Flammability, safety hazard

Great care must be exercised ia the preparation and use of Ziegler-Natta catalysts. They are easily poisoned by moisture, among other things. They are pyrophoric and are used ia conjunction with large amounts of flammable monomer and solvent, and so can present a significant safety hazard. 

Figure 12-40. Process A Batch reaction with all reactants added at the beginning of the reaction. There is a considerable amount of flammable and hazardous material in the reactor at the beginning. (Source S. M. England, Inherently Safer Plants Practical Applications," Process Safety Progress, Vol. 14, No. 1, pp. 63-70, AlChE, 1995.)...

After recovery of the EDC, the vent gas contains both oxygen and fuels (ethane and uncondensed EDC) that would be a flammable mixture and a serious safety hazard if the plant were not designed and operated correctly. 

An alternative may be safer in that it does not meet the criteria for very high concern, but it may have other hazards such as corrosivity or flammability. These hazards are easier to control, but if there is a serious health and safety issue with a proposed substitute, that alternative would not be deemed an available alternative. A proposal for a workable authorisation procedure based on the Substitution Principle is shown schematically in Figure 1. 

Safety and Hazards. The linear carbonate solvents are highly flammable with flash points usually below 30 °C. When the lithium ion cell is subject to various abuses, thermal runaway occurs and causes safety hazards. Although electrode materials and their state-of-charge play a more important role in deciding the consequences of the hazard, the flammable electrolyte solvents are most certainly responsible for the fire when a lithium ion cell vents. The seriousness of the hazard is proportional to the size of the cell, so flame-retarded or nonflammable lithium ion electrolytes are of special interest for vehicle traction batteries. 

The greatest safety hazard in chemical engineering operations is without question caused by uncontrolled chemical reactions, either within the chemical reactor or when flammable chemicals escape from storage vessels or pipes. Many undergraduate students are never exposed to the extremely nonlinear and potentially hazardous characteristics of exothermic free radical processes. 

Operating room safety hazards, such as flammability and explosiveness and (6) prompt patient recovery to psychomotor competence, facilitating the clinician s assessment of the patient and the patient s ability to become physiologically self-supporting. 

In contemporary surgical settings, the only useful nonhalogenated inhalational anesthetic is N2O. Earlier agents, ether and cyclopropane, have fallen out of favor, since they present a serious safety hazard due to their flammability and explosiveness. They remain interesting from a historical point of view, since they were among the first developed. 

Solvent flammability, the solvent, and dust loading in the atmosphere of the working environment and of the products in the ease of edible materials are ihe main factors that conslilute health and safety hazards in extraction plants. General safely and environmental standards must therefore he applied and due recognition taken of Ihe most recently published national regulations relating to acceptable threshold limit values (TLVs) for solvents and dusts. 

Fuel properties are especially important in defining the safety hazards posed by a fuel. Since fuels are flammable, fire and explosion hazards are possible. Some fuels are toxic or contain carcinogenic compounds that present exposure, inhalation, and ingestion hazards. Fuels stored at cryogenic temperatures such as liquefied natural gas and liquefied hydrogen present safety hazards from skin contact... 

Most on-line analyzers are installed as permanent fixtures. Bearing this in mind, environmental issues associated with temperature and vibration become more critical, and the requirement for conformance to safety standards may be enforced by the need for system certification. The latter requires an assessment of the working environment, and the potential for fire and/or explosion hazard, relative to the anticipated presence of flammable vapors or gases. Safety hazard and local electrical design code compliance, which includes CE Mark for Europe, Canadian Standards Association (CSA) for Canada,... 

The health benefits are also clear that businesses can improve the work environment for their employees by using biochemicals and thus reducing health and safety hazards and risks as biochemicals are lower in toxicity, flammability and corrosivity than their petrochemical counterparts. 

Another major concern is hydrogen s flammability. It can ignite in low concentrations and can leak through seals. Leaks in transport and storage equipment could present public safety hazards. These are the practical considerations that need to be addressed before wide-scale use of hydrogen becomes a reality. 

Choice depends on particle characteristics (size, flowability, corrosiveness, abrasiveness, handhng characteristics, safety-hazard [static electrification, fumes, flammability]), and vertical versus horizontal distance. A related topic is covered in Section 16.11.2.5, and bins for storage (Section 16.11.6.35). 

Ethylene glycol poses a number of potential health and safety hazards. It is very flammable and highly toxic. Ingestion of the compound may cause nausea, vomiting, abdominal pain, weakness, convulsions, and cardiac problems. Higher doses can result in severe kidney damage that leads to death. 

Many solvents are good fuels, and will readily bum in air. Ibis can be a safety hazard in laboratories and factories. The temperature at which a solvent catches fire in the absence of a flame is called its aiitiHgnitjon tempeiatiiie. This is surprisingly high for most solvents (Table 10.2). The temperature at which the vapour pressure of a pure solvent in air is sufficient to be ignited by a naked flame is called the flash point of the solvent (Rg. 10.14). This can be very low (Table 10.2). R>r example, the flash point of petroleum ether (a fraction obtained from the distillation of cmde oil and which boils between 30 and 40°C) is —51 C. This means that petroleum ether stored in an open (or leaking) container will still represent a serious fire hazard even if stored in a freezer operating at — 51 C. Rash points are used to classify the flammability of solvents. 

Coauthor Shannon warned that the safety hazard from fire or explosion with hydrogen requires that a hydrogen-inert gas mix be used only below the lower limit of flammability. The lower explosive limit is 4% hydrogen in a hydrogen-air mix. The upper limit is 74.2% hydrogen in an H2-air mix. 

They pose minimal health and safety hazards when handled properly but are highly flammable. 

---