Lower Explosive Limit of Methane ≠ 5.0%! New Chinese National Standard: 4.4%

This is a critical safety issue that everyone should be aware of!

Lower Explosive Limit of Methane ≠ 5.0%!
New Chinese National Standard: 4.4%

China has lowered the lower explosive limit (LEL) of methane from 5.0% to 4.4%! Safety allows no compromise — excellence is a must!
Starting February 2026, the updated Chinese national standard GB 15322.1—2026 has come into force, revising the LEL of methane from the longapplied 5.0% to 4.4%. This 0.6% difference is far from trivial: it directly defines the safety baseline for countless applications including coal mining, chemical engineering and gas supply, and serves as a critical safety alert for everyone.
In high-temperature workshops and confined coal mine spaces, methane’s LEL becomes even lower
As temperature rises, methane molecules gain greater kinetic energy and undergo more effective collisions, enabling combustion at lower concentrations. At 20°C, the LEL is approximately 5.0%, while at 100°C it can drop to around 4.2%. This creates significantly higher hazards in confined spaces such as high-temperature workshops and coal mines.
When methane is mixed with gases of even lower LEL and higher reactivity — such as CO, H₂ and H₂S — the mixture becomes far more ignitable, and its LEL falls well below that of pure methane. For instance, mixed gas in coal mine methane carries far greater risks than pure methane alone. A higher ignition energy source can ignite leaner methane–air mixtures, further lowering the LEL. Strong ignition sources such as electric sparks and hot surfaces present hidden dangers.
Lowering the LEL means alarms trigger at lower methane leakage concentrations
Under the old standard, the 25% LEL alarm threshold was 1.25%; under the new standard it is 1.1%. This allows detection of even minor leakages at an earlier stage, eliminating risks before they escalate. The updated standard aligns with internationally accepted measurement methods and values such as IEC standards, improving compatibility and bringing methane leakage monitoring and explosion-proof design in line with global safety norms.
MaiYa Sensor’s laser methane detector
MaiYa Sensor has launched a laser methane sensor using TDLAS technology, offering ultra-high accuracy of ±0.03% VOL within the 0–1% VOL measurement range. It precisely detects low-concentration leakages and easily complies with the new safety threshold, building a robust explosion-proof barrier for underground mines and gas applications.