Sealing performance under pressure: enabling safe hydrogen infrastructure

Hydrogen is rapidly moving from ambition to deployment, with investment in hydrogen production, storage and distribution infrastructure is growing at pace. The potential is considerable: hydrogen could account for a significant share of global energy demand in the coming decades, while helping to decarbonise sectors that are difficult to electrify, from heavy industry to long-distance transport.

However, scaling the hydrogen economy presents a distinct set of engineering challenges. Unlike many conventional gases, hydrogen molecules are extremely small, making them more prone to leakage. Combined with high operating pressures and the risk of embrittlement in certain materials, this creates a demanding environment where sealing performance is critical.

For operators and OEMs across the hydrogen value chain - from electrolysers to pipelines and end-use systems - getting sealing right is not simply a question of compliance. It is fundamental to safety, efficiency and long-term reliability. Even minor leakage can undermine system performance, increase operational costs and introduce safety risks. The focus therefore shifts from detection to prevention: ensuring that joints, threads and flanges are sealed effectively from the outset and remain secure through fluctuating pressures, temperatures and mechanical stress.

Hydrogen-ready thread sealing

Threaded connections are widely used throughout hydrogen systems, from compressors and valves to storage and distribution equipment. Yet these joints are also among the most common sources of leakage if not properly sealed.

Hydrogen-ready thread sealing technologies are designed to address this challenge by forming a complete seal within the thread geometry. Unlike traditional methods such as PTFE tape or pipe dopes, anaerobic sealants fill the gaps between threads fully, reducing pathways for gas escape and creating a more consistent seal under pressure.

LOCTITE solutions have been specifically developed and tested to withstand hydrogen environments, meeting recognised performance criteria such as KIWA GASTEC QA AR 214 requirements for admixtures up to and including 100% hydrogen gas.

Crucially, this level of performance is not limited to moderate operating conditions. Testing has demonstrated that certain thread sealing technologies can maintain integrity at extremely high pressures, in some cases up to 1,500 bar, depending on the formulation and application.

Beyond pressure resistance, application and usability are equally important. Threads in hydrogen systems can vary significantly, including both NPT and BSPT formats and a range of materials such as stainless steel. Hydrogen-ready sealants are designed to accommodate this diversity, enabling easy application, allowing for adjustment during assembly and avoiding issues such as shredding, tearing or shrinkage that can occur with traditional sealing materials.

In practice, this combination of performance and usability can have a tangible impact. In high-pressure hydrogen compressor systems, for example, switching to a high-strength anaerobic sealing solution has been shown to eliminate leaks, reduce assembly complexity and improve overall system safety.

Hydrogen-ready flange sealing

Flanged joints present a different, but equally important, sealing challenge. Traditionally, these connections rely on pre-formed gaskets, which can be prone to compression set, relaxation over time and variability in sealing performance.

Hydrogen-ready flange sealing technologies offer an alternative approach. Instead of inserting a gasket, liquid anaerobic sealants are applied directly to the flange faces, where they cure in situ to form a uniform, gap-free seal. By filling surface imperfections and eliminating micro-movement between mating components, they reduce the risk of leakage and help maintain joint stability over time.

This approach is particularly relevant in hydrogen applications, where even small imperfections can become leakage pathways. Testing under hydrogen conditions has shown that such sealants can provide reliable, leak-free performance under both ambient and elevated temperature conditions, including exposure to pressurised hydrogen up to 41 bar.

Importantly, these materials also address some of the operational challenges associated with gaskets. By removing the need for multiple gasket types, they simplify inventory management. They also avoid issues such as gasket creep or relaxation, which can lead to loss of bolt preload and subsequent leakage over time.

From a design perspective, the ability to form a seal that adapts to the specific geometry of each flange offers greater consistency and repeatability. For maintenance teams, it can reduce the frequency of intervention and improve long-term reliability across hydrogen systems.

Building reliability into the hydrogen economy

As the hydrogen sector continues to scale, the focus is shifting from pilot projects to industrial deployment. This transition brings increased scrutiny on performance, safety and lifecycle cost across the entire value chain.

Sealing technologies - often overlooked components within larger systems - are emerging as a key enabler of this transition. Effective thread and flange sealing not only helps prevent leaks but also supports broader objectives: improving efficiency, extending equipment life and reducing maintenance requirements. Ultimately, the success of the hydrogen economy will depend on the ability to deliver infrastructure that performs consistently under demanding conditions. By addressing one of the most fundamental challenges - preventing leaks at the point of assembly - advanced sealing technologies are helping to build the confidence required for large-scale adoption.