FAQ Categories: System Design

Requirements for local jurisdictions vary, so the AHJ should be consulted, but NFPA 2:2023, Hydrogen Technologies Code, Chapter 13 has requirements for installation of hydrogen generators up to…

Yes, for all stacks. GH2 has a minimum prescriptive height of 10 ft. There is no minimum prescriptive height for LH2. However, 25 ft has been a best practice for the industry for years. Vent stack…

Refineries and large petrochemical plants will frequently have flare systems for H2 and other flammable materials. One of the major purposes of these flare systems is to prevent a large unignited…

Generally flaring is not recommended. Normally GH2 is not flared for most hydrogen equipment as the piping diameters are smaller. The largest stacks are the LH2 vent stacks on trailers and on…

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

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…

Nearly all hydrogen storage tanks and hydrogen storage systems will need some type of pressure relief system to protect the vessels from overpressure. If there are pressure relief devices, some…

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…

Fuels like gasoline are exempt from OSHA process safety management (PSM) requirements. When asked about the applicability for hydrogen storage larger than 10,000 lb (4500 kg) being used as a…

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

This is a fairly common arrangement and can be acceptable if properly designed. Some considerations:

1. The main concern is low temperature downstream of the mixing point, in case of…

Design of vent header lines is critical to the safety of the system. From a process perspective, the pipe design must be sufficient to withstand back pressure, thrust forces from the flow, and…

Vent stacks must be designed for a fire at the outlet. The mesh is designed to ensure no blockage of the vent stack by animals/insects. 

Additionally, the mesh must be designed for…

No, in nearly all cases, a deluge system is not needed. The proper sizing of relief devices using documents such as CGA S1.3 will ensure that they are of sufficient size to address worst case…

As is mentioned in the question, it should always be assumed that vent stack fires will occur. The vent stack must be designed to withstand a possible deflagration and the heat from a continuous…

There is no maximum flow-rate that can be vented to the atmosphere, but the hazard analysis should consider the potential risk of dispersion, radiation, and overpressure as part of the vent system…

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…

The recognized and generally accepted good engineering practices (RAGAGEP) for employing a purge into a hydrogen vent stack is that inerting is not generally used. Best practice is that the vent…

The recognized and generally accepted good engineering practices (RAGAGEP) for employing a nitrogen purge into a hydrogen vent stack is that inerting is not generally used for nitrogen purge in a…