There are no specific code resources that specifically cover hydrogen liquefaction plants, but they must be built to the general building, electrical, machinery, piping, and mechanical codes for process plants. Codes such as NFPA 2, Hydrogen Technologies Code, for installation and emergency response may also be used for reference. It may also be beneficial to break down the requirements into…
The regulations for electrical classification in Europe and a US jurisdiction such as California are significantly different and should not be assumed to be the same. Consultation with Authorities Having Jurisdiction or a Third- Party expert regarding the application of the US National Electric Code is advised. Some additional important points:
The HSP has concerns with the use of…
The British Standards Institute (BSI) has published BS ISO 22734:2019, a British nationalized version of the packaged water electrolyzer safety certification standard. This standard can be used by a Notified Body (BSI is one of many operating in the UK and in Europe) to certify electrolyzer safety to established norms for this equipment. This standard addresses safety of containerized hydrogen…
The vent system for the excess hydrogen should be vented in accordance with NFPA 2 and CGA G-5.4 and G-5.5. The oxygen also must be vented safely and should be in accordance with NFPA and CGA G-4.4.
Please be extremely cautious with compressing hydrogen. NEC/NFPA 70 and its Articles 500/505 address electrical equipment in flammable atmospheres. Please also consider the…
Regarding cylinders, it is not necessary to capture the fuse-backed devices which are on the cylinder itself. However, all other relief devices and vent valves must exhaust from a vent system designed in accordance with CGA G-5.5. Also, note that NFPA 2-7.1.17 requires compliance with CGA G-5.5 regardless of storage quantity when the vent system is servicing pressure relief devices. Cylinders…
Panel members have not encountered a device or area classification for ATEX approval within Canada. ATEX is a European Union directive and is not generally recognized within North American standards. The second link below references a UL similarity. https://news.nilfiskcfm.com/2017/03/atex-certification-applicable-north-america/; https://www.ul.com/services/atex-certification-…
NFPA 2 has provisions for the use of LH2, and there are many existing fueling stations that store and use liquid hydrogen. One challenge for the use of LH2 in stations with small footprints is the code required separation distances from exposures. NPFA 2 has updated the separation distances with a risk informed approach in the 2023 edition.
Another possibility for public fuel…
The design of vent systems is critical to the safety of the system. From a process perspective, the pipe design must be sufficient to withstand back pressure, internal pipeline pressure, deflagration pressure, thrust forces from the flow, and must be of a sufficient size to not create a restriction that prevents proper flow or activation of the devices.
The vent system…
It is best to avoid planned blowdown of large amounts of hydrogen inventory at high flowrates if possible. Low flow releases from vent systems are normal and occur for purging, delivery operations, and maintenance activity. A challenge with high flow blowdown of a hydrogen system is that venting large quantities of hydrogen can itself be a hazardous activity. …
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…
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