Static electricity discharges

Static electric discharge is a serious problem ia the electronics iadustry. Electronic devices are extremely seasitive to static electric discharges. Examples of the seasitivity to electrostatic discharge (ESD) are givea ia Table 2 (26). 

These can be readily ignited by flames, sparks, static electrical discharges (often the most likely), hot surfaces, and many other sources. Table 7-31 lists dust cloud ignition temperatures ranging from 572°F to 1112° F, and can be contrasted to flammable vapor-air ignition temperatures from 428° F to 1170°F. Generally, ignition tempera-... 

Static electricity discharges and unexpected electrical currents are frequently overlooked as potential sources of ignition that must be controlled. Some of the conditions that may result in sufficiently intense electrical discharges or arcing are ... 

Above 300°C in air, fine tantalum powder can ignite because of the rapid oxygen diffusion through the oxide layer into the substrate. Once burning starts, a dramatic temperature rise usually occurs and the oxidation reaction can accelerate rapidly. Tantalum powder can be ignited by the localized heating associated with a static electrical discharge or contact with a hot surface. 

Discharge of a spray of vapor and liquid under pressure from a cylinder into a fume hood caused ignition of the vapor due to static electricity. Discharge of the gas only did not cause static build-up. 

Maurer, B., Damage to Enamel on stirred apparatus triggered by static electricity discharges of material being stirred, J. Electrostatics, 40 41, 517-522, 1997. 

Caution. Ether is very volatile and inflammable, and mixtures of its vapour with oxygen, nitrous oxide, or air at certain concentrations are explosive. It should not be used in the presence of an open flame or any electrical apparatus liable to produce a spark precautions should be taken against the production of static electrical discharge. Explosive peroxides... 

There are many ways for a person to be shocked electrically including contact with a normally bare energized conductor or a conductor with deteriorated insulation, the equipment failure that causes an open and short circuit, static electrical discharge, and by lightning strike. 

Although the apparent turbulence of the air stream may give rise to interparticulate collisions and hence attrition, this is not usually a severe problem. However, the rapid movement of particles in a hot, dry atmosphere can lead to the development of static electrical discharges. Suitable precautions must therefore be taken, especially if flammable liquids have been used in the granulation process. 

Lead styphnate is a fairly weak primary explosive. Th is material must always be used with a sensitive booster charge. The main advantage of this material that it is very easy to det on ate with a spark. A thin layer of lead styphnate is often used as an initiator for lead azide. The ease with which this material may be detonated makes it quite sensitive to static electricity discharge. 

Static electricity discharge pulses from 1745—the Leyden jar (high-voltage discharge) ... 

Stray current from cross-connection, sneaks-cir-cuits, static electricity discharge, coupling, etc. 

Flammability and Explosibility Ethylene oxide is an extremely flammahle substance (NFPA rating = 4). Ethylene oxide vapor may be ignited by hot surfaces such as hot plates and static electricity discharges, and since the vapor is heavier than air, it may travel a considerable distance to an ignition source and flash back. Ethylene oxide vapor forms explosive mixtures with air at concentrations of 3 to 100% (by volume). Carbon dioxide or dry chemical extinguishers should be used for ethylene oxide fires. Ethylene oxide may explode when heated in a closed vessel. 

Ensuring that where flammable solvents in say a 200 L drum are being decanted into smaller vessels, earthing clips are used to prevent fire from static electrical discharge. 

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