Vapor detection

Early vapor detection and warning Detection by sensors Detection by personnel... 

Operator shuts down operation in response to vapor detection alarm... 

Train operator to shut down operation in response to hazardous vapor detection... 

Colorimetric indicator tubes required 5. Flammable vapor detection apparatus ... 

The probable causes of this accident include (1) use of nonwelded pipe, (2) installation of pipe in trenches, resulting in an accumulation of flammable vapors, and (3) lack of automated vapor detection analyzers and alarms. 

Fig. 4.1 Diagram of the method for selective vapor detection that includes fabrication of core (1) and core shell (2) materials, their assembly into a colloidal crystal film (3), exposure of the film to different vapors (4), measurements of the spectral response of the film (5), and multivariate analysis of the spectra (6) to obtain a vapor selective response of the colloidal crystal film...

Rapid Chemical Vapor Detection Using Optofluidic Ring Resonators... 

Fig. 6.8 Experimental setup for rapid chemical vapor detection...

Potyrailo, R. A. Sivavec, T. M., Boosting sensitivity of organic vapor detection with silicone block polyimide polymers, Anal. Chem. 2004, 76, 7023 7027... 

Figure 20 Schematic diagram of a mass spectrometer for explosive vapor detection [Reproduced from Y. Takada et. al.. Propellants, Explosives, Pyrotechnics, 27 (2002) 224. Copyright 2002, with permission from Wiley-VCH].

M. Tam and H.H. HiU Jr., Secondary electrospray ionization-ion mobility spectrometry for explosive vapor detection. Analytical Chemistry 76(10) (2004) 2741—2747. 

Some important gas and vapor detection system features to consider when selecting a system are self-checking, auto-calibrating or self-diagnosing capabilities with sensor out-of-service, or malfunction alarming. 

When a gas and vapor detection system is used either for fire protection or for personnel exposure protection, the system should be managed, inspected and tested on a scheduled basis, and maintained similar to any other major element of the fire protection system or any process safety interlock or safety instrumented system. 

Enclosures, even partial enclosures, containing equipment handling flammable, combustible, ortoxic materials may permit the accumulation of hazardous concentrations of these materials within the enclosure, potentially resulting in fire, explosion, or personnel exposure. Where the possibility of a flammable spill or release within an enclosure exists, the enclosure design should include a relevant selection from the following features noncombustible construction, adequate ventilation, drainage, appropriate electrical classification, flammable vapor detection, isolation and alarm, and internal automatic sprinkler or water spray protection. 

Fisher, M. M. la Grone, C. Cumming, and E. Towers. Utilization of chemical vapor detection of explosives as a means of rapid minefield area reduction, in Proceedings of the 5th International Symposium on Technology and the Mine Problem, Mine Warfare Association, Monterrey, California, April 2002. 

The technology in this context was first transferred to NPA who named it explosive vapor detection (EVD), and then later Havard Bach renamed and broadened the concept to REST. MEDDS was more scientifically controllable because the training and use of the dogs were separated from the field and sampling problems. 

EXPLOSIVE VAPOR DETECTION USING MICROCANTILEVER SENSORS... 

Explosive-related chemical Explosive remnants of war Electrostatic discharge Explosives trace detection Explosive vapor detection (U.S.) Federal Aviation Administration Field asymmetric ion mobility spectrometry Fertilizer-Grade AN (ammonium nitrate)... 

Chapter 12, Explosive Vapor Detection Using Microcantilever Sensors, is representative of a general class of sensors Surface Effect Microsensors that use the change in some mechanical or electrical property of an ultra-small structure to sense and identify a wide variety of molecules. 

In more recent years, as the kinetics of thermal decompn of expls began to be studied, questions arose whether partial vaporization and vapor phase decompn were important at temps well below the boiling point of the expl. Very recently, as criminal bombings became a matter of international concern, bomb detection schemes based on detection and identification of vapors of the expls used in such bombs were proposed. Expl vapor detection will not be addressed in this article (see under Tagging of Explosives in Vol 9). The interested reader is referred to a summary contained in Ref 25... 

---