The belief that hydrogen will be the fuel of the future is now almost universal. Regardless of whether the industry evolves towards energy production from atoms through nuclear fusion or toward hydrogen fuel cells, this element appears to be a nearly unlimited energy source. However, there is still a long way to go for hydrogen to become a widely used fuel. Another gas that has been widely used in the industry for years is methane. It is used as a fuel in engines, in the production of plastics, in the energy sector, and generally as an energy source.

Both hydrogen and methane are hazardous gases—flammable and explosive. Therefore, ensuring the safety of installations using these media is absolutely crucial. Additionally, methane is a greenhouse gas that significantly contributes to global warming. While hydrogen is not classified as a greenhouse gas, its emission indirectly affects the levels of methane and ozone in the atmosphere.

Thus, the emissions of these gases should—and must—be limited and controlled. SPETECH^® Engineering Team focuses on emissions from flange connections in transmission and process pipelines, flange connections of pressure vessels, and valve packing. Analyzing various data sources concerning emission volumes and their origins, about 60% of emissions come from valves, and about 6% come from flange connections.

For nearly 30 years, SPETECH^® Research Laboratory has conducted tests on flat and gland packings using helium, which is non-flammable, non-explosive, and generally harmless. However, tests based solely on this medium are now insufficient. More and more of our clients are asking to conduct tests with hydrogen and methane. The state of technology, energy trends, and the market demand data on emission levels using these gases. This information is necessary for both engineering—designing the sealing of flange connections—and for market certification requirements in compliance with standards.

Responding to market demand, since 2022, we have been conducting emission tests using hydrogen and methane, analyzing the behavior of flange seals, gland packings, and entire valve systems. Unfortunately, standardization is not keeping pace with changes in hydrogen applications. Thus, the tests we conduct are based on the provisions of standards that do not specifically list hydrogen as a testing medium.

Examples of commonly used standards are:
- 'EN 13555: Flanges and their joints - Gasket parameters and test procedures relevant to the design rules for gasketed circular flange connections' used for flange gasket testing and
- 'EN 15848-1: Industrial valves - Measurement, test and qualification procedures for fugitive emissions, Part 1: Classification system and qualification procedures for type testing of valves' used for valve testing.
Both above standards describe test procedures using helium, and the latter also covers tests using methane.

EX Test Chamber

Due to the explosiveness of hydrogen and methane, SPETECH^® Laboratory Team has built a special test chamber designated for hazardous media. It is equipped with all the necessary safety measures to protect workers from the consequences of a potential rapid increase in gas concentration. These include hydrogen and methane sensors, as well as both gravitational and forced ventilation systems. Our test stations and all tools have been adapted for work in explosive atmospheres.

Newly build laboratory chamber for emission tests with usage of dangerous media

Current Research

The work currently being carried out in SPETECH^® Laboratory involves mostly tests using helium and hydrogen, with fewer tests using methane. Tests are conducted on a specialized PowerPress test rig. In the case of flange connection sealing tests, our goal is to determine design factors (QminL, QsminL), which define the required gasket stresses for the desired sealing classes. These factors are used in the structural calculations of flange connections and, most importantly, in calculating the clamping force and bolt torque. These tests are based on one of the methods described in the EN 13555 standard.

Comparing the results of tests using helium, hydrogen, and methane shows that there are no significant differences in the emission levels generated by these gases.

SPETOBAR^® CNAF [Compressed Non Asbestos Fibre Gasket] testing results

Tightness in function of surface pressure load – leakage shown in [mg/(m*s)] unit

The graphs provided show that helium and hydrogen emissions are at similar levels. Methane generates higher leakage under the same contact stresses on the gasket. However, the graph using the leakage unit [mg/(ms)] can be misleading. This unit refers to the mass of a given gas—milligrams. To capture the relationships without considering the mass differences of the gases, a graph with the unit [mbarl/s] should be used. This eliminates the mass differences.

SPETOBAR^® CNAF [Compressed Non Asbestos Fibre Gasket] testing results 

Tightness in function of surface pressure load – leakage shown in [mbar*l/s] unit

The graph using the unit [mbar*l/s] clearly shows that the differences in gas emissions are not significant. All emissions are within the range typically used in sealing technologies, which generally operate with leakages between 1.0E-1 and 1.0E-4. The graph also shows that at higher stresses, achieving low emissions is possible without exceeding the allowable stresses for a given gasket.

SPETOBAR^® CNAF [Compressed Non Asbestos Fibre Gasket] testing results determined with 3 different testing media

Leakage in function of surface pressure load [MPa]. Leakage shown in [mbar*l/s] unit

SPETOSPIR^® SWG [Spiral Wound Gasket] testing results 

Tightness in function of surface pressure load – leakage shown in [mbar*l/s] unit

The tests of Spiral Wound Gasket also did not show significant differences in the sealing classes achieved for the different gases. The behavior of helium and hydrogen is very similar, whereas at higher contact stresses, methane emissions are noticeably greater. This is unusual, as one would expect that higher stresses would result in lower emissions. This effect is likely dependent on the gasket's construction and the materials used.

Conclusions

1.    Tests using hydrogen and methane should be conducted, even though the results do not differ significantly from those obtained with helium. The design factors obtained from these tests should be used in the EN 1591-1 algorithm when calculating flange connections for the appropriate medium, to minimize emissions.
2.    The presented results are only from tests on two types of gaskets: fiber-elastomer and spiral wound. The tests were conducted at 40 bar pressure. Further research with other types of gaskets, made from different materials, and at various test pressures, is necessary.

The SPETECH^®Laboratory is equipped and ready to conduct such tests. We will continue to publish the results of these tests in nearest future.

Reliability of SPETECH^® Laboratory is proofed by TÜV Rheinland accreditation, which is supported by 30 years of continuous research and development activity. Our Laboratory is placed in Poland / UE, we are an active member of European Sealing Association since 1998.

Our Laboratory is certified acc. to EN ISO/IEC 17025:2018 standards.
If you need any technical support or need to perform any specific test which is not included on our standard offer - feel free to contact us directly via LAB@spetech.com.pl.

Janusz Zajączek
Head of Laboratory, SPETECH^®