Considerations Regarding Gas Monitors

Dependent upon the sort of gas and the range of detection required, one sensor technology is more suitable than others. Gas Monitors are grouped by their sensitivity range and modern gas Monitors fall under 4 main groups: Electrochemical, Semiconductor, Infrared point Sensors and Ultrasonic.



What sorts of Gas Monitors do you get?



Electrochemical gas Monitors consist of a porous membrane and a form of electrode. Gases pass via the porous membrane (which can be customised to numerous concentration ranges) and a current is generated by the electrode equal in porportion to the total of gas optimised at the electrode. Typical gases diagnosed include: Ammonia, Carbon Monoxide, Chlorine, Ethylene, Fluorine, Silane, Hydrogen, Nitrogen Dioxide, Oxygen, Ozone & Sulphur Dioxide.



Semiconductor Sensors rely on chemical reactions which only occur when the sensor comes into direct contact with the gas. Typical gases detected include: HCFC's, CFC's, Hydrocarbons, Natural Gases and Volatile Organic Compounds.



Infrared (IR) Point Sensors exploits the fact that radiation energy is absorbed by distinct gases at different wavelengths. These IR Sensors detect radiation passing by means of a volume of gas to monitor for leaks. Typical gases discovered include: Products emissions such as Carbon Dioxide and flammable gases.



Ultrasonic gas Sensors use ultrasonic sound level Sensors to detect variations in the background noise of the monitored area. Measuring these acoustic variations allows the sensor to not only diagnose leaks but assess the rate of leakage. Such detection is usually used in areas which are subject to exterior conditions (For example outdoors where the weather dissipates gas before it can be detected or underground where a gas can be unevenly absorbed into soil air pocket. ).



Since Electrochemical and Semiconductor Monitors typically have to come into direct contact with the gas they normally tend to have a lesser sensitivity range than Ultrasonic and Infrared point Monitors.



Locating Gas Monitors



Gas Monitors are used in residential and commercial buildings that require uninterrupted monitoring for various gas leaks. Most modern commercial and industrial properties use one or other form of gas detection. E.G.:: Refrigerant Gas Detectors in fresh produce storage units, toxic gas detectors in sewerage plants, combustible gas detectors in a production plant or volatile organic composite Gas Detectors in a science laboratory.





There are two techniques to monitor location: perimeter protection or point detection. Perimeter detection works on the solution of placing Sensors along the perimeter of the area that requires supervising. Typically this would be at the centre of each wall in a room.



Point Detection refers to placing Sensors at distinct locations such as compressors, expansion valves, mechanical joints or cable duct trenches. It is a good rule of thumb to locate Monitors no further than 1.5 meters from the point to be supervised.



Quite often a big difference is made between the real gas monitor and the complete gas detection unit. This is because the sensor is regarded to be one unit of an entire. You can setup various gas sensor units with various functions to a single control panel and all of this would fall under the title of "the gas detection system" or the IAM (Integrated Area Monitor).



Murco Gas Monitors direct from the manufacturers in Ireland. Murco provides gas detection solutions for many commercial and industrial applications throughout Europe, Asia and the US. http://www.murcogasdetection.com