LNG storage, plumbing, and other systems can’t be directly retrofitted to handle hydrogen. The LNG components and systems will need to be removed and replaced with equipment specifically designed for hydrogen. If the concept is to convert existing equipment or an existing ship, then it’s probably impossible. If it’s to convert an existing LNG design on paper, then it’s probably impractical.…
ASTM might be the best point of contact for crafting this test. The ASTM F38 Committee on Unmanned Aircraft Systems is probably the best source of information on drone airworthiness criteria. They have a subcommittee developing a standard on fuel cell drone safety. One Panel member has been involved in a test with an LD vehicle tank filled with hydrogen that was dropped 60m onto a concrete pad…
This is an interesting question because of the special considerations associated with the H2-air mixture flashback scenario during turbine startup and shutdown. In-line deflagration arresters and detonation arresters for H2-air mixtures are different than those for most other fuels and need to be certified for use with hydrogen. They are commercially available, and NFPA 69 has a good chapter…
The HSP discourages the use of this type of piping for hydrogen despite the low likelihood of ignition within the pipe itself. The polyethylene film can indeed develop a charge and, depending on the film thickness and substrate wall material, will eventually produce an electrostatic discharge. Since the nominal hydrogen concentration is so high (and assuming the purge-in and purge-out…
Precautions applicable to oxy-acetylene torches are likely applicable here and are a good starting point. Recommendations for the hardware are best provided by the cylinder supplier, and all these parts can be purchased from their respective catalog. All three devices in the question should have UL listings, FM approvals, or some other nationally recognized testing laboratory (NRTL) listing,…
The information provided is not only outdated in terminology, but also misleading in quantifying the dispersion of hydrogen in terms of comparison of diffusion of air in air. Hydrogen diffuses 4X faster than air, and the rate of mixing has many variables, so there isn’t just one answer. However, it’s generically safe to say that an initial hydrogen gas cloud outdoors and unconfined will…
There is no generalized exception for hydrogen fueling stations. However, PSM is intended for employee protection. It’s not intended for retail operations or customers. Through paragraph 1910.119 (a)(2)(1) of the regulation, PSM exempts retail facilities. Some may use this exemption as a means to exclude H2 retail fuel sites from PSM.
Fuel stations that are non-retail, such as…
Yes, these would be ignitable mixtures. In this case, it does not appear complicated geometry is involved, so 1200 psig pipe should be more than adequate to protect against internal deflagration. The most likely scenario is a "backfire," similar to a car, where ignition occurs too soon and shoots out the open end of the pipe. Consider using an inline deflagration flash arrestor on the…
This is a fairly common arrangement and can be acceptable if properly designed. Some considerations:
Such a compressor should NOT be used for hydrogen. There are many issues with converting a compressor to hydrogen service. First and most important, this must be approved by the manufacturer. Examples of concerns for a non-hydrogen compressor used for hydrogen service include (but are not limited to):
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