Why is gas emitted in cement production?

How is cement produced?

Concrete is one of the most important and commonly used materials in global construction. Concrete is widely used in the construction of both residential and commercial buildings, bridges, roads and more. 

The key component of concrete is cement, a binding substance which binds all the other components of concrete (generally gravel and sand) together. More than 4 billion tonnes of cement is used worldwide every year, illustrating the massive scale of the global construction industry. 

Making cement is a complex process, starting with raw materials including limestone and clay which are placed in large kilns of up to 120m in length, which are heated to up to 1,500°C. When heated at such high temperatures, chemical reactions cause these raw materials to come together, forming cement. 

As with many industrial processes, cement production is not without its dangers. The production of cement has the potential to release gases which are harmful to workers, local communities and the environment. 

What gas hazards are present in cement production?

The gases generally emitted in cement plants are carbon dioxide (CO2), nitrous oxides (NOx) and sulphur dioxide (SO2), with CO2 accounting for the majority of emissions. 

The sulphur dioxide present in cement plants generally comes from the raw materials which are used in the cement production process. The main gas hazard to be aware of is carbon dioxide, with the cement making industry responsible for a massive 8% of global CO2 emissions. 

The majority of carbon dioxide emissions are created from a chemical process called calcination. This occurs when limestone is heated in the kilns, causing it to break down into CO2 and calcium oxide.  The other main source of CO2 is the combustion of fossil fuels. The kilns used in cement production are generally heated using natural gas or coal, adding another source of carbon dioxide into addition to that which is generated through calcination. 

Detecting gas in cement production

In an industry which is a large producer of hazardous gases, detection is key. Crowcon offer a wide range of both fixed and portable detection solutions. 

Xgard Bright is our addressable fixed-point gas detector with display, providing ease of operation and reduced installation costs. Xgard Bright has options for the detection of carbon dioxide and sulphur dioxide, the gases of most concern in cement mixing. 

For portable gas detection, the Gasman’s  rugged yet portable and lightweight design make it the perfect single-gas solution for cement production, available in a safe area CO2 version offering 0-5% carbon dioxide measurement. 

For enhanced protection, the Gas-Pro multi-gas detector can be equipped with up to 5 sensors, including all of those most common in cement production, CO2, SO2 and NO2.

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 Dangers of Gas in Farming and Agriculture 

Farming and agriculture is a colossal industry the world over, providing more than 44 million jobs in the EU and making up over 10% of total US employment. 

With a wide range of processes involved in this sector, there are bound to be hazards that must be considered. These include gas hazards from the likes of methane, hydrogen sulphide, ammonia, carbon dioxide and nitrous oxide. 

Methane is a colourless, odourless gas which can have harmful effects on humans resulting in slurred speech, vision problems, memory loss, nausea and in extreme cases can impact breathing and heartrate, potentially leading to unconsciousness and even death. In agricultural environments, it is created through anaerobic digestion of organic material, such as manure. The amount of methane generated is exacerbated in areas which are poorly ventilated or high in temperature, and in areas with particular lack of airflow, the gas can build up, become trapped and cause explosions. 

Carbon dioxide (CO2) is a gas which is naturally produced in the atmosphere, levels of which can be heightened by agricultural processes. CO2 can be emitted by a range of farming process including crop and livestock production and is also emitted by some equipment which is used in agricultural applications. Storage spaces used for waste and grain and sealed silos are of particular concern due to the capacity for CO2 to build up and displace oxygen, increasing suffocation risk for both animals and humans alike. 

Similarly, to methane, hydrogen sulphide comes from the anaerobic decomposition of organic material and can also be found in a range of agricultural processes relating to the production and consumption of biogas. H2S prevents oxygen from being carried to our vital organs and areas where it builds up often have reduced oxygen concentrations, furthering the risk of asphyxiation where H2S levels are high. Whilst it could be considered easier to detect due its distinct ‘rotten egg’ smell, the intensity of the smell actually decreases at higher concentrations and prolonged exposure. At high levels, H2S can cause severe irritation of, and fluid build-up in the lungs and impact the nervous system. 

Ammonia (NH3) is a gas found in animal waste which is often then spread and emitted further through slurry spreading on agricultural land. As with many of the gases covered, the impact of ammonia is heightened when there is a lack of ventilation. It is harmful to the wellbeing of both livestock and humans, causing respiratory diseases in animals whilst high levels can lead to burns and swelling of the airways and lung damage in humans and can be fatal. 

Nitrogen oxide (NO2) is another gas to be aware of in the agriculture and farming industry. It is present in synthetic fertilisers which are often used in more intensive farming practices to ensure greater crop yields. The potential negative health impacts of NO2 in humans include reduced lung function, internal bleeding, and ongoing respiratory problems.  

Workers in this industry are frequently on the move, and for this specific purpose Crowcon offers a wide range of fixed and portable gas detectors to keep workers safe. Crowcon’s portable range comprises T4, Gas-Pro, Clip SGD and Gasman all of which offer reliable, transportable detection capacities for a variety of gases. 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 and Xgard Bright. 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 farming and agriculture industry we often recommend our Gasmaster, Vortex and Addressable Controllers panels.

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

Detecting dangers in dairy: What gases should you be aware of? 

Global demand for dairy continues to increase in large part due to population growth, rising incomes and urbanisation. Millions of farmers worldwide tend approximately 270 million dairy cows to produce milk. Throughout the dairy farm industry there are a variety of gas hazards that pose a risk to those working in the dairy industry.  

What are the dangers workers face in the dairy industry?

Chemicals

Throughout the dairy farm industry, chemicals are used for variety of tasks including cleaning, applying various treatments such as vaccinations or medications, antibiotics, sterilising and spraying. If these chemicals and hazardous substances are not used or stored correctly, this can result in serious harm to the worker or the surrounding environment. Not only can these chemicals cause illness, but there is also a risk of death if a person is exposed. Some chemicals can be flammable and explosive whilst others are corrosive and poisonous. 

There are several ways to manage these chemical hazards, although the main concern should be in implementing a process and procedure. This procedure should ensure all staff are trained in the safe use of chemicals with records being maintained. As part of the chemical procedure, this should include a chemical manifest for tracking purposes. This type of inventory management allows for all personal to have access to Safety Data Sheets (SDS) as well as usage and location records. Alongside this manifest, there should be consideration for the review of current operation.  

  • What is the current procedure?  
  • What PPE is required?  
  • What is the process for discarding out of date chemicals and is there is a substitute chemical that could pose less of a risk to your workers? 

Confined Spaces

There are numerous circumstances that could require a worker to enter a confined space, including feed silos, milk vats, water tanks and pits in the dairy industry. The safest way to eliminate a confined space hazard, as mentioned by many industry bodies, is to employ a safe design. This will include the removal of any need to enter a confined space. Although, this may not be realistic and from time to time, cleaning routines need to take place, or a blockage may occur, however, there is a requirement to ensure there is the correct procedures to address the hazard. 

Chemical agents when used in a confined space can increase the risk of suffocation with gases pushing out oxygen. One way you can eliminate this risk is by cleaning the vat from the outside using a high-pressure hose. If a worker does need to enter the confined space, check that the correct signage is in place since entry and exit points will be restricted. You should consider isolation switches and check that your staff understand the correct emergency rescue procedure if something were to happen. 

Gas Hazards

Ammonia (NH3) is foundin animal waste and slurry spreading on farming and agricultural land. It is characteristically a colorless gas with a pungent smell that arises through the decomposition of nitrogen compounds in animal waste. Not only is it harmful to human health but also harmful to livestock wellbeing, due to its ability to cause respiratory diseases in livestock, and eye irritation, blindness, lung damage, alongside nose and throat damage and even death in humans. Ventilation is a key requirement in preventing health issues, as poor ventilation heightens the damage caused by this gas.  

Carbon dioxide (CO2) is naturally produced in the atmosphere; although, levels are increased through farming and agricultural processes. CO2, is colorless, odourless, and is emitted from agricultural equipment, crop and livestock production and other farming processes. CO2 can congregate areas, such as waste tanks and silos. This results in oxygen in the air to be displaced and increasing the risk of suffocation for animals and humans.  Sealed silos, waste and grain storage spaces are specifically dangerous as CO2 can accumulate here and lead to them being unsuitable for humans without an external air supply. 

Nitrogen dioxide (NO2) is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NOx). At worst, it can cause sudden death when consumed even from short term exposure. This gas can cause suffocation and is emitted from silos following specific chemical reactions of plant material. It is recognisable by its bleach-like smell and its properties tend to create a red-brown haze. As it gathers above certain surfaces it can run into areas with livestock through silo chutes, and therefore poses a real danger to humans and animals in the surrounding area. It can also affect lung function, cause internal bleeding, and ongoing respiratory problems. 

When should gas detectors be used?

Gas detectors provide added value anywhere on dairy farms and around slurry silos, but above all: 

  • When and where slurry is being mixed 
  • During pumping and bringing out slurry
  • On and around the tractor during slurry mixing or spreading 
  • In the stable during maintenance work on slurry pumps, slurry scrapers and the like 
  • Near and around small openings and cracks in the floor, e.g., around milking robots 
  • Low to the ground in poorly ventilated corners and spaces (H2S is heavier than air and sinks to the floor) 
  • In slurry silos 
  • In slurry tanks 

Products that can help to protect yourself 

Gas detection can be provided in both fixed and portable forms. Installation of a fixed gas detector can benefit a larger space to provide continuous area and staff protection 24 hours a day. However, a portable detector can be more suited for worker’s safety. 

To find out more on the dangers in agriculture and farming, visit our industry page for more information. 

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. 

Cross sensitivity of toxic sensors: Chris investigates the gases that the sensor is exposed to

Working in Technical Support, one of the most common questions from customers is for bespoke configurations of toxic gas sensors. This frequently leads to an investigation into the cross sensitivity of the different gases that the sensor will be exposed to.

Cross sensitivity responses will vary from sensor type to sensor type, and suppliers often express the cross sensitivity in percentages while others will specify in actual parts-per-million (ppm) levels.

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