Blogs listed by tag: carbon monoxide

Gold Mining: What gas detection do I need? 

How is gold mined?

Gold is a rare substance equating to 3 parts per billion of the earth’s outer layer, with most of the world’s available gold coming from Australia. Gold, like iron, copper and lead, is a metal. There are two primary forms of gold mining, including open-cut and underground mining. Open mining involves earth-moving equipment to remove waste rock from the ore body above, and then mining is conducted from the remaining substance. This process requires waste and ore to be struck at high volumes to break the waste and ore into sizes suitable for handling and transportation to both waste dumps and ore crushers. The other form of gold mining is the more traditional underground mining method. This is where vertical shafts and spiral tunnels transport workers and equipment into and out of the mine, providing ventilation and hauling the waste rock and ore to the surface.

Gas detection in mining

When relating to gas detection, the process of health and safety within mines has developed considerably over the past century, from morphing from the crude usage of methane wick wall testing, singing canaries and flame safety to modern-day gas detection technologies and processes as we know them. Ensuring the correct type of detection equipment is utilised, whether fixed or portable, before entering these spaces. Proper equipment utilisation will ensure gas levels are accurately monitored, and workers are alerted to dangerous concentrations within the atmosphere at the earliest opportunity.

What are the gas hazards and what are the dangers?

The dangers those working within the mining industry face several potential occupational hazards and diseases, and the possibility of fatal injury. Therefore, understanding the environments and hazards, they may be exposed to is important.

Oxygen (O2)

Oxygen (O2), usually present in the air at 20.9%, is essential to human life. There are three main reasons why oxygen poses a threat to workers within the mining industry. These include oxygen deficiencies or enrichment, as too little oxygen can prevent the human body from functioning leading to the worker losing consciousness. Unless the oxygen level can be restored to an average level, the worker is at risk of potential death. An atmosphere is deficient when the concentration of O2 is less than 19.5%. Consequently, an environment with too much oxygen is equally dangerous as this constitutes a greatly increased risk of fire and explosion. This is considered when the concentration level of O2 is over 23.5%

Carbon Monoxide (CO)

In some cases, high concentrations of Carbon Monoxide (CO) may be present. Environments that this may occur include a house fire, therefore the fire service are at risk of CO poisoning. In this environment there can be as much as 12.5% CO in the air which when the carbon monoxide rises to the ceiling with other combustion products and when the concentration hits 12.5% by volume this will only lead to one thing, called a flashover. This is when the whole lot ignites as a fuel. Apart from items falling on the fire service, this is one of the most extreme dangers they face when working inside a burning building. Due to the characteristics of CO being so hard to identify, I.e., colourless, odourless, tasteless, poisonous gas, it may take time for you to realise that you have CO poisoning. The effects of CO can be dangerous, this is because CO prevents the blood system from effectively carrying oxygen around the body, specifically to vital organs such as the heart and brain. High doses of CO, therefore, can cause death from asphyxiation or lack of oxygen to the brain. According to statistics from the Department of Health, the most common indication of CO poisoning is that of a headache with 90% of patients reporting this as a symptom, with 50% reporting nausea and vomiting, as well as vertigo. With confusion/changes in consciousness, and weakness accounting for 30% and 20% of reports.

Hydrogen sulphide (H2S)

Hydrogen sulphide (H2S) is a colourless, flammable gas with a characteristic odour of rotten eggs. Skin and eye contact may occur. However, the nervous system and cardiovascular system are most affected by hydrogen sulphide, which can lead to a range of symptoms. Single exposures to high concentrations may rapidly cause breathing difficulties and death.

Sulphur dioxide (SO2)

Sulphur dioxide (SO2) can cause several harmful effects on the respiratory systems, in particular the lung. It can also cause skin irritation. Skin contact with (SO2) causes stinging pain, redness of the skin and blisters. Skin contact with compressed gas or liquid can cause frostbite. Eye contact causes watering eyes and, in severe cases, blindness can occur.

Methane (CH4)

Methane (CH4) is a colourless, highly flammable gas with a primary component being that of natural gas. High levels of (CH4) can reduce the amount of oxygen breathed from the air, which can result in mood changes, slurred speech, vision problems, memory loss, nausea, vomiting, facial flushing and headache. In severe cases, there may be changes in breathing and heart rate, balance problems, numbness, and unconsciousness. Although, if exposure is for a longer period, it can result in fatality.

Hydrogen (H2)

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. Hydrogen poses a fire or explosion risk as well as an inhalation risk. High concentrations of this gas can cause an oxygen-deficient environment. Individuals breathing such an atmosphere may experience symptoms which include headaches, ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting and depression of all the senses

Ammonia (NH3)

Ammonia (NH3) is one of the most widely used chemicals globally that is produced both in the human body and in nature. Although it is naturally created (NH3) is corrosive which poses a serve concern for health. High exposure within the air can result in immediate burning to the eyes, nose, throat and respiratory tract. Serve cases can result in blindness.

Other gas risks

Whilst Hydrogen Cyanide (HCN) doesn’t persist within the environment, improper storage, handling and waste management can pose severe risk to human health as well as effects on the environment. Cyanide interferes with human respiration at cellular levels that can cause serve and acute effects, including rapid breathing, tremors, asphyxiation.

Diesel particulate exposure can occur in underground mines as a result of diesel-powered mobile equipment used for drilling and haulage. Although control measures include the use of low sulphur diesel fuel, engine maintenance and ventilation, health implication includes excess risk of lung cancer.

Products that can help to protect yourself

Crowcon provide a range of gas detection including both portable and fixed products all of which are suitable for gas detection within the mining industry.

To find out more visit our industry page here.

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What causes Hydrocarbon Fires?  

Hydrocarbon fires are caused by fuels containing carbon being burned in oxygen or air. Most fuels contain significant levels of carbon, including paper, petrol, and methane – as examples of solid, liquid or gaseous fuels – hence hydrocarbon fires. 

For there to be an explosion risk there needs to be at least 4.4% methane in air or 1.7% propane, but for solvents as little as 0.8 to 1.0% of the air being displaced can be enough to create a fuel air mix that will explode violently on contact with any spark.

Dangers associated with hydrocarbon fires

Hydrocarbon fires are considered highly dangerous when compared to fires that have ignited as a result of simple combustibles, as these fires have the capacity to burn at a larger scale as well as also having the potential to trigger an explosion if the fluids released cannot be controlled or contained. Therefore, these fires pose a dangerous threat to anyone who works in a high-risk area, the dangers include energy related dangers such as burning, incineration of surrounding objects. This is a danger due to the ability that the fires can grow quickly, and that heat can be conducted, converted and radiated to new sources of fuel causing secondary fires. 

Toxic hazards may be present in combustion products, for example, carbon monoxide (CO), hydrogen cyanide (HCN), hydrochloric acid (HCL), nitrogen dioxide (NO2) and various polycyclic aromatic hydrocarbons (PAH) compounds are dangerous for those working in these environments. CO uses the oxygen that is used to transport the red blood cells around the body, at least temporarily, impairing the body’s ability to transport oxygen from our lungs to the cells that need it. HCN adds to this problem by inhibiting the enzyme that tells the red blood cells to let go of the oxygen they have where it is needed – further inhibiting the body’s ability to get the oxygen to the cells that need it. HCL is a generally an acidic compound that is created through overheated cables. This is harmful to the body if ingested as it affects the lining of the mouth, nose, throat, airways, eyes, and lungs. NO2 is created in high temperature combustion and that can cause damage to the human respiratory tract and increase a person’s vulnerability to and in some cases lead to asthma attacks. PAH’s affects the body over a longer period of time, with serve cases leading to cancers and other illnesses. 

We can look up the relevant health levels accepted as workplace safety limits for healthy workers within Europe and the permissible exposure limits for the United States. This gives us a 15-minute time weighted average concentration and an 8-hour time weighted average concentration. 

For the gases these are: 

Gas  STEL (15-minute TWA)  LTEL (8-hour TWA)  LTEL (8hr TWA) 
CO  100ppm  20ppm  50ppm 
NO2  1ppm  0.5ppm  5 Ceiling Limit 
HCL  1ppm  5ppm  5 Ceiling Limit 
HCN  0.9ppm  4.5ppm  10ppm 

The different concentrations represent the different gas risks, with lower numbers needed for more dangerous situations. Fortunately, the EU has worked it all out for us and turned it into their EH40 standard. 

Ways of protecting ourselves

We can take steps to ensure we do not suffer from exposure to fires or their unwanted combustion products. Firstly of course, we can adhere to all fire safety measures, as is the law. Secondly, we can take a pro-active approach and not let potential fuel sources accumulate. Lastly, we can detect and warn of the presence of combustion products using appropriate gas detection equipment. 

Crowcon product solutions

Crowcon provides a range of equipment capable of detecting fuels and the combustion products described above. Our PID products detect solids and liquid-based fuels once they are airborne, as either hydrocarbons on dust particles or solvent vapours. This equipment includes our Gas–Pro portable. The gases can be detected by our Gasman single gas, T3 multi gas and Gas-Pro multi gas pumped portable products, and our Xgard, Xgard Bright and Xgard IQ fixed products – each of which has the capability of detecting all the gases mentioned. 

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How do Electrochemical sensors work? 

Electrochemical sensors are the most used in diffusion mode in which gas in the ambient environment enters through a hole in the face of the cell. Some instruments use a pump to supply air or gas samples to the sensor. A PTFE membrane is fitted over the hole to prevent water or oils from entering the cell. Sensor ranges and sensitivities can be varied in design by using different size holes. Larger holes provide higher sensitivity and resolution, whereas smaller holes reduce sensitivity and resolution but increase the range.  

Benefits  

Electrochemical sensors have several benefits.  

  • Can be specific to a particular gas or vapor in the parts-per-million range. However, the degree of selectivity depends on the type of sensor, the target gas and the concentration of gas the sensor is designed to detect.  
  • High repeatability and accuracy rate. Once calibrated to a known concentration, the sensor will provide an accurate reading to a target gas that is repeatable. 
  • Not susceptible to poisoning by other gases, with the presence of other ambient vapours will not shorten or curtail the life of the sensor. 
  • Less expensive than most other gas detection technologies, such as IR or PID technologies. Electrochemical sensors are also more economical. 

Issues with cross-sensitivity  

Cross-sensitivity occurs when a gas other than the gas being monitored/detected can affect the reading given by an electrochemical sensor. This causes the electrode within the sensor to react even if the target gas is not actually present, or it causes an otherwise inaccurate reading and/or alarm for that gas. Cross-sensitivity may cause several types of inaccurate reading in electrochemical gas detectors. These can be positive (indicating the presence of a gas even though it is not actually there or indicating a level of that gas above its true value), negative (a reduced response to the target gas, suggesting that it is absent when it is present, or a reading that suggests there is a lower concentration of the target gas than there is), or the interfering gas can cause inhibition. 

Factors affecting electrochemical sensor life  

There are three main factors that affect the sensor life including temperature, exposure to extremely high gas concentrations and humidity. Other factors include sensor electrodes and extreme vibration and mechanical shocks. 

Temperature extremes can affect sensor life. The manufacturer will state an operating temperature range for the instrument: typically -30˚C to +50˚C. High quality sensors will, however, be able to withstand temporary excursions beyond these limits. Short (1-2 hours) exposure to 60-65˚C for H2S or CO sensors (for example) is acceptable, but repeated incidents will result in evaporation of the electrolyte and shifts in the baseline (zero) reading and slower response.  

Exposure to extremely high gas concentrations can also compromise sensor performance. Electrochemical sensors are typically tested by exposure to as much as ten-times their design limit. Sensors constructed using high quality catalyst material should be able to withstand such exposures without changes to chemistry or long-term performance loss. Sensors with lower catalyst loading may suffer damage. 

The most considerable influence on sensor life is humidity. The ideal environmental condition for electrochemical sensors is 20˚Celsius and 60% RH (relative humidity). When the ambient humidity increases beyond 60%RH water will be absorbed into the electrolyte causing dilution. In extreme cases the liquid content can increase by 2-3 times, potentially resulting in leakage from the sensor body, and then through the pins. Below 60%RH water in the electrolyte will begin to de-hydrate. The response time may be significantly extended as the electrolyte or dehydrated. Sensor electrodes can in unusual conditions be poisoned by interfering gases that adsorb onto the catalyst or react with it creating by-products which inhibit the catalyst. 

Extreme vibration and mechanical shocks can also harm sensors by fracturing the welds that bond the platinum electrodes, connecting strips (or wires in some sensors) and pins together. 

‘Normal’ life expectancy of electrochemical Sensor  

Electrochemical sensors for common gases such as carbon monoxide or hydrogen sulphide have an operational life typically stated at 2-3 years. More exotic gas sensor such as hydrogen fluoride may have a life of only 12-18 months. In ideal conditions (stable temperature and humidity in the region of 20˚C and 60%RH) with no incidence of contaminants, electrochemical sensors have been known to operate more than 4000 days (11 years). Periodic exposure to the target gas does not limit the life of these tiny fuel cells: high quality sensors have a large amount of catalyst material and robust conductors which do not become depleted by the reaction. 

Products  

As electrochemical sensors are more economical, We have a range of portable products and fixed products that use this type of sensor to detect gases.  

To explore more, visit our technical page for more information. 

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Our Partnership with Acutest

Background

Acutest have established themselves as a leading player in test instrument supply, repair and calibration, asset management and bespoke training services. Acutest are a complete solution provider who match to each customer’s need. Their team of external account managers support customers with onsite product demonstration as part of the solution identification process. Serving across sectors including utilities (distribution network operators), sole traders, public sector and white goods. Acutest are a trusted partner to many sectors, who have a diverse customer base including the utilities, street works and rail sectors, facilities maintenance teams, manufacturing, processing and industrial plants as well as individual contractors and electricians.

View on Flue Gas Analysers

Providing workers within these sectors with the correct equipment is vital, therefore providing these workers with an essential tool is key at Acutest. This tool is used every day; therefore, Anton by Crowcon flue gas analysers provide an easy-to-use tool that detects CO (Carbon Monoxide) and NO (Nitrogen Oxide).

Working with Crowcon

Acutest have been a long-term partner in which our gas analysers prevent users from having to store, charge, carry, calibrate and transport multiple devices. Our equipment allows Acutest customers to conduct all critical test measurements with just one high performance, innovative solution. “Our partnership with Acutest has enabled them to supply their customers with a readily available, reliable product as well as customer support. Anton by Crowcon provide innovative tools for every engineer needs and has been a go to on many occasions.”

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Carbon Monoxide Awareness: What are the dangers?

Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood, and coal. It is only when fuel does not burn fully that excess CO is produced, which is poisonous. When CO enters the body, it stops the blood from bringing oxygen to cells, tissues, and organs. CO is poisonous as you cannot see it, taste it, or smell it but CO can kill quickly without warning. The Health and Safety Executive (HSE) statistics show every year in the UK around 15 people die from CO poisoning caused by gas appliances and flues that have not been correctly installed, maintained or those that are poorly ventilated. Some levels that present do not kill but can cause serious harm to health if breathed in over a prolonged period, with extreme cases causing paralysis and brain damage because of prolonged exposure to CO. Therefore, understanding the danger of CO poisoning as well as educating the public to take appropriate precautions could inevitably reduce this risk.  

How is CO generated? 

CO is present in several different industries, such as steel works, manufacturing, electricity supply, coal and metal mining, food manufacturing, oil and gas, production of chemicals and petroleum refining to name a few.  

CO is produced by incomplete combustion of fossil fuels such as gas, oil, coal, and wood. This happens where there is a general lack of burner 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 significant water vapour in the atmosphere, this can reduce the burning efficiency still further and speed up CO production. 

Incorrect or poorly maintained appliance such as cookers, heaters or central boiler are the most common cause of carbon monoxide exposure. Other causes include blocked flues and chimneys as this can prevent carbon monoxide form escaping leading to dangerous levels accumulating. Burning fuel in an enclosed or unventilated environment such as running a car engine, petrol-powered generator or barbecue inside a garage or tent can lead to similar CO accumulation. Faulty or blocked car exhausts can lead to inefficient combustion and hence a leak or blockage within the exhaust pipe can cause an excess of CO to be produced. Some vehicles and properties may have flues or exhausts blocked after heavy snowfall which may lead to a build-up of carbon monoxide. A different cause of CO poisoning may result from some chemicals, paint fumes and some cleaning fluids and paint removers contain methylene chloride (dichloromethane), which when inhaled the body breaks this substance down into carbon monoxide leading to possible co poisoning. Though to be fair, since methylene chloride is a listed 1B carcinogen, its breakdown to CO may not be the worst of a subject’s subsequent health problems. Another common cause of low-level CO poisoning is smoking, and smoking shisha pipes can be particularly bad, especially indoors. This is because shisha pipes burn charcoal and tobacco, which can lead to a build-up of carbon monoxide in enclosed or unventilated rooms.  

High concentrations of CO 

In some cases, high concentrations of CO may be present. Environments that this may occur include a house fire, therefore the fire service are at risk of CO poisoning. In this environment there can be as much as 12.5% CO in the air which when the carbon monoxide rises to the ceiling with other combustion products and when the concentration hits 12.5% by volume this will only lead to one thing, called a flashover. This is when the whole lot ignites as a fuel. Apart from items falling on the fire service, this is one of the most extreme dangers they face when working inside a burning building. 

How does CO affect the body? 

Due to the characteristics of CO being so hard to identify, I.e., colourless, odourless, tasteless, poisonous gas, it may take time for you to realise that you have CO poisoning. The effects of CO can be dangerous, this is because CO prevents the blood system from effectively carrying oxygen around the body, specifically to vital organs such as the heart and brain. High doses of CO, therefore, can cause death from asphyxiation or lack of oxygen to the brain. According to statistics from the Department of Health, the most common indication of CO poisoning is that of a headache with 90% of patients reporting this as a symptom, with 50% reporting nausea and vomiting, as well as vertigo. With confusion/changes in consciousness, and weakness accounting for 30% and 20% of reports.  

Carbon monoxide can severely affect the central nervous system and those with cardiovascular disease. As CO prevents the brain from receiving sufficient levels of oxygen it has a knock-on effect with the heart, brain, and central nervous system. along with symptoms including headaches, nausea, fatigue, memory loss and disorientation, increasing levels of CO in the body go on to cause lack of balance, heart problems, cerebral edemas, comas, convulsions and even death. Some of those who are affected may experience rapid and irregular heartbeats, low blood pressure and arrhythmias of the heart. Cerebral edemas caused because of CO poisoning are especially threatening, this is because they can result in the brain cells being crushed, thereby affecting the whole nervous system. 

Another way CO affects the body is through the respiratory system. This is because the body will struggle to distribute air around the body because of carbon monoxide due to the deprivation of blood cells of oxygen. As a result, some patients will experience a shortness of breath, especially when undertaking strenuous activities. Every-day physical and sporting activities will take more effort and leave you feeling more exhausted than usual. These effects can worsen over time as your body’s power to obtain oxygen becomes increasingly compromised. Over time, both your heart and lungs are put under pressure as the levels of carbon monoxide increase in the body tissues. As a result, your heart will try harder to pump what it wrongly perceives to be oxygenated blood from your lungs to the rest of your body. Consequently, the airways begin to swell causing even less air to enter the lungs. With long-term exposure, the lung tissue is eventually destroyed, resulting in cardiovascular problems and lung disease. 

Chronic exposure to carbon monoxide can have extremely serious long-term effects, depending on the extent of poisoning. In extreme cases, the section of the brain known as the hippocampus may be harmed. This part of the brain is accountable for the development of new memories and is particularly vulnerable to damage. Figures have shown that up to 40% of people who have suffered from carbon monoxide poisoning experience problems such as amnesia, headaches, memory loss, personality and behavioural changes, loss of bladder and muscle control, and impaired vision and coordination. Some of these effects do not always present themselves immediately and can may take several weeks or may be highlighted after more exposure. Whilst those who suffer from long-term effects of carbon monoxide poisoning recover with time, there are cases in which some people suffer permanent effects. This may occur when there has been enough exposure to result in organ and brain damage. 

Unborn babies are at the highest risk of carbon monoxide poisoning, since foetal haemoglobin mixes more readily with CO than adult haemoglobin. As a result, the baby’s carboxy haemoglobin levels become higher than the mothers. Babies and children whose organs are still maturing are at risk of permanent organ damage. Additionally, young children and infants breathe faster than adults and have a higher metabolic rate, therefore, they inhale up to twice as much air as adults, especially when sleeping, which heightens their exposure to CO. 

How to identify 

In the event of carbon monoxide poisoning there are a number of treatments, these depend on the levels of exposure, and the age of the patient.  

For low levels of exposure seeking medical advice from your GP is best practice.  

However, if you believe that you have been exposed to elevated levels of CO then your local A&E would be the most suitable place to go. Although your symptoms will usually indicate whether you have CO poisoning, for adults a blood test will confirm the amount of carboxyhaemoglobin in your blood. For children this will lead to an underestimate of the peak exposure since children will metabolise the carboxyhaemoglobin faster. Carboxyhaemoglobin (COHb) is a stable complex of carbon monoxide that forms in red blood cells when carbon monoxide is inhaled, using up the capacity of the red blood cell to transport oxygen.  

The effects of CO poisoning can include breathlessness, chest pain, seizures and loss of consciousness which may lead to death or physical problems that can occur, depending on how much CO is in the air. For example:  

CO volume (parts per million (ppm)   Physical Effects  
200 ppm   Headache in 2–3 hours  
400 ppm   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  

 Around 10 to 15% of people who obtain serve CO poisoning go on to develop long-term complications. These include brain damage, vision and hearing loss, Parkinsonism – an illness that isn’t Parkinson’s disease but has similar symptoms, and coronary heart disease.  

Treatments  

There are several treatments for CO poisoning, these include rest, standard oxygen therapy or hyperbaric oxygen therapy.  

Standard oxygen therapy is provided in hospital in the event you have been exposed to a prominent level of carbon monoxide, or you have symptoms that suggest exposure. This process includes being given 100% oxygen through a tight-fitting mask. Normal air contains around 21% oxygen. Continuous breathing of concentrated oxygen enables your body to quickly replace carboxyhaemoglobin. For best results, this type of therapy is continued until your carboxyhaemoglobin levels decrease to less than 10%. 

The alternative treatment is that of hyperbaric oxygen therapy (HBOT), this treatment consists of flooding the body with pure oxygen, helping it overcome the oxygen shortage caused by carbon monoxide poisoning. However, there is currently not enough evidence about the long-term effectiveness of HBOT for treating severe cases of carbon monoxide poisoning. Although standard oxygen therapy is usually the recommended treatment option, HBOT may be recommended in certain situations – such as, if there’s been extensive exposure to carbon monoxide and nerve damage is suspected. The treatment provided is decided upon purely on a case-by-case basis.

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How Long will my Gas Sensor Last?

Gas detectors are used extensively within many industries (such as water treatment, refinery, petrochemical, steel and construction to name a few) to protect personnel and equipment from dangerous gases and their effects. Users of portable and fixed devices will be familiar with the potentially significant costs of keeping their instruments operating safely over their operational life. Gas sensors are understood to provide a measurement of the concentration of some analyte of interest, such as CO (carbon monoxide), CO2 (carbon dioxide), or NOx (nitrogen oxide). There are two most used gas sensors within industrial applications: electrochemical for toxic gases and oxygen measurement, and pellistors (or catalytic beads) for flammable gases. In recent years, the introduction of both Oxygen and MPS (Molecular Property Spectrometer) sensors have allowed for improved safety.  

How do I know when my sensor has failed? 

There have been several patents and techniques applied to gas detectors over the past few decades which claim to be able to determine when an electrochemical sensor has failed. Most of these however, only infer that the sensor is operating through some form of electrode stimulation and might provide a false sense of security. The only sure method of demonstrating that a sensor is working is to apply test gas and measure the response: a bump test or full calibration. 

Electrochemical Sensor  

Electrochemical sensors are the most used in diffusion mode in which gas in the ambient environment enters through a hole in the face of the cell. Some instruments use a pump to supply air or gas samples to the sensor. A PTFE membrane is fitted over the hole to prevent water or oils from entering the cell. Sensor ranges and sensitivities can be varied in design by using different size holes. Larger holes provide higher sensitivity and resolution, whereas smaller holes reduce sensitivity and resolution but increase the range. 

Factors affecting Electrochemical Sensor Life 

There are three main factors that affect the sensor life including temperature, exposure to extremely high gas concentrations and humidity. Other factors include sensor electrodes and extreme vibration and mechanical shocks.  

Temperature extremes can affect sensor life. The manufacturer will state an operating temperature range for the instrument: typically -30˚C to +50˚C. High quality sensors will, however, be able to withstand temporary excursions beyond these limits. Short (1-2 hours) exposure to 60-65˚C for H2S or CO sensors (for example) is acceptable, but repeated incidents will result in evaporation of the electrolyte and shifts in the baseline (zero) reading and slower response. 

Exposure to extremely high gas concentrations can also compromise sensor performance. Electrochemical sensors are typically tested by exposure to as much as ten-times their design limit. Sensors constructed using high quality catalyst material should be able to withstand such exposures without changes to chemistry or long-term performance loss. Sensors with lower catalyst loading may suffer damage.  

The most considerable influence on sensor life is humidity. The ideal environmental condition for electrochemical sensors is 20˚Celsius and 60% RH (relative humidity). When the ambient humidity increases beyond 60%RH water will be absorbed into the electrolyte causing dilution. In extreme cases the liquid content can increase by 2-3 times, potentially resulting in leakage from the sensor body, and then through the pins. Below 60%RH water in the electrolyte will begin to de-hydrate. The response time may be significantly extended as the electrolyte or dehydrated. Sensor electrodes can in unusual conditions be poisoned by interfering gases that adsorb onto the catalyst or react with it creating by-products which inhibit the catalyst.  

Extreme vibration and mechanical shocks can also harm sensors by fracturing the welds that bond the platinum electrodes, connecting strips (or wires in some sensors) and pins together.  

‘Normal’ Life Expectancy of Electrochemical Sensor 

Electrochemical sensors for common gases such as carbon monoxide or hydrogen sulphide have an operational life typically stated at 2-3 years. More exotic gas sensor such as hydrogen fluoride may have a life of only 12-18 months. In ideal conditions (stable temperature and humidity in the region of 20˚C and 60%RH) with no incidence of contaminants, electrochemical sensors have been known to operate more than 4000 days (11 years). Periodic exposure to the target gas does not limit the life of these tiny fuel cells: high quality sensors have a large amount of catalyst material and robust conductors which do not become depleted by the reaction. 

Pellistor Sensor 

Pellistor sensors consist of two matched wire coils, each embedded in a ceramic bead. Current is passed through the coils, heating the beads to approximately 500˚C. Flammable gas burns on the bead and the additional heat generated produces an increase in coil resistance which is measured by the instrument to indicate gas concentration. 

Factors affecting Pellistor Sensor Life 

The two main factors that affect the sensor life include exposure to high gas concentration and poising or inhibition of the sensor. Extreme mechanical shock or vibration can also affect the sensor life. The capacity of the catalyst surface to oxidise the gas reduces when it has been poisoned or inhibited. Sensor life more than ten years is common in applications where inhibiting or poisoning compounds are not present. Higher power pellistors have greater catalytic activity and are less vulnerable to poisoning. More porous beads also have greater catalytic activity as their surface volume in increased. Skilled initial design and sophisticated manufacturing processes ensure maximum bead porosity. Exposure to high gas concentrations (>100%LEL) may also compromise sensor performance and create an offset in the zero/base-line signal. Incomplete combustion results in carbon deposits on the bead: the carbon ‘grows’ in the pores and creates mechanical damage. The carbon may however be burned off over time to re-reveal catalytic sites. Extreme mechanical shock or vibration can in rare cases also cause a break in the pellistor coils. This issue is more prevalent on portable rather than fixed-point gas detectors as they are more likely to be dropped, and the pellistors used are lower power (to maximise battery life) and thus use more delicate thinner wire coils. 

How do I know when my sensor has failed? 

A pellistor that has been poisoned remains electrically operational but may fail to respond to gas. Hence the gas detector and control system may appear to be in a healthy state, but a flammable gas leak may not be detected. 

Oxygen Sensor 

Long Life 02 Icon

Our new lead-free, long-lasting oxygen sensor does not have compressed strands of lead the electrolyte has to penetrate, allowing a thick electrolyte to be used which means no leaks, no leak induced corrosion, and improved safety. The additional robustness of this sensor allows us to confidently offer a 5-year warranty for added piece of mind. 

Long life-oxygen sensors have an extensive lifespan of 5-years, with less downtime, lower cost of ownership, and reduced environmental impact. They accurately measure oxygen over a broad range of concentrations from 0 to 30% volume and are the next generation of O2 gas detection. 

MPS Sensor  

MPS sensor provides advanced technology that removes the need to calibrate and provides a ‘True LEL (lower explosive limit)’ for reading for fifteen flammable gases but can detect all flammable gases in a multi-species environment, resulting in lower ongoing maintenance costs and reduced interaction with the unit. This reduces risk to personnel and avoids costly downtime. The MPS sensor is also immune to sensor poisoning.  

Sensor failure due to poisoning can be a frustrating and costly experience. The technology in the MPS™ sensor is not affected by contaminates in the environment. Processes that have contaminates now have access to a solution that operates reliably with fail safe design to alert operator to offer a peace of mind for personnel and assets located in hazardous environment. It is now possible to detect multiple flammable gases, even in harsh environments, using just one sensor that does not require calibration and has an expected lifespan of at least 5 years. 

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Keeping the Emergency Services/First Responders Safe

Emergency Service Personnel/First Responders encounter gas related risks as part of their jobs. However, immediate evaluation of their surrounds is key upon arrival as well as continuous monitoring whilst in a rescue situation are vital for the health of all those involved.  

What Gases are Present?

Toxic gases like carbon monoxide (CO) and hydrogen cyanide (HCN) are present if there is a fire. Individually these gases are dangerous and even deadly, the two combined is exponentially worse, known as the toxic twins.  

Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood, and coal. It is only when fuel does not burn fully that excess CO is produced, which is poisonous. When the excess CO enters the body, it stops the blood from bringing oxygen to cells, tissues, and organs. CO is poisonous as you cannot see it, taste it or smell it but CO can kill quickly without warning.  

Hydrogen Cyanide (HCN) is an important industrial chemical and over a million tonnes are produced globally each year. Hydrogen Cyanide (HCN) is a colourless or light blue liquid or gas that is extremely flammable. It has a faint bitter almond odour, although this isn’t detectable to everyone.  There are many uses for hydrogen cyanide, primarily in the manufacture of paints, plastics, synthetic fibres (for example nylon) and other chemicals. Hydrogen cyanide and other cyanide compounds have also been used as a fumigant to control pests. With other uses being in metal cleaning, gardening, ore-extraction, electroplating, dying, printing and photography. Sodium and potassium cyanide and other cyanide salts may be made from hydrogen cyanide. 

What are the risks?

These gases are dangerous individually. However, exposure to both combined is even more dangerous, so an adequate CO and HCN gas detector is essential where the toxic twins are found. Usually, visible smoke is a good guide, however the Toxic Twins are both colourless.  Combined these gases are usually found in fires. in which, Firefighters and other Emergency Personnel are trained to look out for CO poisoning in fires. However, due to the increased use of plastics and man-made fibres, HCN can be released at up to 200ppm in domestic and industrial fires. These two gases cause thousands of fire related deaths annually, so needs more consideration in fire gas detection.  

The attendance of HCN in the environment may not always lead to exposure. However, for HCN to cause any adverse health effects, you need to come into contact with it, i.e., breathing, eating, drinking, or through skin or eye contact with it. Following exposure to any chemical, the adverse health effects are dependent on a number of factors, such as the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals. As HCN is very toxic, it can prevent the body from using oxygen properly. Early signs of exposure to HCN include headache, sickness, dizziness, confusion and even drowsiness. Substantial exposure may rapidly lead to unconsciousness, fitting, coma and possibly death. If a substantial exposure is survived, there may be long-term effects from damage to the brain and other nervous system damage. Effects from skin contact require a large surface of the skin in order to be exposed. 

What Products are Available?

For Emergency Service Teams/First Responders, the use of portable gas detectors is essential. Toxic gases are produced when materials are burnt meaning flammable gases and vapours may be present.  

Our Gas-Pro portable multi gas detector offers detection of up to 5 gases in a compact and rugged solution. It has an easy-to-read top mount display making it easy to use and optimal for confined space gas detection. An optional internal pump, activated with the flow plate, takes the pain out of pre-entry testing and allows Gas-Pro to be worn either in pumped or diffusion modes. In-field pellistor changes for methane, hydrogen, propane, ethane, acetylene (0–100% LEL, with resolution of 1% LEL). By allowing in-field pellistor changes, Gas-Pro detectors give users the flexibility to conveniently test for a range of flammable gases, without needing multiple sensors or detectors. What is more, they can continue to calibrate using existing methane canisters, saving time and money. The gas sensor for hydrogen cyanide has a monitoring measuring range of 0–30 ppm with resolution of 0.1 ppm.  

Tetra 3 portable multi gas monitor can detect and monitor the four most common gases (carbon monoxide, methane, oxygen and hydrogen sulphide), but also an expanded range: ammonia, ozone, sulphur dioxide, H2 filtered CO (for steel plants) and IR carbon dioxide (for safe area use only). 

T4 portable 4-in-1 gas detector provides effective protection against 4 common gas hazards: carbon monoxide, hydrogen sulphide, flammable gases and oxygen depletion. The T4 multi gas detector now comes with improved detection of pentane, hexane and other long chain hydrocarbons. 

Clip Single Gas Detector (SDG) is an industrial gas detector designed for use in hazardous areas and offers reliable and durable fixed life span monitoring in a compact, lightweight and maintenance-free package. Clip SGD has a 2-year life and is available for hydrogen sulphide (H2S), carbon monoxide (CO) or oxygen (O2). 

Gasman is a full function device in a compact and lightweight package – perfect for customers who need more sensor options, TWA and data capability. It comes available with long-life O2 sensor, MPS sensor technology.

MPS Sensor provides advanced technology that removes the need to calibrate and provides a ‘True LEL’ for reading for fifteen flammable gases but can detect all flammable gases in a multi-species environment. Many industries and applications use or have as a by product multiple gases within the same environment. This can be challenging for traditional sensor technology which can detect only a single gas that they were calibrated for and can result in inaccurate reading and even false alarms which can halt process or production. The challenges faced in multi gas species environments can be frustrating and counterproductive. Our MPS™ sensor can accurately detect multiple gases at once and instantly identify gas type. Our MPS™ sensor has a on board environmental compensation and does not require a correctional factor. Inaccurate readings and false alarms are a thing of the past.

Crowcon Connect is a gas safety and compliance insight solution that utilises a flexible cloud data service offering actionable insight from detector fleet. This cloud-based software provides a top level view of device utilisation with dashboard showing proportion of devices that are Assigned or Unassigned to an operator, for the specific region or area selected. Fleet Insights provides overview of devices switch on/off, synced or in alarm.

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What’s so Important about my Monitors Measuring Range?

What is a Monitor Measuring Range?

Gas monitoring is usually measured in PPM range (parts per million), percentage volume or percentage of LEL (lower explosive limit) this enables Safety Managers, to ensure that their operators are not being exposed to any potentially harmful levels of gases or chemicals. Gas monitoring can be done remotely to ensure that the area is clean before a worker enters the area as well as monitoring gas through a permanently fixed device or body worn portable device to detect any potentially leaks or hazardous areas during the course of the working shift.  

Why are Gas Monitors essential and what are the Ranges of deficiencies or enrichments?

There are three main reasons why monitors are needed; it is essential to detect oxygen deficiencies or enrichment as too little oxygen can prevent the human body from functioning leading to the worker losing consciousness. Unless the oxygen level can be restored to a normal level the worker is at risk of potential death. An atmosphere is considered to be deficient when the concentration of O2 is less than 19.5%. Consequently, an environment that has too much oxygen in it is equally dangerous as this constitutes a greatly increased risk of fire and explosion, this is considered when the concentration level of O2 is over 23.5%. 

Monitors are required when Toxic Gases are present of which can cause considerable harm to the human body. Hydrogen Sulphide (H2S) is a classic example of this. H2S is given off by bacteria when it breaks down organic matter, due to this gas being heavier than air, it can displace air leading to potential harm to persons present and is also a broad-spectrum toxic poison.  

Additionally, gas monitors have the ability to detect flammable gases. Dangers that can be prevented through using a gas monitor are not only though inhaling but they are a potential hazard due to combustion. gas monitors with an LEL range sensor detects and alert against flammable gases.  

Why are they important and how do they work?

Measurement or Measuring Range is the total range that the device can measure in normal conditions. The term normal meaning no overpressure limits (OPL) and within maximum working pressure (MWP).  These values are usually found on the product website or specification datasheet. The measuring range can also be calculated by identifying the difference between the Upper Range Limit (URL) and the Lower Range Limit (LRL) of the device. When trying to determine the range of the detector it is not identifying the area of square footage or within a fixed radius of the detector but instead is identifying the yielding or diffusion of the area being monitored. The process happens as the sensors respond to the gases that penetrate through the monitor’s membranes. Therefore, the devices have the ability to detect gas that is in immediate contact with the monitor. This  highlights the significance of understanding the measuring range of gas detectors and highlight their importance for the safety of the workers present in these environments.   

Are there any products that are available?

Crowcon offer a range of portable monitors; The Gas-Pro portable multi gas detector offers detection of up to 5 gases in a compact and rugged solution. It has an easy-to-read top mount display making it easy to use and optimal for confined space gas detection. An optional internal pump, activated with the flow plate, takes the pain out of pre-entry testing and allows Gas-Pro to be worn either in pumped or diffusion modes. 

The T4 portable 4-in-1 gas detector provides effective protection against 4 common gas hazards: carbon monoxide, hydrogen sulphide, flammable gases and oxygen depletion. The T4 multi gas detector now comes with improved detection of pentane, hexane and other long chain hydrocarbons. Offering you compliance, robustness and low cost of ownership in a simple to use solution. T4 contains a wide range of powerful features to make everyday use easier and safer. 

The Gasman portable single gas detector is compact and lightweight yet is fully ruggedised for the toughest of industrial environments. Featuring simple single button operation, it has a large easy-to-read display of gas concentration, and audible, visual and vibrating alarms.  

Crowcon also offer a flexible range of fixed gas detection products that can detect flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment. We use a variety of measurement, protection and communications technologies and our fixed detectors have been proven in many arduous environments, including oil and gas exploration, water treatment, chemical plants and steel mills. These fixed gas detectors are used in many applications where reliability, dependability and lack of false alarms are instrumental to efficient and effective gas detection. These include within the automotive and aerospace manufacturing sectors, on scientific and research facilities and in high-utilisation medical, civil or commercial plants. 

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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.

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Why Do I Need a Personal Carbon Monoxide Monitor?

What is Carbon Monoxide?

Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood, and coal. It is only when fuel does not burn fully that excess CO is produced, which is poisonous. When the excess CO enters the body, it stops the blood from bringing oxygen to cells, tissues, and organs. CO is poisonous as you cannot see it, taste it or smell it but CO can kill quickly without warning. The Health and Safety Executive (HSE) statistics show every year around 15 people die from CO poisoning caused by gas appliances and flues that have not been correctly installed, maintained or those that are poorly ventilated. Although some levels that present do not kill but can cause serious harm to health if breathed in over a prolonged period. with extreme cases causing paralysis and brain damage because of prolonged exposure to CO. Therefore, understanding the danger of CO poisoning as well as educating the public to take appropriate precautions could inevitably reduce this risk.  

Where is CO present and why is it dangerous?

CO is present in several different industries, such as manufacturing, electricity supply, coal and metal mining, food manufacturing, oil and gas, production of chemicals and petroleum refining to name a few.  

The effects of CO poisoning, can include breathlessness, chest pain, seizures and loss of consciousness which may lead to death as well as physical problems that can occur, depending on how much CO is in the air. For example: 

CO volume (parts per million (ppm)  Physical Effects 
200 ppm  Headache in 2–3 hours 
400 ppm  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 

 Around 10 to 15% of people who obtain serve CO poisoning go on to develop long-term complications. These include brain damage, vision and hearing loss, Parkinson’s disease, and coronary heart disease.  

How does a CO Monitor help with safety and compliance and if so, what products are available?

Any operators who are working on commercial installations or domestic application in a home are required to be registered with a relevant association, i.e., Gas safe register, Heating equipment testing and approval scheme (HETAS) – solid fuel applications and Oil firing technical association (OFTEC) – oil appliances. Therefore, personal CO monitors offer the highest quality and portability CO gas detection to protect the operator at work. 

Crowcon Clip SGD is designed for use in hazardous areas whilst offering reliable and durable fixed life span monitoring in a compact, lightweight and maintenance free device. Clip SGD has a 2-year life and is available for hydrogen sulphide (H2S), carbon monoxide (CO) or oxygen (O2). The Clip SDG personal gas detector is designed to withstand the harshest industrial working conditions and delivers industry leading alarm time, changeable alarm levels and event logging as well as user-friendly bump test and calibration solutions. 

Crowcon Gasman with specialist CO sensor is a rugged, compact single gas detector, designed for use in the toughest environments. Its compact and lightweight design makes it the ideal choice for industrial gas detection. Weighing just 130g, it is extremely durable, with high impact resistance and dust/water ingress protection, loud 95 dB alarms, a vivid red/ blue visual warning, single-button control and an easy-to-read, backlit LCD display to ensure clear viewing of gas level readings, alarm conditions and battery life. Data and event logging are available as standard, and there is a built-in 30-day advance warning when calibration is due. 

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