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.

There is no maximum flow-rate that can be vented to the atmosphere, but the hazard analysis should consider the potential risk of dispersion, radiation, and overpressure as part of the vent system design. Flare systems are often used at large hydrogen production facilities as one means to prevent a large unignited cloud from forming but will depend on the specific application.

The routing will be dependent on the system design, size of release, and evaluation of the hazards.
Smaller systems are rarely vented to a flare due to complexity, availability and permitting considerations.
Facilities handling large amounts of hydrogen such as production plants will often have a flare system
since they have more capability for this additional onsite infrastructure.…

There is some indication that toroidal rings can reduce static buildup and ignition of hydrogen from a vent. However, while toroidal rings may help with static, they have not been proven to eliminate all static ignition sources. There are also other sources of ignition that they would not prevent, so they might reduce but not eliminate, vent stack fires. Another method that can be reliably…

The suitability of flame arrestors depends on the design of the system, but generally flame arrestors are
rarely needed for hydrogen systems when there is a 100% hydrogen atmosphere upstream of the vent,
and when the downstream vent system is designed to withstand internal ignition. Flame arrestors can
also cause potential blockage or restriction of flow, so relative risks need to be…

Vent stacks should always be grounded in accordance with electrical standards which will reduce the probability of, but not eliminate, vent stack fires. There are numerous design features, such as toroidal rings, that have been suggested to reduce vent stack fires. However, given the many sources of ignition that can potentially ignite vent stack releases, it is virtually impossible to…