The environmental protection is becoming a major concern for the world today, government laws, and industry association advocate to use the continuous emissions monitoring systems (CEMS) in manufacturing plant to ensure the safety of workers, workplace and environment. These CEMS devices are used to detect toxic and hazardous gases in order to maintain safety. Flue gas analyzer is one of the important device under CEMS system which plays an important role in protection of atmosphere from toxic and hazardous gases while increasing the efficiency of the plant. Generally, a flue is pipe, duct or opening of chimney which are used to exhaust gases to outdoors from boiler, generator of furnaces installed in manufacturing facility. Flue gas analyzer is a device that detects and monitors the composition of exhausting gases from furnaces or boilers and help to determine the proper ratio of air and fuel. Flue gas analyzer directly measures and displays flue gas, temperatures and differential pressure.