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For instance, to safely fill a new container or a pressure vessel with flammable gases, the atmosphere of normal air (containing 20.9 volume percent of oxygen) in the vessel would first be flushed (purged) with nitrogen or another non-flammable inert gas, thereby reducing the oxygen concentration inside the container. When the oxygen ...
n.o.s. = not otherwise specified meaning a collective entry to which substances, mixtures, solutions or articles may be assigned if a) they are not mentioned by name in 3.2 Dangerous Goods List AND b) they exhibit chemical, physical and/or dangerous properties corresponding to the Class, classification code, packing group and the name and description of the n.o.s. entry [2]
In an oxygen system the presence of oxygen is implied, and in a sufficiently high partial pressure of oxygen, most materials can be considered fuel. Potential ignition sources are present in almost all oxygen systems, but fire hazards can be mitigated by controlling the risk factors associated with the oxygen, fuel, or heat, which can limit the ...
The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose. [2] Practical applications include the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock mechanism in firearms; and spark testing ferrous metals.
Controlling gas and vapor concentrations outside the flammable limits is a major consideration in occupational safety and health. Methods used to control the concentration of a potentially explosive gas or vapor include use of sweep gas, an unreactive gas such as nitrogen or argon to dilute the explosive gas before coming in contact with air.
An aerosol must be assigned to Division 2.1 if it is deemed flammable in accordance with the appropriate tests of the UN Manual of Tests and Criteria for flammability. Division 2.2: Non-Flammable, Non-Toxic Gas This division includes compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas and ...
The system can be flushed with an inert gas to reduce the concentration of oxygen so that when the flammable gas is admitted, an ignitable mixture cannot form. In NFPA 56, [1] this is known as purge-into-service. In combustion engineering terms, the admission of inert gas dilutes the oxygen below the limiting oxygen concentration.
The original mass of flammable material and the mass of the oxygen consumed (typically from the surrounding air) equals the mass of the flame products (ash, water, carbon dioxide, and other gases). Lavoisier used the experimental fact that some metals gained mass when they burned to support his ideas (because those chemical reactions capture ...