About Point-Gas Detection Technology
Understanding point gas detection technologies for your hazardous gas monitoring needs.
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- About Point-Gas Detection Technology
Understanding point gas detection technologies for your hazardous gas monitoring needs.
Fixed gas detection systems are used to detect leaks and inadvertent releases of combustible and toxic gases, often in enclosed locations Point gas detectors and transmitters are permanently mounted and hard wired in areas to provide protection of assets & people working in areas where there is a potential for gas leaks to occur. They typically communicate to higher level systems such as PLC or DCS systems that control warning and alarm systems in the event of a gas leak.
Gas detectors that use catalytic sensors work by measuring the voltage change produced from the catalytic combustion of the sensor’s target gas. When exposed to a target gas, it oxidizes, increasing the temperature along with the sensor resistance. The offset voltage created by the higher temperature creates a sensor signal warning of a gas leak. Catalytic gas detectors can detect both organic and inorganic gases, as well as gas mixtures.
Gas detectors that use electrochemical detection work by generating a current when toxic gas molecules react on the sensing electrode. The current generated directly relates to the amount of toxic gas present. Electrochemical gas detectors are ideal for detecting hydrogen sulfide, oxygen and carbon monoxide.
Toxic gas detectors, detect toxic gas leaks and initiate an alarm signal to give warnings or allow shutdown of equipment before the atmosphere gets to a harmful level.
The measurements most often used for the concentration of toxic gases are parts per million (ppm) and parts per billion (ppb).
Three factors are always needed to cause combustion:
There is a limited band of gas/air concentration which will produce a combustible mixture. This band is specific for each gas and vapor and is bounded by an upper level, known as the Upper Explosive Limit (or the UEL) and a lower level, called the Lower Explosive Limit (LEL).
For fire protection, the goal is to remove at least one of these three potentially hazardous items
Fixed gas detectors could be placed in areas with potential leak points. As a gas cloud needs to come into contact with a gas sensor to signal a warning, and since ambient air movement affects where a gas cloud may drift, multiple gas detectors could be used.
