Vent stacks should always be grounded in accordance with electrical standards which will reduce the probability of, but not eliminate, vent stack fires. There are numerous design features, such as toroidal rings, that have been suggested to reduce vent stack fires. However, given the many sources of ignition that can potentially ignite vent stack releases, it is virtually impossible to eliminate all such fires so proper design of the vent stack to be able to withstand over-pressures and continuous flame are critical to the design.

There are dozens of safety considerations for safe design of hydrogen vent stacks. Their primary function
is to vent the hydrogen safely, so vent stacks should be designed such that the gas dispersion and
radiation profile (if ignited) do not impact surrounding equipment, buildings, or people. Documents such
as CGA G5.5, Hydrogen Vent Systems, provide numerous details regarding design. Vent stacks should be
designed to handle expected thrust loads, weather conditions, and hydrogen ignition scenarios. Various
building and electrical codes describe basic grounding requirements.

Static is a frequent source of ignition attributed to various hydrogen releases. Low levels of static
electricity are sufficient to ignite hydrogen – air mixtures. Static charges can be created by the
atmospheric disturbances and storms, high velocity particles entrained by the gas impacting stationary
objects, and human activity. Grounding of equipment and operators is important to lower the probability
of static discharges.

CGA G-5.5 states: All vent stacks shall be grounded and meet the requirements of NFPA 70, National Electrical Code, for integrity and system design and also references NFPA 77, Recommended Practice on Static Electricity, and NFPA 780, Standard for the Installation of Lightning Protection Systems. 

For lightening refer to NFPA 780 and for grounding of the Hydrogen equipment, refer to NFPA 70 (Article 250 and Article 510 are good starting points). 

Best practices in the past have used large stranded wire for grounding connected to a grounding grid. Lightening typically has a larger grounding current requirement than grounding and bonding of nonelectrical equipment for static electricity.