Welded systems are generally preferred, where possible, to reduce the likelihood of leaks.  Generally, even welded systems will need non-welded joints (e.g. unions, flanges, etc.) to allow maintenance replacement of components.  A low-pressure system would not be an exception to this preference.  However, piping at lower pressures and smaller sizes will…

There are several concerns with “snuffing” a hydrogen fire from a vent stack. Most importantly, snuffing a hydrogen fire before the hydrogen is isolated can lead to the buildup of a hydrogen vapor cloud, which may then re-ignite, especially with hot surfaces available from the previous fire. The largest hazard is an explosion of the vapor cloud…

TIA 1783 points out a valid concern about how to address the electrical classification zone around a liquid hydrogen system. The existing requirements specify 3' around the outlet of the stack for Division 1 and 25' around the outlet of the stack for Division 2 area. These distances are historical and date back to the 1960's. They are a "one size fits all" simple approach that is easy to…

The primary safety standards for applicable to this piping in the U.S. are ASME B31.3, B31.12, and NFPA 2. The editions used should be those adopted by the local jurisdiction. Design of an LH2 piping system should always be conducted and reviewed by engineers experienced in cryogenic piping design. The equipment should also be installed per NFPA 2 and NFPA 55. IT is recommended that the piping…

The lifetimes of these components will vary depending upon the application, their installation environment, and usage. It is also important to adhere to the component inspection, maintenance and replacement specifications as recommended by the manufacturer. However, as many are made of stainless steel, their life expectancy is longer than other materials. Estimated lifetimes are below in years…

In the U.S., liquid hydrogen fueling stations and dispensing equipment are addressed within NFPA 2, Chapter 11. Dispensing is covered within Section 11.3. When liquefied hydrogen is used as the supply for high pressure gaseous fueling, then Chapter 10 of NFPA 2 would apply.
ISO standards are also being developed for global LH2 fueling protocols.
 

By definition, liquid hydrogen can BLEVE, but this is highly unlikely. Liquid hydrogen is stored in a double wall tank with vacuum insulation. This protects the primary pressure vessel from direct impingement and the very cold liquid provides self-cooling of the vessel walls. Tanks are also equipped with redundant pressure relief systems that are sized for fire exposure.

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…