There are several concerns with “snuffing” a hydrogen fire from a vent stack. Most importantly, snuffing a hydrogen fire before the hydrogen is isolated can lead to the buildup of a hydrogen vapor cloud, which may then re-ignite, especially with hot surfaces available from the previous fire. The largest hazard is an explosion of the vapor cloud…

TIA 1783 points out a valid concern about how to address the electrical classification zone around a liquid hydrogen system. The existing requirements specify 3' around the outlet of the stack for Division 1 and 25' around the outlet of the stack for Division 2 area. These distances are historical and date back to the 1960's. They are a "one size fits all" simple approach that is easy to…

The lifetimes of these components will vary depending upon the application, their installation environment, and usage. It is also important to adhere to the component inspection, maintenance and replacement specifications as recommended by the manufacturer. However, as many are made of stainless steel, their life expectancy is longer than other materials. Estimated lifetimes are below in years…

Rupture panels can add an additional layer of overpressure protection against internal overpressure. Given the propensity of hydrogen to generate higher over-pressures when ignited compared to other fuels, rupture panels are often part of the safety design for containerized systems. The need for a rupture panel for a specific system will be determined by the system hazard analysis and the…

While not required, Safety Instrumented Systems with a specific SIL rating are often used on hydrogen systems. The hazard analysis provides guidance as to whether a SIL rating for a given exposure is required and at what level. The SIL level depends on the probability and consequence of occurrence of a given hazard. Hydrogen equipment may be provided with different SIL levels within the same…

Both types of valve actuators are used, and both offer advantages and disadvantages for a given application.

In most cases, it is not necessary to depressurize hydrogen systems in an emergency. Pressure vessels are usually isolated in an emergency. The best actions to assure safety during an emergency should be identified during the hazard analysis.

The containerized electrolysis unit should be installed per manufacturer instructions, the requirements
of its listing such as to ISO 22734, Hydrogen generators using water electrolysis - Industrial, commercial,
and residential applications, and NFPA 2, Hydrogen Technologies Code. A primary consideration for
indoor installation is the potential for hydrogen releases from the system,…

The suspected cause was a mixture of oxygen and hydrogen that passed downstream from the electrolysis unit into several storage vessels. Hydrogen-oxygen mixtures are very hazardous. Subsequent ignition resulted in internal pressure that exceeded the limits of the storage system. The design of electrolyzers, detection of upset conditions, and preventing the accumulation of oxygen within the…