Glossery

Term Main definition
Galvanic Electrochemical Sensor
A sensor in which galvanic corrosion is used to determine the concentration of a target gas. Galvanic corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte, such as salt water, forming a galvanic cell with hydrogen formation on the more noble metal. The resulting electrochemical potential then develops an electric current that electrolytically dissolves the less noble material. By measuring the electric current, the concentration of the target gas can be calculated.
Gas
One of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture, such as air, contains a variety of pure gases. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer.
Gas Cylinder
A pressure vessel for storage and containment of gases at above atmospheric pressure. Generally used the gas detection field for storing and carrying calibration and/or bump test gases.
Gas Detection Tubes
See: Colorimetric Gas Sampling Tube
Gas Detector
A device that monitors the atmosphere for gases, typically oxygen, combustible gases and/or toxic gases. A portable detector sounds an alarm when concentrations cross threshold values.
Gas generator
A device to generate specific gases. For gas detection purposes, gas generators are typically used to generate a precise concentration of gas with which to calibrate or test gas detectors. Gas generators are used when the calibration gas is highly unstable in a gas cylinder, e.g. by its corrosiveness in contact with the gas cylinder wall.
Gas Measurement
In gas detection: To detect a gas and to quantify the concentration of that gas in the air.
Gas Value
Althoug many values are appropriate when discussing any gas, in gas detection, gas value means the concentration of a specific gas in a gas cylinder or in an environment.
Gas Valve
Used to regulate the flow of gas from a gas cylinder. Various types are available, for example manually operated valves and demand flow regulators. Automatic bump test- and calibration stations are generally equipped with an electrically operated valve.
Ground Moisture Meter
Calculates soil humidity by measuring the conductivity of the soil between two rod-shaped electrodes that are inserted into the ground. While normally an instrument in the agricultural industry to aid decision making about irrigation, they are also used at soil remediation sites: to prevent hazardous concentrations of contaminated dust in the air, ground moisture meters are used to assess the risk of this happening, enabling operators to prevent dust by spraying water on the remediation site.