Our Partnership with Thorne and Derrick

Background 

Founded in 1985, Thorne & Derrick (T&D) and with offices in Chester-Le-Street and Bristol are leaders in product development and problem solving in hazardous areas. T&D distribute our full range of gas detection products, supplying industries such as utilities, power, renewable energy, construction, rail, offshore, oil, gas and petrochemical industries. Thorne & Derrick provide constancy to their global customer portfolio through high responsivity and are absolutely committed to providing world-class customer service. 

Views on gas detection

Portable gas detection is an essential piece of equipment when detecting toxic or explosive gases and measuring gas concentration. T&D put the customers needs at the forefront, by providing workers in all sectors with safety products that are correctly certified and efficient. This helps to alleviate the risk of working in hazardous areas alongside Thorne & Derrick’s provision of certified and safe portable & temporary lighting, power, heat and ventilation to ensure workers can carry out maintenance, repair and installation works safely. 

Through expertise and confidence given by their sales engineers as well as listening to the customer’s requirements, T&D confidently provide solutions that are fully compliant with regulations and that are tailored to what the customer needs. 

Working with Crowcon

A 10-year partnership and continued communication have allowed Thorne & Derrick to supply their customers with gas detection solutions and aim to continue to educate and meet legislation. “We’re thrilled to be working alongside T&D to provide gas detection to support a wide range of applications of applications in numerous industries”- Natalie Lundie, Marketing Lead. With over 35 years of experience, T&D delivers effective gas detection solutions providing confidence for those working in hazardous areas.  

Are there dangers of gas in telecommunications? 

The telecommunication industry contains includes cable providers, internet service providers, satellite providers and telephone providers and confined spaces. Even simple above ground termination boxes may contain gas hazards that is generated from the cables runs underground. Gases such as methane, carbon monoxide and hydrogen sulphide can run through the cable trunking and appear when the termination box is opened. 

Fixed systems are also required in “hub sites” and remote buildings. These are locations where cables are terminated and junctions or take off points are put into the networks. The danger risk can occur when a worker is sent to do carry out tasks in these locations, that may not have been accessed for a period of time. All telecommunications companies have these in abundance. 

What are the Dangers?

Those working in the telecommunications industry are at risk from many different dangers, all of which could cause harm to their health and safety. Falls from heights are a possibility due to the location of operations from various elevated vantage points, such as communication towers. Therefore, engineers working in the sector are required to secure harnesses whilst ascending telephone poles to check the cables, obviously with suitable training to do so. 

Workers are also at risk due to their proximity to microwave and RF radiation, known as non-ionizing radiation. Working amongst, or near to, electromagnetic waves can lead to severe long-term health issues, such as cancer and leukaemia, although unproven. Conditions such as Alzheimer’s, Parkinson’s, and chronic fatigue are also found in individuals who are exposed to heat waves over a long period of time. Whilst little is proven linking disease to these adverse environments, awareness of them and minimising the risks that could lead to adverse effects is a well-known safety principle. 

Electrical issues such as fluctuating voltage and associated malfunctions and short circuits, put workers at risk of electrocution. Training and proper PPE can help protect workers from these hazards. 

Gas Hazards and Risks 

As there are many confined spaces in the telecommunication industry workers are more at risk from the presence of hazardous and toxic gases here. Hazardous gases can also be linked to seemingly-simple above-ground termination boxes. Gases such as methane, carbon monoxide and hydrogen sulphide sometimes travel through the cable trunking, and therefore, when the termination box is opened, a build-up of these gases can be released. 

Fixed systems in the telecommunication sector also pose a gas risk, specifically in “hub sites” and remote buildings. These locations are dangerous, where cables are terminated and junctions or take off points are put into the networks. The danger risk can become present when a worker is sent to carry out tasks in locations that may not have been accessed for a period of time. This is very common in the telecommunication sector, where the trend towards more reliable equipment results in a reduce need for intervention. Although a positive, increased risks such as these, and the presence of toxic gases that can harm human health needs to be managed and mitigated. This is why it is so important to make sure that all workers have access to the proper gas detection equipment. 

Enclosed or partially enclosed spaces with high levels of methane in the air reduce the amount of oxygen available to breathe and therefore can cause mood changes, speech and vision problems, memory loss, nausea, sickness, facial flushing and headaches. In more severe cases and prolonged exposure, there may be changes in breathing and heart rate, balance problems, numbness, and unconsciousness. There is also a risk of fire as methane is highly flammable. 

Carbon monoxide (CO) consumption also poses serious health issues to workers, with those ingesting the toxic substance facing flu-like symptoms, chest pain, confusion, fainting arrhythmias, seizures, or even worse health effects for high or long lasting exposures. Hydrogen sulphide (H2S) poisoning causes similar issues, as well as delirium, tremors, convulsions, and skin and eye irritation. High concentrations of H2S can produce extremely rapid unconsciousness and death. 

Our solution 

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 Tetra 3 and T4. 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 and Xgard Bright. Combined with a variety of our fixed detectors, our gas detection control panels offer a flexible range of solutions which are able to measure flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment, for the telecommunication industry our panels include Gasmaster 

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

Transportation and Key Gas Challenges 

The transportation sector is one of the largest industries in the world, spanning a variety of applications. The sector offers services concerned with the movement of people and cargo of all types, across air freight and logistics, airlines and airport services, road and rail, transportation infrastructure, trucking, highways, rail tracks, and marine ports and services. 

Gas hazards during transportation  

The transport of dangerous goods is regulated in order to prevent, accidents involving people or property, damage to the environment. There a numerous gas hazards including the transportation of hazardous material, air conditioning emissions, cabin combustion and hangar leaks.  

The transportation of hazardous materials poses a risk to those involved. There are nine classification areas specified by the United Nations (UN) including explosives, gases, flammable liquids and solids, oxidising substances, toxic substances, radioactive materials, corrosive substances and miscellaneous goods. With the risk of an accident occurring being more likely when transporting these materials. Although the biggest cause for concern within the industry being the transportation of non-flammable non-toxic gas is asphyxiation. As a slow leak in a storage container can drain all of the oxygen in the air and cause the individuals in the environment to suffocate. 

Leaks within aircraft hangars and fuel storage areas of highly explosive aviation fuel is an area that must be monitored to prevent fires, equipment damage, and at the worst fatalities. It is essential to choose a suitable gas detection solution that focuses on the aircraft rather than the aircraft hangar, avoids false alarms, and can monitor large areas. 

Not only is it the external environment that faces gas risks in transportation, those working in the sector also face similar challenges. Air conditioning emissions poses a gas hazard threat due to the burning of fossil fuels leading to a subsequent emission of carbon monoxide (CO). high levels of CO in a confined area such as a vehicle cabin, of more than the normal level (30ppm) or an oxygen level below normal (19%) can result in dizziness, feeling and being sick, tiredness and confusion, stomach pain, shortness of breath and difficulty breathing. Therefore, proper ventilation in these spaces with the assistance of a gas detector is paramount to ensuring the safe of those working in the transportation industry.  

Similarly, in the air sector cabin combustion and fuselage fires, in the central portion of an airplane, poses a real threat. Although flame retardant materials are applied, if a fire does start the cabin’s trim and fittings can still generate toxic gases and vapours that could be more dangerous than the fire itself. Inhalation of harmful gases caused by a fire in these environments tend to be the main direct cause of fatalities.  

Transportation Standards and Certifications 

Each mode of transport, (road, rail, air, sea and inland waterway) has its own regulations but they are generally harmonized with the United Nations Economic Commission for Europe (UNECE). The Hazardous Materials Transportation Act (HMTA), enacted in the USA in 1975, states that regardless of the type of transportation, any company whose goods fall into one of the nine categories specified as hazardous by the UN, must comply with the regulations or risk fines and penalties. 

Those working in the transport sector in the UK must comply with the requirements laid out in the UN Model Regulations which assigns each dangerous substance or article a specific class that correlates how dangerous it is. It does this via the packing group (PG) classification, according to PG I, PG II or PG III. 

From an European standpoint the International Carriage of Dangerous Goods by Road (ADR) governs the regulations on how to classify, pack, label and certify dangerous goods. It also comprises vehicle and tank requirements and other operational requirements. The Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations (2009) also is relevant in England, Wales and Scotland. 

Other relevant regulations include the International Carriage of Dangerous Goods by Inland Navigation (ADN), the International Maritime Dangerous Goods (IMDG) and The International Civil Aviation Organization’s (ICAO) Technical Instruction 

Our solution 

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. 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, IRmax. Combined with a variety of our fixed detectors, our gas detection control panels offer a flexible range of solutions which are able to measure flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment, for the transportation industry our panels include Gasmaster and Vortex 

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

Our Partnership with CSL

Background

CSL is one of the largest providers of gas detection in the Irish market and the leading provider of plant and supporting services to the water, wastewater, environmental and industrial sectors. With headquarters in County Carlow, Republic of Ireland, CSL provide 24 hours, 7 days a week, 365 days a year maintenance and support to their customers nationwide through their network of engineers and support personnel located across the country. CSL is a customer-focused company providing a one-stop-shop to their clients. With over 30 years of experience, CSL delivers effective gas detection solutions for the long term. CSL supplies a wide range of gas detection products, from portable devices to complete fixed gas detection systems and customised installations in many sectors. 

Views on gas detection

As a critical safety issue, CSL put the design, equipment selection, long-term maintenance, and clarity of the alarm system to the forefront of our gas detection solutions. “We understand that there is always a balance between investment and striving for the highest level of gas safety. Still, from our point of view, safety wins every time as cutting costs in an area as vital as gas safety is a false economy. This is one of the main reasons we work very hard to develop the relationship and partnership and promote the Crowcon Gas Safety product range. When we meet with our clients and discuss their gas safety challenges, the conversation inevitably discusses costs. Because of the sizeable Crowcon product range, we always have a solution that will meet their budget and safety requirements.”- Peter Nicholson, Head of Marketing. 

Working with Crowcon

A 30-year partnership and continued communication have allowed CSL to supply their customers with gas detection solutions. “Providing fixed and portable solutions ensures a gas safety package that will work for any company or organisation that depends on high-quality gas detection and related equipment.” – Peter Nicholson, Head of Marketing. We’re thrilled to be working alongside CSL to provide gas detection to the Irish market and support with services to the water, wastewater, environmental and industrial sectors. With over 30 years of experience, CSL delivers effective gas detection solutions for the long term through the supply of our portable devices and fixed gas detection systems. 

Our Partnership with Shawcity 

Background

Established in 1976, Shawcity was one of the first companies to introduce specialist gas detection devices to the UK and Irish markets from leading manufacturers around the world. For over 45 years, they have focused on providing the latest monitoring technology in partnership with leading manufacturers to customers across the UK and Ireland.  

Shawcity supports those working in health and safety, occupational hygiene and environmental applications who rely on achieving the highest levels of performance. With instruments available to hire or buy, Shawcity has the capacity to ensure each order is tailored to meet individual project demands. Their portfolio offers an extensive range of monitoring detection including fixed gas detection, potable gas detection and air quality.  

Views on Gas Detection

As the focus on workplace health continues to develop, a better understanding of the ways workers can be impacted is leading to changes in legislation and an increasing responsibility for employers to protect their employees at work. Gas detection, in particular, is critical in terms of potential safety and can, in some cases, involve an immediate threat to life. Ensuring the correct equipment is provided and maintained is one of the key responsibilities that health and safety officers have.  

The latest technology also means that effective monitoring on a personal, area or environmental level has never been easier to achieve. Shawcity works with every customer to ensure the right equipment is supplied for the job every time and also offer free product training. 

Working with Crowcon

The partnership between Crowcon and Shawcity provides an unbeatable combination of industry knowledge and expertise. The two companies work closely together on fixed gas detection projects across many sectors to provide the complete package, from site surveys, planning and design through to installation, commissioning and ongoing service and maintenance.  

Now supplying our portable range, Shawcity now can support an even wider range of new markets and sectors. “Shawcity is an official Trusted Partner. Crowcon and Shawcity collaborate at every stage of the gas detection process – from product development through to technical support – to deliver the best possible service to customers” – Nathan Marks, Fixed Gas Detection Manager at Shawcity. 

Carbon Dioxide: What are the dangers in the Food and Beverage Industry? 

Almost all industries must monitor gas hazards, with the food and beverage industry no exception. Although, there is a lack of awareness regarding the dangers of carbon dioxide (CO2) and the dangers those working in the industry face. CO2 is the most common gas in the food and beverage industry because it is used in the carbonation of drinks, to propel beverages to the tap in pubs and restaurants and to keep food items cold during transportation in the form of dry ice. It is also naturally produced in beverage manufacturing processes by leavening agents like yeast and sugar. Although CO2 may seem harmless at first glance as we exhale it with every breath, and plants need it for survival, the presence of carbon dioxide becomes a problem when its concentration rises to dangerous levels.

The Dangers of CO2

Carbon dioxide occurs naturally in the atmosphere (typically 0.04% in air). CO2 is colourless and odourless, heavier than air, and tends to sink to the floor. CO2 collects in cellars and at the bottom of containers and confined spaces such as tanks or silos.

Since CO2 is heavier than air, it quickly displaces oxygen at high concentrations can result in asphyxiation due to a lack of oxygen or breathable air. Exposure to CO2 is easy, especially in a confined space like a tank or a cellar. Early symptoms of exposure to high levels of carbon dioxide include dizziness, headaches, and confusion, followed by loss of consciousness. Accidents and fatalities occur in the food and beverage industry due to a carbon dioxide leak. Without proper detection methods and processes in place, everyone at a facility could be at risk.

Gas Monitors – what are the benefits?

Any application that uses carbon dioxide puts workers at risk, and the only way to identify high levels before it’s too late is to use gas monitors.

Gas detection can be provided in both fixed and portable forms. Installation of a fixed gas detector can benefit a larger space such as plant rooms to provide continuous area and staff protection 24 hours a day. However, a portable detector can be more suited for worker safety in and around the cylinder storage area and in spaces designated as a confined space. This is especially true for pubs and beverage dispensing outlets for the safety of workers and those unfamiliar with the environment, such as delivery drivers, sales teams or equipment technicians. The portable unit can easily be clipped to clothing and will detect pockets of CO2 using alarms and visual signals, indicating that the user should immediately vacate the area.

Personal gas detectors continuously monitor the air in workers’ breathing zone when worn correctly,  to give them better awareness and the information they need to make smart decisions in the face of danger. Not only can gas monitors detect carbon dioxide in the air, but they can also alert others if an employee is in danger. Carbon dioxide can be monitored using a single gas monitor or by using a multi-gas monitor with a dedicated carbon dioxide sensor. It is important to note the carbon dioxide can escalate to dangerous levels before an oxygen sensor would alarm.

How do Electrochemical sensors work? 

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

Benefits  

Electrochemical sensors have several benefits.  

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

Issues with cross-sensitivity  

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

Factors affecting electrochemical sensor life  

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

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

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

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

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

‘Normal’ life expectancy of electrochemical Sensor  

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

Products  

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

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

What is a Pellistor (Catalytic Beads)? 

Pellistor sensors consist of two matched wire coils, each embedded in a ceramic bead. Current is passed through the coils, heating the beads to approximately 230˚C. The bead becomes hot from the combustion, resulting in a temperature difference between this active and the other ‘reference’ bead.  This causes a difference in resistance, which is measured; the amount of gas present is directly proportional to the resistance change, so gas concentration as a percentage of its lower explosive limit (% LEL*) can be accurately determined. Flammable gas burns on the bead and the additional heat generated produces an increase in coil resistance which is measured by the instrument to indicate gas concentration. Pellistor sensors are widely used throughout industry including on oil rigs, at refineries, and for underground construction purposes such as mines, and tunnels. 

Benefits of Pellistor Sensors?

Pellistor sensors are relatively low in cost due to differences in the level of technology in comparison to the more complex technologies like 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 gases and vapours present. 

Factors affecting Pellistor Sensor Life

The two main factors that shorten the sensor life include exposure to high gas concentration and poisoning or inhibition of the sensor. Extreme mechanical shock or vibration can also affect the sensor life.  

The capacity of the catalyst surface to oxidise the gas reduces when it has been poisoned or inhibited. Sensor lifetimes of up to ten years is known in some applications where inhibiting or poisoning compounds are not present. Higher power pellistors have larger beads, hence more catalyst, and that greater catalytic activity ensures less vulnerability to poisoning. More porous beads allow easier access of the gas to more catalyst allowing greater catalytic activity from a surface volume instead of just a surface area. Skilled initial design and sophisticated manufacturing processes ensure maximum bead porosity. 

Strength of the bead is also of great importance since exposure to high gas concentrations (>100% LEL) may compromise sensor integrity causing cracking. Performance is affected and often offsets in the zero/base-line signal result. Incomplete combustion results in carbon deposits on the bead: the carbon ‘grows’ in the pores and causes mechanical damage or just gets in the way of gas reaching the pellistor. The carbon may however be burned off over time to re-reveal catalytic sites.  

Extreme mechanical shock or vibration can in rare cases cause a break in the pellistor coils. This issue is more prevalent on portable rather than fixed-point gas detectors as they are more likely to be dropped, and the pellistors used are lower power (to maximise battery life) and thus use more delicate thinner wire coils. 

What happens when a Pellistor is poisoned? 

A poisoned pellistor remains electrically operational but may fail to respond to gas as it will not produce an output when exposed to flammable gas. This means a detector would not go into alarm, giving the impression that the environment is safe.  

Compounds containing silicon, lead, sulphur, and phosphates at just a few parts per million (ppm) can impair pellistor performance.  Therefore, whether it’s something in your general working environment, or something as harmless as cleaning equipment or hand cream, bringing it near to a pellistor could mean you are compromising your sensor’s effectiveness without even realising it. 

Why are silicones bad? 

Silicones have their virtues, but they may be more common than you first thought. Some examples include sealants, adhesives, lubricants, and thermal and electrical insulation. Silicones, have the ability to poison a sensor on a pellistor at extremely low levels, because they act cumulatively a bit at a time.  

Products  

Our portable products all use low power portables pellistor beads. This prolongs battery life but can make them prone to poisoning. Which is why we offer alternatives that do not poison, such as the IR and MPS sensors. Our fixed products use a porous high energy fixed pellistor. 

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

 Our Partnership with Point Safety 

Background

Point safety Ltd is one of the UK’s leading gas safety consultants with 20 years of experience, knowledge and background in the instrumentation industry. Founded in 2011, it specialises in sectors such as oil and gas, pharmaceutical, utilities and telecommunication, providing a range of industries, supplying, installing and maintaining bespoke solutions and the service and supply of test equipment. Point Safety provide constancy to their customers as they believe that there is no such thing as ‘one size fits all’ nor does one solution have to be ‘fit for purpose.

Views on Gas Detection

Portable gas detection is an essential piece of equipment when detecting toxic or explosive gasses and measuring gas concentration. Point Safety puts customers at the forefront of gas detection; they believe that it protects their customers’ plants and processes and, more importantly, helps prevent injury, thereby helping to ensure the health, safety, and wellbeing of its workers. 

Through the supply and support of Crowcon, our portable instruments allow Point Safety’s customers to have the freedom to have reliable, efficient service with the confidence and knowledge that the equipment being provided allows for the protection of workers and their employees. Therefore, turnaround is important to Point Safety; ensuring a quick and effective service turnaround for all units is essential, ensuring minimal downtime and increased customer satisfaction.

As Point Safety provide the supply, installation and maintenance of the bespoke solutions, the implementation and servicing of their fixed systems that are provided nationwide are vital to their customers. Point Safety are confident that the continuous monitoring of these systems ensures that our customers’ and their employees’ lives are safe and that of their surroundings.

Working with Crowcon

Through continuous communication of knowledge and expertise with Point Safety, our partnership will allow for the supply of gas detection instruments to ensure the safety of those working within the oil and gas, pharmaceutical, utilities and telecommunication industries.
“We have a long-standing relationship with Point Safety, now a trusted partner in the North. Point Safety offers outstanding service to our end-users and is extremely knowledgeable on Crowcon products” – Katherine Winter, Northern Account Manager. Our partnership, Point Safety, allows for the distributors of Crowcon products throughout the UK in portable and fixed gas detectors/systems. Our partnership has also enabled Point Safety to become a Crowcon calibration site, with all its engineers fully trained and certified to Crowcon standards. “Point Safety Ltd are extremely proud to be associated with Crowcon, the leaders in gas detection systems, not only in the UK but worldwide. Their expertise, knowledge, first-class product range, and total support is second to none.” – Dawn Beever, Head of Sales and Marketing.

Explosion hazards in inerted tanks and how to avoid them

Hydrogen sulphide (H2S) is known for being extremely toxic, as well as highly corrosive. In an inerted tank environment, it poses an additional and serious hazard combustion which, it is suspected, has been the cause of serious explosions in the past.

Hydrogen sulphide can be present in %vol levels in “sour” oil or gas. Fuel can also be turned ‘sour’ by the action of sulphate-reducing bacteria found in sea water, often present in cargo holds of tankers. It is therefore important to continue to monitor the level of H2S, as it can change, particularly at sea. This H2S can increase the likelihood of a fire if the situation is not properly managed.

Tanks are generally lined with iron (sometimes zinc-coated). Iron rusts, creating iron oxide (FeO). In an inerted headspace of a tank, iron oxide can react with H2S to form iron sulphide (FeS). Iron sulphide is a pyrophore; which means that it can spontaneously ignite in the presence of oxygen

Excluding the elements of fire

A tank full of oil or gas is an obvious fire hazard under the right circumstances. The three elements of fire are fuel, oxygen and an ignition source. Without these three things, a fire can’t start. Air is around 21% oxygen. Therefore, a common means to control the risk of a fire in a tank is to remove as much air as possible by flushing the air out of the tank with an inert gas, such as nitrogen or carbon dioxide. During tank unloading, care is taken that fuel is replaced with inert gas rather than air. This removes the oxygen and prevents fire starting.

By definition, there is not enough oxygen in an inerted environment for a fire to start. But at some point, air will have to be let into the tank – for maintenance staff to safety enter, for example. There is now the chance for the three elements of fire coming together. How is it to be controlled?

  • Oxygen has to be allowed in
  • There may be present FeS, which the oxygen will cause to spark
  • The element that can be controlled is fuel.

If all the fuel has been removed and the combination of air and FeS causes a spark, it can’t do any harm.

Monitoring the elements

From the above, it is obvious how important it is to keep track of all the elements that could cause a fire in these fuel tanks. Oxygen and fuel can be directly monitored using an appropriate gas detector, like Gas-Pro TK. Designed for these specialist environments, Gas-Pro TK automatically copes with measuring a tank full of gas (measured in %vol) and a tank nearly empty of gas (measured in %LEL). Gas-Pro TK can tell you when oxygen levels are low enough to be safe to load fuel or high enough for staff to safely enter the tank. Another important use for Gas-Pro TK is to monitor for H2S, to allow you judge the likely presence of the pryophore, iron sulphide.