A gas detector is not just a gas detector. In practice, users often search for a device for “methane”, “CO₂”, “VOC”, “refrigerants” or “toxic gases”. However, the decisive factor is not only the target gas, but also the appropriate sensor technology. An electrochemical sensor works differently from a pellistor, an infrared sensor differently from a PID sensor, and an open-path or laser measurement fulfils a different task than a point gas detector.
The wrong sensor technology can lead to gas being detected too late, cross-sensitivities being evaluated incorrectly, the device triggering false alarms too frequently or maintenance costs increasing unnecessarily. Especially for flammable gases, toxic gases, oxygen monitoring, CO₂, volatile organic compounds and refrigerants, careful selection is therefore worthwhile.
This article explains the most important sensor principles in an understandable way and shows which technology is typically suitable for which application. It also looks at cross-sensitivities, response time, calibration, maintenance and the operating environment. Suitable product areas and devices include gas measurement technology, Gas-Pro PID, Gas-Pro IR, IRmax infrared gas detector, Xgard gas detector and LaserMethane Smart.
Table of contents
- Why sensor technology is decisive in gas detectors
- Clarify target gas, measuring range and alarm limits first
- Electrochemical sensors: Monitoring toxic gases and oxygen
- Pellistor sensors: Detecting flammable gases in the LEL range
- Infrared sensors: Reliably measuring CO₂ and hydrocarbons
- PID sensors: Detecting VOCs and solvent vapours
- Laser and open-path measurement: Monitoring gas clouds and larger areas
- Monitoring methane: Pellistor, infrared or laser?
- Monitoring CO₂: Why infrared is usually the right technology
- Measuring VOCs: Why PID sensors are often useful
- Detecting refrigerants: Why the specific refrigerant matters
- Toxic gases and oxygen: Typical applications for electrochemical sensors
- Correctly assessing cross-sensitivities and false alarms
- Maintenance, calibration and functional testing
- Response time and measuring point: Why the installation location matters
- Portable gas detectors or fixed gas detection system?
- Suitable products and product areas
- Practical example: Gas monitoring in a technical room, storage area and process area
- Conclusion: The target gas alone does not determine the right gas detector
- FAQ: Frequently asked questions about gas detectors and sensor technologies
Why sensor technology is decisive in gas detectors
A gas detector is intended to detect dangerous gas concentrations in time and trigger an alarm before people, systems or processes are put at risk. For this to work reliably, the sensor must match the gas, the environment and the measuring task. A sensor that is very suitable for one gas may be unsuitable or only usable to a limited extent for another gas.
For flammable gases, the focus is often on the risk of explosion. Measurement is therefore often carried out in the range of the lower explosive limit. For toxic gases, the focus is on concentrations that can be harmful to people. For oxygen, the aim is to monitor whether oxygen deficiency or oxygen enrichment is present. For CO₂, the focus is often on asphyxiation risk or workplace monitoring. For VOCs, the issue is often solvent vapours, process monitoring or leak detection.
These applications differ significantly. A pellistor can detect many flammable gases in the LEL range, but it is not the right technology for CO₂. An infrared sensor can measure CO₂ and many hydrocarbons, but it is not suitable for all flammable gases. A PID sensor is very sensitive to many volatile organic compounds, but is not automatically selective for a single substance. Electrochemical sensors are widely used for many toxic gases and oxygen, but require suitable selection for each gas.
Sensor technology also influences maintenance, calibration, service life, response time, cross-sensitivities, environmental influences and costs. For this reason, the selection of a gas detector should not be based only on keywords such as “gas detector for methane” or “CO₂ warning device”, but on a precise assessment of the measuring task.
Clarify target gas, measuring range and alarm limits first
The first step is always to determine which gas actually needs to be monitored. This should be done as specifically as possible. “Flammable gases” is a different requirement from “methane”. “VOC” is a collective term for many volatile organic compounds, not a single gas. “Refrigerant” can refer to very different substances depending on the system. The more precisely the target gas is known, the better the sensor technology can be selected.
It must also be clarified which measuring range is to be monitored. For flammable gases, measurement is often carried out in % LEL. For toxic gases, ppm values are common. For CO₂, ppm, volume percent or other units are used depending on the application. Oxygen is usually measured in volume percent O₂.
The alarm limits are also important. A device for personal safety must meet different requirements than a device for rough leak detection or process observation. A fast alarm in the event of a sudden gas cloud is different from continuous trend measurement in a ventilation system.
| Question | Why is it important? |
|---|---|
| Which target gas should be detected? | Determines the suitable sensor technology |
| Is the gas flammable, toxic, inert or oxygen-displacing? | Determines the hazard and measuring principle |
| Which measuring range is being monitored? | Distinguishes between LEL, ppm, vol. % and leak detection applications |
| Is personal warning or process monitoring required? | Influences alarm concept, response time and device selection |
| What is the operating environment? | Temperature, humidity, dust, airflow and Ex zone influence the selection |
Only once these points are clear can it be decided sensibly whether electrochemical sensors, pellistors, infrared, PID, laser or open-path technology are suitable.
Electrochemical sensors: Monitoring toxic gases and oxygen
Electrochemical sensors are frequently used for toxic gases and oxygen. They contain an electrochemical cell in which the target gas triggers a chemical reaction. This reaction generates an electrical signal that is evaluated proportionally to the gas concentration. Typical applications include measuring carbon monoxide, hydrogen sulphide, chlorine, ammonia, nitrogen oxides, sulphur dioxide or oxygen.
The major advantage of electrochemical sensors is their sensitivity to many toxic gases in the ppm range. They are widely used in portable gas detectors and fixed gas detectors and are well suited for personal protection, workplace monitoring and area monitoring. Oxygen sensors are also often designed electrochemically to detect oxygen deficiency or oxygen enrichment.
However, it should be noted that electrochemical sensors have a limited service life. The electrochemical cell ages, can be stressed by high gas concentrations and may also respond to other gases. Temperature, humidity and storage conditions can also influence sensor performance.
Electrochemical sensors are therefore not maintenance-free components, but must be checked and calibrated regularly. For safety-relevant applications, it is also important to ensure that response time, selectivity and cross-sensitivity match the environment. In areas with several possible gases, it must be checked particularly carefully whether a sensor only evaluates the desired gas or also reacts to other substances.
Pellistor sensors: Detecting flammable gases in the LEL range
Pellistor sensors, also known as catalytic bead sensors, are used for flammable gases and vapours in the range of the lower explosive limit. The gas is burned on a catalytically active sensor element. The resulting temperature change alters the electrical resistance and is evaluated as a measuring signal.
This technology has been established in gas detection for many years. It is suitable for many flammable gases and vapours and is typically displayed in % LEL. Pellistors have a relatively broad response and can therefore be useful for general monitoring of flammable gases if the gas type is known and the environmental conditions are suitable.
An important point is the oxygen requirement. Since the measuring principle is based on combustion, the sensor requires sufficient oxygen. In oxygen-deficient or inerted areas, a pellistor can provide incorrect or too low values. In addition, pellistors can be poisoned or inhibited by certain substances, for example silicones, sulphur compounds or other sensor poisons. This can reduce sensitivity.
For flammable gases such as methane, propane, butane or hydrogen, a pellistor can be suitable depending on the application. However, if oxygen deficiency, high sensor stability, low maintenance or certain hydrocarbons are the focus, an infrared sensor may be the better choice. For hydrogen, however, it must be noted that many infrared sensors cannot detect hydrogen because hydrogen is not infrared-active.
Infrared sensors: Reliably measuring CO₂ and hydrocarbons
Infrared sensors use the absorption of infrared light by certain gases. Many gases absorb light at characteristic wavelengths. The sensor measures how strongly the light is attenuated and derives the gas concentration from this. Infrared measurement is particularly common for CO₂ and many hydrocarbons.
A major advantage of infrared sensors is that they are not based on combustion. They therefore do not require oxygen for the measuring principle. This is particularly important in oxygen-deficient, inerted or oxygen-fluctuating environments. Infrared sensors are also less susceptible to many types of sensor poisoning than pellistors.
For CO₂, infrared is the standard technology in many applications. CO₂ is not flammable, but can become dangerous at higher concentrations because it displaces oxygen and can also be physiologically relevant. Reliable CO₂ monitoring is therefore important in technical rooms, breweries, refrigeration systems, laboratories, greenhouses, storage areas and process areas.
Infrared sensors are also often useful for flammable hydrocarbons such as methane, propane or butane. They can be a robust solution for fixed gas detectors, especially when high long-term stability, low susceptibility to poisoning or use in difficult environments is required. However, not all flammable gases can be measured with IR. Hydrogen is a typical example of a gas that cannot be detected with standard infrared hydrocarbon sensor technology.
PID sensors: Detecting VOCs and solvent vapours
PID stands for photoionisation detector. A PID sensor uses UV light to ionise molecules of certain volatile organic compounds. The ions produced generate an electrical signal, which is evaluated as a measure of concentration. PID sensors are particularly suitable for many VOCs, meaning volatile organic compounds.
Typical applications include solvent vapours, chemical storage areas, painting areas, cleaning processes, leak detection, occupational safety and process monitoring. The major advantage is the high sensitivity to many organic vapours in the ppm or even near-ppb range, depending on device and application.
However, it is important to note that a PID sensor is often not selective for a single substance. It indicates an overall exposure from ionisable VOCs. Which substances it can detect depends, among other things, on the lamp energy and the ionisation potential of the respective compound. Methane, CO₂ and many inorganic gases are not meaningfully monitored with PID.
PID sensors also require care. The UV lamp and sensor cell can be affected by contamination, humidity or process vapours. Regular functional tests, cleaning and calibration are important. For applications with changing VOC mixtures, it must also be clarified which substance is used for calibration and which correction factors are required.
Laser and open-path measurement: Monitoring gas clouds and larger areas
Laser and open-path measurement methods are used when not only a point measuring location needs to be monitored, but a larger area, a path or a possible gas cloud. The measuring device sends light over a defined measuring path or uses laser absorption to detect a specific gas. When gas enters the measuring path, the optical signal changes.
Open-path systems are particularly suitable for large plant areas, outdoor installations, pipelines, tank farms, process areas or locations where a gas cloud does not reliably pass a single point detector. They can be a useful addition to point gas detectors, but do not automatically replace them.
Laser-based methane detectors are particularly interesting for non-contact leak detection and remote detection. Such devices can detect methane from a distance without the user having to approach the leak directly. This is very helpful in hard-to-reach areas, on pipes, fittings, biogas plants or natural gas installations.
The limits lie in line of sight, target gas specificity and environmental conditions. Fog, dust, heavy contamination, poor reflection or unfavourable geometry can influence the measurement. In addition, laser or open-path measurement is usually designed for defined gases and does not replace general multi-gas monitoring.
Monitoring methane: Pellistor, infrared or laser?
Methane is a flammable gas and plays an important role in natural gas supply, biogas, sewage treatment plants, landfills, industrial plants and heating technology. The suitable sensor technology depends strongly on the measuring task. If an explosive atmosphere is to be monitored at a point, pellistor or infrared sensors may be suitable depending on the environment. If a leak is to be detected remotely without contact, laser methane detection is particularly interesting.
Pellistors can detect methane in the LEL range and are suitable for many flammable gas warning applications. However, they require oxygen and can be affected by sensor poisons. Infrared sensors for hydrocarbons can also detect methane and are robust in many fixed applications, especially where oxygen deficiency or sensor poisoning is an issue.
Laser methane detectors are suitable for fast leak detection and remote detection. They are not simply mounted at one point, but enable non-contact inspection from a certain distance. This allows hard-to-reach pipes, ceiling areas, fittings or plant sections to be checked without the user having to enter the danger area directly.
For methane, there is therefore no single correct technology. Point monitoring, fixed gas detection, portable personal warning and non-contact leak detection all place different demands on the device. Selection should therefore be based on objective, environment, alarm concept and maintenance strategy.
Monitoring CO₂: Why infrared is usually the right technology
CO₂ is colourless and odourless and is often underestimated. It is not flammable, but can become dangerous at higher concentrations. CO₂ displaces oxygen and can also have direct physiological effects. CO₂ monitoring is therefore important in many areas, for example in refrigeration systems, beverage technology, breweries, laboratories, greenhouses, storage areas, technical rooms and industrial processes.
For CO₂, infrared measurement is typically the suitable sensor technology. CO₂ absorbs infrared radiation in characteristic wavelength ranges. This enables reliable detection using NDIR sensors. Electrochemical sensors or pellistors are not the typical first choice for CO₂.
When selecting a CO₂ gas detector, measuring range, alarm limits, ventilation situation and installation height are important. CO₂ is heavier than air, but depending on temperature, ventilation and release situation, it may distribute differently. The sensor should be located where a dangerous concentration is realistically likely to occur or accumulate first.
In refrigeration systems, it is also important whether CO₂ itself is the refrigerant or whether other refrigerants are to be monitored. In CO₂ refrigeration systems, a CO₂ infrared sensor is useful. For halogenated refrigerants, other sensor technologies may be required.
Measuring VOCs: Why PID sensors are often useful
VOC stands for volatile organic compounds. These include many solvents, fuel vapours, cleaning agents, paint and coating vapours as well as numerous organic process substances. They can be harmful to health, flammable, odour-intensive or process-relevant. VOCs are often monitored not as a single target gas, but as a group of substances.
PID sensors are particularly suitable for many VOC applications because they respond very sensitively to many ionisable organic compounds. They are therefore well suited for portable measurements, leak detection, clearance measurements, occupational safety and process areas where different VOCs may occur.
The challenge lies in interpretation. A PID sensor often provides a summed signal. If several VOCs are present at the same time, the measured value cannot automatically be assigned to one individual substance. For accurate evaluation, calibration gas, response factors and target substance must be known.
Humidity, contamination and high concentrations can also influence PID sensors. In harsh industrial environments, attention should therefore be paid to maintenance, lamp cleaning, filters and regular calibration. For specific toxic individual gases, an electrochemical sensor may be more suitable, while PID shows its strength in broad VOC detection.
Detecting refrigerants: Why the specific refrigerant matters
For refrigerants, general sensor selection is particularly difficult. There is CO₂ as a natural refrigerant, ammonia, propane, isobutane, HFO, HFC and many other substances. These refrigerants differ greatly in terms of flammability, toxicity, density, environmental behaviour and suitable sensor technology.
CO₂ is typically monitored using infrared sensor technology. Depending on the application, ammonia can be detected using electrochemical sensors or other suitable methods. Flammable refrigerants such as propane or isobutane can be monitored in the LEL range using suitable flammable gas sensors. Halogenated refrigerants often require special refrigerant detectors or suitable infrared or semiconductor technologies, depending on the substance and application.
For refrigerant monitoring, the exact substance designation should therefore always be known. Information such as “refrigeration system” or “refrigerant warning device” is not sufficient. The decisive factors are refrigerant type, expected leak quantity, room size, ventilation, installation position, alarm strategy and legal or normative requirements.
Placement is also important. Some refrigerants are heavier than air and can accumulate near the floor. Others distribute differently depending on temperature, air movement and system geometry. A sensor in the wrong location can respond too late despite using the correct technology.
Toxic gases and oxygen: Typical applications for electrochemical sensors
Electrochemical sensors are very frequently used for toxic gases and oxygen. Typical target gases include carbon monoxide, hydrogen sulphide, nitrogen dioxide, sulphur dioxide, chlorine, ammonia or oxygen. In portable multi-gas detectors, electrochemical sensors are often combined with other sensor technologies, for example pellistor, IR or PID.
For carbon monoxide, the focus is often on personal protection in boiler rooms, underground car parks, industrial plants or combustion processes. Hydrogen sulphide is relevant in wastewater technology, sewage treatment plants, refineries, biogas and certain process areas. Oxygen sensors are used to detect oxygen deficiency caused by displacement or oxygen enrichment caused by leaks or process conditions.
The selection of an electrochemical sensor should not be based solely on the target gas. Measuring range, expected background concentrations, cross-sensitivities and sensor service life are also important. In areas with several toxic gases, a sensor may react to several substances. This can be useful from a safety perspective, but can also lead to misinterpretation.
For safety-relevant applications, it should therefore always be checked whether a single-gas device, a multi-gas detector or a fixed gas detection system is the better solution. Alarm transmission, ventilation control, acoustic and visual signalling and documentation may also be relevant.
Correctly assessing cross-sensitivities and false alarms
Cross-sensitivity means that a sensor does not only react to the target gas, but also to other substances. This is an important point in many sensor technologies. Depending on the type, electrochemical sensors can react to other toxic gases. PID sensors react to many ionisable VOCs. Pellistors respond broadly to flammable gases. Infrared sensors must also be selected to match the target gas and spectral range.
Cross-sensitivities are not fundamentally bad. In a general warning for a group of substances, broad response behaviour can be useful. However, if one specific target gas is to be monitored precisely, cross-sensitivities can lead to false alarms or incorrect evaluation.
The operating environment also influences the measurement. High humidity, dust, solvent vapours, silicones, cleaning agents, oil mist, temperature changes or oxygen deficiency can affect sensors. A gas detector that works reliably in the laboratory does not automatically perform just as stably in a contaminated production environment.
Known accompanying substances should therefore always be specified during selection. If methane, solvent vapours and cleaning agents can occur simultaneously in an area, a different evaluation is required than in a clean technical room with only one target gas.
Maintenance, calibration and functional testing
Gas detectors are safety-relevant measuring instruments. They must be checked, maintained and calibrated regularly. A sensor can age, become contaminated, drift or be affected by high concentrations or sensor poisons. Without regular testing, it is not certain whether the device will alarm correctly in an emergency.
A functional test, often referred to as a bump test, checks whether the device responds to test gas and triggers an alarm. Calibration goes further and adjusts or verifies the measured value using a suitable calibration gas. Different intervals may apply depending on device, sensor, application and internal requirements.
Electrochemical sensors have a limited service life and require regular checks. Pellistors should be checked for sensitivity because sensor poisoning can lead to dangerously low readings. PID sensors require care of the lamp and sensor cell. Infrared sensors are often long-term stable, but must also be checked for contamination, optics and signal behaviour.
Maintenance should match the criticality of the application. A portable gas detector used for personal protection before entering a hazardous area must function particularly reliably. A fixed system with alarm transmission, ventilation control and safety function also requires a clear inspection and maintenance strategy.
Response time and measuring point: Why the installation location matters
The best sensor technology is of little use if the sensor is installed in the wrong place. Gases distribute differently depending on density, temperature, airflow, release type and room geometry. Methane is lighter than air and tends to accumulate in the upper area. CO₂ and many refrigerants can accumulate closer to the floor. VOC vapours can be heavier or lighter than air depending on the substance.
Response time also depends not only on the sensor, but also on whether the gas reaches the sensor at all. In poorly ventilated corners, behind obstacles or far away from possible leak points, a sensor may respond too late. Conversely, strong airflows can dilute gas or carry it past the sensor.
For fixed gas detectors, placement should therefore be derived from the risk assessment, possible leak points, the physical properties of the gas and the ventilation situation. With portable devices, it is important how and where the measurement is taken. A portable device worn on the body measures the user’s surrounding atmosphere, not automatically every remote part of the plant.
For pumped devices, sampling hoses or aspiration systems, dead times, hose length, condensation and material compatibility must also be considered. Some gases can adsorb onto hoses or be influenced by humidity. This can increase response time or distort the measured value.
Portable gas detectors or fixed gas detection system?
The selection of sensor technology is closely connected to the question of whether a portable gas detector or a fixed gas detection system is required. Portable devices protect people during inspections, maintenance work, clearance measurements or work in hazardous areas. They must be robust, portable, quickly ready for use and suitable for the user’s target gases.
Fixed gas detectors, on the other hand, continuously monitor a defined area. They are installed at fixed measuring points and can be connected to alarm devices, controllers, ventilation systems, shutdowns or building management systems. This solution is often useful for technical rooms, refrigeration systems, process areas, tank farms or machine rooms.
In many applications, both concepts are combined. A fixed system continuously monitors the area, while portable devices provide additional personal protection during maintenance and inspections. This combination is often useful especially in chemicals, oil & gas, wastewater technology, refrigeration technology and process industry.
| Application | Portable gas detectors | Fixed gas detectors |
|---|---|---|
| Personal protection during inspection | Very suitable | Possible as a supplement |
| Continuous room monitoring | Not ideal as the only solution | Very suitable |
| Leak detection on pipelines | Suitable, depending on the device | Only at fixed measuring points |
| Alarm transmission and ventilation control | Limited depending on system | Very suitable |
| Work in changing areas | Very suitable | Only fixed areas |
The decision should therefore not depend only on the target gas, but also on whether people need mobile protection, areas need continuous monitoring or leaks need to be located specifically.
Suitable products and product areas
For VOC detection, the Gas-Pro PID is a suitable solution. It uses PID technology and is therefore suitable for applications where volatile organic compounds need to be detected. PID technology can be particularly useful for solvent vapours, chemical storage areas, process areas and occupational safety tasks.
For CO₂ applications, the Gas-Pro IR is interesting if a portable multi-gas detector with infrared sensor technology is required. CO₂ is typically monitored using infrared measurement because this technology is particularly suitable for CO₂.
For fixed hydrocarbon monitoring, the IRmax infrared gas detector is a suitable product basis. Infrared gas detectors are often useful when flammable hydrocarbons need to be monitored and robust fixed sensor technology is required.
If different sensor variants are required for fixed gas monitoring, the Xgard gas detector is a flexible product group. Depending on the version, different sensor principles and target gases can be covered. This is particularly useful when a gas detection system needs to monitor several measuring points or different gases.
For non-contact remote methane detection, the LaserMethane Smart is suitable. Such devices are particularly useful for leak detection at hard-to-reach points, pipes, fittings or plant areas where direct approach is difficult or undesirable.
Practical example: Gas monitoring in a technical room, storage area and process area
An operator wants to protect several areas: a technical room with a CO₂ system, a chemical storage area with solvents and a process area with possible methane release. Initially, the request is simply for “gas detectors”. On closer inspection, however, it becomes clear that there are three very different measuring tasks.
In the technical room, CO₂ is the target gas. Infrared sensor technology is useful here because CO₂ can be measured reliably with it. The sensor must be positioned so that possible CO₂ accumulations are detected in time. Alarm transmission and ventilation control are also important.
Various solvent vapours occur in the chemical storage area. PID technology can be useful here because different VOCs need to be detected. At the same time, it must be clear that the PID sensor provides a summed signal and does not automatically distinguish between all substances. Calibration gas, response factors and known stored substances are considered for evaluation.
Methane may be released in the process area. For fixed point monitoring, pellistor or infrared sensors may be suitable depending on the environment. If hard-to-reach pipes are also to be checked regularly, a laser-based methane leak detector can be useful. This allows methane to be detected from a distance without approaching every possible leak point directly.
The example shows that there is no universal gas detector for all tasks. Only the target gas, measuring task, environment and alarm concept determine which sensor technology is suitable.
Conclusion: The target gas alone does not determine the right gas detector
The selection of a gas detector does not depend only on whether methane, CO₂, VOCs, refrigerants or toxic gases are to be monitored. The decisive factor is the combination of target gas, measuring range, sensor technology, environment, cross-sensitivities, response time, maintenance effort and alarm concept.
Electrochemical sensors are suitable for many toxic gases and oxygen. Pellistors are an established solution for many flammable gases in the LEL range. Infrared sensors are particularly important for CO₂ and many hydrocarbons. PID sensors are suitable for numerous VOC applications. Laser and open-path measurements are useful when larger areas, gas clouds or remote methane leaks need to be detected.
For practical selection, products such as Gas-Pro PID, Gas-Pro IR, IRmax, Xgard and LaserMethane Smart can be suitable starting points. However, the concrete application always remains decisive: Which gas occurs where, at what concentration and under which environmental conditions?
FAQ: Frequently asked questions about gas detectors and sensor technologies
Which sensor technology is suitable for methane?
Depending on the application, pellistor sensors, infrared sensors or laser-based methane detectors can be considered for methane. Pellistors and infrared sensors are suitable for point monitoring, while laser devices are particularly suitable for non-contact leak detection.
Which sensor technology is suitable for CO₂?
CO₂ is typically monitored with infrared sensor technology. CO₂ absorbs infrared radiation, making NDIR sensors very well suited for many CO₂ applications.
What is a PID sensor?
A PID sensor is a photoionisation detector. It uses UV light to ionise certain volatile organic compounds. This makes it particularly suitable for many VOCs and solvent vapours.
What is a pellistor?
A pellistor is a catalytic sensor for flammable gases. The gas is burned on the sensor element, and the resulting temperature change is electrically evaluated. Pellistors typically measure in the range of the lower explosive limit.
When is an infrared gas detector useful?
An infrared gas detector is useful for CO₂ and many hydrocarbons such as methane, propane or butane. It does not require oxygen for the measuring principle and is less susceptible to certain types of sensor poisoning than pellistors.
Can an infrared sensor measure hydrogen?
Standard infrared sensors for hydrocarbons are generally not suitable for hydrogen because hydrogen is not infrared-active. Other sensor technologies are required for hydrogen.
Which sensors are suitable for toxic gases?
Electrochemical sensors are used for many toxic gases, for example CO, H₂S, NO₂, SO₂, Cl₂ or NH₃. The specific selection depends on the target gas, measuring range and environment.
Which gas detector is suitable for VOCs?
PID devices are often suitable for VOCs, for example a Gas-Pro PID. It is important to note that PID sensors often provide a summed signal from many ionisable VOCs and do not automatically measure a single substance selectively.
How do you select a gas detector for refrigerants?
For refrigerants, the exact refrigerant must first be known. CO₂, ammonia, propane, isobutane, HFO and HFC can require different sensor technologies. Room size, ventilation, installation location and alarm concept are also important.
What does cross-sensitivity mean?
Cross-sensitivity means that a sensor also reacts to other gases or vapours besides the target gas. This can lead to false alarms or incorrect evaluation, but in some broadband monitoring tasks it may also be deliberately accepted.
How often does a gas detector need to be calibrated?
This depends on the device, sensor, application, manufacturer’s specifications and internal safety requirements. Safety-relevant gas detectors should be tested regularly with test gas and calibrated at defined intervals.
What is the difference between a portable gas detector and a fixed gas detector?
Portable gas detectors protect people during changing assignments, inspections or clearance measurements. Fixed gas detectors continuously monitor defined areas and can be connected to alarm devices, ventilation or shutdown systems.
Which products are suitable for methane, CO₂, VOCs and fixed gas monitoring?
Depending on the application, Gas-Pro PID for VOCs, Gas-Pro IR for CO₂ applications, IRmax for hydrocarbons, Xgard for fixed gas monitoring and LaserMethane Smart for non-contact remote methane detection may be suitable.