If liquid hydrogen usage is sufficiently high at the fueling station, there may be no need to vent any boiloff generated from the LH2 storage tank. Boil-off gas should be minimized through system design, but where needed, the boil-off hydrogen along with any other hydrogen released must be vented through a local vent stack which is constructed to safely vent the hydrogen in accordance with CGA…

Example safety guidelines are listed below but may not be all-inclusive (e.g., they do not cover general practices such as lockout/tagout, management of change, job safety analysis), and most are the same as for gaseous hydrogen. Also reference NFPA 2 and CGA documents such as H-3, H-5, and H-7. Additional safety training material can also be found on the following link to courses and…

In the U.S., liquid hydrogen fueling stations and dispensing equipment are addressed within NFPA 2, Chapter 11. Dispensing is covered within Section 11.3. When liquefied hydrogen is used as the supply for high pressure gaseous fueling, then Chapter 10 of NFPA 2 would apply.
ISO standards are also being developed for global LH2 fueling protocols.
 

Nitrogen/helium blends are frequently used to leak test hydrogen systems.

Speed of detection, detection limit, location, and cross-sensitivity are some of many criteria that might be used for selecting a detector. A common setpoint for gaseous hydrogen detection is 25% of LFL, or 1% concentration in air. However, the detection limit also depends on the system and exposure. When specific hazards are likely, detectors may have detection limits in the low-ppm range.…

Leak detection system requirements depend on the system design and applicable codes. The
appropriateness of detection equipment depend on many factors, including the type of system,
application, location, and probability of leaks. For example, hydrogen refueling stations are required by
code to be equipped with leak detection systems.

While hydrogen gas detectors are less effective outdoors, they can be an important safeguard as part of an overall hydrogen system design. They have been used in many cases to automatically shut down equipment and isolate hydrogen supply. Location and type of detectors depend on the system design and siting, but when installed, should be in areas that are most likely to be exposed to hydrogen…

Training personnel and equipping them with portable gas detectors to properly identify the gas that is
leaking can play an important role in both troubleshooting and emergency response.

The manufacturer’s calibration requirements should be followed to ensure proper operation of the
detection system. The requirements will vary depending on the type of detector and the environment in
which they are installed. Calibration can usually be performed by the user/owner if properly trained and
supplied with calibration gas, etc.

Flare-less compression style fittings are commonly used. Choose tubing materials and tube wall thicknesses suitable for hydrogen and pressures you are using. Make sure all tubing joints are properly made, mechanically supported to minimize stress and vibration, are in a ventilated space, and are easily accessible for inspection and leak testing.