During this challenging time, keeping your gas monitor clean is more important than ever to ensure you’re keeping yourself, and others, safe.
Cleaning your monitor
The following procedure and precautions should be noted if you intend to clean your Crowcon gas monitor to protect against COVID-19 transmission.
Gas monitors contain sensors that may be affected by the chemicals in cleaning compounds. In general Crowcon recommends cleaning with mild soap and a soft cloth taking care not to introduce excessive amounts of liquid into the product/sensors.
Alcohol-based cleaning products may cause a temporary response on some electrochemical sensors; potentially leading to false-alarms. It is recommended monitors are switched-off before cleaning and not switched back on until the alcohol has fully evaporated.
Cleaning agents that contain chlorine and/or silicones must be avoided, especially on monitors that contain pellistor-type flammable gas sensors as these compounds will ‘poison’ the sensor leading to permanent loss of sensitivity to gas.
Where gas monitor cleaning regimes are introduced or increased Crowcon strongly recommends that sensors are bump tested with the target gas periodically to ensure that sensors remain operational. Pellistor-type sensors in portable monitors should be tested every day before use as prescribed in the European standard EN60079-29 Part 1.
It is extremely likely that any viral agent could get trapped within the pump or filters within an instrument. Maintenance procedures should continue to be performed as described in the Operation and Maintenance Manual for the product and in-line with operating company policy.
For more information on how to keep you or your business safe during the COVID19 pandemic, get in touch and we’d be more than happy to help.
Given the critical nature of gas detectors, it is important to know they are working correctly at all times. Many factors can affect the performance of gas detection sensors, and all sensors will fail eventually, so users must be vigilant and prepared to change their sensors when required. But changing sensors too early, when they actually have plenty of life left, can be a waste of time and money.
A further issue arises with purchasing and storing spares. Replacement sensors have a finite shelf life, which begins from the moment they are made. As time passes, they can degrade even if kept in ideal conditions (i.e. in a contaminant-free, temperature and humidity controlled environment so the period between purchase and first use should be brief.
So, what should users do to extend the life of their sensors without putting people at risk?
Factors affecting sensor life
The life and/or performance of gas detection sensors can be affected by various factors, including:
Temperature
Humidity
Interfering gases
Physical factors, e.g. excessive vibration or impact
Contamination of or damage to the sensor e.g. by incorrect cleaning products
Contamination of filters or sinters e.g. by dust, sand or pests (yes spiders!)
Exposure to poisoning/inhibiting compounds even when the sensor is not powered.
There are multiple sensing technologies available and the life expectancy of a sensor is commonly linked to the technology employed. Electrochemical sensors tend to have a shorter life expectancy as compared to Infrared (IR) or catalytic sensors. The type of gas being detected can also have an impact of the life expectancy, the more ‘exotic’ gases (for example chlorine or ozone) tends to be shorter than that of sensors monitoring the more common gases (carbon monoxide, hydrogen sulphide for example).
Most sensors will also suffer general wear and tear, and the damage caused is not always easy to detect, so the first rule for keeping sensors safe and in good working order is to undertake regular maintenance. This should include scheduled bump testing (also known as a gas or functional test) and calibration; while exposure to substantial volumes of gas may harm some sensors, the small amounts used in bump testing and calibration are absolutely fine
It is not always easy to tell that a sensor has failed; some of the techniques suggested are unreliable and this is not an area in which to take risks. The only sure-fire way to know a sensor is working correctly is through application of the target gas(es) in bump testing/calibration.
Planning gas sensor replacement
It makes sense for users to extend the life of their sensors as far as possible; they cost time and money to replace, after all. The ability to forward-plan and predict sensor consumption also makes sensor purchasing more efficient and helps to reduce the time spare sensors are kept in storage.
To predict and plan sensor replacement, users must understand the factors that influence their sensors’ performance. These will be specific to their own setting, which is why users must also be able to draw upon knowledge and experience built up through regular testing and calibration of sensors in their particular environment and applications.
Good quality sensors will come with a warranty, but while this may indicate a general life expectancy there are too many variables and too much at stake for it to stand alone. There really is no substitute for user knowledge and regular maintenance: with these in place, gas detector sensors are far more likely to live long and prosper.
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.
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.
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.
It’s only natural for us to associate the need for gas detection in the oil and gas, and steel industries, but have you thought about the need to detect hazardous gases such as carbon dioxide and nitrogen in the brewing and beverage industry?
Maybe it’s because nitrogen (N2) and carbon dioxide (CO2) are naturally present in the atmosphere. It could be that CO2 is still under-valued as a hazardous gas. Although in the atmosphere CO2 remains at very low concentrations – around 400 parts per million (ppm), greater care is needed in brewery and cellar environments where in confined spaces, the risk of gas canisters or associated equipment leaking could lead to elevated levels. As little as 0.5% volume (5000ppm) of CO2 is a toxic health hazard. Nitrogen on the other hand, can displace oxygen.
CO2 is colourless, odourless and has a density which is heavier than air, meaning pockets of CO2 gather low on the ground gradually increasing in size. CO2 is generated in huge amounts during fermentation and can pose a risk in confined spaces such as vats, cellars or cylinder storage areas, this can be fatal to workers in the surrounding environment, therefore Health & Safety managers must ensure the correct equipment and detectors are in place.
Brewers often use nitrogen in multiple phases of the brewing and dispensing process to put bubbles into beer, particularly stouts, pale ales and porters, it also ensures the beer doesn’t oxidise or pollute the next batch with harsh flavours. Nitrogen helps push the liquid from one tank to another, as well as offer the potential to be injected into kegs or barrels, pressurising them ready for storage and shipment. This gas is not toxic, but does displace oxygen in the atmosphere, which can be a danger if there is a gas leak which is why accurate gas detection is critical.
Gas detection can be provided in the form of both fixed and portable. Installation of a fixed gas detector can benefit a larger space such as plant rooms to provide continuous area and staff protection 24 hours a day. However, for worker safety in and around cylinder storage area and in spaces designated as a confined space, a portable detector can be more suited. This is especially true for pubs and beverage dispensing outlets for the safety of workers and those who are unfamiliar in the environment such as delivery drivers, sales teams or equipment technicians. The portable unit can easily be clipped to belts or clothing and will detect pockets of CO2 using alarms and visual signals, indicating that the user should immediately vacate the area.
At Crowcon, we’re dedicated in growing a safer, cleaner, healthier future for everyone, every day by providing best in class gas safety solutions. It’s vital that once gas detectors are deployed, employees should not get complacent, and should be making the necessary checks an essential part of each working day as early detection can be the difference between life and death.
Quick facts and tips about gas detection in breweries:
Nitrogen and CO2 are both colourless and odourless. CO2 being 5 times heavier than air, making it a silent and deadly gas.
Anyone entering a tank or other confined space must be equipped with a suitable gas detector.
Early detection can be the difference between life and death.
We are all familiar with the term global warming and often see statistics about the potential effects this could have on our planet. One such prediction is by the end of this century the globe will increase in temperature by between 0.8 and 4 degrees.
What many of us may not know is that volcanoes, which are a completely natural phenomenon, contribute a significant amount of gases into our atmosphere. And these gases are currently not considered in the world’s climate models, which means there is potentially a large margin of error.
However, this could be about to change as Yves Moussallam, an inspiring French Volcanologist, who with the support of Rolex and the 2019 Rolex Awards for Enterprise, has made it his mission to understand volcanos and how they impact on our planet. He ventures into these dramatic and dangerous environments to take measurements which are used by scientists and climatologists to improve their prediction models.
By observing volcanos, and gathering this vitally important data, he is helping the world understand the impact volcanos are having on climate change.
Yves is no stranger to volcanic expeditions. In 2015, he led a small team to the Nazca subduction zone in South America. Their mission was to provide the first accurate and large-scale estimate of the flux of several volatile gas species.
To keep the team safe, Yves selected Crowcon detection equipment and was delighted with Gas man and Gas-Pro’s lightweight, clean and safe functionality.
Now Yves is back with a new expedition and has turned to Crowcon once again. This time, Yves is heading to the region of Melanesia in Italy. Satellites, which are used to track volcanic behaviour, have shown that this region is responsible for approximately a third of global volcanic gas emissions.
His expedition will climb these volcanoes and take measurements directly in the volcanic plume.
There are two main methods to measure gases in volcanoes. The first is via satellite which takes images from space. The second is to go directly into the field and measure gas released at its source.
Experts believe the method of working directly in the field is the most accurate as it is positioned far closer to the source so there is a reduced risk of error.
To conduct these measurements requires tried, tested and trusted equipment and with Crowcon’s proven track record, Yves turned again to Gas-Pro.
Crowcon’s Gas-Pro includes an onboard datalogging feature which will provide an extra line of data and an idea of average exposure, which is important for expeditions that span longer periods. It is also lightweight which is hugely beneficial when carrying bulky equipment.
Everyone at Crowcon wishes Yves a safe and successful expedition and we hope the data he gathers will help us understand the impact volcanos have on our world.
Who doesn’t love a summer BBQ? Come rain or shine we light up our BBQs with usually the only worries being whether it will rain, or the sausages are fully cooked through.
While these are important, (especially making sure the sausages are cooked!) many of us are completely unaware of the potential risks.
Carbon monoxide is a gas that has received its fair share of publicity with many of us installing detectors in our homes and businesses, but completely unaware carbon monoxide is associated with our BBQs.
If the weather is poor, we may decide to barbeque in the garage doorway or under a tent or canopy. Some of us may even bring our BBQs into the tent after use. These can all be potentially fatal as the carbon monoxide collects in these confined areas.
Equally with a propane or butane gas canister, we store in our garages, sheds and even our homes unaware that there is a risk of a potentially deadly combination of an enclosed space, a gas leak and a spark from an electrical device. All of which could cause an explosion.
All of that said, BBQs are here to stay and if we use them safely, are a great way to spend a summer afternoon. So, here is a selection of facts and tips from our safety team at Crowcon which we hope will help you enjoy a safe and delicious summer ahead!
Quick facts and tips about BBQ charcoals:
Carbon monoxide is a colourless and odourless gas so just because we can’t smell or see it, doesn’t mean it’s not there
Carbon monoxide is a by-product of burning fossil fuels, which include charcoal and BBQ gas
Always use your BBQ in a well-ventilated open area as it can accumulate to toxic levels in enclosed spaces
Never bring a charcoal into a tent, even if it seems cold. Remember a smouldering BBQ will still give off carbon monoxide
Be aware and act quickly if someone experiences the symptoms of carbon monoxide poisoning which include headaches, dizziness, breathlessness, nausea, confusion, collapse and unconsciousness. These symptoms can be potentially fatal
Quick facts and tips about gas cannisters:
Gas barbecues tend to use propane, butane or LPG (which is a mixture of the two)
Gas BBQs have holes in the bottom to prevent a build-up of gas. This is because gas is heavier than air so will accumulate in low areas or fill a space from the bottom up
To avoid the accumulation of gas, cannisters should always be stored outside, upright, in a well-ventilated area, away from heat sources, and away from enclosed low spaces
If you store your BBQ in the garage, make sure you disconnect the gas cannister and keep this outside
When you are using your BBQ, keep the cannister to one side so it isn’t underneath and close to the heat source and position the BBQ in an open space
Always keep the cannister away from ignition sources when changing cannisters
Always make sure you turn off the gas at the BBQ as well as on the regulator on the cannister, after use
The recent Sky Atlantic TV series Chernobyl sent out a powerful message about the catastrophic and far reaching consequences of radiation gases, both to people and the environment.
The series is based on true events from the 1986 nuclear disaster in the then USSR; the largest uncontrolled radioactive release into the environment ever recorded. The accident resulted in an untold number of fatalities, as well as serious social and economic disruption for large populations within the USSR and beyond.
The Chernobyl explosion resulted in a radioactive gas cloud which travelled across Europe, including the UK; falling to the ground in the form of ‘nuclear rain’.
There are many disturbing facts we read about. Not least that according to the British Ministry of Health, 369 farms and 190,000 sheep in Britain still contain traces of radioactive fallout from the Chernobyl disaster.
Both human and mechanical error contributed to the disaster and thankfully safety standards, regulations, awareness and new technologies have significantly improved since the disaster.
The principal of safety, whether a huge nuclear facility or small manufacturing plant, must remain the same. Here at Crowcon we are dedicated to keeping people and the environment protected. Our technologies support organisations across multiple industries, including nuclear plants, improving plant and personal safety. Our technologies help our customers be protected from the dangers of gases.
At Crowcon, we welcome shows such as Chernobyl which document historical disasters such as this and highlight in a dramatic but real way, the importance of ensuring companies understand the need for safety measures, however big or small, are in place. Protecting their people, the environment and the world.
Hydrogen sulphide (H2S) is known for being extremely toxic, as well as highly corrosive. In an inerted tank environment, it poses an additional and serious hazard combustion which, it is suspected, has been the cause of serious explosions in the past.
Hydrogen sulphide can be present in %vol levels in “sour” oil or gas. Fuel can also be turned ‘sour’ by the action of sulphate-reducing bacteria found in sea water, often present in cargo holds of tankers. It is therefore important to continue to monitor the level of H2S, as it can change, particularly at sea. This H2S can increase the likelihood of a fire if the situation is not properly managed.
Tanks are generally lined with iron (sometimes zinc-coated). Iron rusts, creating iron oxide (FeO). In an inerted headspace of a tank, iron oxide can react with H2S to form iron sulphide (FeS). Iron sulphide is a pyrophore; which means that it can spontaneously ignite in the presence of oxygen
Excluding the elements of fire
A tank full of oil or gas is an obvious fire hazard under the right circumstances. The three elements of fire are fuel, oxygen and an ignition source. Without these three things, a fire can’t start. Air is around 21% oxygen. Therefore, a common means to control the risk of a fire in a tank is to remove as much air as possible by flushing the air out of the tank with an inert gas, such as nitrogen or carbon dioxide. During tank unloading, care is taken that fuel is replaced with inert gas rather than air. This removes the oxygen and prevents fire starting.
By definition, there is not enough oxygen in an inerted environment for a fire to start. But at some point, air will have to be let into the tank – for maintenance staff to safety enter, for example. There is now the chance for the three elements of fire coming together. How is it to be controlled?
Oxygen has to be allowed in
There may be present FeS, which the oxygen will cause to spark
The element that can be controlled is fuel.
If all the fuel has been removed and the combination of air and FeS causes a spark, it can’t do any harm.
Monitoring the elements
From the above, it is obvious how important it is to keep track of all the elements that could cause a fire in these fuel tanks. Oxygen and fuel can be directly monitored using an appropriate gas detector, like Gas-Pro TK. Designed for these specialist environments, Gas-Pro TK automatically copes with measuring a tank full of gas (measured in %vol) and a tank nearly empty of gas (measured in %LEL). Gas-Pro TK can tell you when oxygen levels are low enough to be safe to load fuel or high enough for staff to safely enter the tank. Another important use for Gas-Pro TK is to monitor for H2S, to allow you judge the likely presence of the pryophore, iron sulphide.
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.
or.
Who doesn’t love a summer BBQ? Come rain or shine we light up our BBQs with usually the only worries being whether it will rain, or the sausages are fully cooked through.
The series is based on true events from the 1986 nuclear disaster in the then USSR; the largest uncontrolled radioactive release into the environment ever recorded. The accident resulted in an untold number of fatalities, as well as serious social and economic disruption for large populations within the USSR and beyond.
