In the global pursuit of low-carbon energy, high-pressure hydrogen (H2) applications are on the rise. Our article in the September 2026 issue of H2Tech, titled “How to select pressure relief valves for hydrogen and other high-pressure gas applications,” discusses key requirements for pressure relief valves (PRVs) in these challenging applications.
The growing need for H2
High-pressure H2 applications were once uncommon, but that is changing as the world seeks green energy solutions.
Several promising technologies have notable downsides: renewable energy sources such as solar and wind only produce power intermittently, and electric vehicles have limited range between charges. H2 can help address these problems by serving as a storage medium for excess renewable energy and as an alternative vehicle fuel.
High-pressure H2 storage
Storing significant amounts of H2 requires compression to high pressures, but this introduces several serious challenges. Because H2 atoms are extremely small, they readily leak through typical sealing surfaces, wasting product and creating a flammability hazard. H2 can also diffuse into metals, causing embrittlement that worsens as pressures increase.
Every storage tank requires a PRV, but suitable PRVs for these conditions have historically been difficult to find.
PRV requirements
PRVs protecting H2 storage equipment must operate at pressures as high as 14,500 psi, and other high-pressure gas applications may exceed 21,000 psi. These PRVs must also be fabricated from materials that resist H2 embrittlement, and they must reliably seal to prevent product losses and safety hazards. Because H2 can pass through typical metal-to-metal seals, polymeric seating materials are used to achieve very low leakage rates.
Some existing high-pressure PRVs may not carry the ASME Section VIII and XIII certifications typically found in other PRVs. Few manufacturers have the resources to fully test valves at very high pressure setpoints on a certified test bench.
An effective option
Historically, options for very high-pressure PRVs have been limited and ill-suited for H2 service. Emerson’s Anderson Greenwood™ Type 84 PRV addresses this gap, with a pop-acting design that responds quickly at set pressure to control overpressure immediately. The valve is rigorously tested and certified to operate at pressures up to 20,000 psig for H2 and helium applications, and 21,756 psig for other gases.
A polymeric seat backed by metal components enables the seat to withstand high impact forces during valve closure. Metal materials were carefully chosen for strength, galling resistance, and compatibility with high-pressure H2.
Another key safety feature is a design where the cap, bonnet and body are all pressure-containing components to keep any gas from escaping to the local environment, greatly reducing flammability hazards in the vicinity of the PRV.
Each valve undergoes hydrostatic testing, set pressure verification, and leakage testing in specialized high-pressure test facilities prior to shipment.
Closing thoughts
Proper PRV selection is critical for safe operation, especially in very high-pressure gas applications like H2 storage. While options have been limited historically, certified PRVs with very low-leakage polymeric seating, pressure-containing components, and embrittlement resistance are now available to meet the needs of the growing H2 storage industry segment.
