Author: Janusz Zajączek, Head of SPETECH^® Laboratory

The belief that hydrogen will be the fuel of the future is now almost universal. Regardless of whether industry evolves towards energy production from atoms—through fusion—or towards hydrogen fuel cells, this element appears to be a nearly unlimited energy source. However, for hydrogen to become a widely used fuel, engineers still have a long way to go.
Another widely used industrial gas is methane. It serves as an engine fuel, is used in plastic production processes, in the energy industry, and generally as an energy source.

Growing importance of hydrogen and methane as test media

Both hydrogen and methane are dangerous gases—flammable and explosive. Ensuring the safety of installations that use these gases is, therefore, a critical issue. Additionally, methane is a greenhouse gas that significantly contributes to global warming. While hydrogen is not classified as a greenhouse gas, its emissions indirectly affect methane and ozone levels in the atmosphere.

For these reasons, emissions of these gases should—and must—be limited and controlled. SPETECH^® engineering consulting group focuses on emissions from flanged pipeline connections, flanged connections of pressure vessels, and valve stem seals. Various data sources indicate that about 60% of emissions originate from valve systems, while approximately 6% come from flange connections.

For nearly 30 years, the SPETECH^® research laboratory has been conducting tests on flat and gland packings, using helium—a non-flammable, non-explosive, and generally harmless gas—as the test medium. However, studies based solely on helium are now insufficient. More and more clients inquire about testing using hydrogen and methane. Industry advancements, energy sector trends, and market demands require data on emissions from these gases. This data is essential from both an engineering perspective—designing flange joint tightness—and for formal certification requirements aligned with applicable norms and standards.

Responding to market demand, since 2022, we have been conducting emission tests using hydrogen and methane, analyzing the performance of flange gaskets, gland packings, and entire valve systems. Unfortunately, standardization efforts have not kept pace with the evolving approach to hydrogen applications. Therefore, our tests are based on the provisions of existing norms and standards, even though they do not explicitly list hydrogen as a test medium.

For example, the most commonly used standards include:

• EN 13555: "Gasket parameters and test procedures for the design of circular gasketed flange connections"—used for testing flange gaskets.
• EN 15848-1: "Measurement, test, and qualification procedures for fugitive emissions—Part 1: Classification system and qualification procedures for type testing of valves"—describes procedures for helium and methane testing.

EX test chamber for hazardous media

Due to the explosiveness of hydrogen and methane, the SPETECH^® research laboratory has constructed a dedicated test chamber classified as a hazardous area. It is equipped with all necessary safety measures to protect personnel from the consequences of potential gas concentration increases. These measures include hydrogen and methane sensors, natural and forced ventilation systems, and explosion-proof testing stations and tools.

Figure 1: Laboratory for testing hazardous media

Currently, our research primarily focuses on helium and hydrogen, with fewer tests using methane. Testing is conducted at a specialized PowerPress2 test station. When testing gaskets for flange joints, our goal is to determine design factors (QminL, QsminL) that define the required gasket stress to achieve specific tightness classes. These factors are crucial for flange joint strength calculations, particularly for determining the required bolt tightening force and torque. These tests are based on methods outlined in EN 13555.
A comparison of test results using helium, hydrogen, and methane reveals no significant differences in emission levels among these gases.

Test results for CNAF Compressed Non Asbestos Fiber material gasket (SPETOBAR^®BAS340) 

 Figure 2: Tightness vs. stress (unit: mg/(m*s)

The graph in Figure 2 shows that helium and hydrogen emissions are at similar levels, while methane exhibits higher leakage rates at the same gasket contact stresses. However, this graph may be misleading because its unit—mg/(ms)—refers to the gas mass. To compare emissions without considering gas mass differences, a different unit—mbarl/s—is used.

 Figure 3: Tightness vs. stress (unit: mbar*l/s)

The graph in Figure 3 clearly shows that emission differences among the gases are not significant. All emissions fall within typical sealing technology ranges, generally operating between 1.0E-1 and 1.0E-4. At higher stresses, low emissions can be achieved without exceeding allowable gasket stresses.

 Figure 4: Differences in emission levels as a function of gasket contact stress

Test results for SWG Spiral Wound Gasket (SPETOSPIR^®SWZ)

Emission tests for a spiral wound gasket with inner and outer 316L steel rings and graphite filler are shown in Figure 5.

Figure 5: Tightness vs. stress (unit: mbar*l/s)

Again, no significant differences were observed in the sealing performance of these gases. Helium and hydrogen behaved similarly, while methane emissions were higher at increased contact stresses. This is unexpected, as higher stress should typically result in lower emissions. This effect likely depends on the gasket’s construction and materials.

Conclusions

1. Testing with hydrogen and methane is necessary, even though the results are similar to those obtained with helium. The design coefficients derived from these tests should be applied in the EN 1591-1 calculation algorithm for flange joints to minimize emissions.
2. The presented results apply only to two types of gaskets—fiber-reinforced elastomeric and spiral wound—tested at 40 bar pressure. Further research is needed on other gasket types, materials, and pressure conditions.

The SPETECH^® Testing and Research Laboratory is fully equipped to conduct such tests, and we will continue to publish our findings.
This article provides a brief overview of our laboratory’s capabilities in testing flat flange gaskets. In an upcoming scientific publication, we will present emission test results for valve systems using helium and methane.