In an Industrial Compliance article, Emerson’s Nick Pinto stresses the importance of gas detection for a safety system.
Anyone designing or working with safety systems for refineries and chemical plants must be fluent in the language of standards created by ISA, ANSI, IEC, UL, NFPA and other alphabet-soup regulatory organizations. When it comes to fire detection and suppression systems in the U.S., the National Fire Protection Association (NFPA) carries a lot of weight on a huge range of matters from wiring terminations to sprinkler systems. NFPA standards are enormous documents since they cover every imaginable type of facility, including but not limited to apartment complexes, hospitals, and oil refineries. Plus, they go into great detail on the individual topics.
Except when they don’t. Sometimes NFPA doesn’t have much to say on an important topic, which is the main point of my article in the Winter issue of Industrial Compliance. Combustible gas detectors should be part of any fire detection system, but someone looking for detail on how they must be deployed won’t get much help.
NFPA 72: National Fire Alarm and Signaling Code is normally used by system designers and inspectors in conjunction with NFPA 70: National Electrical Code. But an inspector wanting to evaluate use of combustible gas detectors has little to go on because NFPA 72, 17.10 Gas Detection is a very short section in the long chapter on initiating devices. How should gas detectors fit into the picture to ensure compliance?
Gas detectors in this context include Emerson’s Net Safety Millennium II SC310 Catalytic Bead Combustible Gas Sensor and Net Safety Millennium II SC311 Infrared Combustible Gas Sensors. These point -source detectors are designed for harsh environments common to refineries and chemical plants, and can detect the presence of combustible gases before they reach the low-explosive level (LEL).
[We’d include a reference to the open-path detectors, but there still does not appear to be a relevant web page, outside of the one for Spectrex.]
The key is to know combustible gases are present before a fire begins so the source can be shut off before the release ignites. Once a fire starts, an incident and necessary response escalate very quickly, with a huge potential for damage, disruption, and personnel injuries. Hence the importance of combustible gas detectors, summed up in the concluding points of the article:
- The paucity of information on combustible gas detectors in NFPA 72 does not diminish the technologies’ capability or its importance in a comprehensive system.
- Without specific instruction, it is all the more important to consult with experts for detector selection and placement.
- The lack of clear standards can be an advantage since there are few constraints on technology selection. New detector advances can be adopted without having to wait for the standard to catch up.
Are combustible gas detectors part of your safety systems? If not, they should be as they provide an important layer of protection between product release and full-blown fire.
Visit the Flame and Gas Detection pages at Emerson.com for more on technologies and solutions for gas detectors and sensors, gas leak detectors, flame detectors, and aspirators. You can also connect and interact with other engineers in the Oil & Gas and Chemical Groups at the Emerson Exchange 365 community.