Industrial Fire Journal - Fire & Rescue - Hemming Group Ltd

Gas detection

- a very sensitive issue

Published:  01 September, 2006

Draeger Safety has been active in the industry since 1889. Since that time the company has built up considerable expertise with gas detection equipment and its installation. IFJ spoke to Ian White, Draeger’s UK product manager for fixed and portable gas detection and Jon Shine, the UK Sales manager.

The company offers bespoke detection solutions for any need. “We specialise in tailor-making equipment to meet the needs of any application that we come across. This ranges from large multi-channel petrochemical plants to single points of detection in a lab,” explains Ian.
Apart from monitoring toxic or explosive gases and vapours and measure oxygen content, these systems are also used to sound alarms and initiate evacuation. Additionally, whole processes can be switched off when necessary. All data from Draeger systems is recorded to provide a valuable backlog for future use. Incorporating HART technology, Draeger REGARD controllers, for example, can be used in conjunction with Polytron infrared, explosion proof and open path transmitters in any application where fail-safe protection is required.
“The modular design of the new REGARD 3900 Gas Detection Controller means that the system can be extended or changed at any time to meet the future need of the application. Stand alone and self-contained, the unit interfaces with transmitters to detect toxic, oxygen and explosive (Ex) hazards and with its robust PI65 housing, can be installed in almost any location. Designed for use under the toughest conditions, these innovative Controllers are also protected against RFI, high vibration, shock and corrosion,” Ian continues.
Personal monitors
Apart from fixed systems, the company also manufactures a range of personal monitors, the new Draeger Pac range, which is better suited for short-term products. The Draeger Pac 1000 provides three alarm functions and offers 100 days of maintenance free-protection, without requiring battery or sensor replacement.
“We also manufacture the Pac 3000 range for people who need regular personal monitoring. This sensor is completely maintenance-free for two years. It is small, yet robust and features simple push-button operation as well as a language-free, backlit crystal display. It incorporates an extra infra red interface to make configuration and calibration easy.”
As each sensor is pre-calibrated and is recognised automatically by the instrument, this instrument can be reconfigured simply by changing a sensor and without requiring additional service or maintenance.   In addition, the measuring range of these sensors can be changed to any other gas detected by that sensor, by the push of a button and without needing recalibration.  As a result, the accuracy and range of the monitored substance is substantially increased. 
The search for leaks in flanges, shut off devices and valves, etc., has also been simplified by the addition of a new, flexible gooseneck probe.  When in tracking mode,  it generates an increasing or decreasing rate of beeps in accordance with the gas concentration detected.
Other  ‘two-in-one’ instruments are also available for use where combination hazards involving explosive gases and a lack or surplus of oxygen may exist. 
“For maximum flexibility, the Draeger PacEx2, for instance, can be supplied in two versions: as an instrument for explosive gas measurement, or as a ‘plug-and-play’, combination instrument for explosive gas and oxygen measurement.   Combining extended operational time with minimal training and charging requirements, it features ‘smart’ technology and is designed to monitor hazard concentrations continuously, simultaneously and independently.”
Maintenance issues
Maintenance of the fixed detectors varies, based on a number of different factors such as site standard, detector type, gas type, etc. As a basic rule, catalytic systems require six monthly service.  All others require annual service.
“However,” John Shine adds. “The Draeger Sensor Exchange programme, which provides extended warranty on Draeger manufactured equipment for the duration of the Sensor Exchange contract, has been specifically developed to lower the cost of maintenance. 
“Designed to meet individual needs, it also enables the projection of fixed costs into the future whilst allowing users to set maintenance budgets over the duration of the contract.  Eliminating the need to carry out six-monthly on-site calibration, or to store and transport awkward cylinders of toxic gas, the programme removes the requirement for replacement sensors and will mean the end of Hot Work Permits for most organisations.  As an added bonus, it also avoids the need for expensive access equipment,” he says.
Control system integration
The majority of Draeger transmitters communicate using 4-20mA outputs, which enables them to be connected to a wide variety of control systems as well as the range of Draeger control panels.  Some devices are also available with ‘HART’ which enables multi-dropping and remote interrogation for diagnostics and faultfinding.  Via the REGARD range of Control Panels, repeat 4-20mA, Volt Free contacts and ModBus are also available, making it possible to interface with third party Control Panels and Safety Systems.
“Potential atmospheric hazards are concerns in most industries and proper protection of employees is a requirement. Common atmospheric hazards may include toxic gases or oxygen deficiencies. In many cases protection may be very simple with the use of a single gas detector that is worn by the employees when entering potentially affected areas,” explains Jullienne Marine of Biosystems.
“Biosystems is a manufacturer of gas detection instruments and our goal is to develop detectors which are reliable, easy-to-use and offer more features - all at a lower cost.
The ToxiPro, Toxi and Toxi3 are the latest in a family of single gas detectors from Biosystems. All of them offer a large display, a 20-incident event logger as standard and are also available with an internal vibrating alarm for use in loud noise environments. The ToxiPro, Toxi and Toxi3 are ATEX approved and rated IP65/IP67 for dust and water ingress protection.”
The ToxiPro is full-featured gas detector with Real-time, Peak, STEL and TWA readings, as well as a standard black box recorder and with an optional fully-enabled data logger. The Toxi Pro is available with wide range of sensors, including O2, CO, H2S, SO2, NH3, Cl2, ClO2, PH3 and NO2. The ToxiPro has a replaceable battery that provides 9000 hours of continuous use.
The Toxi is a two-year disposable gas detector available for the detection of O2, CO, H2S or SO2. The Toxi3 is the newest addition to the family and is a 3-year disposable gas detector available for the detection of CO or H2S.  The Toxi and the Toxi3 are designed for 2 or 3 years of maintenance free operation and once they reach the end of their respective service life the detectors will continue to operate for an additional 7 days while intermittently reminding the user it is time for a replacement.
“The ToxiPro, Toxi and the Toxi3 can be used with the Biosystems IQ Express Dock for fully automatic bump testing, calibration, instrument performance testing and record keeping,” Jullienne concludes.
Approvals for Crowcon
“Crowcon’s ATEX-certified Xgard fixed gas detectors have gained new approvals, making them compliant with the safety requirements of an extensive range of markets. The Xgard range is designed to offer protection from a wide range of flammable and toxic gases and oxygen,” marketing director Paul Dunn told IFJ.
The range of detectors are available in explosion-proof or intrinsically safe forms.
The first of these new approvals, for Xgard explosion-proof detectors, is from Underwriters Laboratories Inc (UL) in the USA. This will allow these detectors to be used for hazardous area applications in countries where UL approval is required, including North and South America and parts of the Middle East.
Xgard’s ATEX certification has also been extended to include use in ATEX Zones 21 and 22, for detecting flammable and toxic gases and oxygen where explosive dusts may be present.
Xgard types 1 and 2 oxygen have gained approval to the Marine Equipment Directive (96/98/EC) detectors level as part of the Gasmaster oxygen monitoring system. This means Xgard oxygen/Gasmaster systems can now be installed on vessels registered in Europe or other countries recognising the Directive.
Paul reports: “Finally, all our Xgard models are now certified to the IECEx Standard. IECEx is an international certification scheme created by the International Electrotechnical Commission to eliminate the need for multiple national certifications by providing one international certificate and certification mark accepted by all participating countries.”

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