Releases from high pressure hydrogen systems often make a sound. In those cases, sound might be the
easiest way for a person to know there is a hazard. However, leaks can be relatively small and diffuse,
thereby not making much sound, or alternately large and so loud that they can be very difficult to find. In
both cases, it can be hazardous to move into or through an area.

Situations where extinguishing a hydrogen leak prior to stopping flow is safer are rare. Hydrogen releases have a high potential for inadvertent re-ignition and subsequent explosion. Some vent stacks might be equipped with an extinguishing system, but these often can be more hazardous than allowing a properly designed vent stack to continue to burn until the source is isolated.

No, this is not a common or preferred approach. Isolating the source of hydrogen is the best safety practice. Water systems could extinguish the flame but allow the gas to continue leaking and result in an explosion if reignited.

Hydrogen has been transported safely through pipelines for over 50 years. There are dozens of pipeline networks in safe operation globally, with several individual networks that approach up to 1000 miles. 

Significant testing and some demonstration projects are underway to ensure safety. Some of the aspects under investigation include compatibility of the pipe and other materials,…

The conversion is based on the condition as determined from a variety of non-destructive techniques which are commonly used for pipeline mechanical integrity programs. Existing natural gas pipelines are frequently evaluated for conversion to hydrogen, hydrogen-natural gas blend, and other fluid services.
The conversion can be done safely if handled with the proper expertise and…

Double pipes can be used in certain circumstances to reduce the likelihood of external leaks and increase
the likelihood of detection by monitoring the space between the two pipes. Vacuum jacketed piping is
double walled and is used in liquid hydrogen service to provide insulation. While not equipped with gas
detection in the annular space, loss of vacuum is used to indicate an…

Flammable hydrogen releases can result in deflagration and transition to a detonation. Whether the
deflagration transitions to a detonation depends on numerous parameters such as cloud size, hydrogen
concentration, confinement, and congestion. Releases into confined or congested areas are more
susceptible to generating significant deflagration over-pressures and more likely to…

There are numerous models that can be used to assess the consequence and risk of leaks and releases.
One such model is HYRAM which is publicly available from Sandia and the US DOE.

Emergency response procedures must be developed for each system based on its design. The
procedures generally include steps to clear personnel from the immediate area, isolate the hydrogen,
shut down the equipment, contact local responders, and protect surrounding equipment/structures until
the hazard is mitigated or the incident is over.

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…