FAQ Categories: Hazards Analysis
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…
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…
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…
Several programs can predict this such as HyRAM or PHAST. The inputs are critical to a safe
answer.
This is not a simple answer due to the many types of flame lengths and flame…
Outside storage is generally considered safer and is required for large amounts of gas. Stationary storage should be located outside at a safe distance from structures and ventilation intakes, and…
There are many potential sources of delayed ignition. Hydrogen is easily ignited, and the larger the cloud, the more likely it is for it to find an ignition source. The cloud itself may serve as…
The answer is dependent upon the nature of the system and a hazard assessment which evaluates a balance of risk.
Keeping the hydrogen in the vessel is better so the hydrogen release…
AICHE ELA253 CHS ” Introduction to Hydrogen Safety for First Responders” is a good reference and discusses both LH2 and GH2. LH2 fires are very unusual. LH2 releases usually are GH2 so the fires…
The key concern with any hydrogen release is the risk of creating a flammable mixture. There should be no environmental issues if you properly vent hydrogen to a safe area where it is diluted in…
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…
Sprinkler systems and other fire suppression means are prescribed per building and fire codes to limit fire spread to other materials. In the case of a hydrogen leak and fire, it is best practice…
Flammable hydrogen releases can result in deflagration and transition to a detonation. Whether the
deflagration transitions to a detonation depends on numerous parameters such as cloud size,…
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…
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…
Delayed ignition is a significant hazard for hydrogen releases, either intended or unintended. The primary concern is the overpressure and energy release created from a vapor cloud which could…
Because hydrogen leaks frequently ignite, and because about half the time the ignition source is not identified, when evaluating hazards with hydrogen leaks, many people just assume the leak will…
CGA G-5.5 states: All vent stacks shall be grounded and meet the requirements of NFPA 70, National Electrical Code, for integrity and system design and also references NFPA 77, Recommended…
If the concentration of hydrogen is less than the Lower Flammability Limit (LFL) of 4% in an inert gas, it is unlikely that a leak of this gas mix will form a flammable mixture as it dilutes into…
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…