Requirements for TPRD/PRD’s depend on the local regulations. Some jurisdictions require them, some do not. Others make them optional based on results of performance testing.

This is a complicated subject. Thermally activated pressure relief devices can be an important safeguard for hydrogen vessels if properly designed and installed in accordance with code requirement. Requirements vary globally and often depend on the type of vessel and its intended service (e.g. mobile or stationary). However, as with any device, TPRD’s offer both advantages and disadvantages.…

No, this is not a common or preferred approach. Isolating the source of hydrogen is the best safety practice. Water systems could extinguish the flame but allow the gas to continue leaking and result in an explosion if reignited.

Situations where extinguishing a hydrogen leak prior to stopping flow is safer are rare. Hydrogen releases have a high potential for inadvertent re-ignition and subsequent explosion. Some vent stacks might be equipped with an extinguishing system, but these often can be more hazardous than allowing a properly designed vent stack to continue to burn until the source is isolated.

Releases from high pressure hydrogen systems often make a sound. In those cases, sound might be the
easiest way for a person to know there is a hazard. However, leaks can be relatively small and diffuse,
thereby not making much sound, or alternately large and so loud that they can be very difficult to find. In
both cases, it can be hazardous to move into or through an area.

There is no consensus on the “correct” answer. Small leaks of short duration have a much lower
probability of ignition compared to large releases. Ignition probability is affected by the operating
conditions, whether the release is from a leak or vent stack, and the surrounding environment. Since the
probability of ignition is high, hazard analyses will usually assume the hydrogen…

Static is a frequent source of ignition attributed to various hydrogen releases. Low levels of static
electricity are sufficient to ignite hydrogen – air mixtures. Static charges can be created by the
atmospheric disturbances and storms, high velocity particles entrained by the gas impacting stationary
objects, and human activity. Grounding of equipment and operators is important to…

After moving people to a safe location, if it safe to do so, isolate the source of hydrogen feeding the fire. Burns and explosions are hazards when exposed to a hydrogen fire. For more best laboratory preventative safety practices as well as first responder response to a hydrogen incident See both CHS training resources: 

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Frequency and severity off consequences are situational and subject to the safety review team’s best judgement. One measure of severity is an estimate of the energy released if ignited. Assuming the worst-case mix to be stoichiometric, the energy content of a 500 mL of hydrogen in air is about 0.2 Wh (700 Joules), comparable to the energy release of a wooden, blue-tipped matchstick (~1kJ or 1…

Using tools inside a fume hood that may have a flammable gas mixture should be prohibited. A properly operating hood of the right capacity should keep the mixture of hydrogen in air inside the hood below the Lower Flammability Limit (LFL) of hydrogen further reducing any risk. 

If the use of tools is necessary, the source of hydrogen should be isolated before the work begins even if…