Our Partnership with Guardsman 

Background

Guardsman Ltd. are one of the leading suppliers of Personal Protective Equipment and Workwear in the UK, based centrally in Leicester with their Sales and Distribution Centre. Guardsman have been a part of Bunzl PLC, a global £9.2 billion FTSE 100 company, who specialise in the supply of Personal Protection Equipment (PPE), Cleaning and Hygiene Supplies and Contractors’ Site Equipment, for 9 years. Although Guardsman has been supplying safety equipment, workwear and PPE to major industrial customers and utilities for over 45 years. During this time, they have followed their simple philosophy “To provide the correct protection at a competitive price, through friendly and efficient staff with flexible supply arrangements.” throughout this time they have built a substantial portfolio of blue-chip clients across all sectors of industry, where they now supply to 27 countries across 5 continents. Guardsman’s customers are striving for excellence in their fields and expect to receive excellence from Guardsman as a supplier.  

Views on Gas Detection  

With the Personal Protective Equipment at Work Regulations 2022 scheduled for amendment with the 1992 Regulations being extended to employers’ and employees’ duties in respect of PPE to a wider group of workers. These changes will mean that employers will now have duty to concern the provision and use of personal protective equipment (PPE) at work.  

With these scheduled changes leading to a shift in who is responsible for workplace PPE, Guardsman have in response to this begun developing conversations with existing relationships in gas detection to identify the pains their customers may have and to allow the easiest way to provide correct equipment.  

Working with Crowcon  

Through continuous communication Crowcon will allow Guardsman to extend the safety they provide. Our partnership has also allowed for the enhanced understanding of gas detection and its importance in certain industries, all of which allow for Guardsman to provide gas detection products within the industries they provide, such as manufacture and automotive. “Our partnership with Crowcon now offers a solution to our customers that we were unable to offer previously, thereby enhance our specialism in providing PPE to existing and future customers.”   

Our Partnership with Frontline Safety

The Safety Distribution Industry has transformed a great deal in the last few years, as companies rely more on the use of the Internet to gather information about products, applications and pricing.

Background 

Founded in 2003 and headquartered in Glasgow, Frontline Safety is a global supplier of gas detection, environmental monitoring and occupational safety equipment. Frontline has over 30 years of experience in the service of gas detection systems, providing tailored support  working with individuals and organisations of varying degrees and sizes across various sectors, including oil and gas, energy, general process, chemical, pharmaceutical, and environmental.

Views on Gas Detection

Due to industrial environments having the possibility to house a range of gases for commercial production purposes, a variety of gas detectors may be required, including both portable, multi-gas detectors and fixed detectors, both being an essential part of health and safety requirements. Therefore, providing the most appropriate equipment and service that will meet both the needs of the customer and HSE requirements. 

Working with Crowcon

“As Gas detectors are at the forefront of Frontline Safety’s product offering, our partnership allows Frontline to provide the highest quality possible. Our Partnership with Crowcon allows us to give our customers access to a well-recognised brand. Their extensive gas detection range complements our existing product range and enables us to produce the required equipment to reduce injury to workers within the oil and gas, energy, general process, chemical, pharmaceutical, and environmental industries as well as helping the environment.” 

As a Crowcon partner, Frontline Safety UK is fully trained and authorised in the use, calibration, servicing, and repair of Crowcon equipment.

What is Purge Testing and when should I be doing it?

Purge testing is vital when installing, replacing or maintaining a natural gas pipeline or storage tank, or filling new pipework with flammable gas. This process uses an inert gas to clear the enclosed environment of flammable gases prior to air being introduced thereby preventing air and flammable gas mixing. Such mixtures could of course lead to explosive combustion.

What is Purge Testing? 

Purge testing is a key part of the process of making a working environment safe prior to entering it to carry out work. Analysis of the atmosphere in the pipe or enclosure shows the starting point – usually 100% flammable gas. Purge testing is the measurement and reporting of the atmosphere as an inert gas is introduced. As the flammable gas declines to a safe level well below concentrations that would be dangerous in air, the atmosphere is continually analysed, and the flammable gas concentration reported. Once a low concentration has been achieved, air may be introduced. During this phase the flammable gas concentration is analysed to check it remains low, and oxygen concentration is measured to indicate when the atmosphere becomes breathable. Work may then commence – all the while protected by the measurement of flammable gas and oxygen concentration. If, as is likely, the purge testing is being carried out via suction of atmosphere through a sample tube, then this sample tube must at all times and all along its length be held above the flash point of the flammable gas in the tank. This is vital to both your safety and the safety of those working with you.  

Purging removes or displaces hazardous gases from the tank or pipework to prevent them from mixing with the air you need to introduce into the tank to carry out the inspection or maintenance task. The most used and preferred purge gas is Nitrogen, due to its inert properties. After conducting the inspection or maintenance task the reverse process is carried out, reintroducing the inert gas and reducing the oxygen level to near zero prior to allowing natural gas to re-enter. Often a service valve on the line with a standpipe or diffuser attached is cracked to release the venting gas or nitrogen. Purging systems are generally designed to redirect additional gases away from the work area preventing them from remixing with the gas within the tank or pipework. 

Why Conventional Gas Detection isn’t enough 

Traditional gas detection systems are not designed to work in oxygen-deprived environments. This is because they are primarily designed as safety equipment with the specific purpose to detect small traces of target gases in otherwise normal breathable environments. Gas detection equipment designed for use in purge testing activities must be able to function in low oxygen environments and with all contaminants likely to be found in tanks and pipes being purge tested. If sensors can be poisoned by the contaminants present or if there isn’t enough oxygen in the air to enable the selected sensor technology to be used, it may lead to the sensors on the device producing inaccurate results, posing a threat to those working within that environment. An additional point to note to note is that certain gas combinations, concentrations and corrosive liquids may damage the gas detection equipment, rendering it useless. For these reasons, Infrared technology or thermal conductivity is usually chosen as the measurement technology of choice for purge tests. Crowcon uses infrared technology in these applications. A fortunate by-product of that design decision is better accuracy than required over the full sensing range. 

More about Purge testing 

Purge Testing is essential for workers as some may be breathing in toxic gases without even realising it if the sensors on their detection equipment have become defective, don’t measure the required gas type or don’t measure over the required gas range, or environmental range present. Toxic or asphyxiant gas exposure can lead to respiratory issues, significant injury, even death. 

Workers cannot merely rely on a standard confined space gas detection instrument to adequately test for safe conditions during this process, as the high gas level may overwhelm or damage an LEL (Lower Explosive Limit) sensor depending upon type. Or the sensor may not function in an oxygen-depleted atmosphere leading to an unreported dangerous condition. 

What products do we offer? 

Our Gas-Pro TK is a specialised tank monitor that is perfect for customers who want to purge, free, or maintain storage and transportation tanks due to its integrated auto switching dual range IR sensor technology. Other sensors in the product, for example the H2S (Hydrogen Sulphide) sensor option cover other potential risks if gases vent during purging. 

The Future of Connected Safety

Connected safety is becoming a popular phrase in health and safety settings generally, and gas detection in particular. That’s a good thing – because it’s no overstatement to describe connected safety as an evolutionary step in gas monitoring and protection, and it’s a field that is developing all the time.

In this post we’ll establish exactly what connected safety means for anyone monitoring gas hazards, and find out why it pays to take note of developments in this area.

What is Connected Safety?

In gas monitoring terms, connected safety refers to using the internet of things (IoT) to connect gas detection devices (for example, portable gas monitors) to software that pulls the gas exposure information and other data stored on the detector (the identity of the user for any given session, the extent to which the device was used correctly, etc.), analyses it and presents it in useful forms.

By wirelessly connecting each gas monitor – and the data it collects during each work session – to a specialist software package, you can spot patterns of gas exposure, patterns of use and misuse of detectors and automatically store all of the information you need to quickly prove regulatory and legal compliance.

When this information is scaled up across entire device fleets, naturally the data it produces also scales up and can be aggregated. And if that data is acted upon, it can improve safety across your business and drive better, more informed decisions.

That is, in a nutshell, how our Crowcon Connect solution works.

How does Crowcon Connect work for Connected Safety?

Crowcon Connect is Crowcon’s own software, which works with all current (manufactured from 2004 onwards) and future Crowcon portable gas detectors. Because we own and develop the software, we are constantly upgrading it in light of customer feedback and can make customised versions where required (although it’s also really easy for users to configure the standard dashboard to suit their own needs).

Quick User Assignment easily links devices, events and people

For each work session, anyone who needs a portable detector simply scans in their ID (for example, their work ID badge) and is allocated a device. If they don’t like that device (for example, if it’s not suitable for the job in hand) they can simply re-scan their badge to be assigned another detector.

When the user returns the detector to its dock at the end of the work session, the dock transfers the data to the Crowcon Connect portal while simultaneously un-allocating the device, ready for the next user.

The data transferred to the portal includes details of the user and the device, exposure and alarm information and a full range of gas data. Once that data reaches the portal, Crowcon Connect can crunch the numbers and work its magic.

Connected Safety streamlines processes, improves outcomes

The Crowcon Connect user interface is very intuitive and easy to customise, which means every user can see precisely the information that matters to them, whenever and wherever they need it.

For example, it becomes very straightforward to prove regulatory compliance when real-time data is available, and easy to spot potentially dangerous areas when alarm data begins to cluster. Mundane tasks – such as flagging those detectors that are due for calibration and/or maintenance – can be automated, which saves time and reduces the risk of human error.

Of course you can also aggregate fleet-wide, site-wide and/or team-wide data, which lets you to spot patterns (for example, of exposure events or device losses) and make relevant changes. This helps you to improve your site and workforce safety, and you can always locate detectors (and any workers attached to them) in real time.

Is Connected Safety the way of the future?

In a word, yes. We live in a data-driven world and the use of information is driving improvements in all sectors, gas detection included. Our increasing (and increasingly widespread) reliance on technology is only going to amplify that.

After all, data can do much to offset the shortcomings of human management. Data is objective, not driven by assumptions or bias, and gives an honest reflection of what is actually happening in the field, rather than what is intended to happen. If you’ve ever worn a fitness tracker for a while, you’ll get this idea!

However, data analytics are only useful if they are based on top quality, current information – and that’s where connected safety comes in. Connected safety applications collect information accurately and in real time. If you manage gas monitoring, with data straight from the device you will be operating on the basis of objective, trustworthy information. What is more, you can use that information to make people safer – and even save lives.

We’ll be sharing some more posts about connected safety in the coming weeks, so please come back to this page for those. In the meantime, why not have a look at our white paper on connected safety for more detailed information, or check out our Crowcon Connect pages?

Why HVAC professionals are at risk from Carbon Monoxide – and how to manage it

Carbon Monoxide (CO) is an odourless, colourless and tasteless gas that is also highly toxic and potentially flammable (at higher levels: 10.9% Volume or 109,000ppm). It is produced by the incomplete combustion of fossil fuels such as wood, oil, coal, paraffin, LPG, petrol and natural gas. Many HVAC systems and units burn fossil fuels, so it’s not hard to see why HVAC professionals may be exposed to CO in their work. Perhaps you have, in the past, felt dizzy or nauseous, or had a headache during or after a job? In this blog post, we’ll look at CO and its effects, and consider how the risks can be managed.

How is CO generated?

As we have seen, CO is produced by incomplete combustion of fossil fuels. This generally happens where there is a general lack of maintenance, insufficient air – or the air is of insufficient quality – to allow complete combustion.

For example, the efficient combustion of natural gas generates carbon dioxide and water vapour. But if there is inadequate air where that combustion takes place, or if the air used for combustion becomes vitiated, combustion fails and produces soot and CO. If there is water vapour in the atmosphere, this can reduce the oxygen level still further and speed up CO production.

What are the dangers of CO?

Normally, the human body uses haemoglobin to transport oxygen via the bloodstream. However, it is easier for the haemoglobin to absorb and circulate CO than oxygen. Consequently, when there is CO around, danger arises because the body’s haemoglobin ‘prefers’ CO over oxygen. When the haemoglobin absorbs CO in this way, it becomes saturated with CO, which is promptly and efficiently transported to all parts of the body in the form of carboxyhaemoglobin.

This can cause a range of physical problems, depending on how much CO is in the air. For example:

200 parts per million (ppm) can cause headache in 2–3 hours.
400 ppm can cause headache and nausea in 1–2 hours, life threatening within 3 hours.
800 ppm can cause seizures, severe headaches and vomiting in under an hour, unconsciousness within 2 hours.
1,500 ppm can cause dizziness, nausea, and unconsciousness in under 20 minutes; death within 1 hour.
6,400 ppm can cause unconsciousness after two to three breaths; death within 15 minutes.

Why are HVAC workers at risk?

Some of the most common events in HVAC settings may lead to CO exposure, for example:

Working in confined spaces, such as basements or lofts.
Working on heating appliances that are malfunctioning, in a poor state of repair, and/or have broken or worn seals; blocked, cracked or collapsed flues and chimneys; allowing products of combustion to enter the working area.
Working on open-flued appliances, especially if the flue is spilling, ventilation is poor and/or the chimney is blocked.
Working on flue-less gas fires and/or cookers, especially where the room volume is of inadequate size and/or the ventilation is otherwise poor.

How much is too much?

The Health and Safety Executive (HSE) publishes a list of workplace exposure limits for many toxic substances, including CO. You can download the latest version free of charge from their website at www.hse.gov.uk/pubns/books/eh40.htm but at time of writing (November 2021) the limits for CO are:

Workplace Exposure Limit

Gas Formula CAS Number Long Term Exposure Limit
(8-hr TWA Reference Period)
Short Term Exposure Limit
(15-min Reference period)
Carbon monoxide CO 630-08-0 20ppm (parts per million) 100ppm (parts per million)

How can I stay safe and prove compliance?

The best way to protect yourself from the hazards of CO is be wearing a high quality, portable CO gas detector. Crowcon’s Clip for CO is a lightweight 93g personal gas detector that sounds at 90db alarm whenever the wearing is being exposed to 30 and 100 ppm CO. The Clip CO is a disposable portable gas detector that has a 2-year lifespan or a maximum of 2900 alarm minutes; whichever is sooner.

What are Area Monitors and how do I use one?

Outdoor leaks from storage tanks or pipelines are a particular kind of hazard. With many outdoor areas not housing permanent, fixed detectors. If you’re relying solely on a personal monitor, by the time it alarms, there is a possibility that you may be engulfed in a hazardous gas cloud. Therefore, a temporary early warning system between you and the potential source of a gas hazard has the ability to alert you to trouble coming your way.

What are Area monitors and where would they be used? 

Temporary Area monitors are usually rugged units that can be placed, stand-alone to monitor a small area or multiple units can be linked together via wired or wireless networking to create a perimeter defence of a larger area. Area Monitor devices help safety personnel protect their workers from gas hazards in situations, in addition to—or sometimes in substitution of—personal, portable gas monitors used as Personal Protective Equipment (PPE). Area monitors can be positioned to produce a guard between potential hazards and workers, to notify what they are heading into or what potential hazards are coming their way.  This occurs most often when work takes place outside of normal operations where the risks are higher and/or different such as special projects, construction, maintenance, shutdowns, temporary sites or rigs, etc. In this way, they can be used to form a barrier around a tank or along a portion of pipeline close to the location of work being carried out. Portable units can be easily deployed to provide fence line monitoring during maintenance, shutdowns or turnaround. The objective is to ensure that the devices are not so far apart that gas could pass between them undetected.  If a fixed system is being taken offline for maintenance a network of fast to deploy temporary area monitors is an ideal option to use in place of the fixed system until maintenance is complete and the system is brought back online. 

How do you use one? 

Units can be connected by cables. However wireless connection between individual area monitors is also available and avoids introducing a potential trip hazard. This could add significantly to an already risky task, for example, if working at height. Some wireless systems create a “self-healing” mesh network. In this case, should the wireless connection between two devices weaken, the network will automatically re-route communications via alternate enabled devices, creating a mesh type network allowing a more robust and efficient wireless network. 

The benefit from a wireless connection is that it is practical to use repeaters or extra units to relay alerts directly to the control room. Besides the gas alert signals, some detectors will transmit other faults i.e., the loss of signal, or “battery low” alarm. This programmed alert mode is often conveyed by a specific sequence of signals, such as the beacon and lights will flash for 3 seconds followed by 5 second pause which will be repeated until an operator acknowledges the alarm. 

Wireless temporary area monitoring allows for quick deployment whilst ensuring a high level of protection for workers in circumstances where the risks are tricky to monitor. Personnel working at height can be alerted to any gas hazards on the ground, or vice versa and the same alarm can be relayed to the control room by having an additional detector in the control room. The audible alarm is significantly louder than a standard portable and light sequence is brighter and flashes faster on the Detective+ unit when gas is detected. , whilst the sequence on other units in the network is slower. This differentiates the unit nearest the gas from the rest, so everyone is alerted to the location of the hazard. In contrary, to the benefits of this products, the configuration tends to be straightforward without additional hardware. The batteries in Detective+ are larger and last longer than conventional portables. All in all, these units offer a simple yet effective solution for protecting workers outside of normal operations. 

Crowcon’s Detective+ is ideal for temporary area monitoring while workers carry out a repair. Detective+ is portable and can be easily deployed to provide fence line monitoring during shutdowns or turnaround. If working on a cooling tower fin fan, Detective+ units are connected to other units (up to 70m away) via Detective Wireless modules, which eliminate the need for cabling between units. Detective Wireless uses the proven RICOCHET mesh network. In the unusual circumstance that the wireless connection between two devices weaken, the network will automatically re-route communications via alternate RICOCHET enabled devices and so ‘self-heal’. In essence, this creates a mesh type network allowing a more robust and efficient wireless network.

Read more about Area Monitoring  

What do you need to know about Hydrogen?

Hydrogen is one of the most abundant sources of gas contributing approximately 75% of the gas on our Earth. Hydrogen is found in various things including light, water, air, plants, and animals, however, is often combined with other chemicals, the most familiar combination is with oxygen to make water.

What is Hydrogen and what are its benefits?

Historically, Hydrogen Gas has been used as a component for rocket fuel as well as in gas turbines to produce electricity or to burn to run combustion engines for the power generation. In the Oil and Gas Industry, excess hydrogen from the catalytic reforming of naphtha has been used as fuel for other unit operations.

Hydrogen Gas is a colourless, odourless, and tasteless gas which is lighter than air. As it is lighter than air this means it float higher than our atmosphere, meaning it is not naturally found, but instead must be created. This is done by separating it from other elements and collecting the vapour. Electrolysis is completed by taking liquid usually water and separating this from the chemicals found within it. In water the hydrogen and oxygen molecules separate leaving two bonds of hydrogen and one bond of oxygen. The hydrogen atoms form a gas which is captured and stored until required, the oxygen atoms are released into the air as there is no further use. The hydrogen gas that is produced leaves no damaging impact on the environment, leading to many experts believing this is the future.

Why Hydrogen is seen as a cleaner future.

In order to make energy a fuel that is a chemical is burnt. This process usually means chemical bonds are broken and combined with oxygen. Traditionally, Methane gas has been the natural gas of choice with 85% of homes and 40% of the UK’s electricity depending on gas. Methane was seen as a cleaner gas compared to coal, however, when its burnt carbon dioxide is produced as a waste product thereby contributing to climate change. Hydrogen Gas when burnt only produces water vapour as a waste product, this being already a natural resource.

The difference between blue hydrogen and green hydrogen.

Blue hydrogen is produced from non-renewable energy sources, through two methods either Steam or Autothermal. Steam Methane reformation is the most common when producing hydrogen in bulk. This method uses a reformer which produces steam at a high temperature and pressure and is combined with methane and a nickel catalyst to produce hydrogen and carbon monoxide. Autothermal reforming uses the same process however, with oxygen and carbon dioxide. Both methods produce carbon as a by-product.

Green hydrogen is produced using electricity to power an electrolyser that separates hydrogen from the water molecule producing oxygen as a by-product. It also allows for excess electricity to electrolysis to create hydrogen gas that can be stored for the future.

The characteristics that hydrogen presents, has set a precedence for the future of energy. The UK Government have seen this a way forward for a greener way of living and have set a target for a thriving hydrogen economy by 2030. Whilst Japan, South Korea and China are on course to make significant progress in hydrogen development with targets set to match the UK for 2030. Similarly, the European Commission have presented a hydrogen strategy in which hydrogen could provide for 24% of the world’s energy by 2050.

What’s the difference between a pellistor and an IR sensor?

Sensors play a key role when it comes to monitoring flammable gases and vapours. Environment, response time and temperature range are just some of the things to consider when deciding which technology is best.

In this blog, we’re highlighting the differences between pellistor (catalytic) sensors and infrared (IR) sensors, why there are pros and cons to both technologies, and how to know which is best to suit different environments.

Pellistor sensor

A pellistor gas sensor is a device used to detect combustible gases or vapours that fall within the explosive range to warn of rising gas levels. The sensor is a coil of platinum wire with a catalyst inserted inside to form a small active bead which lowers the temperature at which gas ignites around it. When a combustible gas is present the temperature and resistance of the bead increases in relation to the resistance of the inert reference bead. The difference in resistance can be measured, allowing measurement of gas present. Because of the catalysts and beads, a pellistor sensor is also known as a catalytic or catalytic bead sensor.

Originally created in the 1960’s by British scientist and inventor, Alan Baker, pellistor sensors were initially designed as a solution to the long-running flame safety lamp and canary techniques. More recently, the devices are used in industrial and underground applications such as mines or tunnelling, oil refineries and oil rigs.

Pellistor sensors are relatively lower in cost due to differences in the level of technology in comparison to IR sensors, however they may be required to be replaced more frequently.

With a linear output corresponding to the gas concentration, correction factors can be used to calculate the approximate response of pellistors to other flammable gases, which can make pellistors a good choice when there are multiple flammable vapours present.

Not only this but pellistors within fixed detectors with mV bridge outputs such as the Xgard type 3 are highly suited to areas that are hard to reach as calibration adjustments can take place at the local control panel.

On the other hand, pellistors struggle in environments where there is low or little oxygen, as the combustion process by which they work, requires oxygen. For this reason, confined space instruments which contain catalytic pellistor type LEL sensors often include a sensor for measuring oxygen.

In environments where compounds contain silicon, lead, sulphur and phosphates the sensor is susceptible to poisoning (irreversible loss of sensitivity) or inhibition (reversible loss of sensitivity), which can be a hazard to people in the workplace.

If exposed to high gas concentrations, pellistor sensors can be damaged. In such situations, pellistors do not ‘fail safe’, meaning no notification is given when an instrument fault is detected. Any fault can only be identified through bump testing prior to each use to ensure that performance is not being degraded.

 

IR sensor

Infrared sensor technology is based on the principle that Infrared (IR) light of a particular wavelength will be absorbed by the target gas. Typically there are two emitters within a sensor generating beams of IR light: a measurement beam with a wavelength that will be absorbed by the target gas, and a reference beam which will not be absorbed. Each beam is of equal intensity and is deflected by a mirror inside the sensor onto a photo-receiver. The resulting difference in intensity, between the reference and measurement beam, in the presence of the target gas is used to measure the concentration of gas present.

In many cases, infrared (IR) sensor technology can have a number of advantages over pellistors or be more reliable in areas where pellistor-based sensor performance can be impaired- including low oxygen and inert environments. Just the beam of infrared interacts with the surrounding gas molecules, giving the sensor the advantage of not facing the threat of poisoning or inhibition.

IR technology provides fail-safe testing. This means that if the infrared beam was to fail, the user would be notified of this fault.

Gas-Pro TK uses a dual IR sensor – the best technology for the specialist environments where standard gas detectors just won’t work, whether tank purging or gas freeing.

An example of one of our IR based detectors is the Crowcon Gas-Pro IR, ideal for the oil and gas industry, with the availability to detect methane, pentane or propane in potentially explosive, low oxygen environments where pellistor sensors may struggle. We also use a dual range %LEL and %Volume sensor in our Gas-Pro TK, which is suitable for measuring and switching between both measurements so it’s always safely operating to the correct parameter.

However, IR sensors aren’t all perfect as they only have a linear output to target gas; the response of an IR sensor to other flammable vapours then the target gas will be non-linear.

Like pellistors are susceptible to poisoning, IR sensors are susceptible to severe mechanical and thermal shock and also strongly affected by gross pressure changes. Additionally, infrared sensors cannot be used to detect Hydrogen gas, therefore we suggest using pellistors or electromechanical sensors in this circumstance.

The prime objective for safety is to select the best detection technology to minimise hazards in the workplace. We hope that by clearly identifying the differences between these two sensors we can raise awareness on how various industrial and hazardous environments can remain safe.

For further guidance on pellistor and IR sensors, you can download our whitepaper which includes illustrations and diagrams to help determine the best technology for your application.

You won’t find Crowcon sensors sleeping on the job

MOS (metal oxide semiconductor) sensors have been seen as one of the most recent solutions for tackling detection of hydrogen sulphide (H2S) in fluctuating temperatures from up to 50°C down to the mid-twenties, as well as humid climates such as the Middle East.

However, users and gas detection professionals have realised MOS sensors are not the most reliable detection technology. This blog covers why this technology can prove difficult to maintain and what issues users can face.

One of the major drawbacks of the technology is the liability of the sensor “going to sleep” when it doesn’t encounter gas for a period of time. Of course, this is a huge safety risk for workers in the area… no-one wants to face a gas detector that ultimately doesn’t detect gas.

MOS sensors require a heater to equalise, enabling them to produce a consistent reading. However, when initially switched on, the heater takes time to warm up, causing a significant delay between turning on the sensors and it responding to hazardous gas. MOS manufacturers therefore recommend users to allow the sensor to equilibrate for 24-48 hours before calibration. Some users may find this a hinderance for production, as well as extended time for servicing and maintenance.

The heater delay isn’t the only problem. It uses a lot of power which poses an additional issue of dramatic changes of temperature in the DC power cable, causing changes in voltage as the detector head and inaccuracies in gas level reading. 

As its metal oxide semiconductor name suggests, the sensors are based around semiconductors which are recognised to drift with changes in humidity- something that is not ideal for the humid Middle Eastern climate. In other industries, semiconductors are often encased in epoxy resin to avoid this, however in a gas sensor this coating would the gas detection mechanism as the gas couldn’t reach the semiconductor. The device is also open to the acidic environment created by the local sand in the Middle East, effecting conductivity and accuracy of gas read-out.

Another significant safety implication of a MOS sensor is that with output at near-zero levels of H2S can be false alarms. Often the sensor is used with a level of “zero suppression” at the control panel. This means that the control panel may show a zero read-out for some time after levels of H2S have begun to rise. This late registering of low-level gas presence can then delay the warning of a serious gas leak, opportunity for evacuation and the extreme risk of lives.

MOS sensors excel in reacting quickly to H2S, therefore the need for a sinter counteracts this benefit. Due to H2S being a “sticky” gas, it is able to be adsorbed onto surfaces including those of sinters, in result slowing down the rate at which gas reaches the detection surface.

To tackle the drawbacks of MOS sensors, we’ve revisited and improved on the electrochemical technology with our new High Temperature (HT) H2S sensor for XgardIQ. The new developments of our sensor allow operation of up to 70°C at 0-95%rh- a significant difference against other manufacturers claiming detection of up to 60°C, especially under the harsh Middle Eastern environments.

Our new HT H2S sensor has been proven to be a reliable and resilient solution for the detection of H2S at high temperatures- a solution that doesn’t fall asleep on the job!

Click here for more information on our new High Temperature (HT) H2S sensor for XgardIQ.

An ingenious solution to the problem of high temperature H2S

Due to extreme heat in the Middle East climbing up to 50°C in the height of summer, the necessity for reliable gas detection is critical. In this blog, we’re focusing on the requirement for detection of hydrogen sulphide (H2S)- a long running challenge for the Middle East’s gas detection industry.

By combining a new trick with old technology, we’ve got the answer to reliable gas detection for environments in the harsh Middle Eastern climate. Our new High Temperature (HT) H2S sensor for XgardIQ has been revisited and improved by our team of Crowcon experts by using a combination of two ingenious adaptations to its original design.

In traditional H2S sensors, detection is based on electrochemical technology, where electrodes are used to detect changes induced in an electrolyte by the presence of the target gas. However, high temperatures combined with low humidity causes the electrolyte to dry out, impairing sensor performance so that the sensor has to be replaced regularly; meaning high replacement costs, time and efforts.

Making the new sensor so advanced from its predecessor is its ability to retain the moisture levels within the sensor, preventing evaporation even in high temperature climates. The updated sensor is based on electrolytic gel, adapted to make it more hygroscopic and avoiding dehydration for longer.

As well as this, the pore in the sensor housing has been reduced, limiting the moisture from escaping. This chart indicated weight loss which is indicative of moisture loss. When stored at 55°C or 65°C for a year just 3% of weight is lost. Another typical sensor would lose 50% of its weight in 100 days in the same conditions.

For optimal leak detection, our remarkable new sensor also features an optional remote sensor housing, while the transmitter’s displays screen and push-button controls are positioned for safe and easy access for operators up to 15metres away.

 

The results of our new HT H2S sensor for XgardIQ speak for themselves, with an operating environment of up to 70°C at 0-95%rh, as well featuring a 0-200ppm and T90 response time of less than 30 seconds. Unlike other sensors for detecting H2S, it offers a life expectancy of over 24 months, even in tough climates like the Middle East.

The answer to the Middle East’s gas detection challenges fall in the hands of our new sensor, providing its users with cost-effective and reliable performance.

Click here for more information about the Crowcon HT H2S sensor.