3.3.2 Regulations
In Europe, the principal regulations covering hydrogen facilities arise from the national legislation passed to implement the ATEX Directives [12, 15] and the Pressure Equipment Directive (PED [13]). Their requirements are not specific to hydrogen and would equally apply to any fuel that is capable of generating a flammable atmosphere, for example natural gas or LPG, or equipment that contains a fuel under pressure. For some components of the installation, for example if the hydrogen is produced in-situ by the reformation of natural gas, the requirements of the Gas Appliances Directive (GAD) [11] may also be applicable.
ATEX is the name commonly given to the framework for controlling explosive atmospheres arising from gases, vapours, mists or dusts, and the standards of equipment and protective systems used in them. It is based on the requirements of two European Directives. The first is Directive 94/9/EC [12] (also known as ATEX 95 or ATEX Equipment Directive) on the approximation of the laws of member states concerning equipment and protective systems intended for use in potentially explosive atmospheres. Any equipment (electrical or non-electrical) or protective system designed, manufactured or sold for use in potentially explosive situations has to comply with the essential health and safety requirements (EHSR) set out in the directive. The second is Directive 99/92/EC [15] (also known as ATEX 137 or the ATEX Workplace Directive) on the minimum requirements for improving the health and safety protection of workers potentially at risk from explosive atmospheres. This directive requires the employer to prepare an explosion protection document that includes identification of the fire and explosion hazards, classification of the areas where explosive atmospheres may exist, an evaluation of the risks and specification of the measures to prevent or, where this is not possible, mitigate the effects of an ignition.
As the ATEX Directives only apply to the workplace, hydrogen fuel cells installed in domestic premises are outside their scope. Nonetheless the hazard identification process required by the workplace directive would serve as a useful model for assessing the safety requirements of domestic installations.
The Pressure Equipment Directive (97/23/EC) [13] harmonises national laws of member states on the design, manufacture and conformity assessment of pressure equipment that is subjected to an internal pressure greater than 0.5 bar above atmospheric pressure. It covers equipment such as pressure vessels, heat exchangers, steam generators, boilers, piping, safety devices and pressure accessories. Thus some of the components of a hydrogen fuel cell installation may fall within the scope of the Directive, although these are usually bought on the market as certified products. PED is a complex new approach directive. Each affected item of pressure equipment has to be assigned into a hazard category according to specific criteria. which then determines the overall essential safety requirements to be met. Depending on the categories, different conformity assessment options are permitted to demonstrate compliance by variants on quality assurance, direct inspection or surveillance of testing by the Notified Body. It is recommended that advice from consultants who specialise in pressure systems be sought in selecting the most appropriate conformity option, as an inappropriate choice can lead to unnecessary delays and costs in demonstrating compliance.
The Gas Appliances Directive [11] applies to appliances burning gaseous fuels used for cooking, heating, hot water production, refrigeration, lighting or washing and having, where applicable, a normal water temperature not exceeding 105oC. It also specifies requirements for certain fittings, including safety, regulating and controlling devices and sub-assemblies. For the purposes of this directive a ‘gaseous fuel’ means any fuel that is in a gaseous state at a temperature of 15oC at a pressure of 1 bar. Though fuel cells do not burn gaseous fuels and would be expected to be excluded from the scope of the Directive, guidance issued on what appliances are covered by the Directive includes fuel cells where the primary function is heating. The essential safety requirements of the Directive could also be applied to certain components of the installation, e.g. a reformation unit for generating hydrogen and safety, regulating and control devices. Hydrogen fuel cell installations would also need to comply with the relevant parts of the EU Directives on Machinery (89/392/EC) [9], Low Voltage equipment (73/23/EEC) [10], Electromagnetic Compatibility (89/336/EEC) [14] and Chemical Agents (98/24/EC) [17], as well as EU directives and national legislation covering general health and safety.
Further information on the procedures for demonstrating conformity with EU directives and obtaining CE marking for equipment is given in 3.1 and Appendix A4.