generation systems with a capacity of less than 400 m3/h that convert the input fuel to a hydrogen-rich stream of composition and condition suitable for the type of device using the hydrogen, e.g. a fuel cell. Input streams include one or a combination of the following fuels:
- natural gas and other methane-rich gases derived from biomass or fossil fuel sources;
- fuels derived from oil refining such as petrol, diesel and LPG; alcohols, esters, ethers, aldehydes, ketones and other hydrogen-rich organic compounds; and
- gaseous mixtures containing hydrogen.
Part 2 [21] of the standard dealing with procedures to determine the efficiency of these types of generator is under development.
ISO has also published a standard (ISO 22734-1:2008) [22] on hydrogen generators using the water electrolysis process for industrial and commercial applications. It covers the construction, safety and performance requirements of packaged or factory matched generators for both indoor and outdoor use. Hydrogen generators that can also be used to generate electricity such as reversible fuel cells are excluded from the scope of the standard. Part 2 [23] of the standard, covering generators for residential applications, is under development with publication expected in May 2010.
Hydrogen fuel cells such as PEMFC and AFC usually require a hydrogen supply of high purity, as their performance and operational life can be adversely affected by even trace impurities in the hydrogen supply. This is less so for SOFC. ISO standard ISO 14687:1999 [24] deals with product specification for hydrogen fuel. The European Industrial Gases Association (EIGA) document on gaseous hydrogen stations ((IGC Doc 15/06/E) [25] contains some guidance on the operation of purification systems.
Consideration also needs to be given to the environmental aspects of hydrogen generation. The environmental impacts of hydrogen plants are dealt with in EIGA document IGC Doc 122/00 [26]. This gives guidelines on identifying and reducing the environmental impacts of hydrogen and carbon monoxide production. It is relevant to the production of hydrogen, central or on-site, by electrolysis or chemical processes and covers the impacts from gas compression, desulphurisation, reforming, maintenance and storage. Guidance on the environmental aspects of decommissioning gas installations is given in EIGA document IGC Doc 137/06/E [27], which includes a section on hydrogen plants.