There are three conditions that are required for a fire or explosion: a fuel (or combustible gas), oxygen, and an ignition source. When those three conditions are present at the same time and at a certain ratio, flames and smoke will follow. With an LEL gas sensor, you can ensure that the ratio of combustible gases stays below a certain threshold so that you can respond quickly to even the smallest leak.

GDS Corp is proud to offer a number of gas sensor products for you to choose from. Take a look at the details of each sensor and find the one that works best for your application.

GDS-48

the GDS-48 Remote Sensor is compatible with all GDS Corp detection systems. Features include:

• Designed to reduce voltage and interface circuitry within GDS Corp controllers to provide the lowest cost per point
• Field-replaceable catalytic bead LEL, infrared & PID sensors modules
• Standard stainless steel sensor housing
• Easy interface to GASMAX II monitors and C1, C2, C2 Quad, and C64 Protector series controllers

GDS-50

As a three-wire 4-20mA remote sensor transmitter, the GDS-50 is designed to detect combustible gases and is compatible with all of GDS Corp’s controllers and monitoring systems. Features include:

• Designed for Class I Division 1 Hazardous Locations
• Interchangeable infrared sensors for CO2 and hydrocarbons
• No voltage or balance adjustments during setup or operation
• Field-replaceable sensor module for easy maintenance
• SmartIR sensor fully temperature compensated from -20°C to +50°C
• Extended temperature version for Methane and Propane available for -40°C to +65°C
• Stainless steel sensor enclosure for high noise immunity

GDS-IR Remote Combustible Sensor

Designed specifically for harsh industrial settings, the GDS-IR Remote Combustible Sensor uses infrared sensing technology to detect dangerous or explosive gas levels. Features include:

• CSA Certified for Class I, Div 1 explosion-proof installations
• A straight-line optical path eliminates the need for mirrors
• Suitable for use in SIL-2 rated safety systems
• High-speed response for critical applications (T50 less than 3 sec)
• Rugged stainless steel construction with no moving parts
• The heated optical chamber maintains accuracy in cold conditions
• Operates in constant hydrocarbon and anaerobic atmospheres
• Ten discrete fault indication values for all failure states
• Routine span calibration not required for normal operation
• Random power-up delay reduces the initial load on the power supply

Reliable LEL Gas Detection

Do you have a dependable way to monitor the hazardous gases in your facility? Analyzing your set of needs and finding a solution that will maximize your safety is our specialty. We’ll consider which gases you regularly work with, what type of LEL gas sensor is suitable, and how you can start implementing gas monitoring as soon as possible. 

Get in touch with our team for more information about our different types of gas detection systems.

Understanding LEL Gas & LEL Gas Detectors

Combustible gases like methane, butane, hydrogen, and carbon monoxide pose a safety risk to both workers and environments if not properly monitored. One way to guard against the risk of explosion or fire is to have an LEL gas detector calibrated to the specific gas in the vicinity. If you are unfamiliar with LEL gas detection and how it affects your safety program, get answers from our most frequently asked LEL gas questions.

1) What does LEL stand for?

LEL is short for the lower explosive limit of a specific combustible gas. To put it simply, it is the lowest concentration of a specific gas that it would take for that gas to ignite under the right conditions. Alternatively, the upper explosive limit (UEL) of a specific gas is the maximum amount of gas in the air that it would take to burn. If a specific gas goes over the UEL range, it is considered too rich to burn and will not combust due to a lack of oxygen

2) How is the LEL of gas measured?

The LEL of a gas is measured as a percentage of volume. If you’re using an LEL gas detector, the display will show a 0-100% LEL readout. For example, hydrogen gas has an LEL of 4% by volume in the air. When the volume of hydrogen gas has reached the point of 2% by volume, then the detector will read 50% LEL. If the amount of hydrogen gas continues to rise to 4% by volume, the gas detector will reach 100% LEL.

3) What are safe LEL levels?

While it depends on the target gas that you’re monitoring in your environment, most LEL gas detectors are configured to signal an alarm between 10-20% LEL. It’s best to set alarm points as conservatively as possible to allow enough response time to make necessary decisions to mitigate potential problems.

4) How do LEL sensors work?

One of the most common types of LEL gas sensors is a catalytic bead sensor. It monitors gas concentrations through a process known as catalytic oxidation. By heating up combustible gases through an active bead, the gases create a higher temperature on the bead. This increase in temperature is then compared against a reference bead which does not change in temperature. Depending on the specific gases in the atmosphere, the gas detector, which is configured with a catalytic bead sensor, will increase signal output, activate relays, and/or send digital information. 

5) What features should an LEL gas detector have?

When it comes to choosing an LEL detector for your facility, there are two considerations to keep in mind.

• Is it reliable for your application? – The detector needs to be designed to the highest standard of operation. The detector has to offer peace of mind that it will perform and the facility will be protected. The detector needs to detect the target gas(es) all the time, even in the harshest environments.
• Will it save time and money for the user?? – Detector operation and reliability is one thing however useful features are just as important. Gas detectors should provide sensor life indication, data-logging, and lower the total cost of ownership.  

A Reliable Way to Monitor LEL Levels

GDS Corp is proud to offer a number of different LEL gas detectors that can be configured for a range of gases. It is our goal to provide you with the equipment necessary to keep your employees and equipment safe.

Get in touch with us to design a customized solution for safeguarding your environment.

If you work around sources of gas that are flammable or combustible, you may have noticed the term LEL, a term that is short for Lower Explosive Limit. If there is a risk that hazardous levels of flammable or combustible gas may be present, safety and insurance conditions may require a fixed gas detection system. Thus, in the unfortunate event that a leak was to occur, you can be sure that you have the resources necessary to take quick action 

Defining Lower Explosive Limits (LEL)

What is LEL, you may ask? LEL stands for “Lower Explosive Limit” and is the lowest concentration of a particular gas that has the potential to be flammable or combustible. In other words, it’s the minimum amount of gas that will catch fire or explode when an ignition source is present. If a gas concentration is less than the lower limit, there is insufficient gas for the mixture to ignite.

For example, methane or natural gas has a 5% by volume LEL and 17% by volume UEL. The upper limit is not important when considering the risk of explosion, but if the percent volume of methane present was 5% gas then the gas monitor would display 100% LEL. 

LEL & Gas Detection Systems

When you consider LEL gas detection, the goal is to monitor gases and turn on alarms when they pass the LEL limit to reduce accidents. Fixed LEL gas detectors are permanently installed in a facility and monitor the atmosphere for combustible gases 24 hours per day, seven days per week. This is very important, as dangerous leaks or spills may go unnoticed during nights or weekends.

Fixed LEL detectors are typically installed close to sources of leaks, adjacent to air handler intake vents, or in the ceiling of an enclosed building or room. In most cases, fixed LEL monitors are connected to a central controller which can activate audible and visual alarms in the monitored area as well as in a centrally-located control room. The GASMAX II or GASMAX CX are examples of a fixed gas monitor or detector. 

Another type of LEL monitor is called a Sample Draw Monitor or Sample Draw Detector. This device uses a pump to pull a sample from a remote location and push it across the sensor. A sample draw monitor allows the gas detector to be mounted in an area that provides easy access and maintenance while sampling air inside confined spaces like paint cabinets or combustible gas storage rooms. The GDS-58NXP is an example of a sample draw monitor. 

LEL Gas Detectors You Can Trust

Whether in a refinery, petrochemical or wastewater plant, or perhaps a warehouse, it’s crucial to have a reliable gas detection system you can depend on. With nationally recognized hazardous area certifications, GDS Corp.  LEL gas detectors are guaranteed to safeguard your facility 

Connect with our engineers to design a system that properly monitors the LEL gases in your facility.

Also known as Lower Explosive Limit detectors, these monitors play a key role in keeping employees and facilities safe from disaster. To learn more about these systems, here are some reasons to consider installing LEL monitors.

Real-Time Data

When a gas leak occurs, time is of the essence. Having the ability to monitor real-time data can make the difference between averting disaster or having a catastrophic event occur. To accomplish this, most LEL gas detectors are connected to centralized controllers, DCS systems  or wireless data networks. When connected properly, combustible detectors can provide a warning or alarm signal within 30 seconds of an event. If an even faster response is needed, high performance infrared detectors can often respond within three to five seconds. 

Confined Space Hazards

For many employees, much of their workday is spent in what are called confined spaces, where they install or repair equipment. However, these are some of the most hazardous areas of most industrial facilities and require very careful monitoring to ensure gas levels do not reach critical stages. To keep these areas safe, companies not only install LEL gas leak detectors within them, but also provide workers with portable LEL detectors. Employees can clip portable gas detectors to their belts or shirts and monitor gas levels during work.

Pro Tip: A confined space may require a safety permit to be considered usable. Check the criteria to see if yours qualifies.

Reliable Calibration Methods

For any LEL monitor to work effectively, it must be initially calibrated when installed and then re-calibrated every three to six months thereafter. Calibration should always be done using certified reference gas (“Cal gas”) that has not passed its expiration date. In most cases, the gas used should be identical to the expected target gas; for example, use Methane 50% LEL  for natural gas detectors for the greatest safety. If you are unsure as to which gas you might expect to see, there are calibration methods that will provide reliable warnings in all cases. Contact GDS Corp for more information on the calibration of LEL combustible gas monitors. 

Contact us and learn more about using gas detectors to promote workplace safety.

Because of this, companies have long used Lower Explosive Limit (LEL) gas leak detectors equipped with infrared technology. Infrared sensors are far more stable and reliable than traditional catalytic bead sensors. To gain a better understanding of how and why these sensors are better long term solutions, let’s take a closer look at the risks and rewards associated with infrared LEL meters.

Sensor Costs

Unlike catalytic bead sensors, infrared sensing elements require intelligent signal processing to generate a stable, linearized output. This means that each infrared sensor contains a dedicated microprocessor that performs multiple operations on the sensing elements signal that include analog-to-digital conversion, temperature compensation, response curve linearization and fault checking. While they are more expensive than simple cat-bead sensors, they are considered very good investments due to their stability over time and reduced need for calibration. As a result, they are far more likely to operate when needed and keep employees and multi-million dollar equipment and facilities safe.

Broad-spectrum Monitoring

Modern infrared combustible gas sensors can sense methane, propane, butane, methane, benzene, and many more combustible hydrocarbons.  However, note the importance of the word ‘hydrocarbon’. Infrared absorption sensors work by detecting a drop in infrared light levels due to the absorption of infrared light by the hydrogen-carbon bonds in combustible hydrocarbons. Combustible gases such as hydrogen that have no H-C bonds cannot be detected and so do require cat-bead sensors. Given this limitation, however, infrared detectors can be placed virtually anywhere in a facility to provide constant monitoring for hazardous conditions. 

Locating Sensors

Infrared combustible gas sensors do not have a ‘detection radius’ but rather respond to the presence of combustible gases in ambient air. To maximize the effectiveness of combustible gas detectors, they should be placed in areas where gases are most likely to be present – around valves or fittings, or next to air return ducts. If lighter-than-air combustible gases are a hazard, placing detectors in or near the ceiling will be beneficial; for heavier-than-air gases such as propane, placing sensors a few feet above the floor is recommended. 

Pro Tip: For fence perimeter monitoring, consider using an Open Path combustible gas detection system. While they use the same absorption principle as ambient detectors, they transmit long-range beams of infrared light between a separate transmitter and receiver.

Harsh Environments

LEL detectors are designed, certified, and tested to withstand the harshest work environments. From an industrial plant that has confined spaces with high humidity levels to an offshore drilling platform where high temperatures, vibration, and other factors may make some detectors unreliable, modern infrared LEL units are the ideal solution.  A quality LEL gas detector is a worthwhile investment for any facility with potentially hazardous conditions.

If you need to learn more about the risks and rewards associated with these sensors, check out our social media or get in touch with us today.

Gas detection systems that are designed to alarm when combustible gas is present use LEL Detectors based on catalytic bead or infrared absorption technology. These measure the amount of combustible gas on a scale of zero to one hundred percent (100%) of the Lower Explosive Limit, or “LEL” of the target gas. 

Combustible Gas Sensing

Often there is a choice of sensors that can be used to detect combustible gases. The two most common are Catalytic Beads and Infrared. Catalytic bead sensors detect the presence of any combustible gas by safely burning a small amount of the gas on a hot ceramic bead coated with a special catalyst. These sensors will detect any combustible gas, including hydrogen, but are subject to drift and poisoning. Poisoning can occur if certain substances containing silicon or similar compounds come in contact with the bead; if this happens, the compounds can coat the bead with an insulation layer that can keep the Catalytic Bead sensor from responding to a combustible gas. The only sure way to ensure the operation of a catalytic bead sensor is periodic calibration or bump tests where sensor response is measured when actual gas is applied to the sensor.

Infrared sensors use a completely different technique. These sensors measure the absorption of infrared light by hydrocarbon gases. Since they are microprocessor-based, they perform multiple self-checks to ensure correct operation without the need for bump tests. As with all sensors, they should be calibrated periodically to make sure they generate accurate readings. 

Multi-Alarm Capability

In sophisticated gas detection systems, the output of LEL detectors is generally combined into a single combustible gas alarm, either a strobe or horn, or both. This is very important in situations where the environment is noisy and where a simple display output is insufficient. In smaller systems, alarm horns and strobes can be directly attached to each gas detector to provide instant local warnings of hazardous conditions. 

Expandable Wireless Networks

With most facilities now adopting multiple wireless networks, today’s gas detection systems can be equipped with wireless LEL detection technology using ultra-low-power infrared sensors. Battery-powered wireless LEL detectors can be deployed around hot work sites, temporary buildings, and other areas where the installation of permanent detectors is unwarranted. 

State-of-the-Art Calibration

As part of normal maintenance, periodic calibration is extremely important in making sure your combustible gas detection system is fully functional and ready to provide that all-important early warning should hazardous conditions exist. Calibration procedures should be easy to follow and as automated as possible to eliminate human error. GDS Corp gas detectors include a user-prompted two-point calibration procedure that reduces errors and ensures that all calibration upper and lower performance limits are met. 

If you choose the proper sensor, keep up regular maintenance and perform periodic calibrations, you can be sure that your combustible gas detection system will be ready to protect your equipment and keep your employees safe when hazardous conditions occur. 

Ready to equip your worksite with reliable combustible gas detectors and improve your safety rating? Connect with us to get started.

Lower Explosive Limit detectors, commonly referred to as LEL monitors, play an important role in various industrial facilities throughout many industries. With many factors at play during the monitoring process, it becomes important to pay attention to details, as overlooking one important element of the monitoring process could result in tragedy.

LEL Detection Principles

An LEL gas detector is designed to detect the presence of combustible gases such as hydrogen or hydrocarbons like methane, propane, or gasoline fumes. Most common LEL detectors use either Catalytic Bead sensors or Infrared Absorption sensors. CatBead sensors, as they are commonly known, detect gas by burning a small amount of gas (carefully!) on a hot wire; the resulting heat changes the wire’s resistance and indicates the presence of gas. Infrared Absorption sensors detect combustible hydrocarbon gases using a frequency of infrared light that is absorbed by the hydrogen-carbon bonds in hydrocarbon gases.

Detection of Multiple Gases

When using an LEL gas detector, it is common to include a second sensor to detect oxygen depletion or toxic gases such as hydrogen sulfide or sulfur dioxide. Dual-channel detectors such as the GASMAX II and GASMAX CX make it easy to add a second local or remote sensor. 

Wireless Technology

Up to a few years ago, battery-powered wireless LEL detection was impractical given the amount of power required to operate an infrared sensor. Recent advances in sensor technology now allow battery-powered detectors to continuously monitor for explosive levels of combustible gas for more than six months. Information from the wireless sensor is transmitted to a central controller every five minutes, and more often if high levels of gas are detected. 

Pro Tip: LEL detectors can be programmed to send real-time reports and alerts to a website or manager’s smartphone. Get in touch with our expert team to find out how.

Calibration Methods

Of course, to ensure that the value shown on the monitor and recorded in the plant management system is accurate, LEL gas monitors must always be properly calibrated. Ignoring the need for calibration can lead to catastrophic results. To make sure this does not happen, many of today’s LEL gas detection devices are designed with electronics and software that simplify the calibration process and/or provide helpful reminders when calibration is due. 

Confined Space Monitoring

One of the most important areas to monitor are confined spaces where equipment malfunctions or leaks in pipes or valves can occur, resulting in a build-up of combustible gas. Sample draw monitors that incorporate integral sample pumps and low-flow warning devices can be mounted outside the confined space and continuously monitor the air inside the space for the presence of combustible or toxic gases, reducing the risk of explosion or injury in the event that a leak should occur. 

Connect with us to speak to an expert about LEL detectors in your business.

If there is a risk that hazardous levels of combustible gas may be present, safety and insurance conditions may require a fixed combustible gas detection system and/or portable gas detectors. Both types of products will help you monitor the combustible gas concentration in your facility and will provide early warning in the unfortunate event a leak were to occur. 

Defining LEL (Lower Explosive Limit)

What is LEL? LEL stands for “Lower Explosive Limit” and is the lowest percentage concentration of a particular gas that has the potential to be flammable. Most gases have a lower explosive limit (LEL) and an upper explosive limit (UEL). Below the lower limit, there is insufficient gas for the mixture to ignite. Above the upper limit, there is insufficient oxygen to support combustion.

For example, methane or natural gas has a 5% by volume LEL and 17% by volume UEL. The upper limit is not important when considering the risk of explosion, but if the percent volume of methane present was 5% gas (95% AIR) then the gas monitor would display 100% LEL. 

LEL Gas Detection Options

When trying to measure the LEL level inside a building or confined space, there are two different types of detectors: portable gas detectors and fixed gas detectors. 

Portable gas detectors are often issued to maintenance personnel and will emit a loud warning tone if combustible gas is present. This can give the wearer time to evacuate the area, but unless someone is present in an area, the presence of combustible gas will not be identified. 

Fixed LEL gas detectors are permanently installed in a facility and monitor the atmosphere for combustible gases 24 hours per day, seven days per week. This is very important, as dangerous leaks or spills may go unnoticed during nights or weekends.

Fixed LEL detectors are typically installed close to sources of leaks, adjacent to air handler return vents or in the ceiling of an enclosed building or room. In most cases, fixed LEL monitors are connected to a central controller that can sound warning tones or activate strobe lights in the monitored area as well as in a centrally-located control room. The GASMAX II or GASMAX CX are examples of a fixed gas monitor or detector. 

Another type of LEL monitor is called a Sample Draw Monitor or Sample Draw Detector. This device uses a pump to pull a sample from a remote location and push it across the sensor. A sample draw monitor allows the gas detector to be mounted in an area that provides easy access and maintenance while sampling air inside confined spaces like paint cabinets or combustible gas storage rooms. The GDS-58NXP is an example of a sample draw monitor. 

Pro Tip: Protect your facility from the risk of explosion by installing a fixed combustible gas detection system to reliably detect the flammable levels of your gas materials.

Install Gas Detection in Your Facility  

To abide by the local and federal regulations of storing combustible materials, it’s crucial to have a reliable gas detection system in your warehouse. With industry-grade accuracy and nationally recognized hazardous area certifications, our LEL gas monitors/detectors will keep your facility safe.

Does your industry store or work with combustible gases? Connect with our engineers to help you design and install a system to monitor for the presence combustible gases.

Electrochemical Technology

One of the most vital advancements in gas detection technology, electrochemical sensing is perhaps the biggest reason LEL sensors have gotten a reputation for accuracy and reliability in virtually any type of industrial setting. Whereas many types of earlier gas detectors relied on only one particular pathway to detect gases, an electrochemical LEL gas detector uses various pathways to quickly detect high levels of dangerous gases. Using both open path and sample draw detection, these LEL detectors can detect gas levels at much smaller amounts, allowing engineers to make the necessary changes in equipment before a situation becomes critical.

Alarm Systems

When potentially dangerous gas levels are detected, it’s vital those in the surrounding area be notified as quickly as possible. To accomplish this, an LEL gas leak detector is often equipped with multiple types of alarm systems, allowing it to be effective in many different work environments. For example, if the sensors are installed in a large area where noise may hinder a worker’s ability to hear sirens, they can instead look to warning lights or flashing strobes that change colors to alert them of nearby danger. Likewise, if the detectors are installed in areas where workers are spread out and may be unable to visually detect lights and strobes, sirens can be used very effectively as a warning system.

High-Tech Calibration

Needless to say, because these detectors are responsible for discovering very small amounts of potentially lethal gases, they must be properly calibrated to provide accurate and reliable results 24/7. To do so, they have been equipped with technology allowing them to be calibrated both on-site and from remote locations. If calibrated on-site, technicians use controlled amounts of gas to gauge the sensor’s effectiveness. However, if calibrated from a remote monitoring center, engineers use sophisticated computer programs to run simulations, allowing them to then calibrate the sensors.

Wireless Networks

To ensure monitoring is as effective as possible, today’s Lower Explosive Limit detectors use wireless networks to stay online day and night. By doing so, engineers can monitor data in real-time, and can add as many as 12 more sensors to an existing network if needed, giving them even greater monitoring flexibility. Not only can they monitor more areas with this technology, but also make quicker decisions should an emergency situation present itself that requires evacuations.

Electrochemical Gas Sensors

To learn how an LEL monitor works, it’s best to start by understanding how its sensors monitor for dangerous gas levels. Perhaps the biggest advantage these electrochemical toxic gas sensors offer is their ability to detect gases by way of both open paths or sample draws, enabling them to detect gases that are traveling in various pathways. By doing so, the LEL monitor has a much better chance of detecting gas levels that may just be approaching dangerous levels, rather than detecting them after they have already reached critical levels that could lead to fires or explosions.

Automatic Alarms

Along with being able to detect gas levels before they reach levels that lead to fires or explosions, LEL monitors are also equipped with an electrochemical gas sensor that can trigger automatic alarms when lower explosive limits reach percentage levels between 10-20 percent of the LEL. Able to provide greater protection to employees working in confined spaces or other hazardous areas, the alarms on the monitors are designed to sound once when gas levels near the critical stage, since this is a requirement of current federal regulations.

Accurate and Reliable Calibration

Because the environments in which LEL monitors are placed require careful and reliable monitoring to keep workers safe, they have also been designed to allow for easy calibration both on-site and from remote locations. By introducing a controlled amount of gas, the electrochemical sensor can then measure the gas and be properly calibrated. Once this is done, technicians can then create wireless connections between the LEL monitor and monitoring centers in other locations, enabling gas levels to be monitored 24/7 from different locations. Along with this, up to 12 additional sensors can be added to the monitor, letting it be used in virtually any type of work environment.

Data in Real-Time

Once a wireless connection is made, the LEL monitor is then able to transmit real-time data that on-site managers and technicians can access, as well as those monitoring the facility from an off-site monitoring center. Along with this, the sensors have displays showing concentration graphs updated in real-time, enabling safety engineers to make quick decisions if gas readings approach dangerous levels. No matter what type of workplace an LEL monitor is installed, there’s no doubt safety levels increase substantially.