Eranntex MS104K-M LEL Combustible Gas Detector Explained Malaysia
Eranntex MS104K-M LEL Combustible Gas Detector Explained Malaysia
An Eranntex MS104K-M configured with a combustible-gas sensor can warn users when flammable gas or vapour is accumulating in the work area.
The reading is commonly displayed as %LEL, but this is often misunderstood. It does not mean the percentage of gas by volume.
Understanding LEL is essential when selecting and using a multi-gas detector for confined spaces, tanks, fuel-storage areas and factory maintenance.
What Does LEL Mean?
LEL means Lower Explosive Limit.
It is the minimum concentration of a combustible gas or vapour in air that can support ignition under specified conditions.
When the concentration is below the LEL, the mixture may be too lean to ignite. As the concentration approaches and exceeds the LEL, the risk becomes more serious.
The detector displays how close the atmosphere is to that lower explosive limit.
What Does 10% LEL Mean?
A reading of 10% LEL means the detected concentration has reached 10% of the gas’s lower explosive limit.
It does not mean that the atmosphere contains 10% gas by volume.
For example:
0% LEL: No measurable combustible-gas response
10% LEL: One-tenth of the lower explosive limit
50% LEL: Halfway to the lower explosive limit
100% LEL: The lower explosive limit has been reached
Actual alarm settings must follow the site procedure and applicable safety requirements.
LEL Is Different for Every Gas
Different gases have different explosive limits.
The detector’s response also depends on:
Calibration gas
Target gas
Sensor technology
Correction factor
Temperature
Humidity
Oxygen level
Sensor condition
A detector calibrated using one combustible gas may respond differently to another gas.
Customers should tell MTM Precision which combustible gas or vapour is expected at the site.
Where Is LEL Monitoring Required?
Possible applications include:
Fuel-storage areas
Oil and gas facilities
Petrochemical plants
Tank entry
Boiler rooms
Gas pipelines
Paint and solvent areas
Wastewater facilities
Manholes and sewers
Generator rooms
Chemical plants
Confined-space work
Leak investigation
Hot-work preparation
The correct detector and sensor technology depend on the application.
Common Four-Gas Configuration
For general industrial and confined-space use, the MS104K-M may be configured with:
EX: Combustible gas in %LEL
O₂: Oxygen
CO: Carbon monoxide
H₂S: Hydrogen sulphide
This combination covers several common hazards using one portable detector.
However, it does not detect every combustible vapour or toxic gas equally. The expected substances must be confirmed before ordering.
Catalytic vs Infrared Combustible Sensors
Depending on the ordered configuration, combustible-gas detection may use catalytic-combustion or infrared technology.
Catalytic-Combustion Sensor
A catalytic sensor is commonly used for combustible gases in %LEL.
Its performance may be affected by:
Low oxygen
Sensor poisons
Inhibiting chemicals
High gas exposure
Ageing
Infrared Sensor
An infrared combustible-gas sensor can offer advantages for selected hydrocarbons and may be less affected by some catalyst poisons.
However, it has its own gas-response characteristics and may not be suitable for every combustible gas.
The sensor technology should be confirmed according to the expected gas and working environment.
Why Oxygen Level Matters
Some combustible-gas sensor technologies require sufficient oxygen to operate correctly.
If the atmosphere is severely oxygen-deficient, the combustible reading may not respond as expected.
This is one reason LEL and oxygen are commonly monitored together during confined-space testing.
Users should interpret all gas readings as a complete atmospheric assessment rather than viewing each sensor in isolation.
Pump Sampling Before Entry
The MS104K-M supports connection to an external pump for remote sampling.
This allows the operator to check for combustible gas inside:
Tanks
Manholes
Underground chambers
Process vessels
Pipelines
Enclosed machinery spaces
The sample should be collected from appropriate levels and locations because gas distribution may not be uniform.
Allow enough time for the sample to pass through the hose and reach the sensors.
Can the Sampling Hose Affect the Reading?
Yes.
Some vapours may be absorbed by or react with unsuitable tubing. Long hoses may also increase response time.
Confirm:
Hose material
Hose length
Target gas
Pump flow
Filter compatibility
Presence of moisture
Required sample time
Using the wrong hose may cause delayed or reduced readings.
Why Does the LEL Reading Stay at Zero?
Possible reasons include:
No combustible gas is present
Gas concentration is below the detector’s response level
Wrong sensor or calibration gas
Blocked sampling line
Pump failure
Sensor poisoning
Oxygen level is too low for the sensor technology
Detector requires calibration
Target gas produces a weak response
Sensor has failed
A zero reading must not be assumed safe if the detector, sensor or sampling system has not been verified.
Why Does the LEL Reading Suddenly Rise?
Possible causes include:
Actual gas leakage
Opening of a tank or pipeline
Disturbance of sludge
Solvent vapour
Fuel vapour
Cross-response to another combustible substance
Contaminated tubing
Sensor instability
Treat any alarm as a potentially real hazard until the area and detector have been properly assessed.
What Should You Do When the LEL Alarm Activates?
If the MS104K-M gives a combustible-gas alarm:
Follow the site’s emergency procedure
Leave or do not enter the affected area
Eliminate ignition sources where authorised and safe
Warn nearby personnel
Report the condition
Investigate from a safe location
Ventilate where appropriate
Retest before work resumes
Do not continue hot work or electrical work in an alarm condition.
Bump Test and Calibration
A bump test confirms that the combustible sensor responds to gas and activates the alarms.
Calibration verifies and adjusts the sensor using a certified reference gas.
Testing is especially important because a poisoned combustible sensor may still display zero in clean air but respond poorly to gas.
The detector should be removed from safety use if it fails its bump test or calibration.
Common LEL Monitoring Mistakes
Avoid:
Treating %LEL as gas volume percentage
Failing to identify the target gas
Using the wrong calibration gas
Ignoring correction factors
Using unsuitable sampling tubing
Relying on the EX sensor in severely oxygen-deficient air without confirming sensor suitability
Skipping bump tests
Continuing work after an alarm
Assuming every combustible vapour produces the same response
Starting hot work based on one old reading
LEL monitoring must be part of a complete risk-control procedure.
Information Required for a Quotation
Provide:
Expected combustible gas or vapour
Required measuring range
Other gases to be monitored
Working environment
Diffusion or pump-sampling requirement
Sampling distance
Required sensor technology, if specified
Number of detectors
Accessories and documentation required
This helps ensure that the combustible sensor matches the application.
Why Choose MTM Precision?
MTM Precision supplies gas detectors, environmental monitoring instruments, industrial testing equipment and safety measurement solutions throughout Malaysia.
Our team can assist with:
LEL detector selection
Combustible-gas configuration
Target-gas and measuring-range confirmation
Confined-space application matching
Diffusion and pump-sampling requirements
Sampling accessories
Product quotation and availability
Basic operating guidance
After-sales and technical coordination
Request an Eranntex MS104K-M Quotation
Tell MTM Precision which combustible gas or vapour may be present and which additional gases must be monitored.
We can help determine whether an EX-equipped MS104K-M is suitable for the application.
Contact MTM Precision
MTM Precision Sdn Bhd
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia.
Website: www.mtmpre.com.my
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
We support customers throughout Selangor, Kuala Lumpur, Johor, Penang, Melaka, Negeri Sembilan, Perak, Pahang, Kedah, Perlis, Terengganu, Sabah and Sarawak.
14 Sep 2026
