Static electricity, electrical hazards

In general, sample ethylene product using Practice F 307, or a similar method. Do not take liquid ethylene samples in order to prevent over-pressuring of sample containers and elimination of fire and explosion hazards. Static electricity can develop when discharging excess hydrocarbon at a fairly rapid rate from a sample cylinder to ambient conditions. Use a grounding system or strap. 

Electrostatic charges are also geaerated whea Hquids move ia coatact with other materials, Hquid or sofld, eg, duriag pumping of gasoliae. Serious iadustrial hazards caused by static ia chemical and related fields have been described (28), and a study of accidents ia the chemical iadustry revealed that 115 out of 1600 accideats, or 7%, were ascribed to static electricity (29) (see Plant safety). 

Dust Explosions Static Electricity Hazards of Vacuum Hazards of Inert Gases Gas Dispersion... 

Static charge generation causes an ignition hazard only if the accumulated charges create an electric field sufficient to produce an electrical discharge in a flammable atmosphere. In most processes, this means that the electric field intensity at some location must reach the breakdown strength of air (nominally 3 X lO " V/m). The objective of static-control measures is to ensure that electric field intensities cannot reach this value. 

In most chemical areas, grounded persons can wear any type of clothing safely. For the unusually sensitive environments hsted above, antistatic or conductive clothing shoiild be worn, and persons must be grounded. Removal of outer garments in a flammable location can cause hazardous discharges and should be avoided (NFPA 77, Static electricity, para. 2-2, 1993). 

The purpose of this book is to assist the user in controlling the hazards associated with the generation, accumulation, and discharge of static electricity by presenting... 

Static electricity hazards and nuisances are typified by the generation of large potentials (0.1-100 kV) by small charging currents (0.01-100 pA) flowing in high resistance circuits (10 -10 Q). This in part differentiates static electricity from other electrical phenomena. For example, stray currents in low resistance circuits are typically of the order 1 A for potential differences of the order 1 volt (A-4-1.3). The electric field at any point in relation to a conductor is proportional to its potential, while magnetic field is proportional to... 

These do not pose a recognized static hazard if the curtain device and all equipment that could be electrically charged during operation is bonded and grounded [45,46]. 

Velocity of liquid in pipes versus static electricity hazards. Vapour venting and gas balancing. 

The incident shows once again how a simple modification, in this case adding liquid to the bottom of a tank instead of the top, can produce an unforeseen hazard. In the oil and chemical industries we are taught to add liquid to the bottom of a tank, not the top, to prevent splashing, the production of mist, and the generation of static electricity (see Section 5.4.1). No rule is universal. 

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