FAQ Keywords: System Design

Panel members have not encountered a device or area classification for ATEX approval within Canada. ATEX is a European Union directive and is not generally recognized within North American…

The vent system for the excess hydrogen should be vented in accordance with NFPA 2 and CGA G-5.4 and G-5.5. The oxygen also must be vented safely and should be in accordance with NFPA and CGA G-4.…

There are several resources that can help review designs, such as the Hydrogen Safety Panel and other outside consultants that are members of the Center for Hydrogen Safety.

The potential of an explosive atmosphere is inherent with any vent system and must be addressed through adequate design. Purging for most vent stacks is impractical due to availability or cost. In…

This decision would depend on the system design, system operation, and a hazard assessment. Likely it would be better to run all hydrogen vents to a common vent or flare system, but this might…

CGA G-5.5 provides several options for vent stack outlets but not all options, nor does it tell when one outlet type is better than another design.

Figure 7, is one design, but in my opinion…

Welded joints are always best, but they cannot always be used as a connection to tanks and tubes, as mechanical joints are needed for maintenance. Supports for the reaction forces can help ensure…

Based on the question, it’s not clear if the reference to stress corrosion cracking (SCC) has been proven or is only suspected. It can be difficult to identify the nature of the cracks (SCC vs H2…

It is difficult to provide trustworthy answers to these questions without understanding the design and configuration of the specific installation. It may be best to consult with a pressure systems…

The Global Asset Protection Services (GAPS) standard was written 20 years ago for property loss prevention at crowded chemical plants and is intended for existing and new oil and chemical…

NFPA 2 has provisions for the use of LH2, and there are many existing fueling stations that store and use liquid hydrogen. One challenge for the use of LH2 in stations with small footprints is the…

While HSP members have limited experience with MFCs in experimental setups, the Panel does not consider them to be reliable to provide a positive flow shutoff. For safety, a shutoff valve in…

The answer could be no devices at all, just a TPRD, just a PRD, or both. It depends on the potential overpressure scenarios identified during a hazard assessment. TPRDs typically are not used on…

There are no specific code resources that specifically cover hydrogen liquefaction plants, but they must be built to the general building, electrical, machinery, piping, and mechanical codes for…

See H2Tools, Best Practices: Purging, for a description of different purging approaches for hydrogen systems.

Purging of vent systems is not required and in most instances is not recommended.

A nitrogen purge is generally not needed for a vent system designed in accordance with CGA G-5.5.  …

Regarding cylinders, it is not necessary to capture the fuse-backed devices which are on the cylinder itself. However, all other relief devices and vent valves must exhaust from a vent system…

Yes, these would be ignitable mixtures.  In this case, it does not appear complicated geometry is involved, so 1200 psig pipe should be more than adequate to protect against internal…

LNG storage, plumbing, and other systems can’t be directly retrofitted to handle hydrogen. The LNG components and systems will need to be removed and replaced with equipment specifically designed…

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…