The UN ECE R134 regulation is a good requirement to follow as it copies the language in the UN GTR #13 regulation. The updated version of this UN document (UN GTR #13 Phase 2) is currently in approval review at the GRSP in Geneva and should be approved by the end of 2023. Nevertheless, since the US Department of Transportation’s National Highway Traffic Safety Administration is a contracting…

Because hydrogen is labeled as a hazardous substance, sometimes people are concerned about the environmental impact of releasing liquid hydrogen. There are currently no regulations that require reporting of hydrogen releases for environmental reasons.

However, there are safety implications. For example, the US DOT requires reporting of hazardous materials releases under certain…

The end use of hydrogen usually drives the cleaning for initial construction. 

1. When the hydrogen is used for combustion, normal care during construction and leak testing is usually adequate. 
2. When the hydrogen needs to be very pure, as is the case for PEM fuel cell applications, more attention needs to be paid to installing clean system components, keeping them…

Cylinders are required to be tested periodically to verify structural integrity. The most common test method is hydrotesting, which means water is the most likely impurity that solidified in the inlets. Drying the tanks is normally a requirement after performing a hydrotest. In the USA, CFR 49 CFR § 180.209 applies: https://www.law.…

Requirements for local jurisdictions vary, so the AHJ should be consulted, but NFPA 2:2023, Hydrogen Technologies Code, Chapter 13 has requirements for installation of hydrogen generators up to 100 kg H2/h. Section 13.3.1 General says permitted water electrolysis systems are to be listed to ISO 22734:2019, Hydrogen Generators Using Water Electrolysis - Industrial, Commercial, and Residential…

It depends on the facility and risk assessment, but generally multiple pressure and temperatures to one vent stack is not the best practice unless all are similar in pressure and temperature, and the streams have compatible composition and flow rate. Care must also be taken to prevent reverse flow and misdirected flow between portions of the system. Additionally, one vent stack can become a…

The answers are in context of PEM and alkaline electrolysis operating at or below 30 bar and below 85 deg C°. A general suggestion: Ask component suppliers about material compatibility, but do an independent investigation to confirm. As a general resource,  safety data sheets (SDSs) sometimes provide material compatibility information. Specific recommendations follow. 

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A "drop and swap" delivery system using tube trailers is a common and accepted method of supply for both industrial and fueling station applications. While NFPA 2 - 2023, paragraph 10.6.3.5 states, "The use of hose in a hydrogen dispensing system shall be limited to vehicle fueling hose," this is intended for the dispenser itself, not the entire fueling station. This does not limit the use of…

Many methods are used to mitigate the risk of a tube trailer hose loss of containment incident. Examples that otherwise exceed code requirements are provided below. These have been deployed in various combinations depending on the risk analysis for a particular system: 

1. Installation of automatic shutoff valves on the tube trailer upstream of the hose to activate upon hose…

In the U.S., there is no specific national requirement for fuel cell test equipment to be certified. There may be requirements from the local authority having jurisdiction (AHJ). Local building codes will likely point to compliance with NFPA 2/55 for the hydrogen and other gas supply systems, ASME Boiler and Pressure Vessel Code for vessels, ASME B31 piping codes for piping, and National…