Fumes, defined

The effectiveness of the fume cupboard can be expressed in a number of ways. Several of these ways are discussed by Melin and Olaiider. Nordtest defines an escape safety parameter as... 

Different protection factors have been defined. One method is to define it as the ratio of the concentration of a contaminant in the exhaust duct (CJ to the concentration in the breathing zone (C[,) of a person standing in front of the enclosure, for example, a laboratory fume hood ... 

Fumes are defined as solid airborne particulates that have been produced by a change of state. Many industrial operations produce fumes which affect both the indoor environment and the outdoor environment. For many operations, fumes are generated by a high-temperature process. The gas stream containing the fume is usually of high temperature and contains combustibles. The combustibles may form an explosive mixture, thus necessitating specialized design inputs for most fume control ventilation systems. The major elements of a fume control system are pictured in Fig. 13.28. 

Hazard, risk, failure, and reliability are interrelated concepts concerned witli uncertain events and tlierefore amenable to quantitative measurement via probability. "Hazard" is defined as a potentially dangerous event. For example, tlie release of toxic fumes, a power outage, or pump failure. Actualization of the potential danger represented by a hazard results in undesirable consequences associated with risk. 

This has been defined as "a wrong done to a man by unlawfully disturbing him in the enjoyment of his property or in the exercise of a common right . Examples of this are the emission of toxic fumes from a factory that affect occupiers of surrounding property or of toxic effluents affecting adjacent watercourses. 

Fumes are defined in the 1956 Act as being smaller than dust and thus are a constituent of smoke if visible and smaller than 76 pm. However, fumes are traditionally classified as being smaller than I pm (see Table 45.1). 

By the components of the system we are to understand the least number of independently variable constituents, in terms of which the composition of every phase in the system can be completely specified. The number of components will therefore contribute to the total number of independent variables defining the state of chemical and physical equilibrium of the system. It is not necessary that the components shall be actual constituents of the system all that is required is that they shall be independently variable, Le.y the least number has been chosen. Thus, in systems composed of solid fuming sulphuric acid in presence... 

The aerosol (visible) fraction is mbber fume as defined by the UK HSE, i.e., the fume evolved in the mixing, milling and blending of natural mbber and mbber or synthetic elastomers, or of natural mbber and synthetic polymers combined with chemicals, and in the processes which convert the resultant blends into finished process dust products or parts thereof, and including any... 

Chemical/Physical. Decomposes at 320 °C (Windholz et al., 1983) emitting toxic fumes of bromides and nitrogen oxides (Lewis, 1990). Diquat absorbs water forming well-defined, pale yellow crystalline hydrate but in aqueous alkaline solutions, diquat decomposes forming complex colored products including small amounts of dipyridone (Calderbank and Slade, 1976). 

The evaluation assumes that the hazard and possible risk of the defined (top-ten) mixture of chemicals is representative for the hazard and risk of the entire complex mixture. For some mixtures that are relatively easily available (e.g., combustion fumes, food products, pesticide mixtures), this assumption could be validated by comparing the toxicity of the top-ten mixture with the toxicity of the original complex mixture in short-term test. 

Ten trials at the same load are performed, then the load is either increased or decreased depending upon the result. Reactions are recorded as audible reports, visible flashes, flash marks on the blocks, smoke, or fumes. The sensitivity is defined in terms of the load required to give one ignition in ten trials... 

Fuming flasks, white lab coats, explosions, toxic substances—these are images that often come to mind when people think of chemists and chemistry. For ordinary people, chemistry is often vastly misunderstood and is often considered too difficult to grasp. Steve Zumdahl (1993) writes that it is impossible to define (chemistry) concisely because the field is so diverse and because its practitioners perform such an incredible variety of jobs. This statement provides a much broader vision of chemistry than simply the study of matter. An understanding of chemical concepts is essential not only for chemistry majors but also for other science majors and even students with undecided majors as it leads to a richer understanding of other science disciplines, health fields, and societal issues. 

In the United States the Department of Transportation (DOT) defines three categories of nitric acid 1) nonfuming, more than 70 wt % acid 2) nonfuming, less than 70 wt % acid and 3) red fuming nitric acid. All must be labeled corrosive . Red fuming acid must also be labeled oxidizeT and poison. ... 

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