The HSP is not familiar with this particular fitting or its potential application in H2 service but can offer engineering judgment. Many similar compression-type swaged fittings are used in H2 service. These fittings must be used within the manufacturer recommendations for pressure, temperature, and fluid service. Deformation is also introduced into stainless steel tubing in other ways, such…
The Panel considers two approaches to be acceptable.
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…
Regarding the concept of introducing hydrogen gas into natural gas pipelines, this is indeed a hot topic and there are recent quantitative treatments of fatigue crack growth driven by pressure cycling and potentially accelerated by hydrogen. Some analysis has shown that it can be acceptable to operate natural gas pipelines with a hydrogen blend. However, this is highly dependent…
Hydrogen cylinders contain pure hydrogen unless they are specifically manufactured for and marked as a mixture. The purity grade is usually between 99.5% and 99.9999%. The balance is typically inert gases (such as nitrogen) with just ppm levels of other contaminants, but this can vary depending upon the production source. When emptied, the residual is still the same purity of hydrogen, just at…
It is possible to store large quantities of gaseous hydrogen above ground, but it will likely require a large footprint due to its relatively low density even at high pressure. Also, if the quantity equals or exceeds 10,000 lb., the facility will need to comply with OSHA 1910.119 process safety management requirements if located in the US. Similar regulations exist in Europe and Asia that…
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