White Paper

LEL Portable Gas Detector

Choosing the right combustible gas portable detector
It is quite often LEL portable gas detectors has been generalised without taking into the consideration of combustible gases in the work environment. If the LEL portable gas detector is calibrated with methane gas, it will not be suitable for a working environment with the potential present of hydrogen gas or ethylene gas detection. This is simply because 5 %vol of methane gas can meet the combustible criteria with 100% LEL but it takes 4% vol of hydrogen gas to achieve the same condition.


Figure 1, Methane Gas %LEL, %Vol


Figure 2. Hydrogen Gas %LEL, %Vol and ppm

In the event the operator bring a portable detector calibrated with methane gas to the site with hydrogen gas or some other gases with higher combustibility, the gas detector might not be showing the correct indication on the LEL scale or worst case no indication at all. This will pose a grave danger to the operator in the event of serious gas leakage when the operator is supposed to be alarmed by the gas detector and evacuated.

It is impractical to keep different type of LEL portable detector for different combustible gases. The problem can be resolved by having a LEL portable detector with configurable conversion factor for different type of combustible gases.


Figure 3. Combustion gas conversion factors

The operator need to plan and be aware of the potential combustible gases at the work site and choose the specific gas type on the portable gas detector before going to site. The %LEL shown on the portable gas detector will reflect the actual reading from the particular gas.

Riken Keiki new generation of multi gas portable detector GX 3R can address the challenging need of the operator.

GX-3R Four Gas Monitor Features

  • Smallest & lightest 4 gas monitor
  • 2.2″ W x 2.55″ H x 1.02″ D, 3.52 ounces
  • Simultaneous detection of 4 gases
  • LEL, O2, H2S & CO
  • H2 Compensated CO sensor available
  • Simple 2-button operation
  • Non-Compliance Indicator
  • Alarms: audible, visual, & vibration
  • 3 user adjustable alarm levels
  • Impact resistant body with removable rubber boot
  • Large LCD Auto-backlit display
  • 25 hours of operation (Lithium-ion battery)
  • Field replaceable sensors & filters
  • Water and dust resistant design, IP66/68
  • 3 Year warranty