Oxygen Depletion Risks from Nitrogen in Pharmaceutical Processing

Within the air, a normal concentration of oxygen is 21%, while nitrogen makes up 78% of the rest of the atmosphere along with some trace gases. Inert gases such as nitrogen, argon and helium although aren’t toxic, they do not help to support human breathing. These are odourless, colourless and tasteless making them undetectable. An increase in the volume of any other gases that are not oxygen can lead to a circumstance in which individuals may be at risk of asphyxiation which can cause serious injury or even death. This removal of oxygen gas in the air we breathe makes having an oxygen depletion sensor not just useful, but essential to maintaining life.

How is Nitrogen used to control oxygen levels?

Nitrogen (N2) can be used to control levels of oxygen in a laboratory. When carrying out tasks within the pharmaceutical industry, when transferring products or packaging process, nitrogen is used. Nitrogen is used to take oxygen away from the packaging prior to it being sealed, to make certain the product is preserved. As a result of this the need for an oxygen deficiency monitor is very important. Fixed or portable devices have the ability to detect oxygen levels within a laboratory, plant or utility room. Fixed gas detection systems are suitable for monitoring an area or room, whereas a portable gas detector is designed to be worn on the person within your breathing area.

What are the Risks of Oxygen depletion?

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

In the absence of adequate ventilation, the level of oxygen can be reduced surprisingly quickly by breathing and combustion processes. Oxygen levels 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). For example, helium is lighter than air and will displace the oxygen from the ceiling downwards whereas carbon dioxide, being heavier than air, will predominately displace the oxygen below the breathing zone. Ventilation patterns must also be considered when locating sensors.

Oxygen monitors usually provide a first-level alarm when the oxygen concentration has dropped to 19% volume. Most people will begin to behave abnormally when the level reaches 17%, and hence a second alarm is usually set at this threshold. Exposure to atmospheres containing between 10% and 13% oxygen can bring about unconsciousness very rapidly; death comes very quickly if the oxygen level drops below 6% volume. Oxygen sensors are often installed in laboratories where inert gases (e.g., nitrogen) are stored in enclosed areas.

How do Fixed or Portable Devices Detect Oxygen?

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

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

Crowcon’s fixed detector XgardIQ is an intelligent and versatile fixed detector and transmitter compatible with Crowcon’s full range of sensor technologies. Available fitted with a variety of sensors for fixed flammable, toxic, oxygen or H2S gas detection. Providing analogue 4-20mA and RS-485 Modbus signals as standard, XgardIQ is optionally available with Alarm and Fault relays and HART communications. The 316 stainless steels are available with three M20 or 1/2“NPT cable entries. This device is also (SIL-2) Safety integrity level 2 certified fixed detector.

Keeping the Emergency Services Safe

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

What Gases are Present?

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

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

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

What are the risks?

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

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

What Products are Available?

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

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

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

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

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

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

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

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

What are the Dangers of Confined Space Entry?

What is Confined Space and is it Classified? 

Confined Space is a global concern. In this blog we are referencing the UK’s Health and Safety Executive’s dedicated documentation, as well as the United States OSHA ones, as these are broadly familiar to other countries own health and safety procedures. 

A Confined Space is a location that is substantially enclosed although not always entirely, and where serious injury can occur from hazardous substances or conditions within the space or nearby such as a lack of oxygen. As they are so dangerous, it has to be noted that any entry to confined spaces must be the only and final option in order to carry out work. 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. 

The Risks and Hazards:

A Confined Space that contains certain hazardous conditions may be considered a permit-required confined space under the standard. Permit-required confined spaces can be immediately dangerous to operator’s lives if they are not properly identified, evaluated, tested and controlled. Permit-required confined space can a defined as a confined space where there is a risk of one (or more) of the following: 

  • Serious injury due to fire or explosion 
  • Loss of consciousness arising from increased body temperature  
  • Loss of consciousness or asphyxiation arising from gas, fume, vapour, or lack of oxygen  
  • Drowning from an increase in the level of a liquid  
  • Asphyxiation arising from a free-flowing solid or being unable to reach a respirable environment due to being trapped by such a free-flowing solid 

These arise from the following hazards: 

  • Flammable substances and oxygen enrichment (read more) 
  • Excessive heat 
  • Toxic gas, fume or vapours 
  • Oxygen deficiency 
  • Ingress or pressure of liquids 
  • Free-flowing solid materials 
  • Other hazards (such as exposure to electricity, loud noise or loss of structural integrity of the space) 

Confined Space Identification

HSE classify Confined Spaces as any place, including any chamber, tank, vat, silo, pit, trench, pipe, sewer, flue, well or other similar space in which, by virtue of its enclosed nature, there arises a reasonably foreseeable specified risk, as outlined above.  

Most Confined Spaces are easy to identify although, identification is sometimes required as a Confined Space is not necessarily be an enclosed on all sides – some, such as vats, silos and ships’ hold, may have open tops or sides. Nor are exclusive to a small and/or difficult to work in space – some, like grain silos and ships’ holds, can be very large. They may not be that difficult to get in or out of – some have several entrances/exits, others have quite large openings or are apparently easy to escape from. Or a place where people do not regularly work – some Confined Spaces (such as those used for spray painting in car repair centres) are used regularly by people in the course of their work 

There may be instances where a space itself may not be defined as a Confined Space, however, while work is ongoing, and until the level of oxygen recovers (or the contaminants have dispersed by ventilating the area), it is classified as a Confined Space. Example scenarios are: welding that would consume some of the available breathable oxygen, a spray booth during paint spraying; using chemicals for cleaning purposes which can add volatile organic compounds (VOCs) or acidic gases, or an area subjected to significant rust which has reduced available oxygen to dangerous levels. 

What are the Rules and Regulations for Employers?

OSHA (Occupational Safety and Health Administration) have released a factsheet that highlights all the rules and regulations of residential workers in Confined Spaces.  

Under the new standards, the obligation of the employer will depend on what type of employer they are. The controlling contractor is the main point of contact for any information about PRCS on site.  

The Host employer: The employer who owns or manages the property where the construction work is taking place. 

Employer can’t rely solely on the emergency services for rescue. A dedicated service must be ready to act in the event of an emergency.  The arrangements for emergency rescue, required under regulation 5 of the Confined Spaces Regulations, must be suitable and sufficient. If necessary, equipment to enable resuscitation procedures to be carried out should be provided. The arrangements should be in place before any person enters or works in a confined space. 

The Controlling contractor: The employer who has overall responsibility for construction at the worksite. 

 The Entry employer or Sub Contractor: Any employer who decides that an employee it directs will enter a permit-required confined space. 

Employees have the responsibility to raise concern such as helping highlight any potential workplace risks, ensuring that health and safety controls are practical and increasing the level of commitment to working in a safe and healthy way.  

Testing/ Monitoring the Atmosphere:

Prior to entry, the atmosphere within a confined space should be tested to check the oxygen concentration and for the presence of hazardous gas, fume or vapour. Testing should be carried out where knowledge of the confined space (e.g. from information about its previous contents or chemicals used in a previous activity in the space) indicates that the atmosphere might be contaminated or to any extent unsafe to breathe, or where any doubt exists as to the condition of the atmosphere. Testing should also be carried out if the atmosphere is has been previously contaminated and was ventilated as a consequence (HSE Safe Work in Confined Spaces: Confined Spaces Regulations 1997 and Approved Codes of Practice). 

The choice of monitoring and detecting equipment will depend on the circumstances and knowledge of possible contaminants and you may need to take advice from a competent person when deciding on the type that best suits the situation – Crowcon can help with this.  

Monitoring equipment should be in good working order. Testing and calibration may be included in daily operator checks (a response check) where identified as necessary in accordance with our specification.  

Where there is a potential risk of flammable or explosive atmospheres, equipment specifically designed to measure for these will be required and certified Intrinsically Safe. All such monitoring equipment should be specifically suited for use in potentially flammable or explosive atmospheres. Flammable gas monitors must be calibrated for the different gases or vapours which the risk assessment has identified could be present and these may need alternative calibrations for different confined spaces. Get in touch if you require any help 

Testing should be carried out by people who are competent in the practice and aware of the existing standards for the relevant airborne contaminates being measured and are also instructed and trained in the risks involved in carrying out such testing in a confined space. Those carrying out the testing should also be capable of interpreting the results and taking any necessary action. Records should be kept of the results and findings ensuring that readings are taken in the following order: oxygen, flammable and then toxics. 

The atmosphere in a confined space can often be tested from the outside, without the need for entry, by drawing samples through a long probe. Where flexible sample tubing is used, ensure that it does not draw water or is not impeded by kinks, blockages, or blocked or restricted nozzles, in-line filters can help with this. 

What products are Intrinsically Safe and are suitable for Confined Space Safety?

These products are Certified to meet local Intrinsically Safe Standards.  

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

Gas-Pro TK offers the same gas safety benefits as the regular Gas-Pro, while offering Tank Check mode which can auto-range between %LEL and %Volume for inerting applications. 

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

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

Why it’s Important to Measure Nitrogen Oxide (NOx)?

In the EU and UK it is now obligatory for all new domestic heating and plumbing products (rated up to 400 kw) to comply with maximum nitrogen oxide (NOx) emission levels. This is line with a great deal of international regulation: NOx emissions are controlled by law or regulation in many countries (including the US, Canada, Australia and Singapore) and these may vary further by sector (maritime and automotive may have their own specific codes and limits, for example). 

The regulation of NOx required because this gas is a major pollutant, associated with thousands of deaths worldwide through its effects – both direct and indirect – on human health. It has been associated with asthma in children, lung inflammation and a host of other respiratory disorders, as well as cardiovascular damage. NOx is dangerous to animals, plants and ecosystems and is a major constituent of acid rain and smog. 

Despite its singular name, NOx is actually a collective term for nitrogen oxides – a family of highly reactive and poisonous gases – which are produced when fossil fuels are burned. Although NOx pollution is a global problem, large cities are particularly badly affected through vehicle exhaust fumes and heating system emissions; around a third of any large city’s NOx pollution comes from heating. In addition, nitrogen dioxide reacts in sunlight with other gases (such as volatile organic compounds) to generate ozone, which is a greenhouse gas.  

Why measure NOx? 

Since NOx emissions are increasingly regulated, they must be measured to ensure compliance with relevant directives. The measurement of NOx from boilers and other domestic appliances is also carried out to check that these are running safely, and to ensure the owner/operator and those around them are not being exposed to excessive NOx. 

Measuring NOx with a flue gas analyser/combustion analyzer 

Sprint ProAs well as having to meet the demands of regulation, the HVAC sector recognises the growing importance of NOx measurement due to the worldwide focus on sustainability and green issues, and awareness of its harmful effects on health. This is reflected in a growing market for combustion analyzers that calculate NOx (e.g. the Sprint Pro 5 and the Sprint Pro 6).  

In the short to medium term, demand for NOx measurement seems likely to increase; the reduction of NOx emissions is a key component of sustainability policies worldwide and HVAC engineers and designers are prioritising the design of better, cleaner forms of heating (which will have to be benchmarked, verified and maintained).  

Over time, highly efficient, ultra-low-NOx systems are likely to dominate, and the measurement of NOx will therefore become an increasingly important parameter and a more prominent part of day-to-day work in the HVAC sector. 

Our Sprint Pro 5 and 6 models come complete with dedicated NO sensors allowing for a range of NO and NOx measurement options

What is a Flame Detector and How Does it Work?

What is a Flame Detector? 

A flame detector is a type of sensor that can detect and respond to the presence of a flame. These detectors have the ability to identify smokeless liquid and smoke that can create open fire. For example, in boiler furnaces flame detectors are widely used, as a flame detector can detect heat, smoke, and fire. These devices can also detect fire according to the air temperature and air movement. The flame detectors use Ultraviolet (UV) or Infra-Red (IR) technology to identify flames meaning they can alert to flames in less than a second. The flame detector would respond to the detection of a flame according to its installation, it could for example sound an alarm, deactivate the fuel line, or even activate a fire suppression system. 

Where would you find these Detectors? 

  • Industrial warehouses
  • Chemical production plants 
  • Chemical stores 
  • Petrol storage and pump stations 
  • Arc welding workshops 
  • Power plants 
  • Transformer stations 
  • Underground tunnels 
  • Motor testbeds 
  • Wood stores 

What are the Components of a Flame Monitoring System and does it work?

The major component of a flame detector system is the detector itself. It comprises of photoelectric detective circuits, signal conditioning circuits, microprocessor systems, I/O circuits, and wind cooling systems. The sensors in the flame detector will detect the radiation that is sent by the flame, the photoelectric converts the radiant intensity signal of the flame to a relevant voltage signal and this signal would be processed in a single chip microcomputer and converted into a desired output. 

How many types of Flame Detectors are there and how do they work? 

There are 3 different types of flame detector: Ultra-Violet, Infra-Red and a combination of them both Ultra-Violet-Infra-Red 

Ultra-Violet (UV) 

This type of flame detector works by detecting the UV radiation at the point of ignition. Almost entirely all fires emit UV radiations, so in case of the flame, the sensor would become aware of it and produce a series of the pulses that are converted by detector electronics into an alarm output.  

There are advantages and disadvantages of a UV detector. Advantages of UV detector include High-speed response, the ability to respond to hydrocarbon, hydrogen, and metal fires. On the other hand, the disadvantages of UV detectors include responding to welding at long range, and they may also respond to lightning, sparks, etc. 

Infra-Red (IR) 

The infra-red flame detector works by checking the infrared spectral band for certain ornamentation that hot gases release. However, this type of device requires a flickering motion of the flame. The IR radiation may not only be emitted by flames, but may also be radiated from ovens, lamps, etc. Therefore, there is a higher risk for a false alarm 

UV-IR 

This type of detector is capable to detect both the UV and IR radiations, so it possesses both the UV and IR sensor. The two sensors individually operate the same as those described, but supplementary both circuitry processes signals are present due to there being both sensors. Consequently, the combined detector has better false alarm rejection capability than the individual UV or IR detector. 

Although there are advantages and disadvantages of UV/IR flame detector. Advantages include High-speed response and are immune to the false alarm. On the other hand, the disadvantages of UV/IR flame detector include the issue that it cannot be used for non-carbon fires as well as only being able to detect fires that emits both the UV/IR radiation not individually.  

Are any products available? 

The FGard IR3 delivers superior performance in the detection of hydrocarbon fires. The device utilises the latest IR flame detection algorithms to ensure maximum false alarm immunity. The detector has been independently tested to demonstrate it can detect a hydrocarbon fuel pan fire at nearly 200 feet in less than 5 seconds. The FGuard IR3 has a multi spectrum IR allowing for 60 metre flame detection range. That can detect all Hydrocarbon fires with no condensation forming on the window, improving reliability and performance across temperature. This product has fast detection time responding in less than 5 seconds to 0.1m² fire at 60 metres.  

Crowcon offers a range of infra-red (IR) and ultra-violet (UV) based flame detectors for quickly detecting flames at a distance. Depending on model, this includes a variety of gas and fuel fires including those generated from hydrocarbons, hydrogen, metals, inorganic and hydroxyl sources.

What’s the difference between a pellistor and an IR sensor?

Sensors play a key role when it comes to monitoring flammable gases and vapours. Environment, response time and temperature range are just some of the things to consider when deciding which technology is best.

In this blog, we’re highlighting the differences between pellistor (catalytic) sensors and infrared (IR) sensors, why there are pros and cons to both technologies, and how to know which is best to suit different environments.

Pellistor sensor

A pellistor gas sensor is a device used to detect combustible gases or vapours that fall within the explosive range to warn of rising gas levels. The sensor is a coil of platinum wire with a catalyst inserted inside to form a small active bead which lowers the temperature at which gas ignites around it. When a combustible gas is present the temperature and resistance of the bead increases in relation to the resistance of the inert reference bead. The difference in resistance can be measured, allowing measurement of gas present. Because of the catalysts and beads, a pellistor sensor is also known as a catalytic or catalytic bead sensor.

Originally created in the 1960’s by British scientist and inventor, Alan Baker, pellistor sensors were initially designed as a solution to the long-running flame safety lamp and canary techniques. More recently, the devices are used in industrial and underground applications such as mines or tunnelling, oil refineries and oil rigs.

Pellistor sensors are relatively lower in cost due to differences in the level of technology in comparison to IR sensors, however they may be required to be replaced more frequently.

With a linear output corresponding to the gas concentration, correction factors can be used to calculate the approximate response of pellistors to other flammable gases, which can make pellistors a good choice when there are multiple flammable vapours present.

Not only this but pellistors within fixed detectors with mV bridge outputs such as the Xgard type 3 are highly suited to areas that are hard to reach as calibration adjustments can take place at the local control panel.

On the other hand, pellistors struggle in environments where there is low or little oxygen, as the combustion process by which they work, requires oxygen. For this reason, confined space instruments which contain catalytic pellistor type LEL sensors often include a sensor for measuring oxygen.

In environments where compounds contain silicon, lead, sulphur and phosphates the sensor is susceptible to poisoning (irreversible loss of sensitivity) or inhibition (reversible loss of sensitivity), which can be a hazard to people in the workplace.

If exposed to high gas concentrations, pellistor sensors can be damaged. In such situations, pellistors do not ‘fail safe’, meaning no notification is given when an instrument fault is detected. Any fault can only be identified through bump testing prior to each use to ensure that performance is not being degraded.

 

IR sensor

Infrared sensor technology is based on the principle that Infrared (IR) light of a particular wavelength will be absorbed by the target gas. Typically there are two emitters within a sensor generating beams of IR light: a measurement beam with a wavelength that will be absorbed by the target gas, and a reference beam which will not be absorbed. Each beam is of equal intensity and is deflected by a mirror inside the sensor onto a photo-receiver. The resulting difference in intensity, between the reference and measurement beam, in the presence of the target gas is used to measure the concentration of gas present.

In many cases, infrared (IR) sensor technology can have a number of advantages over pellistors or be more reliable in areas where pellistor-based sensor performance can be impaired- including low oxygen and inert environments. Just the beam of infrared interacts with the surrounding gas molecules, giving the sensor the advantage of not facing the threat of poisoning or inhibition.

IR technology provides fail-safe testing. This means that if the infrared beam was to fail, the user would be notified of this fault.

Gas-Pro TK uses a dual IR sensor – the best technology for the specialist environments where standard gas detectors just won’t work, whether tank purging or gas freeing.

An example of one of our IR based detectors is the Crowcon Gas-Pro IR, ideal for the oil and gas industry, with the availability to detect methane, pentane or propane in potentially explosive, low oxygen environments where pellistor sensors may struggle. We also use a dual range %LEL and %Volume sensor in our Gas-Pro TK, which is suitable for measuring and switching between both measurements so it’s always safely operating to the correct parameter.

However, IR sensors aren’t all perfect as they only have a linear output to target gas; the response of an IR sensor to other flammable vapours then the target gas will be non-linear.

Like pellistors are susceptible to poisoning, IR sensors are susceptible to severe mechanical and thermal shock and also strongly affected by gross pressure changes. Additionally, infrared sensors cannot be used to detect Hydrogen gas, therefore we suggest using pellistors or electromechanical sensors in this circumstance.

The prime objective for safety is to select the best detection technology to minimise hazards in the workplace. We hope that by clearly identifying the differences between these two sensors we can raise awareness on how various industrial and hazardous environments can remain safe.

For further guidance on pellistor and IR sensors, you can download our whitepaper which includes illustrations and diagrams to help determine the best technology for your application.

You won’t find Crowcon sensors sleeping on the job

MOS (metal oxide semiconductor) sensors have been seen as one of the most recent solutions for tackling detection of hydrogen sulphide (H2S) in fluctuating temperatures from up to 50°C down to the mid-twenties, as well as humid climates such as the Middle East.

However, users and gas detection professionals have realised MOS sensors are not the most reliable detection technology. This blog covers why this technology can prove difficult to maintain and what issues users can face.

One of the major drawbacks of the technology is the liability of the sensor “going to sleep” when it doesn’t encounter gas for a period of time. Of course, this is a huge safety risk for workers in the area… no-one wants to face a gas detector that ultimately doesn’t detect gas.

MOS sensors require a heater to equalise, enabling them to produce a consistent reading. However, when initially switched on, the heater takes time to warm up, causing a significant delay between turning on the sensors and it responding to hazardous gas. MOS manufacturers therefore recommend users to allow the sensor to equilibrate for 24-48 hours before calibration. Some users may find this a hinderance for production, as well as extended time for servicing and maintenance.

The heater delay isn’t the only problem. It uses a lot of power which poses an additional issue of dramatic changes of temperature in the DC power cable, causing changes in voltage as the detector head and inaccuracies in gas level reading. 

As its metal oxide semiconductor name suggests, the sensors are based around semiconductors which are recognised to drift with changes in humidity- something that is not ideal for the humid Middle Eastern climate. In other industries, semiconductors are often encased in epoxy resin to avoid this, however in a gas sensor this coating would the gas detection mechanism as the gas couldn’t reach the semiconductor. The device is also open to the acidic environment created by the local sand in the Middle East, effecting conductivity and accuracy of gas read-out.

Another significant safety implication of a MOS sensor is that with output at near-zero levels of H2S can be false alarms. Often the sensor is used with a level of “zero suppression” at the control panel. This means that the control panel may show a zero read-out for some time after levels of H2S have begun to rise. This late registering of low-level gas presence can then delay the warning of a serious gas leak, opportunity for evacuation and the extreme risk of lives.

MOS sensors excel in reacting quickly to H2S, therefore the need for a sinter counteracts this benefit. Due to H2S being a “sticky” gas, it is able to be adsorbed onto surfaces including those of sinters, in result slowing down the rate at which gas reaches the detection surface.

To tackle the drawbacks of MOS sensors, we’ve revisited and improved on the electrochemical technology with our new High Temperature (HT) H2S sensor for XgardIQ. The new developments of our sensor allow operation of up to 70°C at 0-95%rh- a significant difference against other manufacturers claiming detection of up to 60°C, especially under the harsh Middle Eastern environments.

Our new HT H2S sensor has been proven to be a reliable and resilient solution for the detection of H2S at high temperatures- a solution that doesn’t fall asleep on the job!

Click here for more information on our new High Temperature (HT) H2S sensor for XgardIQ.

An ingenious solution to the problem of high temperature H2S

Due to extreme heat in the Middle East climbing up to 50°C in the height of summer, the necessity for reliable gas detection is critical. In this blog, we’re focusing on the requirement for detection of hydrogen sulphide (H2S)- a long running challenge for the Middle East’s gas detection industry.

By combining a new trick with old technology, we’ve got the answer to reliable gas detection for environments in the harsh Middle Eastern climate. Our new High Temperature (HT) H2S sensor for XgardIQ has been revisited and improved by our team of Crowcon experts by using a combination of two ingenious adaptations to its original design.

In traditional H2S sensors, detection is based on electrochemical technology, where electrodes are used to detect changes induced in an electrolyte by the presence of the target gas. However, high temperatures combined with low humidity causes the electrolyte to dry out, impairing sensor performance so that the sensor has to be replaced regularly; meaning high replacement costs, time and efforts.

Making the new sensor so advanced from its predecessor is its ability to retain the moisture levels within the sensor, preventing evaporation even in high temperature climates. The updated sensor is based on electrolytic gel, adapted to make it more hygroscopic and avoiding dehydration for longer.

As well as this, the pore in the sensor housing has been reduced, limiting the moisture from escaping. This chart indicated weight loss which is indicative of moisture loss. When stored at 55°C or 65°C for a year just 3% of weight is lost. Another typical sensor would lose 50% of its weight in 100 days in the same conditions.

For optimal leak detection, our remarkable new sensor also features an optional remote sensor housing, while the transmitter’s displays screen and push-button controls are positioned for safe and easy access for operators up to 15metres away.

 

The results of our new HT H2S sensor for XgardIQ speak for themselves, with an operating environment of up to 70°C at 0-95%rh, as well featuring a 0-200ppm and T90 response time of less than 30 seconds. Unlike other sensors for detecting H2S, it offers a life expectancy of over 24 months, even in tough climates like the Middle East.

The answer to the Middle East’s gas detection challenges fall in the hands of our new sensor, providing its users with cost-effective and reliable performance.

Click here for more information about the Crowcon HT H2S sensor.

Once again, Gas-Pro is ‘detector of choice’ for volcano environmental expedition

We are all familiar with the term global warming and often see statistics about the potential effects this could have on our planet.  One such prediction is by the end of this century the globe will increase in temperature by between 0.8 and 4 degrees.

What many of us may not know is that volcanoes, which are a completely natural phenomenon, contribute a significant amount of gases into our atmosphere. And these gases are currently not considered in the world’s climate models, which means there is potentially a large margin of error.

However, this could be about to change as Yves Moussallam, an inspiring French Volcanologist, who with the support of Rolex and the 2019 Rolex Awards for Enterprise, has made it his mission to understand volcanos and how they impact on our planet.  He ventures into these dramatic and dangerous environments to take measurements which are used by scientists and climatologists to improve their prediction models.

By observing volcanos, and gathering this vitally important data, he is helping the world understand the impact volcanos are having on climate change.

Yves is no stranger to volcanic expeditions. In 2015, he led a small team to the Nazca subduction zone in South America. Their mission was to provide the first accurate and large-scale estimate of the flux of several volatile gas species.

To keep the team safe, Yves selected Crowcon detection equipment and was delighted with Gas man and Gas-Pro’s lightweight, clean and safe functionality.

Now Yves is back with a new expedition and has turned to Crowcon once again. This time, Yves is heading to the region of Melanesia in Italy.  Satellites, which are used to track volcanic behaviour, have shown that this region is responsible for approximately a third of global volcanic gas emissions.

His expedition will climb these volcanoes and take measurements directly in the volcanic plume.

There are two main methods to measure gases in volcanoes.  The first is via satellite which takes images from space.  The second is to go directly into the field and measure gas released at its source.

Experts believe the method of working directly in the field is the most accurate as it is positioned far closer to the source so there is a reduced risk of error.

To conduct these measurements requires tried, tested and trusted equipment and with Crowcon’s proven track record, Yves turned again to Gas-Pro.

Crowcon’s Gas-Pro includes an onboard datalogging feature which will provide an extra line of data and an idea of average exposure, which is important for expeditions that span longer periods.  It is also lightweight which is hugely beneficial when carrying bulky equipment.

Everyone at Crowcon wishes Yves a safe and successful expedition and we hope the data he gathers will help us understand the impact volcanos have on our world.

#Rolex #RolexAwards #PerpetualPlanet #Perpetual

Identifying Leaks from Natural Gas pipelines at a Safe Distance

The use of natural gas, of which methane is the principle component, is increasing worldwide. It also has many industrial uses, such as the manufacture of chemicals like ammonia, methanol, butane, ethane, propane and acetic acid; it is also an ingredient in products as diverse as fertilizer, antifreeze, plastics, pharmaceuticals and fabrics.

Natural gas is transported in several ways: through pipelines in gaseous form; as liquefied natural gas (LNG) or compressed natural gas (CNG). LNG is the normal method for transporting the gas over very long distances, such as across oceans, while CNG is usually carried by tanker trucks over short distances. Pipelines are the preferred transport choice for long distances over land (and sometimes offshore), such as between Russia and central Europe. Local distribution companies also deliver natural gas to commercial and domestic users across utility networks within countries, regions and municipalities.

Regular maintenance of gas distribution systems is essential. Identifying and rectifying gas leaks is also an integral part of any maintenance programme, but it is notoriously difficult in many urban and industrial environments, as the gas pipes may be located underground, overhead, in ceilings, behind walls and bulkheads or in otherwise inaccessible locations such as locked buildings. Until recently, suspected leaks from these pipelines could lead to whole areas being cordoned off until the location of the leak was found.

Precisely because conventional gas detectors – such as those utilising catalytic combustion, flame ionisation or semiconductor technology – are not capable of remote gas detection and are therefore unable to detect gas leaks in hard to access pipelines, there has been a lot of recent research into ways of detecting methane gas remotely.

Remote Detection

Cutting edge technologies are now becoming available which allow the remote detection and identification of leaks with pinpoint accuracy. Hand-held units, for example, can now detect methane at distances of up to 100 metres, while aircraft-mounted systems can identify leaks half a kilometre away. These new technologies are transforming the way natural gas leaks are detected and dealt with.

Remote sensing is achieved using infrared laser absorption spectroscopy. Because methane absorbs a specific wavelength of infrared light, these instruments emit infrared lasers. The laser beam is directed to wherever the leak is suspected, such as a gas pipe or a ceiling. Because some of the light is absorbed by the methane, the light received back provides a measurement of absorption by the gas. A useful feature of these systems is the fact that the laser beam can penetrate transparent surfaces, such as glass or perspex, so it may be possible to test an enclosed space prior to entering it. The detectors measure the average methane gas density between the detector and target. Readings on the handheld units are given in ppm-m (a product of the concentration of methane cloud (ppm) and path length (m)). In this way, methane leaks can be quickly confirmed by pointing a laser beam towards the suspected leak or along a survey line, for example.

An important difference between the new technology and conventional methane detectors is that the new systems measure average methane concentration, rather than detecting methane at a single point – this gives a more accurate indication of the severity of the leak.

Applications for hand-held devices include:

  • Pipeline surveys
  • Gas plant
  • Industrial and commercial property surveys
  • Emergency call out
  • Landfill gas monitoring
  • Road surface survey

Municipal Distribution Networks

The benefits of remote technology for monitoring pipelines in urban settings are now being realised.

The ability of remote detection devices to monitor gas leaks from a distance makes them extremely useful tools in emergencies. Operators can stay away from potentially dangerous leak sources when checking the presence of gas in closed premises or confined spaces as the technology allows them to monitor the situation without actually gaining access. Not only is this process easier and quicker, but it is also safe. Moreover, it is not affected by other gases present in the atmosphere since the detectors are calibrated to only detect methane – therefore there is no danger of getting false signals, which is important in emergency situations.

The principle of remote detection is also applied when inspecting risers (the above-ground pipes carrying gas to the customers’ premises and normally running along the building outside walls). In this case, the operators point the device towards the pipe, following its route; they can do this from ground level, without having to use ladders or access the customers’ properties.

Hazardous Areas

In addition to detecting gas leaks from municipal distribution networks, explosion-proof, ATEX approved devices can be used in Zone 1 hazardous areas such as petrochemical plants, oil refineries, LNG terminals and vessels, as well as certain mining applications.

When inspecting an LNG/LPG underground tank, for example, an explosion-proof device would be required within 7.5 metres of the tank itself and one metre around the safety valve. Operators therefore need to be fully aware of these restrictions and equipped with the appropriate equipment type.

GPS Coordination

Some instruments now allow spot methane readings to be taken at various points around a site – such as an LNG terminal – automatically generating GPS tracking of the measurement readings and locations. This makes return trips for additional investigations far more efficient, while also providing a bona-fide record of confirmed inspection activity – often a prerequisite for regulatory compliance.

Aerial Detection

Moving beyond hand-held devices, there are also remote methane detectors which can be fitted to aircraft and which detect leaks from gas pipelines over hundreds of kilometres. These systems can detect methane levels at concentrations as small as 0.5ppm up to 500 metres away and include a real-time moving map display of gas concentrations as the survey is conducted.

The way these systems work is relatively simple. A remote detector is attached beneath the aircraft’s fuselage (usually a helicopter). As with the handheld device, the unit produces an infrared laser signal, which is deflected by any methane leakage within its path; higher methane levels result in more beam deflection. These systems also utilise GPS, so the pilot can follow a real-time moving map GPS route display of the pipeline, with a real-time display of aircraft path, gas leaks and concentration (in ppm) presented to the crew at all times. An audible alarm can be set for a desired gas concentration, allowing the pilot to approach for closer investigation.

Conclusion

The range of remote methane detection systems is increasing rapidly, with new technologies being developed all the time. All these devices, whether hand-held or fitted to aircraft, allow quick, safe and highly targeted identification of leaks – whether beneath the pavement, in a city or across hundreds of kilometres of Alaskan tundra. This not only helps prevent wasteful and costly emissions – it also ensures personnel working on or near the pipelines are not exposed to unnecessary danger.

Because the use of natural gas is increasing worldwide we foresee rapid technological advances in remote gas detection in applications as diverse as leak survey, transmission integrity, plant and facilities management, agriculture and waste management, as well as process engineering applications such as coke and steel production. Each of these areas have situations where access may be difficult, combined with the need to put personnel protection at the top of the agenda. Opportunities for remote methane detectors are therefore growing all the time.