Most common odorants will contaminate fuel cells. Additionally, hydrogen's small molecule and high buoyancy make it challenging to find a compatible odorant. Research is being conducted on fuel cell compatible odorants, but there are none currently in use. Like liquefied natural gas, liquid hydrogen also can’t be odorized due to its cryogenic temperature.

Each installation should be evaluated based on the results of a hazard analysis considering both of these
scenarios. Separation distances as listed in documents such as NFPA 2, Hydrogen Technologies Code, are
a minimum starting point but may need to be adjusted based on analysis. Recent work by NFPA 2 has
also included overpressure criteria, but the consequences can vary depending on…

Each system should be evaluated for exposure of equipment to jet fires. The design team should develop
a plan to mitigate exposure as part of the hazard analysis. Fire barriers, walls, enclosures, and insulation
systems are frequently installed to meet code requirements where separation distances are not
sufficient or where the probability of exposure to a jet fire is high. Barriers…

Codes and standards to address issues like this one are under development, along with applied research and field trials. As with any new application, appropriate codes and standards must be developed to meet public risk targets.

Systems should be sited in accordance with national and local standards such as NFPA 2, Hydrogen
Technologies Code. The nature of a trailer filling operation is not much different than a vehicle fueling
station, so the hazards are comparable and similar safeguards such as walls and sensors will apply. These
facilities might be larger and industrial standards and regulations will also…

Exposure between these products is bidirectional. A hazard analysis should consider what happens to
alternate fueling equipment if an incident with one of the fuels occurs. Care must be taken to have the
appropriate separation distance and mitigations according to the applicable codes. Limited experience
with existing stations has shown that these multi-fuel stations can be successful…

Previous versions of NFPA 55 listed overhead power lines within the separation distance tables with no voltage distinction. The separation distances were 15 ft for GH2 and 25 ft for LH2 for all overhead electrical lines. The current edition of NFPA 2 includes these in overhead utilities; the distance for GH2 and LH2 will vary with pressure and diameter of the hydrogen piping. In practice, high…

The Global Asset Protection Services (GAPS) standard was written 20 years ago for property loss prevention at crowded chemical plants and is intended for existing and new oil and chemical facilities to limit explosion over-pressure and fire exposure damage; thus, the purpose is different than NFPA 2. NFPA distances were based on studies from the 1960s as well as qualitative factors that were…

There is technically no upper limit for GH2 storage listed within the separation distance tables within Chapter 7 of NFPA 2. For LH2, there is a 75000-gallon upper limit for the LH2 storage separation distance tables within Chapter 8 for LH2. 
It’s important to note that many facilities have site specific issues such as large quantities, confinement, and congestion, so it may be…

These distances are based primarily on hydrogen piping releases and resultant vapor clouds and jet flames based on pipe diameter and pressure. It’s important to note that many facilities have issues such as confinement and congestion, so it may be applicable to apply contemporary engineering models to assess risk.