The National Fire Protection Association (NFPA) establishes fire safety standards, including standards for the safe operation of processes. In our world we focus specifically on NFPA86, THE Standard for Ovens and Furnaces.
It addresses the safe operation of Class A, Class B, Class C, and Class D ovens, dryers, and furnaces, thermal oxidizers, and any other heated enclosure used for processing of materials and related equipment.
This intricate standard contains many sections and annexes and at first glance can be overwhelming. How can we select a monitoring system to meet all of these requirements?
A solvent vapor monitoring system consists of these integral parts:
- The gas sample system that delivers the oven atmosphere sample to the analyzer
- The solvent vapor concentration analyzer
- The safety logic system that is activated by the analyzer
With this in mind, let’s discuss the 6 essential requirements for a Reliable Solvent Vapor Analyzer (Monitoring requirements are found in section 11.6.10):
- Sample delivery system. 11.6.10.11
- Speed of Response. 11.6.10.2
- Accurate calibration and response 11.6.10.5
- Avoidance of condensation.11.6.10.11
- Failsafe malfunction logic. 11.6.10.8
- Maintenance. 11.6.10.11
Operators must select a sensor that meets all of the requirements. Annex E provides guidance in selecting the appropriate sensor from a list of possible choices. These sensor choices include:
- Catalytic
- Infrared
- Flame Temperature
- Flame Ionization
For the next few weeks let's focus on how well each of these sensors meets the requirements of this standard.
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