Assuming this question relates to the roof of the enclosure, there are no design criteria on this topic to the Panel’s knowledge. The key to the design would be ensure that the exhaust ventilation inlet is located at the highest point and that there are no pockets that can capture hydrogen (restrict flow to the exhaust inlet).
Information on Toyota’s repair garage approach is available…
A best practice, even for small hydrogen vents, is to vent to a dedicated vent system outside the building where possible. Several international codes and standards can be used to provide guidance; the Panel recommends discussing the configuration with a local fire official to ensure their required standards are followed. In the U.S. NFPA 2, Hydrogen Technologies Code, has information in…
It is always recommended that the area in which this work would be done be adequately ventilated and in accordance with the Building Code, NFPA 2 and NFPA 45 if applicable. In the Panel’s opinion, it’s recommended that the weight measuring equipment as you’ve described it be designed for Class 1, Group B, Division 2. Also consult with the local authority having jurisdiction as to the…
While HSP members have limited experience with MFCs in experimental setups, the Panel does not consider them to be reliable to provide a positive flow shutoff. For safety, a shutoff valve in series is recommended. Projects will also need to consider hazardous electrical rating and location when flowing H2. Regarding Coriolis mass flow measuring devices, Coriolis flow meters measure mass rate…
It is difficult to provide trustworthy answers to these questions without understanding the design and configuration of the specific installation. It may be best to consult with a pressure systems expert to evaluate the specific installation and uses. The gas provider may also be a good resource for specifics on gas equipment use. Other beneficial resources include the…
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…
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