Combustible Gas Detector

Quick Answer: A combustible gas detector is an instrument that senses flammable gases such as LPG, methane (natural gas) or hydrogen in air and warns the user, so that leaks from gas lines, cylinders and fittings can be traced before a flammable mixture builds up. The sensor type, gas list and alarm levels for this model are confirmed on request.

Finding Flammable Gas Leaks

A flammable gas only burns or explodes in air within a certain concentration band. The lower edge of that band is the lower explosive limit (LEL), and combustible gas detectors commonly report readings as a percentage of it, with alarms set well below the point where ignition is possible. That scale is useful because it tells the user how close the air is to danger, whichever gas is present.

Common sensor types include catalytic bead (pellistor) sensors, which respond to most flammable gases, semiconductor sensors used in many handheld leak finders, and infrared sensors for hydrocarbons. Each responds differently from one gas to another, so a detector is calibrated for a particular gas and reads other gases only approximately. The sensor in this model and its calibration gas should be confirmed before use.

Where a leak is looked for matters. LPG (propane and butane) is heavier than air and settles at floor level and in drains; methane is lighter and rises. In a school lab, sweep the probe or inlet slowly along the gas taps, burner tubing and cylinder regulators, with the room ventilated and no flames lit.

Specifications

Care & Handling

• Switch the combustible gas detector on and let it zero in clean air, away from the suspected leak.
• Keep silicone sprays, solvent vapour and heavy dust away from the sensor, as some of these can poison catalytic sensors.
• Check the alarm with a test gas before relying on it, and have the detector calibrated at the recommended interval.
• Never test for a leak with a flame; use the detector, then soapy water on the joints.

Applications

• Checking laboratory gas taps, Bunsen burner tubing and supply lines for leaks
• Tracing leaks at LPG cylinder valves and regulators in labs, kitchens and canteens
• Checking rooms or cabinets where flammable gas may have collected before entry
• Explaining explosive limits in chemistry and safety training

Why Choose LabEquip

School laboratories with piped gas, college chemistry departments, canteens and maintenance teams buy handheld detectors to check their gas installations routinely. LabEquip lists this detector in its General Lab Products range alongside the ammonia gas detector for a toxic gas; contact LabEquip with the gases you need to detect.

Frequently Asked Questions

What does %LEL mean on a gas detector?

LEL is the lower explosive limit, the lowest concentration of a gas in air that can ignite. A reading of 10 %LEL means the air holds one tenth of that amount, so it is still well below the ignition point.

Where should I look for an LPG leak?

LPG is heavier than air, so it collects at floor level, in drains and in low cupboards. Check near the floor as well as at the cylinder valve and regulator.

What should I do if the detector alarms?

Do not operate switches or light anything. Turn off the gas supply at the valve if it is safe to reach, open doors and windows, clear the room and call the gas supplier or a qualified technician.

Can one detector measure all flammable gases accurately?

Not exactly. Sensors are calibrated for one gas and respond to others with different sensitivity. The detector still warns of most flammable gases, but the reading is approximate for gases other than the calibration gas.

Why must the detector be switched on in clean air?

It sets its zero point when switched on. If it starts in air that already contains gas, it treats that level as zero and under-reads the leak.

Is soapy water still useful for leak testing?

Yes. Brushing soapy water on a joint shows bubbles at the exact leak point. The detector finds the area of the leak quickly; soapy water then pinpoints it.

Last Updated: September 2026