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…

Composite cylinders can be manufactured to standards written by CSA, ASME, and ISO depending on the application and local requirements. Several ISO standards can serve as the basis for composite cylinder approvals within North America.

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,…

Liquid hydrogen is much less likely to pool than liquified natural gas (LNG) due to its low heat of vaporization. Very large facilities are often equipped with methods to enhance vaporization, such as crushed stone under tanks, as well as diversion systems to allow liquid hydrogen to spill and boil off in a safe area. Care needs to be taken that diversion systems do not create a hazardous…

By definition, liquid hydrogen can BLEVE, but this is highly unlikely. Liquid hydrogen is stored in a double wall tank with vacuum insulation. This protects the primary pressure vessel from direct impingement and the very cold liquid provides self-cooling of the vessel walls. Tanks are also equipped with redundant pressure relief systems that are sized for fire exposure.

Underground storage tanks can be either installed in a vault or directly buried. Both offer additional
protection from external impact and fire, but each has unique challenges. Vaults must be properly
ventilated and designed to not create an explosion or asphyxiation risk. Direct burial vessels should not
have any underground leak points and must be protected from corrosion. Both…

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.

The design of vent systems is critical to the safety of the system. From a process perspective, the pipe design must be sufficient to withstand back pressure, internal pipeline pressure, deflagration pressure, thrust forces from the flow, and must be of a sufficient size to not create a restriction that prevents proper flow or activation of the devices. 

The vent system…