Gas Hazards in Battery Power Storage

Batteries are effective at reducing power outages since they can also store excess traditional grid energy. The energy stored within batteries can be released whenever a large volume of power is needed, such as during a power failure at a data centre to prevent data being lost, or as a back-up power supply to a hospital or military application to ensure the continuity of vital services. Large scale batteries can also be used to plug short-term gaps in demand from the grid. These battery compositions can also be used in smaller sizes to power electric cars and may be further scaled down to power commercial products, such as phones, tablets, laptops, speakers and – of course – personal gas detectors.

Gas hazards

The main gas risk emitted by batteries, specifically lead acid batteries, is hydrogen. It is possible to get both hydrogen and oxygen evolved during charging however, a lead acid battery is likely to have catalytic recombination parts internally, so oxygen is less of a risk. Hydrogen is always a cause for concern, as it can collect and build up. A situation that is obviously worsened when they are charged in a space with a poor airflow.

When charging, lead-acid batteries consist of lead and oxide at the positive terminal, and of spongy lead at the negative anode, using concentrated sulfuric acid as the electrolyte. The presence of sulfuric acid is another cause for concern if the battery leaks or is ever damaged because concentrated acids harm people, metals and the environment.

When charging batteries also emit oxygen and hydrogen because of the electrolysis process. The levels of hydrogen produced soar when a lead acid battery cell “blows” or is unable to be charged properly. The amount of gas present is relevant because high levels of hydrogen make it highly explosive, even though it is not toxic. Hydrogen has a 100% lower explosive limit of 4.0% by volume, at which level an ignition source would cause fires or for hydrogen more usually, explosions. Fires and explosions are an issue not only for the workers within the space, but also for the surrounding equipment and infrastructure.

Importance of Gas Detection Technology

Gas detection is an invaluable safety technology often equipped in battery charging rooms. Ventilation is also advised, and while helpful, it is not fool proof as fan motors can fail and should not be relied upon as the sole safety measure for battery charging areas. Fans mask the problem while gas detection notifies personnel to act before problems escalate. Gas detection systems are crucial in informing personnel of increasing gas leaks before becoming dangerous. Gas detection units comply with local building codes and NFPA 111, the National Fire Protection Association standard on stored electrical energy emergency and standby power systems. They include maintenance, operation, installation, and testing provisions regarding the system’s performance. In addition to permanent gas detection systems, handheld units are available. The benchmark products are provided by Crowcon and are listed below.

Portable Gas Detectors

Crowcon’s portable gas detectors (Gasman, Gas-Pro, T4x, Tetra 3 and T4) protect against a wide range of industrial gas hazards, with both single gas and multi-gas monitors available. With a wide range of sizes and complexities, you can find the right portable gas detection solution to meet the number and type of gas sensors you need and your display and certification requirements.

Fixed Gas Detectors

Crowcon gas detection fixed systems offer a flexible range of solutions that can measure flammable, toxic, and oxygen gases, report their presence, and activate alarms or associated equipment. Crowcon fixed gas monitoring systems (Xgard, Xgard Bright and XgardIQ) are designed to be interfaced with manual call points, fire and gas detectors, and distributed control systems (DCS).

Control Panels

Crowcon gas detection control panels offer a flexible range of solutions that can measure flammable, toxic, and oxygen gases, report their presence, and activate alarms or associated equipment. Crowcon fixed gas (Vortex, GM Addressable Controllers, Gasmaster) monitoring systems are designed to be interfaced with manual call points, fire and gas detectors and distributed control systems (DCS). In addition, each system can be engineered to drive remote annunciators and mimic panels. Crowcon has a gas detection product to suit your application regardless of your operation.

Temperature Measurement

Crowcon has extensive experience with temperature measurement. There are several models of temperature measurement, from pocket thermometers to industrial kits ranging from -99.9 to 299.9°C with probes and clamps. They are enhancing their fixed detection capabilities by adding high-temperature electrochemical sulphur dioxide detection for battery manufacturing and charging stations. This is critical during the first charge of a battery, as a fault is most likely at that time. Their fast-acting systems detect the precursors to thermal runaway and quickly terminate power to the batteries to avoid damage.

To find out more on the dangers of gas hazards in battery power visit our industry page for more information.

The Importance of Gas Detection in the Power Industry

The energy industry is the very backbone of our industrial and domestic worlds, supplying essential energy to industrial, manufacturing, commercial and residential customers around the globe. With the inclusion of fossil fuel industries (petroleum, coal, LNG); electricity generation, distribution and sales; nuclear energy and renewable energy, the power generation sector is essential in supporting the increasing demand for power from emerging countries and an increasing world population.

Gas Hazards in Power Sector

Gas detection systems have been installed extensively in the power industry to minimise potential consequence through the detection of gas exposure with those working within this industry are exposed to a variation of power plant gas hazards.

Carbon monoxide

The transport and pulverisation of coal poses a high risk of combustion. Fine coal dust becomes suspended in air and highly explosive. The smallest spark, for example from plant equipment, can ignite the dust cloud and cause an explosion that sweeps up more dust, which explodes in turn, and so on in a chain reaction. Coal power plants now require combustible dust certification, in addition to hazardous gas certification.

Coal power plants generate large volumes of carbon monoxide (CO) which is both highly toxic and flammable and must be accurately monitored. A toxic component of incomplete combustion, CO comes from boiler casing leaks and smouldering coal. It is vital to monitor CO in coal tunnels, bunkers, hoppers and tipper rooms, along with infrared-type flammable gas detection to detect pre-fire conditions.

Hydrogen

With hydrogen fuel cells gaining popularity as alternatives to fossil fuel, it is important to be aware of the dangers of hydrogen. Like all fuels, hydrogen is highly flammable and if it leaks there is real risk of fire. Hydrogen burns with a pale blue, almost invisible, flame that can cause serious injuries and severe equipment damage. Therefore, hydrogen must be monitored, to prevent seal-oil system fires, unscheduled shutdowns and to protect personnel from fire.

In addition, power plants must have back-up batteries, to ensure the continued functioning of critical control systems in cases of power outage. Battery rooms generate considerable hydrogen, and monitoring is often carried out in conjunction with ventilation. Traditional lead acid batteries produce hydrogen when they are being charged. These batteries are normally charged together, sometimes in the same room or area, which can generate an explosion risk, especially if the room is not properly ventilated.

Confined Space Entry

Confined space entry (CSE) is often considered to be a dangerous type of work performed in power generation. It is therefore important that the entry is strictly controlled and detailed precautions are taken. Lack of oxygen, toxic and flammable gases are risks that can occur during work in confined spaces, which should never be considered as simple or routine. However, the hazards of working in confined spaces can be predicted, monitored, and mitigated through the use of portable gas detection devices. Confined Spaces Regulations 1997. Approved Code of Practice, Regulations and guidance is for employees that work in Confined Spaces, those who employ or train such people and those who represent them.

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, 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 BrightXgardIQ 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 power industry our panels include Vortex and Gasmonitor.

To find out more on the gas hazards in the power industry visit our industry page for more information.

The importance of gas detection in the Petrochemical Industry

Closely linked to oil and gas, the petrochemicals industry takes raw materials from refining and gas processing and, through chemical process technologies, converts them into valuable products. In this sector, the organic chemicals produced in the largest volumes are methanol, ethylene, propylene, butadiene, benzene, toluene and xylenes (BTX). These chemicals are the building blocks of many consumer goods including plastics, clothing fabric, construction materials, synthetic detergents and agrichemical products.

Potential Hazards

Exposure to potential hazardous substances is more likely to occur during shutdown or maintenance work as these are a deviation from the refinery’s routine operations. As these deviations are out of normal routine, care should be exercised at all times to avoid the inhalation of solvent vapours, toxic gases, and other respiratory contaminants. The assistance of constant automated monitoring is helpful in determining the presence of solvents or gases, allowing their associated risks to be mitigated. This includes warning systems such as gas and flame detectors, supported by emergency procedures, and permit systems for any kind of potentially dangerous work.

The petroleum industry is split into upstream, midstream and downstream and these are defined by the nature of the work that takes place in each area. Upstream work is typically known as the exploration and production (E&P) sector. Midstream refers to the transportation of products through pipelines, transit and oil tankers as well as the wholesale marketing of petroleum-based products. The downstream sector refers to the refining of petroleum crude oil, the processing of raw natural gas and the marketing and distribution of finished products.

Upstream

Fixed and portable gas detectors are needed to protect plant and personnel from the risks of flammable gas releases (commonly methane) as well as from high levels of H2S, particularly from sour wells. Gas detectors for O2 depletion, SO2 and volatile organic compounds (VOCs) are required items of personal protection equipment (PPE), which is usually highly visible colour and worn near breathing space. Sometimes HF solution is used as a scouring agent. Key requirements for gas detectors are rugged and reliable design and long battery life. Models with design elements that support easy fleet management and compliance obviously have an advantage. You can read about VOC risk and Crowcon’s solution in our case study.

Midstream

Fixed monitoring of flammable gases situated close to pressure relief devices, filling and emptying areas is necessary to deliver early warning of localised leaks. Multi-gas portable monitors must be used to maintain personal safety, especially during work in confined spaces and supporting hot work permit area testing. Infrared technology in flammable gas detection supports purging with the ability to operate in inert atmospheres and delivers reliable detection in areas where pellistor type detectors would fail, due to poisoning or volume level exposure. You can read more on how infrared detection works in our blog and read our case study of infrared monitoring in refinery settings in Southeast Asia.

Portable laser methane detection (LMm) allows users to pin-point leaks at distance and in hard-to-reach areas, reducing the need for personnel to enter potentially dangerous environments or situations while performing routine or investigative leak monitoring. Using LMm is a quick and effective way to check areas for methane with a reflector, from up to 100m away. These areas include closed buildings, confined spaces and other difficult-to-reach areas such as above-ground pipelines that are near water or behind fences.

Downstream

In downstream refining, the gas risks may be almost any hydrocarbon, and may also include hydrogen sulphide, sulphur dioxide and other by-products. Catalytic flammable gas detectors are one of the oldest flammable gas detector types. They work well, but must have a bump testing station, to ensure each detector responds to the target gas and is still functional. The ongoing demand to reduce facility down-time whilst ensuring safety, especially during shutdown and turnaround operations, means that gas detection manufacturers must deliver solutions offering ease of use, straightforward training and reduced maintenance times, along with local service and support.

During plant shutdowns, processes are stopped, items of equipment are opened and checked and the number of people and moving vehicles at the site is many times higher than normal. Many of the processes undertaken will be hazardous and require specific gas monitoring. For example, welding and tank cleaning activities require area monitors as well as personal monitors to protect those on site.

Confined space

Hydrogen sulphide (H2S) is a potential problem in the transport and storage of crude oil. The cleaning of storage tanks presents a high hazard potential. Many confined-space entry problems can occur here, including oxygen deficiency resulting from previous inerting procedures, rusting, and oxidation of organic coatings. Inerting is the process of reducing the oxygen levels in a cargo tank to remove the oxygen element required for ignition. Carbon monoxide can be present in the inerting gas. In addition to H2S, depending on the characteristics of the product previously stored in the tanks, other chemicals that may be encountered include metal carbonyls, arsenic, and tetraethyl lead.

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 Clip SGD, Gasman, Tetra 3,Gas-Pro, T4, Gas-Pro TK 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, Fgard IR3 Flame Detector 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 petrochemical industry our panels include Addressable Controllers, Vortex and Gasmonitor.

To find out more on the gas hazards in the petrochemical industry visit our industry page for more information.

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.  

Gas Safety Protocols in Water Treatment

Water is vital to our daily lives, both for personal and domestic use and industrial/commercial applications. It is everywhere, promoting some chemical reactions and inhibiting others. Being used to clean surfaces, carry chemicals to where they are used and to carry unwanted chemicals away. Do anything and you create a gas somewhere in some quantity. Do anything with water there are so many permutations of things that can come together and react, dissolved gases that can come out of solution, dissolved liquids and solids that can react to generate gases. Additionally, you must determine what gases you generate when you collect, clean, store, transport or use water. Gas detectors must be chosen to suit the specific environment in which they operate, in this case highly humid, often dirty, but rarely outside the temperature range 4 to 30 degrees C. All the risks are present in these complex environments, with multiple toxic and flammable gas hazards and often the additional risk of oxygen depletion.

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.

Chlorine (Cl2) gas appears yellow green in colour, used to sterilise drinking water. However, most chlorine is used in the chemical industry with typical applications including water treatment as well as within the plastics and cleaning agents. Chlorine gas can be recognised by its pungent, irritating odour, which is like the odour of bleach. The strong smell may provide adequate warning to people that they are exposed. Cl2 itself is not flammable, but it can react explosively or form flammable compounds with other chemicals such as turpentine and ammonia.

Ammonia (NH3) is a compound of nitrogen and hydrogen and is a colourless and pungent gas, also known to be highly soluble when in contact with water. This means that NH3 dissolves quickly into the water supply. Found at very low levels in humans and in nature. It is also often used in some household cleaning solutions. Although NH3 has many benefits, it can be corrosive and dangerous in certain circumstances. Ammonia can enter wastewater from several different sources, including urine, manure, cleaning chemicals, process chemicals and amino acid products. If NH3 enters a copper piping system, it can cause extensive corrosion. If NH3 enters water, its toxicity varies depending on the exact pH of the water. It is possible for ammonia to break down into ammonium ions, which can react with other compounds present.

Chlorine dioxide (ClO2) is an oxidising gas commonly used to disinfect drinking water. When used in very small quantities, it is safe and does not lead to significant health risks. But ClO2 is a strong disinfectant that kills bacteria, viruses, and fungi, and when used in high doses, it can be dangerous to people since it can damage red blood cells and the lining of the gastrointestinal (GI) tract.

Ozone (O3) is a gas with an antiseptic smell and no colour that, mostly, forms naturally in the environment. When inhaled, ozone can have a range of harmful effects on the body. As it is colourless gas it is difficult to trace without an effective detection system in place. Even when relatively small amounts are inhaled, the gas can have a damaging impact on the respiratory tract, causing inflammation and chest pain, alongside coughing, shortness of breath and throat irritation. It can also act as a trigger causing diseases such as asthma to worsen.

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.

Legislation

European Commission Directive 2017/164 established an increased 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. Non-binding but best practice. 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 solution

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 people against a wide range of gas hazards, and include T4x, Clip SGD, Gasman, Tetra 3, Gas-Pro, T4 and Detective+. Our fixed gas detectors are used where reliability, dependability and lack of false alarms are instrumental to efficient and effective protection of assets and areas, and include the Xgard, Xgard Bright and IRmax product ranges. 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 we often recommend our Gasmaster panel.

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

Gas Hazards in Wastewater

Water is vital to our daily lives, both for personal and domestic use and industrial/commercial applications making water sites both numerous and widespread. Despite the quantity and location of water sites, only two environments predominate, and these are quite specific. They are clean water and wastewater. This blog details gas risks encountered at wastewater sites and how they may be mitigated. 

The wastewater industry is always wet, with temperatures between 4 and 20oc near the water and rarely far from that limited temperature range even away from the immediate location of the wastewater. 90%+ relative humidity, 12 +/- 8oc, atmospheric pressure, with multiple toxic and flammable gas hazards and the risk of oxygen depletion. Gas detectors must be chosen to suit the specific environment in which they operate, and whilst high humidity is generally challenging to all instrumentation, the constant pressure, moderate temperatures and narrow temperature range is a far greater benefit to safety instrumentation. 

Gas Hazards  

The main gases of concern in wastewater treatment plants are:

Hydrogen sulphide, methane and carbon dioxide are the by-products of the decomposition of organic materials that exist in the waste flows feeding the plant. The build-up of these gases may lead to the lack of oxygen, or in some cases, explosion when coupled with a source of ignition. 

Hydrogen sulphide (H2S)

Hydrogen sulphide is a common product of the biodegradation of organic matter; pockets of H2S can collect in rotting vegetation, or sewage itself, and be released when disturbed. Workers in sewerage and wastewater plants and pipework can be overcome by H2S, with fatal consequences. Its high toxicity is the main danger of H2S. Prolonged exposure to 2-5 parts per million (ppm) H2S can cause nausea and headaches and bring tears to the eyes. H2S is an anaesthetic, hence at 20ppm, symptoms include fatigue, headaches, irritability, dizziness, temporary loss of the sense of smell and impaired memory. Severity of symptoms increase with concentration as nerves shut down, through coughing, conjunctivitis, collapse and rapid unconsciousness. Exposure at higher levels can result in rapid knock down and death. Prolonged exposure to low levels of H2S may cause chronic illness or can also kill. Because of this, many gas monitors will have both instantaneous and TWA (Time-Weighted Average) alerts. 

Methane (CH4)

Methane is a colourless, highly flammable gas that is the primary component of natural gas, also referred to as biogas. It can be stored and/or transported under pressure as a liquid-gas. CH4 is a greenhouse gas that is also encountered in normal atmospheric conditions at a rate of approximately 2 parts per million (ppm). High exposure can lead to slurred speech, vision problems and memory loss. 

Oxygen (O2)

The normal concentration of oxygen in the atmosphere is approximately 20.9% volume. In the absence of adequate ventilation, the level of oxygen can be reduced surprisingly quickly by breathing and combustion processes. Olevels may also be depleted due to dilution by other gases such as carbon dioxide (also a toxic gas), nitrogen or helium, and chemical absorption by corrosion processes and similar reactions. Oxygen sensors should be used in environments where any of these potential risks exist. When locating oxygen sensors, consideration needs to be given to the density of the diluting gas and the “breathing” zone (nose level). 

Safety Considerations 

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. 

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 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 visit our industry page for more information.