Industry Overview: Waste to Energy

The waste to energy industry utilises several waste treatment methods. Municipal and industrial solid waste is converted into electricity, and sometimes into heat for industrial processing and district heating systems. The main process is of course incineration, but intermediate steps of pyrolysis, gasification, and anaerobic digestion are sometimes used to convert the waste into useful by-products that are then used to generate power through turbines or other equipment. This technology is gaining wide recognition globally as a greener and cleaner form of energy than traditional burning of fossil fuels, and as a means of reducing waste production.

Types of waste to energy

Incineration

Incineration is a waste treatment process that involves the combustion of energy rich substances contained within waste materials, typically at high temperatures around 1000 degrees C. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities and are often sizeable power stations in their own right. Incineration and other high-temperature waste treatment systems are often described as “thermal treatment”. During the process waste is converted into heat and steam that can be used to drive a turbine in order to generate electricity. This method currently has an efficiency of around 15-29%, although it does have potential for improvements.

Pyrolysis

Pyrolysis is a different waste treatment process where decomposition of solid hydrocarbon wastes, typically plastics, takes place at high temperatures without oxygen present, in an atmosphere of inert gases. This treatment is usually conducted at or above 500 °C, providing enough heat to deconstruct the long chain molecules including bio-polymers into simpler lower mass hydrocarbons.

Gasification

This process is used to make gaseous fuels from heavier fuels and from waste containing combustible material. In this process, carbonaceous substances are converted into carbon dioxide (CO2), carbon monoxide (CO) and a small amount of hydrogen at high temperature. In this process, gas is generated which is a good source of usable energy. This gas can then be used to produce electricity and heat.

Plasma Arc Gasification

In this process, a plasma torch is used to ionise energy rich material. Syngas is produced which may then be used to make fertiliser or generate electricity. This method is more of a waste disposal technique than a serious means of generating gas, often consuming as much energy as the gas it produces can provide.

Reasons for Waste to Energy

As this technology is gaining wide recognition globally in regards to waste production and the demand for clean energy.

  • Avoids methane emissions from landfills
  • Offsets greenhouse gas (GHG) emissions from fossil fuel electrical production
  • Recovers and recycles valuable resources, such as metals
  • Produces clean, reliable base-loaded energy and steam
  • Uses less land per megawatt than other renewable energy sources
  • Sustainable and steady renewable fuel source (compared to wind and solar)
  • Destroys chemical waste
  • Results in low emission levels, typically well below permitted levels
  • Catalytically destroys nitrogen oxides (NOx), dioxins and furans using an selective catalytic reduction (SCR)

What are the Gas Hazards?

There are many processes to turn waste into energy, these include, biogas plants, refuse use, leachate pool, combustion and heat recovery. All these processes pose gas hazards to those working in these environments.

Within a Biogas Plant, biogas is produced. This is formed when organic materials such as agricultural and food waste are broken down by bacteria in an oxygen-deficient environment. This is a process called anaerobic digestion. When the biogas has been captured, it can be used to produce heat and electricity for engines, microturbines and fuel cells. Clearly, biogas has high methane content as well as substantial hydrogen sulphide (H2S), and this generates multiple serious gas hazards. (Read our blog for more information on biogas). However, there is an elevated risk of, fire and explosion, confined space hazards, asphyxiation, oxygen depletion and gas poisoning, usually from H2S or ammonia (NH3). Workers in a biogas plant must have personal gas detectors that detect and monitor flammable gas, oxygen and toxic gases like H2S and CO.

Within a refuse collection it is common to find flammable gas methane (CH4) and toxic gases H2S, CO and NH3. This is because refuse bunkers are built several metres underground and gas detectors are usually mounted high up in areas making those detectors hard to service and calibrate. In many cases, a sampling system is a practical solution as air samples can be brought to a convenient location and measured.

Leachate is a liquid that drains (leaches) from an area in which waste is collected, with leachate pools presenting a range of gas hazards. These include the risk of flammable gas (explosion risk), H2S (poison, corrosion), ammonia (poison, corrosion), CO (poison) and adverse oxygen levels (suffocation). Leachate pool and passageways leading to the leachate pool requiring monitoring of CH4, H2S, CO, NH3, oxygen (O2) and CO2. Various gas detectors should be placed along routes to the leachate pool, with output connected to external control panels.

Combustion and heat recovery requires the detection of O2 and toxic gases sulphur dioxide (SO2) and CO. These gases all pose a threat to those who work in boiler house areas.

Another process that is classed as a gas hazard is an exhaust air scrubber. The process is hazardous as the flue gas from incineration is highly toxic. This is because it contains pollutants such as nitrogen dioxide (NO2), SO2, hydrogen chloride (HCL) and dioxin. NO2 and SO2 are major greenhouse gases, while HCL all of these gas types mentioned here are harmful to human health.

To read more on the waste to energy industry, visit our industry page.

Car Parks are More Dangerous Than You Think

Road vehicles can emit a number of harmful gases through exhaust fumes, the most common being carbon monoxide (CO) and nitrogen dioxide (NO2). Whilst these cause gases are an issue in open air environments, there is particular cause for concern in more confined spaces such as underground and multi-storey car parks. 

Why are car parks of specific concern? 

The gases emitted through exhaust fumes are absolutely an issue regardless of where they are being emitted, and contribute to a wide variety of issues including air pollution. However, in car parks any dangers these gases cause are exasperated due to the high number of vehicles in a small, confined area and the lack of natural ventilation to ensure that these gases do not reach dangerous levels. 

What gases are present in car parks? 

Vehicles emit a variety of exhaust gases including carbon dioxide, carbon monoxide, nitrogen dioxide and sulphur dioxide. Carbon monoxide and nitrogen dioxide are the most common and are also of particular concern due to the potential negative impacts on human health that exposure to these gases can have. 

What are the dangers of gases in car parks? 

Out of the two most common gases in car parks, carbon monoxide poses the more significant threat to human health. It is an odourless, colourless and tasteless gas making it almost impossible to detect without some sort of detection equipment. 

Carbon monoxide is dangerous as it negatively impacts the transport of oxygen around the body which can cause a wide range of health problems. Breathing low levels of CO can cause nausea, dizziness, headaches, confusion and disorientation. Regularly breathing low levels of CO may cause more permanent health issues. At very high levels carbon monoxide can cause loss of consciousness and even death, with around 60 deaths attributed to carbon monoxide poisoning in England and Wales every year. 

Breathing in nitrogen dioxide also has negative health impacts including breathing and respiratory issues as well as damage to lung tissue. Exposure to high concentrations can cause inflammation of the airways and prolonged exposure can lead to irreversible damage to the respiratory system 

What regulations are there? 

In 2015, a new European Standard (EN 50545-1) was introduced, specifically relating to the detection of toxic gases such as CO and NO2 in car parks and tunnels. EN 50545-1 specifies requirements for remote gas detectors and control panels to be used in car parks. The goal of the standard is to increase the safety of gas detection systems in car parks and prevent the use of inadequate systems. Th standard also the alarm levels to be used for gas detection in car parks, shown in the table below. 

  Alarm 1  Alarm 2  Alarm 3 
CO  30 ppm  60 ppm  150 ppm 
NO2  3 ppm  6 ppm  15 ppm 

 

Crowcon Park System 

Crowcon have recently launched a new range of fixed detectors and control panels designed specifically for gas detection in car parks. 

The SMART P set of detectors, consisting of the SMART P-1 and SMART P-2 can detect CO, NO2 and petrol vapours, with the SMART P-2 offering simultaneous detection of both CO and NO2 in a single detector. The MULTISCAN++PK control panel can manage and monitor up to 256 detectors. Every product in the range has been designed to fulfil the requirements of the European Standard EN 50545-1. 

The importance of Gas Detection in the Water and Wastewater Industry 

Water is vital to our daily lives, both for personal and domestic use and industrial/commercial applications. Whether a facility focuses on the production of clean, potable water or treating effluent, Crowcon is proud to serve a wide variety of water industry clients, providing gas detection equipment that keeps workers safe around the world. 

Gas Hazards 

Apart from common gas hazards known in the industry; methane, hydrogen sulphide, and oxygen, there are bi-product gas hazards and cleaning material gas hazards that occur from purifying chemicals such as ammonia, chlorine, chlorine dioxide or ozone that are used in the decontamination of the waste and effluent water, or to remove microbes from clean water. There is great potential for many toxic or explosive gases to exist as a result of the chemicals used in the water industry. And added to these are chemicals that may be spilled or dumped into the waste system from industry, farming or building work. 

Safety Considerations  

Confined Space Entry 

The pipelines used to transport water require regular cleaning and safety checks; during these operations, portable multi-gas monitors are used to protect the workforce. Pre-entry checks must be completed prior to entering any confined space and commonly O2, CO, H2S and CH4 are monitored. Confined spaces are small, so portable monitors must be compact and unobtrusive for the user, yet able to withstand the wet and dirty environments in which they must perform. Clear and prompt indication of any increase in gas monitored (or any decrease for oxygen) is of paramount importance – loud and bright alarms are effective in raising the alarm to the user. 

Risk assessment 

Risk assessment is critical, as you need to be aware of the environment that you are entering and thus working in. Therefore, understanding the applications and identifying the risks regarding all safety aspects. Focusing on gas monitoring, as part of the risk assessment, you need to be clear on what gases may be present.  

Fit for purpose 

There is a variety of applications within the water treatment process, giving the need to monitor multiple gases, including carbon dioxide, hydrogen sulphide, chlorine, methane, oxygen, ozone and chlorine dioxide. Gas detectors are available for single or multiple gas monitoring, making them practical for different applications as well as making sure that, if conditions change (such as sludge is stirred up, causing a sudden increase in hydrogen sulphide and flammable gas levels), the worker is still protected.  

Legislation   

European Commission Directive 2017/164 issued in January 2017, established a new list of indicative occupational exposure limit values (IOELVs). IOELV are health-based, non-binding values, derived from the most recent scientific data available and considering the availability of reliable measurement techniques. The list includes carbon monoxide, nitrogen monoxide, nitrogen dioxide, sulphur dioxide, hydrogen cyanide, manganese, diacetyl and many other chemicals. The list is based on Council Directive 98/24/EC that considers the protection of the health and safety of workers from the risks related to chemical agents in the workplace. For any chemical agent for which an IOELV has been set at Union level, Member States are required to establish a national occupational exposure limit value. They also are required to take into account the Union limit value, determining the nature of the national limit value in accordance with national legislation and practice. Member States will be able to benefit from a transitional period ending at the latest on 21 August 2023.  

The Health and Safety Executive (HSE) state that each year several workers will suffer from at least one episode of work-related illness. Although, most illnesses are relatively mild cases of gastroenteritis, there is also a risk for potentially fatal diseases, such as leptospirosis (Weil’s disease) and hepatitis. Even though these are reported to the HSE, there could be significant under-reporting as there is often failure to recognise the link between illness and work.  

Under domestic law of the Health and Safety at Work etc Act 1974, employers are responsible for ensuring the safety of their employees and others. This responsibility is reinforced by regulations. 

The Confined Spaces Regulations 1997 applies where the assessment identifies risks of serious injury from work in confined spaces. These regulations contain the following key duties: 

  • Avoid entry to confined spaces, e.g., by doing the work from the outside. 
  • If entry to a confined space is unavoidable, follow a safe system of work.
  • Put in place adequate emergency arrangements before the work start. 

The Management of Health and Safety at Work Regulations 1999 requires employers and self-employed people to carry out a suitable and sufficient assessment of the risks for all work activities for the purpose of deciding what measures are necessary for safety. For work in confined spaces this means identifying the hazards present, assessing the risks and determining what precautions to take. 

Our solutions

Elimination of these gas hazards is virtually impossible, so permanent workers and contractors must depend on reliable gas detection equipment to protect them. Gas detection can be provided in both fixed and portable forms. Our portable gas detectors protect against a wide range of gas hazards, these include T4x, Clip SGD, Gasman, Tetra 3,Gas-Pro, T4 and Detective+. Our 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 Xgard, Xgard Bright and IRmax. Combined with a variety of our fixed detectors, our gas detection control panels offer a flexible range of solutions that measure flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment, for the wastewater industry our panels include Gasmaster.    

To find out more on the gas hazards in wastewater and water treatment visit our industry page for more information.  

Construction and Key Gas Challenges

Workers in the construction industry are at risk from a wide variety of hazardous gases including Carbon Monoxide (CO), Chlorine Dioxide (CLO2), Methane (CH4), Oxygen (O2), Hydrogen Sulphide (H2S) and Volatile Organic Compounds (VOC’s). 

Through the use of specific equipment, transport and the undertaking of sector specific activities, construction is a main contributor to the emission of toxic gases into the atmosphere, which also means construction personnel are more at risk of ingestion of these toxic contaminants. 

Gas challenges can be found in a variety of applications including building material storage, confined spaces, welding, trenching, land clearing and demolition. Ensuring the protection of workers within the construction industry from the multitude of hazards they may encounter is very important. With a specific focus on safeguarding teams from harm by, or the consumption of, toxic, flammable and poisonous gases. 

Gas Challenges 

Confined Space Entry 

Workers are more at risk from hazardous gases and fumes when they are operating within confined spaces.  Those entering these spaces need to be protected from the presence of flammable or/and toxic gases such as Volatile Organic Compounds (ppm VOC), Carbon Monoxide (ppm CO) and Nitrogen Dioxide (ppm NO2). Undertaking clearance measurements and pre-entry safety checks are paramount to ensure safety before a worker enters the space. Whilst in confined spaces gas detection equipment must be worn ongoingly in case of environmental shifts which make the space no longer safe to work in, due to a leak for example, and evacuation is needed. 

Trenching and Shoring 

During excavation works, such as trenching and shoring, construction workers are at risk of inhaling harmful gases generated by degradable materials present in certain ground types. If undetected, as well as posing risks to the construction workforce, they can also migrate through subsoil and cracks into the completed building and harm housing residents. Trenched areas can also have reduced oxygen levels, as well as contain toxic gases and chemicals. In these cases atmospheric testing should be performed in excavations that exceed four feet. There is also the risk of hitting utility lines when digging which can cause natural gas leaks and lead to worker fatalities. 

Building Material Storage  

Many of the materials used within construction can release toxic compounds (VOC’s). These can form in a variety of states (solid or liquid) and come from materials such as adhesives, natural and plywood’s, paint, and building partitions. Pollutants include phenol, acetaldehyde and formaldehyde. When ingested, workers can suffer from nausea, headaches, asthma, cancer and even death. VOCs are specifically dangerous when consumed within confined spaces, due to the risk of asphyxiation or explosion. 

Welding and Cutting 

Gases are produced during the welding and cutting process, including carbon dioxide from the decomposition of fluxes, carbon monoxide from the breakdown of carbon dioxide shielding gas in arc welding, as well as ozone, nitrogen oxides, hydrogen chloride and phosgene from other processes. Fumes are created when a metal is heated above its boiling point and then its vapours condense into fine particles, known as solid particulates. These fumes are obviously a hazard for those working in the sector and  illustrate the importance of reliable gas detection equipment to reduce exposure. 

Health and Safety Standards 

Organisations working in the construction sector can prove their credibility and safety operationally by gaining ISO certification. ISO (International Organisation for Standardisation) certification is split across multiple different certificates, all of which recognise varying elements of safety, efficiency and quality within an organisation. Standards cover best practice across safety, healthcare, transportation, environmental management and family. 

Although not a legal requirement, ISO standards are widely recognised as making the construction industry a safer sector by establishing global design and manufacturing definitions for almost all processes. They outline specifications for best practice and safety requirements within the construction industry from the ground up. 

In the UK, other recognised safety certifications include the NEBOSH, IOSH and CIOB courses which all offer varied health and safety training for those in the sector to further their understanding of working safely in their given field.  

To find out more on the gas challenges in construction visit our industry page for more information. 

Did you know about the Sprint Pro’s Ambient Air Monitor?

You probably know that the Sprint Pro has a host of useful functions, but have you ever scrolled through the menu of your Sprint Pro, found the ambient air monitor and wondered how you could use it?  

Well, you need wonder no longer – because in this post we will look at the Sprint Pro ambient air monitor and its uses.

Who needs to carry out ambient air monitoring? 

As a gas engineer, your need for ambient air monitoring may vary according to the type of work you do, but if you specialise in Carbon monoxide (CO)/Carbon dioxide (CO2) detection – for example, if you have CMDDA1 certification for dwellings or undertake COMCAT (commercial catering) reports in the UK, or have equivalent domestic or catering CO/CO2) certification elsewhere in the world – you will probably find this function very useful.  

How does ambient air monitoring work? 

In general terms, ambient air monitoring is simply the measurement of pollutants in the atmosphere, but in a gas detection context it refers to analysis of how much carbon monoxide is in the air.  

In some cases, the level of CO2 is also measured. The Sprint Pro 4 and Sprint Pro 6 both have a direct CO2 infrared sensor fitted, therefore they can measure both CO and CO2.

Ambient air monitoring may be carried out anywhere that CO and/or CO2 present a risk. For example, to detect CO leakages in the home (perhaps from a boiler), or to monitor CO2 levels in commercial catering premises.  

With the Sprint Pro, ambient air monitoring is carried out over a given time period, which may be anything from a few minutes to several days, during which time the analyser samples the ambient air at intervals of between one and thirty minutes. At the end of the test, the device gives readings for the current, peak and whole-test average rates for both CO and CO2. You can save these directly to your log and/or print them out as paper reports. 

Even when it comes to report printing, the Sprint Pro gives you options, so you can print as much or little of the relevant information as you need. This can be very handy when you have just taken literally hundreds of samples over a 7-day period! 

Ambient air monitoring for CO is available on all Sprint Pro models 

Why do I need ambient air monitoring functionality? 

Regardless of specialist certification, having the capacity to analyse ambient air is increasingly useful to HVAC professionals and gas engineers. This is particularly true in light of the COVID-19 pandemic, when the benefits of fresh air and good indoor ventilation have been highlighted. Excessive CO and CO2 are threats to both human and environmental health, and with growing awareness of this, and sustainability becoming an increasingly important social/political/policy topic, the need to quantify and measure them is likely to increase. 

What are the Dangers of 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 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.  

Regulation  

The Health and Safety Executive (HSE) prohibit worker exposure to more than 20ppm (parts per million) during an 8-hour long term exposure period and 100ppm (parts per million) during a 15 minute short term exposure period. 

OSHA standards prohibit worker exposure to more than 50 parts of CO gas per million parts of air averaged during an 8-hour time period. The 8-hour PEL for CO in maritime operations is also 50 ppm. Maritime workers, however, must be removed from exposure if the CO concentration in the atmosphere exceeds 100 ppm. The peak CO level for employees engaged in roll-on roll-off operations during cargo loading and unloading) is 200 ppm. 

What are the dangers? 

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.   

What are the health implications? 

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.  

Implication to Health  Physical Effects 
Oxygen Deprivation  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.  
Central Nervous system and Heart Problems  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. Symptoms including headaches, nausea, fatigue, memory loss and disorientation.  

Increased levels of CO in the body go on to cause lack of balance, heart problems, 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. 

Respiratory System  As the body struggles to distribute air around the body as a result of carbon monoxide due to the deprivation of blood cells of oxygen. 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  Chronic exposure 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.  

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  Since foetal haemoglobin mixes more readily with CO than adult haemoglobin, 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 meet compliance?

The best way to protect yourself from the hazards of CO is be wearing a high quality, portable CO gas detector. 

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.  

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.  

Our partnership with Heating Engineer Supplier (HES) 

Background  

Founded in 2012 (11 years as a limited company) and based in County Limerick in Ireland, Heating Engineer Supplies (HES) are one of the main suppliers of Anton and Crowcon in Ireland, supplying Cork, Dublin, Galway, Waterford and throughout Ireland. HES provide an extensive range including; flow and pressure, flue gas analysers, gas detectors and oil accessories.  

Views on HVAC 

Providing workers within the HVAC (heating, ventilation and air conditioning) sectors with the correct equipment is vital, therefore providing these workers with an integral tool is crucial. SprintPro is a tool that is used every day by HVAC; therefore, Anton by Crowcon flue gas analysers provides a five-gas analysis through an easy-to-use tool. Sprint Pro is manufactured in the UK to exacting standards, stay on the job longer with a reliable device you can trust. Multi-function and easy-to-use, it is designed to last with troubleshooting built in and triple filter water trap system for total hydrophobic protection. 

Providing gas detection equipment that is lifesaving allows HES’ customers to have a full solution option best suited to their needs and requirements. HES work by providing their customers with the knowledge, expertise and advise in order to keep them safe when using gas detection products, whilst highlighting and focusing on the awareness of why this type of equipment is required in a variety of industries. 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. 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. The Clip SGD  is a CO personal monitor that can sense what you can’t, giving you time to react and ultimately can save you and your customers lives. 

Working with Anton by Crowcon 

A 12-year partnership through continued communication and support has allowed Heating Engineer Supplies to supply their customers with both flue gas analysers and gas detection solutions. HES is an official service centre for Anton by Crowcon located in house at their base in county Limerick, with the possibility of portable calibration coming soon. “Over many years we have built up an excellent relationship with Anton by Crowcon. It’s fantastic to know we have brilliant Technical support and we know moving forward with Fixed & Portable gas detection this will continue, we look forward to growing our respective businesses.” Although previously our partnership has predominately been focused on both flue gas analysers and portable gas detection solutions, HES are expanding their offering to cover sales and calibration of our portable gas detection equipment with future hopes being focussed on our fixed product range.  

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.

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 GasPro 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. 

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.