Zero Calibration

Establishes sensor baseline reading (typically 20.9%) Oxygen and free of toxic gas and vapors. Zero calibrations should be performed in a fresh air environment.

Toxic Gas or Vapor

Any substance that causes illness or death when inhaled or absorbed by the body in relatively small quantities.


(Range) The algebraic difference between the upper and lower values of a range. In laymen’s terms – Think of it as establishing two walls. When the instrument reads in between the values established by the walls, all is good. A reading outside of either wall (too high...


A sniffer is another term for a gas detector. See gas detector and gas monitor.

Single Gas Monitor

Tests for the presence of a single gas or in the case of oxygen, appropriate oxygen level. They can be used to measure many different single gases with the appropriate sensor installed. Examples are Chlorine, Carbon Monoxide or Hydrogen Sulfide and many more.