Gas detection specialist Crowcon has expanded the capabilities of its highly successful Tetra:3 (T3) personal multi-gas detector with three more toxic gas sensors: ozone (O3), sulphur dioxide (SO2) and ammonia (NH3). This complements the existing sensor range which includes flammable gases, oxygen (O2), hydrogen sulphide (H2S), and carbon monoxide (CO). The new sensors widen the applications for the T3 to include the chemical, pharmaceutical, food and beverage processing industries, as well as water and wastewater treatment facilities.

Crowcon's Tetra 3 (T3) portable, multi-purpose gas detector for industrial applications

Photo (industrial background):
http://www.halmapr.com/crowcon/t3_industry.jpg (611 KB)

Crowcon's Tetra 3 (T3) portable gas detector for water and wastewater applications

Photo (wastewater background):
http://www.halmapr.com/crowcon/t3_wastewater.jpg (564 KB)

Featuring a top-mount display and the capacity to detect up to four gases at once, the T3 is designed for use in the most demanding industrial environments, including confined space work. It features intuitive, single button operation, essential for users with gloved hands.

If a hazard is detected, the T3 gives rapid and effective warning with a powerful 95 dBA audible alarm, an extremely bright red/blue LED visual warning, and by vibrating. Despite its compact size and low weight (less than 300g), the T3 is very rugged. It has a shatterproof housing with rubber over-moulding, providing extra shock and vibration protection and giving it water and dust resistance to IP67.

A lithium-ion battery provides over 18 hours continuous operation from a single charge, and there is a 30 day countdown warning of the calibration due date. The T3 is provided with a stainless steel alligator pocket clip as standard and has an optional harness for chest mounting.

To coincide with the expanded T3 gas sensor range, Crowcon has also launched a new ‘universal charger’, developed in response to the market need for reliable vehicle charging of detectors used by service and maintenance crews in the field. This latest addition firmly supports the T3 in a mountable cradle, offering a quick and easy storage solution as well as dependable charging with status indication.

Comments (0) »

In this article Andy Avenell, Crowcon’s Fixed Systems Product Manager, considers the shift towards infrared (IR) gas sensor technology in the oil and gas industry.

Abstract

Flammable gases and vapours can present considerable dangers in many industrial applications, none more so than the processes involved in extracting, transporting and processing oil and gas. Fast and reliable detection of gas accumulations in sub-LEL (Lower Explosive Limit) levels is essential in order to prevent potential explosions. The longest established and most prevalent sensor technology employed for detecting flammable gas is the Pellistor (or Catalytic Bead as it is otherwise known).

Pellistor-based detectors are widely available at low cost, but are vulnerable to permanent poisoning by contaminants, do not fail safe, require very regular maintenance and calibration and have a limited life-span. Infrared (IR) gas detectors overcome all of the limitations associated with pellistors to provide fast and reliable detection of hydrocarbon gases. IR detectors provide rapid gas detection, fail-safe operation, and in some cases compliance with the IEC61508 safety standard. IR detector prices have fallen significantly in recent years, and although the price per point is still higher than pellistor based detectors, industry experience confirms that IR detectors quickly pay for themselves by reducing operational/maintenance costs.

Replacing pellistor-based detectors usually means that the control equipment will also need upgrading. This is due to the mV bridge type signal interface between detector and controller. IR detectors typically require a power supply of between 12 and 30 Volts dc, and provide a 4-20mA signal to the controller. Thus a pellistor control card is inherently incompatible with conventional IR gas detectors. ‘Pellistor Replacement’ IR gas detectors simulate a pellistor mV type signal and are specifically designed to replace pellistor sensors with IR technology, whilst retaining the original control equipment, cabling and detector junction box. Thus the very significant cost associated with upgrading controllers and re-installation is avoided.

One of the more difficult problems to overcome with pellistor IR replacement technology is signal drift. Systems operating using a mV (Wheatstone) bridge, such as pellistor based systems, are very vulnerable to this problem. In order for a control card to show a zero gas reading the four resistances in the bridge must be balanced. Resistance imbalances can however be introduced by poor cable connections either due to loose terminals, temperature effects or through oxidation of conductors. Any cable/terminal resistance changes are manifested as zero drift on the control card. The challenge is that to be a genuine pellistor replacement, an IR detector must have very low power consumption (ie less than 1 Watt), and a well designed power supply so that potential cable influences on the signal are negated.

Pellistor replacement IR detectors should be rigorously designed and tested to ensure reliable operation at all times. High integrity products are designed to comply with the demanding requirements of IEC61508 (ideally to SIL 2) in terms of both hardware and software. Gas detection performance (response time, short and long-term stability, linearity, accuracy, temperature stability etc) should be verified to a performance standard such as EN61779:2000.

Finally, independent verification of the product by a recognized testing body should have been conducted. The product should be performance tested in simulated offshore conditions to ensure reliable performance in even the most extreme conditions.

Introduction

Flammable gases and vapours can present considerable dangers in many industrial applications, none more so than the processes involved in extracting, transporting and processing oil and gas. Fast and reliable detection of gas accumulations in sub-LEL (Lower Explosive Limit) levels is essential in order to prevent potential explosions. The longest established and most prevalent sensor technology employed for detecting flammable gas is the Pellistor (or Catalytic Bead as it is otherwise known).

Pellistor technology

Pellistors were originally developed for the mining industry during the early 1960’s; earlier simple platinum coil sensors were unsuitable for continuous operation due to their high power consumption and excessive zero drift.

Pellistor detectors consist of two matched platinum coils, each embedded in a bead of alumina. The detecting element is coated with a catalyst which promotes oxidation when in contact flammable gases; the compensating element is treated so that catalytic oxidation does not occur. The compensating element is fitted to ensure that signals are not generated due to environmental effects (eg changes in ambient temperature or gas flow rate).

Pellistor-based systems operate in a Wheatstone Bridge circuit whereby the pellistor and compensator in the detector represent one half of the bridge, the other half being fitted to the control card usually located in the control room. The control card supplies a voltage to the bridge (typically 2V to 3.5Vdc), which generates a current flow and raises the temperature of the beads to a level where oxidation of gases will occur (>300°C). The control card measures a small voltage offset in the bridge due to the increased resistance in the pellistor element when gas is present. This voltage is then amplified and used to display the gas level and activate alarms.

Because pellistors are relatively high power devices, and as they operate at a temperature that will ignite flammable gases they need to be sealed behind a flame arrestor (sinter).

Pellistors are typically fitted within a stainless steel housing, mounted on an Exd (Flameproof) or Exe (Increased Safety) certified junction box. The detector is connected to the control equipment via a 3-core (or sometimes 4-core) cable.

Advantages and Disadvantages of Pellistor Technology

Advantages:

•    Low cost technology; pellistor-based detectors are widely available at low cost.
•    Pellistors will detect a wide range of gases and vapours. Correction factors can be applied so that the sensor can be scaled for a particular substance.
•    Pellistors are very simple devices; apart from calibration gas, no special equipment is required for commissioning or maintenance.

Disadvantages:

•    Pellistors are vulnerable to permanent poisoning by silicones, lead, sulphurs or chlorinated compounds. If exposed to these compounds, a pellistor may fail to respond to flammable gas.
•    Pellistors must be operated behind a sinter (flame arrestor) which may become blocked, thus preventing gas from reaching the sensor.
•    Pellistors do not fail-safe; poisoned pellistors remain electrically operational; thus the control system will continue to display zero gas when flammable gas may be present.
•    Sensitivity to flammable gas is reduced in the presence of some compounds (notably hydrogen sulphide and halogens).
•    Pellistors need at minimum of 12% volume oxygen present to operate. Their efficiency reduces in oxygen deficient atmospheres.
•    Pellistors may burn-out and require replacement if exposed to gas concentrations greater than 110% LEL.
•    Pellistor sensitivity degrades over time.
•    Pellistors have a limited life-span, sensors typically last 3-5 years.
•    Pellistors require regular gas testing to ensure they are operational, and regular calibration of offset signal loss due to poisoning or bead contamination.

Typical Pellistor Gas Detector

Typical Pellistor Gas Detector

Infrared technology

Gases which contain more than one type of atom absorb infrared (IR) radiation. Therefore hydrocarbons and other gases such as carbon dioxide and carbon monoxide can be detected by this means, but gases such as oxygen, hydrogen, helium and chlorine cannot.

Specific gases are detected by measuring their absorption at particular frequencies of infrared light which correspond to the resonance of the molecular bonding between dissimilar atoms. For example the wavelength at which the carbon atom and each of the four hydrogen atoms resonate in a methane molecule is 3.3µ (microns). Most commonly encountered hydrocarbons absorb IR energy in the range 3.3µ to 3.4µ. IR gas detectors are therefore filtered to respond to IR absorption in this range. Carbon dioxide absorbs IR energy in the 4.2µ range and thus different filters are required for a CO2 detector.

The output from the IR sensor is non-linear, and will vary with ambient temperature (due to thermal expansion effects on optical components). Therefore IR detectors use sophisticated software algorithms to ‘linearise’ the output signal to correspond to 0-100% LEL for the target gas, and also compensate for temperature shifts. The sensor will respond differently to each gas or vapour, and therefore a unique ‘linearisation’ algorithm must be developed for each target gas. Depending on sensor quality and/or production repeatability, individual sensors may need linearising.

In order to differentiate between IR absorption due to gas and other substances such as dust, dirt or water, an additional sensor with a bandwidth of (typically) 2.7-3.0µ is employed: hydrocarbon gases do not absorb IR energy at this wavelength. This prevents false alarms occurring and compensates for a reduction in signal from the interfering substance. This ‘Dual Beam’ design is also used to provide a fault alarm to notify operators of contamination of optical components.

In a typical fixed point detector, the IR source(s) and receiver(s) are mounted in the main body of the housing, with the light beam being reflected by a mirror at the far end of the housing. Parts of the light beam are exposed to atmosphere so that, using natural or forced diffusion, gas can intersect the beam. As the gas concentration increases more infrared energy is absorbed by the gas and less reaches the sensors. Using this method, received energy is inversely proportional to gas concentration.

Crowcon IR Gas Detector

IR Gas Detector

Advantages and Disadvantages of IR Technology

Advantages:

•    Very fast response: T90 response typically less than 7 seconds.
•    Fail-safe operation: no un-revealed failures (power faults, signal faults, software errors are always reported to the control system).
•    Immune to signal inhibition by contaminant gases.
•    No consumable parts; life-span typically > 10 years.
•    Reduced maintenance costs.
•    Does not require oxygen to be present.
•    Will not burn-out in high gas concentrations.
•    Premium models do not utilise a sinter (flame arrestor), and thus associated blockages cannot occur.

Disadvantages:

•    Purchase price is higher than pellistor based detectors.
•    IR detectors cannot detect hydrogen.
•    IR detectors cannot provide a linear response to a group of different gases: the detector is ‘linearised’ for a particular gas, and will respond to others but in a non-linear fashion.

The Move Towards IR Technology

IR gas detectors (in combination with other detector technologies such as Open-Path Infrared and Acoustic sensors) are now the accepted technology for protecting oil and gas installations against flammable gas hazards.

Independent reference to the market shift from pellistors to IR gas detectors is made in the 2006 Frost and Sullivan report F868-321.

It is now common practise to validate safety systems in accordance with IEC615082 (”Functional Safety of electrical/electronic/programmable electronic safety-related systems”); it is however difficult to achieve a satisfactory SIL rating (Safety Integrity Level) using pellistor based gas detectors. This is due to the significant possibility of un-revealed failures of sensors due to poisoning or sinters becoming blocked (the sensor is electrically operational, but will fail to respond to gas).

IR detectors also provide significant maintenance cost reductions: pellistors require very regular testing (by application of test gas). Some offshore platforms test sensors as often as every six weeks. Many platforms have 400+ gas detectors fitted, and thus such a regular test regime, combined with the need to replace sensors every 3-5 years represents a huge cost. Sinter-free IR detectors are self-checking (ie lamps, sensors, windows, mirrors, software) and thus the risk of an un-revealed failure is minimal. This combined with very low levels of zero and sensitivity drift means that calibration/testing routines can be extended to six or even twelve months on IR detectors. Routine maintenance is usually restricted to cleaning optical components, and a test with calibration gas. IR sensors typically last in excess of 10 years and thus parts replacement is usually restricted to consumables such as filters that may be needed for very dusty environments.

IR detector prices have fallen significantly in recent years, and although the price per point is still higher than pellistor based detectors, industry experience confirms that IR detectors quickly pay for themselves by reducing operational/maintenance costs.

Upgrading From Pellistors to IR

Replacing pellistor-based detectors usually means that the control equipment will also need upgrading. This is due to the mV bridge type signal interface between detector and controller (refer to the Pellistor Technology section for details): IR detectors typically require a power supply of between 12 and 30 Volts dc, and provide a 4-20mA signal to the controller. Thus a pellistor control card is inherently incompatible with conventional IR gas detectors.

‘Pellistor Replacement’ IR gas detectors simulate a pellistor mV type signal and are specifically designed to replace pellistor sensors with IR technology, whilst retaining the original control equipment, cabling and detector junction box. Thus the very significant cost associated with upgrading controller and re-installation is avoided.

Pellistor Replacement IR detectors are typically fitted with a mounting spigot compatible with the most commonly used junction boxes (eg M20 thread). This enables the unit to be directly screwed into the original detector junction box. Pellistor Replacement IR detectors are certified for use in hazardous areas (usually to ATEX3, IECEx4 and/or UL5, standards), and thus can be installed in any area for which the original detector would have been certified. The detector wires are simply connected to the original terminals (and thus the original cable). Sophisticated Pellistor Replacement IR detectors operate from the voltage source from the original control card, and are zeroed and calibrated in exactly the same way as the original pellistor: no adjustments are necessary at the detector.

Operation and Maintenance

One of the more difficult problems to over-come with pellistor IR replacement technology is signal drift. Systems operating using a mV (Wheatstone) bridge, such as pellistor based systems, are very vulnerable to this problem. In order for a control card to show a zero gas reading the four resistances in the bridge must be balanced. Resistance imbalances can however be introduced by poor cable connections either due to loose terminals, temperature effects or through oxidation of conductors. Any cable/terminal resistance changes are manifested as zero drift on the control card. The challenge is that to be a genuine pellistor replacement, an IR detector must have very low power consumption (ie less than 1 Watt), and a well designed power supply so that potential cable influences on the signal are negated.

Flammable gas detectors are often installed in areas that may be difficult to access. To enable testing and calibration detectors may be fitted with a pipe connector. A flexible pipe can then be fixed to the connector and run to a more accessible point. Calibration gas can then be applied to the pipe, and the performance of the detector can be verified without needing to access the detector directly. More advanced IR detectors may actually be calibrated via this means, as oppose to the traditional method of temporarily replacing the detectors’ weather-cap with a calibration cap.

Routine maintenance should be restricted to gas testing (with re-calibration only as required: typically annually at most) and cleaning of optical components (algorithms are utilised to provide a fault signal if the window or mirror are more then 75% obscured by contaminants).

Some pellistor replacement IR detectors utilise sinters to achieve Exd Flameproof compliance. Sinters slow the response time of the IR detector significantly (T90 response time may actually be longer than achieved by pellistors), and are vulnerable to blocking. Sinters blocked by contaminants will prevent gas reaching the sensor; this represents a potentially dangerous ‘un-revealed failure’ which necessitates regular testing to avoid.

Pellistor Replacement IR detectors need to operate continuously in very harsh environments. 316 stainless steel construction and an effective weather-cap are essential to protect the optical components.

Crowcon IREX Pellistor Replacement IR Gas Detector

Pellistor Replacement IR Gas Detector

Performance and Testing

Pellistor replacement IR detectors should be rigorously designed and tested to ensure reliable operation at all times. High integrity products are designed to comply with the demanding requirements of IEC615082 (ideally to SIL 2) in terms of both hardware and software. Gas detection performance (response time, short and long-term stability, linearity, accuracy, temperature stability etc) should be verified to a performance standard such as EN61779:20006.

Finally, independent verification of the product by a recognized testing body should have been conducted. The product should be performance tested in simulated offshore conditions to ensure reliable performance in even the most extreme conditions.

References

1. Frost and Sullivan Report F868-32, 2006: World Industrial Gas Sensors Detectors and Analyzers markets. Relevant references are made on pages 3-2 and 3-42.

2. International Electrotechnical Commission (IEC), IEC61508 Functional Safety of electrical/electronic/programmable electronic safety-related systems

3. ATEX: European Directive defining standards for equipment for use in potentially explosive atmospheres.

4. IECEx: is an international certification scheme created by the IEC to facilitate international trade in electrical equipment intended for use in explosive atmospheres.

5. UL: Underwriters Laboratories Inc is a privately owned company that tests to make sure that products meet safety standards.

6. EN61779:2000: Electrical apparatus for the detection and measurement of flammable gases. General requirements and test methods.

4 Comments »

Crowcon gas detector ensures constant O2 and CO2 levels in enclosed chambers

Crowcon’s CellarSafe O2/CO2 gas detector and control system is being used  to monitor the level of the two gases in unique ‘artificial mountains’ – enclosed endurance training chambers designed to simulate depleted oxygen levels at high altitudes. The chambers are manufactured by German company Höhenbalance AG.

Crowcon’s CellarSafe Gas Detector Helps Athletes Train Safely in 'Artificial Mountains’

Photo:  http://www.halmapr.com/crowcon/art_mnt_cellarsafe.jpg (749 KB)

Generators filter O2 molecules out of the air feeding the chambers, resulting in concentrations of 14% or even lower, depending on the settings. In this way the ‘altitude’ can be simulated up to 6000m.

While training in the chamber an athlete will breath out a lot of CO2 which, if not monitored closely, can build up to dangerous concentrations. The compact CellarSafe is therefore equipped with both O2 and CO2 sensors and constantly monitors the concentration of the two gasses in the chamber. O2 and CO2 levels are transmitted to an adjacent control unit which adds or removes O2, depending on the demand. In this way a safe, constant ‘altitude’ is maintained for the athlete.

“Minor variations in O2 concentration are not immediately dangerous for the athletes, but reliability and accuracy are nevertheless our main concerns to achieve optimal training conditions,” said Christian Blauth, a sports scientist and member of the Höhenbalance AG management team. “Crowcon, which is well known as a leading supplier of gas detection equipment, was therefore chosen to ensure the required safety levels.”

The training chambers are not just used by athletes but also by people preparing for climbing or trekking in mountain regions, preparing their bodies for strenuous activities at high altitudes. Research has also shown that high altitude training supports weight loss programs and helps to reduce stress.

The CellarSafe gas detector also has many other applications. It is most commonly used in wineries, breweries, food processing facilities and pub cellars to monitor and control CO2 levels. Long term exposure to as little 0.5% volume of CO2 represents a toxic health hazard and concentrations greater than 15% volume can lead to death. The CellarSafe was specifically designed to warn personnel of these hazards.

Simple to use, the CellarSafe not only continuously monitors CO2 and O2, but can also be connected with control systems to automatically turn on ventilation fans, trigger alarms or, as in this application, adjust O2 concentrations to within set parameters. It has a clear, easy to read backlit display of gas readings, a bright LED warning light and a loud built-in alarm. Ingress protected to IP65 against dust and water ingress, it can operate over a wide temperature range.

Comments (0) »

The water and wastewater industries produce many toxic and flammable gases that need to be detected and eliminated. The gas hazards vary considerably depending on the application, location and treatment process, but the solution is always the same – a combination of fixed and portable gas detectors.

Detecting Gas Hazards in the Water and Wastewater Industries using Crowcon gas detectors

At each stage in the processing and treatment regime – for both water and wastewater – there will be variety of gas hazards. Some of these hazards will be common to most if not all facilities, while in many cases there will be peripheral or specialised treatment processes unique to a particular site, with its own unique gas detection requirements. In the majority of cases both fixed and portable gas detectors will be required.

It is important to recognise that gas detectors are not simply installed for process monitoring – they are required to save lives. However, this life saving equipment must also be robustly constructed to survive the rigours of deployment in a water plant. A variety of harsh environments can exist, from unpredictable water levels and physical damage, to the acidic or caustic conditions which result from gases such as hydrogen sulphide or chlorine mixing with water.

Drinking water facilities

In drinking water facilities gas hazards include chlorine, sulphur dioxide, ammonia, ozone and chlorine dioxide, originating from locations such as gas storage areas, gas dosing plant and ozone generators.

Most pre-treatment of drinking water is a physical process involving flocculation, filtration and ion exchange and it is only at the treatment/disinfection stage that chemicals are used, with the resulting gas hazards. Chlorine is the traditional disinfectant used in water treatment – in most countries it is a legal requirement, even if other non-chemical methods (such as UV disinfection) are used, as it provides residual disinfection downstream. Everything in the chlorination process, from the chlorine gas storage tanks to the final production of clean water, should be properly monitored. This includes valves and any rooms the chlorine pipes pass through.

Detection of chlorine gas hazards in the water and wastewater industries using Crowcon gas detectors

While chlorination is still the treatment method of choice in most water works, some are now switching to alternative methods such as ozone, chlorine dioxide or sodium hypochlorite. In addition, in those plants that still use chlorine, sulphur dioxide is often used to dechlorinate the water when treatment is complete. All the above mentioned gases are hazardous and should be effectively monitored. Sulphur dioxide needs only very low concentrations to be a danger to life, while chlorine is a very heavy gas and is readily absorbed by most materials, making it difficult to detect in storage areas. Concerns have also been raised recently about the levels of carbon dioxide in confided spaces in chalk areas.

Due to the differences not only in gas hazards but also in the human presence in certain parts of a water treatment plant, a combination of both portable and fixed gas detectors are usually required. Gas storage areas, ozone generators, rooms that gases pass through, as well as the treatment plant, should always have fixed detectors installed for the particular gas (or combination of gases) in use. In addition, portable detectors should always be mandatory when operators enter confined spaces where these gases can be present – even if fixed detectors are installed – as a safe back-up. Again, depending on requirements, these can be single or multi-gas portable detectors.

Wastewater treatment facilities

In wastewater facilities there are many gas hazards, including methane (a flammable gas), oxygen, hydrogen sulphide, chlorine, carbon monoxide and carbon dioxide. These gases originate from many sources, such as sewers, pumping stations, aeration tanks, sludge digester tanks, deodorising plant and treatment plants.

Primary and secondary treatment processes such as aerating and sludge digestion are some of the ‘high risk’ areas where biogases from sludge, including methane, hydrogen sulphide, oxygen and carbon dioxide are a hazard. Apart from being highly explosive, methane also displaces oxygen, increasing the risk of asphyxiation. Hydrogen sulphide, on the other hand, has a distinctive odour at low concentrations (0.0047ppm), but as levels increase to over 150ppm the olfactory nerves are damaged, masking the danger from workers, who will not be able to smell the gas even if it reaches the lethal concentration of 800ppm. Biogas from sludge digestion is used for electricity generation and, because it is highly flammable, any leak from a digestor is very dangerous and could lead to an explosion.

Detecting gas hazards in confined spaces using Crowcon gas detectors

As with drinking water treatment, wastewater is also usually treated with chlorine (or chlorine alternatives) before it leaves the plant, so the same gas monitoring procedures should be rigorously followed from storage through to final treatment.

Flammable fixed gas detectors are required for installations such as sewage inlets and wet wells, where one of the biggest risks comes from the emptying of flammable liquids into drains, which float on the surface and collect in the wet well where they can reach a flammable level. Methane, carbon dioxide, oxygen and hydrogen sulphide fixed detectors should also be fitted in all sludge aeration and processing areas. In addition, deodorising plants need fixed high and low concentration hydrogen sulphide monitoring. Portable gas detectors should be worn by operators entering any confined spaces, including sewers, pumping stations, sludge digestors and treatment plants. Multi-gas monitors are the norm in these situations.

Case study

Southern Water (UK) has now purchased over 800 Tetra portable gas detectors from Crowcon for staff working in confined spaces in the wastewater, sewerage, clean water and process water sectors and for procedures such as chlorine change-over. They are also used by support staff such as scientists, technicians and health and safety advisors, and for staff training.

Crowcon Tetra portable gas detector for the water and wastewater industry

“We are now in the era of the ‘intelligent worker’, who wants to understand better what is going on around them,” says Southern Water’s senior health and safety advisor Andy Nicholls. “Our staff are fully conversant with health and safety legislation and expect to have the right equipment at all times. We chose the Tetra units because they are simple to use, easy to maintain and extremely durable. They are life-preserving bits of equipment and you simply can’t compare the cost of a life against the cost of a detector.”

Designed for the most demanding conditions, Crowcon’s Tetra detectors can monitor up to four gases at once, including methane, oxygen and a full range of toxic gases such as hydrogen sulphide and carbon dioxide.

Conclusion

Every gas has its own characteristics, so fixed and portable gas detectors should be located or worn wherever they will have the best potential for monitoring a gas build-up (or gas depletion in the case of oxygen). The water and wastewater industries, like other industries, are constantly looking at ways to save costs. Worker safety, however, should never be compromised; gas accidents in these industries do not simply cause injuries – they kill.  As part of a comprehensive safety programme, gas detection should therefore be given a high priority and be based on industry best practices. This will go a long way to ensuring the safety of all workers – even in the most hazardous locations.

2 Comments »

Crowcon’s new Gas-Tec portable gas detector is designed to rapidly identify and localise methane leaks from landfill sites and waste processing facilities. Using Crowcon’s tried and tested flame ionisation chamber, the Gas-Tec also features next generation technology such as GPS, data and event logging. The new device allows survey teams to track progress and quickly pinpoint and record areas of significant interest.

Methane poses a severe explosion risk, is damaging to surrounding plant life and is also a greenhouse gas. It is generated during the working life of a landfill site and for as long as 30-40 years after a site has been covered over. The UK Landfill Regulations (England and Wales) 2002 stipulate that all landfill site operators carry out effective monitoring of this and other gases for a set period after closing, as stipulated by the Environment Agency.

Storing survey reports and service and calibration records are also a more frequent requirement, influenced by health and safety regulations. Finally, with many operating companies being forced to reduce personnel, there is an increased demand for products that require minimal training and set-up times to use.

Crowcon developed the Gas-Tec specifically to address these issues, including features to help companies identify methane leaks quickly and efficiently, with minimal manpower. GPS position logging, for example, enhances record keeping by assigning latitude, longitude and distance above sea level to data readings. Users can also view their current location, offering the precise location to back-up crews for immediate leak management. Another useful feature is data and event logging, allowing users to download full survey information for survey traceability using ‘drag and drop’ via a USB interface.

Weighing just 2.4kg (without the gas bottle), the Gas-Tec is worn across the body and is ergonomically designed to sit comfortably whilst in use. Simple and intuitive to operate, its liquid crystal display and soft keys offer full sequence instructions, in-operation options, service and calibration set-up and alerts. Menu prompts guide users through start-up and shut-down procedures, reducing training requirements. The device can also be customised, with users able to set preferences for features such as preferred units, display settings, date format and language.

Enhanced electronic controls increase battery and cylinder life, while pressure and flow transducers manage hydrogen and sample flow rates. A service and calibration timer also reminds operators when maintenance is required, ensuring the unit is always operable and in optimum working condition. The Gas-Tec also includes an optional ‘service lock’ facility, ensuring it cannot be used in the field whilst out of calibration.

Based around Crowcon’s original tried and tested Gas-Tec ‘engine’ detection method, this next generation model is already proven, fit for purpose and suited to the rigours of everyday use in the field. With a response time of less than two seconds, the Gas-Tec is calibrated to methane, with conversion factors for other common hydrocarbons available. It has a detection range of 0 – 10,000 ppm and is accurate to within +/-10%. Battery life is over 22 hours, allowing continual use for a full shift. Battery recharge time is only 2 ½ hours.

Supplied in a wheeled ABS impact resistant case with a fitted foam insert, it is ingress protected to IP54 and can be used outdoors in all weather conditions. Accessories include a trigger survey kit and an in-vehicle survey tool allowing detection at speeds of up to 30km/hour. Probe assemblies are also available for all types of applications, including borehole, straight probe, cup attachment and detection trolley. Other useful accessories are available, such as vehicle chargers, earphones, spare hydrogen cylinders and a hydrogen filling panel.

Comments (0) »

Crowcon’s new Gas-Tec portable hydrocarbon gas detector is designed for rapid leak survey and localisation applications. Using Crowcon’s tried and tested flame ionisation chamber, the Gas-Tec also features next generation technology such as GPS, data and event logging. The new device allows survey teams to track progress and quickly pinpoint and record areas of significant interest.

Increasingly, gas distribution and infrastructure companies are focussing on reducing the number and volume of leaks along their pipelines. Leaks have cost, environmental and safety implications, so pinpointing and repairing them quickly is essential. Storing survey reports and service and calibration records are also a more frequent requirement, influenced by health and safety regulations. Finally, with many companies being forced to reduce personnel, there is an increased demand for products that require minimal training and set-up times to use.

Crowcon developed the Gas-Tec specifically to address these issues, including features to help companies minimise leaks quickly and efficiently, with minimal manpower. GPS position logging, for example, enhances record keeping by assigning latitude, longitude and distance above sea level to data readings. Users can also view their current location, offering the precise location to back-up crews for immediate leak management. Another useful feature is data and event logging, allowing users to download full survey information for survey traceability using ‘drag and drop’ via a USB interface.

Weighing just 2.4kg (without the gas bottle), the Gas-Tec is worn across the body and is ergonomically designed to sit comfortably whilst in use. Simple and intuitive to operate, its liquid crystal display and soft keys offer full sequence instructions, in-operation options, service and calibration set-up and alerts. Menu prompts guide users through start-up and shut-down procedures, reducing training requirements. The device can also be customised, with users able to set preferences for features such as preferred units, display settings, date format and language.

Enhanced electronic controls increase battery and cylinder life, while pressure and flow transducers manage hydrogen and sample flow rates. A service and calibration timer also reminds operators when maintenance is required, ensuring the unit is always operable and in optimum working condition. The Gas-Tec also includes an optional ‘service lock’ facility, ensuring it cannot be used in the field whilst out of calibration.

Based around Crowcon’s original tried and tested Gas-Tec ‘engine’ detection method, this next generation model is already proven, fit for purpose and suited to the rigours of everyday use. With a response time of less than two seconds, the Gas-Tec is calibrated to methane, with conversion factors for other common hydrocarbons available. It has a detection range of 0 – 10,000 ppm and is accurate to within +/-10%. Battery life is over 22 hours, allowing continual use for a full shift. Battery recharge time is only 2 ½ hours.

Supplied in a wheeled ABS impact resistant case with a fitted foam insert, it is ingress protected to IP54 and can be used outdoors in all weather conditions. Accessories include a trigger survey kit and an in-vehicle survey tool allowing detection at speeds of up to 30km/hour. Probe assemblies are also available for all types of applications, including borehole, straight probe, cup attachment and detection trolley. Other useful accessories are available, such as vehicle chargers, earphones, spare hydrogen cylinders and a hydrogen filling panel.

Comments (0) »

Crowcon’s innovative new IREX infrared (IR) pellistor-replacement flammable gas detector has been proven suitable for offshore use after undergoing rigorous performance testing by Micropack Engineering Ltd, the highly respected testing authority based in Aberdeen, Scotland.

IREX is designed to replace pellistor (catalytic bead) type flammable gas detectors, resulting in faster response times and greatly reduced zero drift. Capable of detecting methane, butane, propane and many other hydrocarbons, IREX is specifically designed for applications such as offshore platforms, refineries, gas storage and distribution networks, sewage treatment plants and certain manufacturing processes (such as aerosol production).

Pellistor and some other IR type gas detectors are fitted with sinters (flame arrestors) to achieve Exd flameproof certification. Sinters slow response times significantly and can become blocked by contaminants, a frequently underestimated problem. Because IREX does not use sinters it has an extremely fast T90 response time of less than four seconds – comparable with the most expensive conventional IR gas detectors. Excellent zero stability is also achieved, with none of the drift issue associated with pellistors and cables.

Because IREX operates from the same control systems as pellistor-based detectors, it allows existing pellistor-based systems to be easily upgraded without any of the costs associated with installing a new control system. Sophisticated systems and algorithms ensure reliable operation at all times, with no adjustments necessary to the detector itself. Zero and span adjustments (if required) are performed at the control panel, and gas response tests and calibration can also be done remotely, with test gas simply applied via a tube to the standard weather cover.

IREX is designed to provide over 10 years reliable operation, and as there are no sensors which need replacing and because routine testing requirements are minimised, operating costs during its entire lifetime are minimal. The detector produces a mV Wheatstone Bridge type signal (identical to a pellistor) and operates from as little as 2.9Vdc.  In addition, it is supplied with a M20 type fixing, allowing originally installed detector junction boxes and cables to be retained. Manufactured from 316 stainless steel; IREX has both ATEX and IECEx approval and is undergoing assessment for IEC61508 SIL 2 compliance.

Micropack Engineering Ltd is a recognised industry leader in fire detection technologies. The company is also involved in research on the effects of offshore environmental conditions on optical detection methods and is a recognised independent testing authority.

Comments Off

Five instruments in one small handheld unit
Erlanger, KY (May 29, 2009) – Following the success of the Sprint V family of multi-function combustion analyzers in the United Kingdom, the product is now available in the United States, Canada and Mexico.  The Sprint V range has been programmed to meet work safety regulations and legislation with country-specific calculations and language.

Designed to assist heating engineers in the safe installation, commissioning and servicing of furnaces and combustion systems, the Sprint V range provides five instruments in one small, convenient handheld unit: a combustion analyzer, a differential thermometer, a differential manometer, a gas escape detector and a carbon monoxide room safety monitor.

The range includes the basic Sprint V2 unit with the features mentioned above; the Sprint V3, which has all the functions of the V2 but is also Bluetooth™-enabled for rapid data transfer; the Sprint V4, which is like the V2 but has additional Nitric Oxides (NO and NOx) capability; and finally the Sprint V5, which has all the functions of the V4 and is also Bluetooth-enabled.

An important feature of the entire Sprint V range is ‘Smart Purge’ technology which clears potentially acidic gases from the unit. This helps save battery, pump and filter life, enables intelligent purging for switch-on and switch-off, and allows the purging of gas while other tests are being carried out.

The Sprint V range was recently named ‘Gas Safety Product of the Year’ at the UK’s annual gas industry awards ceremony. The UK’s leading gas utility company, British Gas, has ordered over 7,000 units as part of a six year supply and service contract. 

Comments (0) »

Crowcon Detection Instruments has been named ‘Company of the Year’ by its parent company, Halma p.l.c. The prize was announced at Halma’s recent CEO Conference and is awarded for overall company performance across a range of criteria.

 (Photo caption: Warren Rees (left), Crowcon’s Managing Director, receiving the ‘Company of the Year’ Award from Geoff Unwin, the Chairman of Halma p.l.c.)

Crowcon is a world leader in portable and fixed gas detection for industries ranging from oil, gas and petrochemical processing to pharmaceutical manufacturing, construction and facilities management, transport, food processing, brewing and winemaking. Its products are designed to save lives by detecting and warning of dangerous levels of toxic or flammable gases.

“We are absolutely delighted to have won this award,” said the company’s Managing Director Warren Rees. “There are 40 Halma subsidiaries worldwide, many of which are leaders in their specialised fields, so to be named the best is an honour indeed, especially in the current economic climate. I strongly believe that this is just the start of a new phase of growth for Crowcon – we have implemented many changes over the last year, and there are more to come.”

Halma p.l.c. is an international market leader in safety, health and sensor technology. It is a FTSE 250 listed company on the London Stock Exchange and has over 3600 employees in 40 subsidiaries worldwide with a  total turnover of over US$780m (2008). Halma’s businesses make products that protect lives and improve the quality of life for people through innovation in market leading products which make its customers safer, more competitive and more profitable.

Comments Off

Telegan Gas Monitoring and its exclusive industry partner, Anton Industrial Services, are providing a fleet of flue gas analysers and gas detectors to all Gas Safe Register™ inspectors. The contract involves 106 award-winning Telegan ‘Sprint V’ multi-purpose flue gas analysers and 106 Crowcon (Telegan’s parent company) ‘Eikon’ carbon monoxide monitors. Gas Safe Register™ replaced the CORGI gas registration scheme in Great Britain and the Isle of Man on April 1, 2009.

(Photo caption: Telegan’s Bluetooth™-enabled Sprint V flue gas analyser)

The Sprint V is Bluetooth™-enabled and features a flue gas analyser, a differential thermometer, a differential manometer, a carbon monoxide room safety monitor and a gas escape detector with gooseneck probe and ultra-bright LED searchlight as standard – all in one small handheld unit. An important feature of the Sprint V is ‘Smart Purge’ technology, which cleans out potentially acidic gases from the unit. This helps save battery, pump and filter life, enables intelligent purging for switch-on and switch-off, and allows the purging of gas while other tests are being carried out. The Sprint V has already been awarded ‘Gas Safety Product of the Year’ in industry awards.

The Crowcon Eikon is a small, disposable single-gas detector guaranteed to operate without the need for parts or maintenance for two years. It is ideal for temporary use by inspectors and on-site contractors. In addition to carbon monoxide, versions are also available to detect ammonia, hydrogen sulphide, chlorine, or for oxygen deficiency monitoring. Sealed to IP65, the Eikon warns of gas hazards with a powerful 94 dBA alarm and four high-intensity LEDs visible from all angles.

Commenting on the contract, Louise Early, Crowcon and Telegan’s product manager said, “We are very pleased to work in partnership with Anton on this tender. The support that Anton offer is second to none and their relationship with Corgi and now Gas Safe Register is a testament to this. The deal also reinforces our reputation as one of the leading suppliers of gas safety equipment to the UK’s utility industries.”

Comments Off