Title:                PrevEx® Flammability Analyzers versus Infrared Sensors for Process Applications

Summary:        Most flammable vapor analyzers respond differently to different vapors. Whenever the process solvent is changed, the analyzer must be either recalibrated or reprogrammed to ensure that it’s measurement of the new solvent vapor is still accurate. This creates a challenge when trying to measure a mixture of solvent vapors. This application note shows how the PrevEx® Flammability Analyzer has the unique ability to measure most common process solvent vapors, including mixtures, to within a few percent of their lower flammable limit, without recalibrating, unlike narrow-banded infrared sensors.

The following explain why a Flammability Analyzer is more accurate than an Infrared Sensor: 

• Solvents do not vaporize at the same rate and their ratios do not remain constant. Process changes or upsets will dramatically alter the vapor mixture. Even when calibrated to code, infrared sensors can generate false alarms or, more importantly, fail to generate alarms and initiate safety actions when these process variations occur.

• The National Fire Protection Association’s NFPA-86 1999 Standard for Safe Operation of Class A Oven and Furnaces, has concluded that, “…Infrared calibration can vary considerably for various solvent types. Its area of application is for single solvent systems...” (Appendix D-1.b)

• The same document (Appendix D-1.c) in describing Flame Temperature systems stated that, “…calibration is relatively constant for various solvents...”    ›Read The Complete Application Note. ( Required).